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AMERICAN TEACHERS SERIES 
 
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 EDITED BY 
 
 JAMES E. RUSSELL, PH.D. 
 
 DEAN OF TEACHERS COLLEGE, COLUMBIA UNIVERSITY 
 
 THE 
 
 TEACHING OF CHEMISTRY AND PHYSICS 
 IN THE SECONDARY SCHOOL 
 
 BY 
 
 ALEXANDER SMITH 
 
 AND 
 
 EDWIN H. HALL 
 
The Teaching of Chemistry and 
 
 Physics in the Secondary 
 
 School 
 
 BY 
 ALEXANDER SMITH, B.Sc., PH.D. 
 
 ASSOCIATE PROFESSOR IN THE UNIVERSITY OF CHICAGO 
 AND 
 
 EDWIN H. HALL, PH.D. 
 
 PROFESSOR IN HARVARD UNIVERSITY 
 
 UNIVERSITY 
 
 
 
 LONGMANS, GREEN, AND CO. 
 
 91 AND 93 FIFTH AVENUE, NEW YORK 
 
 LONDON AND BOMBAY 
 
 1902 
 
It) 
 
 
 REESE 
 
 Copyright, 1902 
 By LONGMANS, GREEN, AND Co. 
 
 .<4// rights reserved 
 
 UNIVERSITY PRESS JOHN WILSON 
 AND SON CAMBRIDGE, U.S.A. 
 
Editor's Note 
 
 THE present volume in the American Teachers Series follows 
 the lines marked out in the preface to the first volume. No 
 effort has been made to bias or harmonize the views of the 
 authors. It has been deemed better to have a logical presen- 
 tation, even at the risk of disagreement, than to give the impres- 
 sion that there is only one way of conceiving or giving class 
 instruction. These volumes are intended as teachers' helps, 
 and their purpose is served if they are suggestive to teachers 
 who are earnestly seeking for improvement. 
 
 The authors of the separate parts on Chemistry and Physics 
 have conferred frequently during the progress of the work, and 
 have endeavoured to avoid unnecessary duplication. There 
 are thus some subjects of equal importance to teachers of 
 chemistry and physics which are discussed in one of the sec- 
 tions only. Some references, equally suited to either part, 
 appear only once for the same reason. In a few instances, 
 however, the divergence between the opinions of the authors 
 seemed to make it desirable that each should present his own. 
 
 JAMES E. RUSSELL. 
 
 TEACHERS COLLEGE, 
 
 COLUMBIA UNIVERSITY. 
 
 O Q f* :T o 
 
Contents 
 
 THE TEACHING OF CHEMISTRY IN THE 
 SECONDARY SCHOOL 
 
 CHAPTER I 
 
 INTRODUCTION 
 
 PAGE 
 
 I. Reasons for the Study of Science 8 
 
 II. History of Chemical Instruction 18 
 
 III. Present Condition of Chemical Instruction .... 21 
 
 CHAPTER II 
 CHEMISTRY IN THE CURRICULUM 
 
 I. Precedence of Physics 29 
 
 a. The Report of the Committee of Ten .... 29 
 
 b. Observations in Chemistry a Study of Physical 
 
 Properties 30 
 
 c. The Conclusion 33 
 
 II. Arguments in Favour of the Precedence of Chemistry 33 
 
 III. In which Year of the High School Course shall Chem- 
 istry be taught ? 37 
 
 IV. The Time to be allotted to Chemistry 40 
 
 V. Continuous Courses in Chemistry 42 
 
 VI. Articulation of School and College Chemistry ... 44 
 
 CHAPTER III 
 THE INTRODUCTION OF THE SUBJECT 
 
 I. Impediments to be overcome or avoided 49 
 
 II. What Phenomena shall furnish the Basis of the Intro- 
 ductory Work ? 52 
 
 a. Classification of Various Principles of Arrange- 
 ment 53 
 
viii CONTENTS 
 
 PAGE 
 
 b. Various Arrangements illustrated by Reference to 
 
 existing Text-Books 55 
 
 c. The Present Ideal of the Secondary School 
 
 Course in Chemistry 60 
 
 III. Earlier Generalizations of a Qualitative Nature . . . 69 
 
 IV. Further Generalizations of a Quantitative Character . 72 
 V. The Relation of the Quantitative Laws to Formulae and 
 
 Equations 77 
 
 CHAPTER IV 
 INSTRUCTION IN THE LABORATORY 
 
 I. The Value of Laboratory Work for General Education 87 
 
 a. For teaching Knowledge-making by Observation 
 
 and Induction 87 
 
 b. For teaching Knowledge-making by the Study of 
 
 Natural Objects and Phenomena .... 87 
 
 c. For teaching Caution and Mental Rectitude . . 89 
 
 d. Other Benefits of a General Nature 90 
 
 II. The Value of Laboratory Work for Instruction in Chem- 
 istry 90 
 
 a. For giving First-hand Knowledge 90 
 
 b. For holding Interest and Attention 91 
 
 c. For securing Clear and Pregnant Expression . 92 
 
 III. The Laboratory Directions 94 
 
 a. Laboratory Directions should be coherent . . 94 
 
 b. Main Points in regard to the Directions for each 
 
 Experiment 97 
 
 c. Selection of Experiments 100 
 
 d. An Illustration JO2 
 
 IV. The Pupil and his Attitude . 105 
 
 a. The Verification of Laws 106 
 
 b. The Attitude of Discoverer; the Heuristic Method 106 
 
 c. Summary 1 10 
 
 V. Laboratory Technique in 
 
 VI. Quantitative Experiments 113 
 
 a. Limitations 114 
 
 b. Equipment for Quantitative Experiments . . . 115 
 
 c. Suitable Quantitative Experiments 117 
 
CONTENTS ix 
 
 PAGE 
 
 d. The Application of Quantitative Experiments . 119 
 
 e. Benefits and Objections 120 
 
 VII. The Role of the Teacher in the Laboratory ... 122 
 
 VIII. The Note-book 123 
 
 IX. Emergencies 125 
 
 CHAPTER V 
 INSTRUCTION IN THE CLASSROOM 
 
 a. Oral and Written Quizzes 128 
 
 b. Experimental Demonstrations 133 
 
 c. Stoichiometric Problems 135 
 
 d. Use of the Text-book 136 
 
 e. The Importance of keeping the Subject in Contact 
 
 with E very-day Life 138 
 
 f. Necessity for Unification of the Whole . . . 143 
 
 g. Some Misleading Words 144 
 
 h. Some Common Fallacies 145 
 
 i. The Grammar of Science 146 
 
 CHAPTER VI 
 SOME CONSTITUENTS OF THE COURSE 
 
 I. Th* Atomic Theory: its Nature and Place in Elemen- 
 tary Instruction 154 
 
 a. The Atomic Theory not a Fact 1 54 
 
 b. Its Limited Application 156 
 
 c. The Place of the Theory in Elementary Instruc- 
 
 tion 158 
 
 II. The Treatment of Valency 162 
 
 III. Use of the Results of Physico-chemical Investigation . 165 
 
 IV. Shall Qualitative Analysis be included, and if so, in 
 
 what Form ? 171 
 
 a. Arguments in Favour of Qualitative Analysis . 172 
 
 b. Arguments against Qualitative Analysis . . . 173 
 
 c. Exercises in Identification 178 
 
 V. The General Content 182 
 
 VI. The Selection of the Text-Book and Laboratory Manual 184 
 
CONTENTS 
 
 CHAPTER VII 
 
 THE LABORATORY, EQUIPMENT AND ILLUSTRATIVE 
 
 MATERIAL 
 
 PAGE 
 
 I. Accommodations required 187 
 
 II. Laboratory Furniture 189 
 
 a. The Desks 189 
 
 b. The Hoods 191 
 
 c. The Side-shelves 192 
 
 d. Other Laboratory Furniture 193 
 
 III. Laboratory Equipment 193 
 
 IV. Apparatus and Chemicals, and the Store-room . . . 195 
 V. The Classroom and its Fittings 200 
 
 VI. Illustrative Material 201 
 
 VII. The Teacher's Private Room 206 
 
 CHAPTER VIII 
 
 THE TEACHER, HIS PREPARATION AND 
 DEVELOPMENT 
 
 I. The Training of the Teacher 207 
 
 II. The Development of the Teacher during Professional 
 
 Life 214 
 
 III. Literature for the Teacher 218 
 
 THE TEACHING OF PHYSICS IN THE 
 SECONDARY SCHOOL 
 
 CHAPTER I 
 
 WHETHER TO BE A TEACHER OF PHYSICS 
 Motives Influencing Decision. Natural Qualities Needed 233-237 
 
 CHAPTER II 
 PREPARATION FOR TEACHING 
 
 Objects of Education in Science. The Teacher should be 
 able to Advise. Ph.D. or A.M. for the Teacher? Sup- 
 
CONTENTS xi 
 
 PAGE 
 
 plementary Studies. Knowledge of History of Physics. 
 Habit of General Observation. Study of Art of Teaching 
 
 238-246 
 
 CHAPTER III 
 
 THE TEACHER AS STUDENT, OBSERVER, AND 
 WRITER 
 
 Original Research ? Work akin to Research. Physics out 
 of Doors. Change and Variety. Writing and Speaking 
 
 247-252 
 
 CHAPTER IV 
 PROBLEMS OF LABORATORY PRACTICE 
 
 Water-Proofing Wooden Blocks. Correction and Use of 
 Spring Balance. Use of Platform Balance. Preparation 
 of Apparatus for Measurement of Expansion of Air . 253-266 
 
 CHAPTER V 
 
 SCHOOL TEXT-BOOKS OF PHYSICS 
 Retrospect. General Information. Type of Book. Change 
 of View and Method. Harvard College Action on Physics 
 for Admission. Influence of Harvard "Descriptive List." 
 A Revision. Influence of Ann Arbor. No All-sufficient 
 Text-Book 267-273 
 
 CHAPTER VI 
 DISCOVERY, VERIFICATION, OR INQUIRY? 
 
 " Inductive and Deductive." Abuses of " Inductive 
 Method." Art of Discovering General Laws cannot be 
 Taught. Verification. Prejudice perverts Evidence. 
 Method of Inquiry ; Illustrations. Inaccuracy of Some 
 "Laws." Pooling of Observations in Difficult Inquiries; 
 Illustrations : Laws of Bending, Acceleration, Test of Mass, 
 Action and Reaction, Density of Air. Pupils' Blunders. 
 Repetition of Exercises 274-288 
 
CONTENTS 
 
 CHAPTER VII 
 
 THE TECHNIQUE OF LABORATORY MANAGEMENT 
 
 PAGE 
 
 Report on Methods by Committee of Eastern Association 
 of Physics Teachers. Even-Front Progression. Wasteful- 
 ness of Irregular Order of Progression. Reduplication of 
 Apparatus. Size of Laboratory Section. Individual or 
 Group Work ? Length of Laboratory Exercise. The 
 Teacher's Preparation of Work. Use of a Manual. The 
 Pupil's Preparation. Record of Laboratory Work ; Illus- 
 tration. Time and Place for Calculations. Oversight of 
 Note-Book. First Record should Stand. " Data Slips " 
 and " Result Slips " for " Scrap-Book " Record. Lessons 
 from Laboratory Work. Care of Apparatus. Relief from 
 Manual Labor 289-303 
 
 CHAPTER VIII 
 LECTURES AND RECITATIONS 
 
 Laboratory Work not Enough. Function of Lectures, etc. 
 Abuse of the " Quiz." Numerical Problems. Preparation 
 for Lectures. Lecture-Room Galvanometers. Projecting 
 Lantern. Qualitative Experiments. Applications of Physics. 
 Care for Form in Lectures 3 o 4-3 r 5 
 
 CHAPTER IX 
 PHYSICS IN PRIMARY AND GRAMMAR SCHOOLS 
 
 " Nature Study." Children's Experimental Knowledge. 
 Difficulty with Words. Qualitative or Quantitative Work? 
 Need of Progress. Physics in Grammar Schools of 
 Cambridge 316-323 
 
 CHAPTER X 
 
 PHYSICS IN VARIOUS KINDS OF SECONDARY 
 
 SCHOOLS 
 
 College Entrance Physics of the National Educational 
 Association. History of the N. E. A. Report. Detailed 
 
CONTENTS xiii 
 
 PAGE 
 
 List of Exercises. Action of Middle States Board. Dif- 
 ference between Preparatory and Non-Preparatory Schools. 
 What High Schools should do. Physics in the High School 
 of Brookline 324-340 
 
 CHAPTER XI 
 ON THE PRESENTATION OF DYNAMICS 
 
 Difficulty of the Subject Increased by Poor Teaching. 
 Multiplicity of Force-Units. Tabulation of Equations. 
 Mass in the Language of Engineering 341-347 
 
 CHAPTER XII 
 PLAN AND EQUIPMENT OF A LABORATORY 
 
 Working Tables. The Laboratory-room, Apparatus-cases, 
 etc. Workshop. Lecture-room. Some Equipments. 
 General Apparatus 348-355 
 
 CHAPTER XIII 
 
 PHYSICS TEACHING IN OTHER COUNTRIES 
 In Germany. In England. In France 356-371 
 
 INDEX 373 
 
THE TEACHING OF CHEMISTRY IN 
 THE SECONDARY SCHOOL 
 
 BY ALEXANDER SMITH, B.Sc. PH.D. 
 ASSOCIATE PROFESSOR OF CHEMISTRY IN THE UNIVERSITY OF CHICAGO 
 
Prefatory Note 
 
 WHILE there is only one science of chemistry, there are many 
 opinions on the teaching of it. A tendency to seeming dogma- 
 tism is almost unavoidable in writing on the subject. It can 
 only be said that, by an attempt to present the various views, 
 even where there is a very distinct inclination towards one view 
 on the part of the majority of chemists, an effort has been 
 made to avoid real intolerance. The references to articles and 
 books dealing with all controversial points will enable the reader 
 to acquaint himself with the best that can be said for each 
 opinion by its special advocates and to reach a decision for 
 himself. Where the writer has felt certain that fundamental 
 faults are committed by any considerable number of the less 
 well-trained teachers, as, for example, in connection with 
 equations, the atomic theory, natural law, etc., the view held to 
 be correct may appear to have been presented in an extreme 
 form or with needless vigour. Perhaps it is hardly necessary to 
 explain that the precise treatment given here in such cases is 
 not necessarily suited as it stands for the consumption of the 
 pupil. If it impresses the teacher strongly by putting a different 
 view in high relief, and shows him the standpoint of the chemist 
 as opposed to that of some pedagogues, it will have served its 
 purpose. 
 
 The book assumes the reader's familiarity with the science. 
 Many brief references to chemical matters would have been 
 greatly expanded or carefully limited if they had been intended 
 for beginners. 
 
 There has been no intention to recommend particular text- 
 books. Many have been cited as possessing some point of 
 special excellence, but this must not be taken to indicate 
 
4 THE TEACHING OF CHEMISTRY 
 
 emphatic approval of those works as wholes, say for use with a 
 class of beginners. 
 
 The author is indebted to many friends for helpful sugges- 
 tions. Special thanks are due to Messers. J. B. Tingle, Illinois 
 College, M. S. Walker, West Division High School, Chicago, 
 W. A. Noyes, Rose Polytechnic Institute, and J. B. Garner, 
 Wabash College, who have read all the work in manuscript or 
 proof. 
 
 ALEXANDER SMITH. 
 
 THE UNIVERSITY OF CHICAGO, 
 March, 1902. 
 
OF THE 
 
 The 
 
 Teaching of Chemistry in the 
 Secondary School 
 
 CHAPTER I 
 
 INTRODUCTION 
 BIBLIOGRAPHY. 
 
 Spencer, Herbert. Education, Intellectual, Moral and Physical. 
 London, Williams & Norgate. New York, D. Appleton & Co. 1860. 
 
 Bain, Alexander. Education as a Science. London, Kegan Paul, 
 Trench & Co. New York, D. Appleton & Co. 1881. 
 
 Macgregor, J. G-. The Utility of Knowledge-making as a Means of 
 Liberal Training. NATURE, LXI. (1899), 159-163; extracts in SCHOOL 
 REVIEW, VIII. (1900), 372. 
 
 Eliot, C. W. Educational Reform. New York, The Century Co. 
 1898. 
 
 Mach, Ernst. On Instruction in the Classics and the Sciences. 
 Popular Scientific Lectures. Chicago, The Open Court Publishing Co. 
 London, Kegan Paul, Trench & Co. 1895. 
 
 Coulter, J. M. The Mission of Science in Education. SCIENCE 
 [N. S.], XII. (1900), 281-293. 
 
 "Wilson, C. C. What is the Consensus of Opinion as to the Place of 
 Science in the Preparatory Schools ? SCHOOL REVIEW, VI. (1898), 
 203-211. 
 
 Huxley, T. H. Science and Education. Collected Essays, Vol. III. 
 London and New York, Macmillan. 1893. 
 
 Perkin, W. H., Jr. The Modern System of Teaching Practical In- 
 organic Chemistry and its Development. Vice-Presidential Address. 
 Report of the British Association, 1900. Reprinted in NATURE, LXII. 
 476-481. 
 
 Perkins, A. S. Elementary Chemistry in the High School. SCHOOL 
 SCIENCE, I. 72-77. 
 
 Williams, R. P. The Teaching of Chemistry in Schools, 1876-1901. 
 SCIENCE [N. S.], XIV. 100-104. 
 
 Long, J. H. Early History and Present Condition of the Teaching 
 of Chemistry in the Medical Schools of the United States. Vice-Presi- 
 
6 INTRODUCTION 
 
 dential Address before the American Association for the Advancement of 
 Science (1901). Reprinted in SCIENCE [N. S.], XIV. 360-372. 
 
 Russell, J. E. German Higher Schools. New York and London, 
 Longmans, Green & Co. 1899. P P- 329-35 1 - 
 
 Cooley, LeR. C. Science for Education. Presidential Address be- 
 fore the New York State Science Teachers' Association. High School 
 Bulletin No. 7. Albany, N. Y., The University of the State of New 
 York. Pp. 578-594- 
 
 Butler, N. M. The Scope and Functions of Secondary Education. 
 EDUCATIONAL REVIEW, XVI. (1898), 15-27. 
 
 IN introducing the subject of the teaching of chemistry it is 
 fitting first to state as briefly as may be some of the reasons for 
 the inclusion of this study in the curriculum of the secondary 
 school. We shall thus have in hand the key to the point of 
 view which will be preserved in the treatment of the subject as 
 a whole, and our statements will indicate the ideal towards which 
 the means of education that we may discuss are to be directed. 
 Since the ideal which we set before ourselves must be brought 
 into relation with the actual conditions, it will be advisable also 
 to say something in regard to the present state of chemistry in 
 the secondary schools of this country. We shall then be able 
 more easily to determine the means by which the actual may be 
 converted into, or at least be brought to approach this ideal. 
 
 In advocating the study of a science, all intention of regarding 
 
 it as the only worthy means of education, and of urging that it 
 
 shall supplant other subjects, must be discarded. 
 
 Reasonsfor ^ * s true ^ at ^ e su PP ort f no mean authority 
 the study of might be found even for this radical position. 
 Herbert Spencer, in his chapter on " What knowl- 
 edge is of most worth," attempts to show, and with some success, 
 that the information which the study of science furnishes is incom- 
 parably more useful for our guidance in life than any other kind. 
 Q Starting from the thesis that education is intended to teach us 
 how to live, and considering all the activities of human life, he 
 demonstrates that science furnishes equally in all cases the need- 
 ful preparation. Considering next its use as a discipline, he 
 concludes " that for discipline, as well as for guidance, science 
 is of chiefest value. In all its effects, learning the meanings of 
 
INTRODUCTION 7 
 
 things, is better than learning the meanings of words. Whether 
 for intellectual, moral or religious training, the study of sur- 
 rounding phenomena is immensely superior to the study of 
 grammars and lexicons. 'J He contends that the value of the 
 information furnished by history and consisting of a mere tissue 
 of names and dates has a conventional value only. On the 
 other hand an acquaintance with Latin and Greek, since it fur- 
 nishes extra knowledge of our own language, but can be of value 
 only so long as certain languages and races exist, may be held 
 to have a value that is at least quasi-intrinsic. The knowledge 
 furnished by the truths of science, such as that resistance to the 
 motion of a body varies as the square of the velocity, and that 
 chlorine is a disinfectant, are truths which will bear on human 
 conduct ten thousand years hence as they do now, and can 
 therefore alone lay claim to true intrinsic value. 
 
 While we cannot doubt the great and in many ways entirely 
 wholesome influence which Spencer's views have exercised, 
 we may be permitted to point out, that, in supporting the 
 claims of some particular subject or class of subjects to inclusion 
 in a course of education, one is always in danger of comparing 
 the subject he favours at its best, and in the ideal form it may 
 receive at the hands of an ideal teacher, with other subjects at 
 their average or even at their worst. This essay was written 
 before 1860, and was published in that year with the others form- 
 ing the volume on education. Perhaps the circumstances of 
 that time justified much of what is said, in a way that the cir- 
 cumstances of the present would not. There have undoubtedly 
 been great improvements in language teaching at its best since 
 that time, and while Spencer states that " science forms scarcely 
 an appreciable element in our so-called civilized training," and 
 in another place speaks of it as " that which our school course 
 left almost entirely out," these statements could not be made 
 with justice in the same form at the present time. 
 
 Our task will be rather to show that science undoubtedly has 
 an aptitude for educational employment sufficient to make it a 
 valuable study. We may fairly say also that its use is justi- 
 
8 INTRODUCTION 
 
 t 
 
 fied by the desirability of introducing variety into our means 
 of instruction. This must increase its strength and effective- 
 other Reasons ness m y i ew f tne many-sidedness of the inter- 
 for the study es t s and therefore of the avenues of approach in 
 each individual case, and of the differences in the 
 tastes of different individuals. We may perhaps even go so far 
 as to demand its employment on the ground that in some direc- 
 tions, even at its average, it can furnish certain constituents of 
 an all round discipline of the mind more easily or in a more 
 conspicuous degree than other subjects at their average. 
 
 We must begin with characteristics which are common to all 
 science, with physical science chiefly in mind, and afterwards 
 more briefly refer to the special claims of chemistry. The order 
 in which the reasons for the study of science are given is not so 
 much that of importance as that of convenience of presentation. 
 
 I. Reasons for the Study of Science. 
 
 f Our first reason for the study of science rests on the training 
 in observation for which it furnishes the opportunity. To use 
 Training in the common expression, the employment of the 
 Observation. i aDOra t O ry method in science furnishes an exercise 
 not merely for the senses but for the mind. This practice of 
 observation is, however, common to all forms of scholarship, 
 and is applied in languages, for example, as persistently as in 
 science. But in the latter this training directs attention to 
 material objects, and so, while theoretically the same process, it 
 awakens an interest in, and develops a capacity to exercise an 
 entirely different and most worthy set of activities. Its applica- 
 tion to the study of nature and her laws gives, as nothing else can, 
 a distinct view of the universe as a well-ordered system. As Pres- 
 ident Eliot says (Educational Reform, no),^The student of 
 natural science scrutinizes, touches, weighs, measures, analyzes, 
 dissects, and watches things. By these exercises his powers of 
 observation and judgment are trained, and he acquires the pre- 
 cious habit of observing the appearances, transformations, and 
 processes of nature. Like the hunter and the artist, he has 
 
INTRODUCTION 9 
 
 open eyes and an educated judgment in seeing. He is at home 
 in some large tract of nature's domain.'!/ Mach (Scientific 
 Lectures, 280) makes the same point as follows : " I shall 
 meet with no contradiction when I say that without at least an 
 elementary mathematical and scientific education a man remains 
 a total stranger in the world in which he lives, a stranger in the 
 civilization of the time which bears him. Whatever he meets in 
 nature, or in the industrial world, either does not appeal to him 
 at all, from his having neither eye nor ear for it, or it speaks to 
 him in a totally unintelligible language." This interest in a 
 knowledge of nature is an essential element in robust life. The 
 study of books alone, at its worst, often submerges the victim of 
 it in an unpractical and even mediaeval spirit which we all recog- 
 nise as characteristic of the bookworm. 
 
 LThe second reason for the study of science is that it trains 
 the pupil in the organization of his observations by comparison 
 and induction.) This again is an operation not by Trainin ln 
 any means peculiar to scientific work. Every Comparison 
 human being from the earliest months of his exist- and ^t"** 011 ' 
 ence onwards is occupied in the co-ordination of the observations 
 he makes, and in building up, with rapidly increasing speed, a 
 mass of rationalized experience. The business of life, when it is 
 entered upon, is promoted by the same processes.! Consciously 
 or unconsciously observations are made and generalizations pro- 
 duced from them, and on the ability to do this correctly the 
 man depends for his success in lifej This has been called by 
 Professor J. G. Macgregor 1 the " knowledge-making " process, by 
 which he means that separate facts do not constitute knowledge 
 in themselves, and that all we know which is of value is made 
 by putting together our isolated observations. It is our ability 
 to do this which counts in scholarship or in life, and it is this 
 therefore which education should be specially directed to culti- 
 vate. As Professor Macgregor points outs, the old curriculum, 
 and particularly the study of the classics, affords abundant op- 
 
 1 In a most interesting inaugural address delivered at the opening of 
 the fortieth session of Dalhousie College and printed in full in NATURE. 
 
TO INTRODUCTION 
 
 portunity for the exercise of this power. The study of language 
 involves the continual putting together of instances of the use 
 of words and phrases. "The lexicon," he continues, "would 
 give little more than a clew in many cases to the English equiva- 
 lents of, say, Latin words, the exact equivalents, whether words 
 or phrases, being determinable only by the study of the context 
 and the fruitful drawing upon experience." 
 
 There are two differences between this process as carried out 
 in the study of a language and the same process employed in 
 
 the study of a science. In handling the grammar, 
 Differences ,. . J , . . . 
 
 between Work dictionary and text, it is almost impossible for this 
 
 inLan|uag;es instruction in its early stages, and at all events at 
 ' its average if not at its best, to avoid confirming the 
 tendency usually fostered by ordinary home training of relying 
 upon authority for information and opinions. Even the most 
 elementary work in science must be considerably below the 
 average if it does not place the experimental facts themselves 
 before the pupil, and suggest to him no other ultimate source 
 of information, whether for the learner, the teacher, or the 
 author of thejext-book,j;han the study of nature itself. The 
 other advantage which natural science possesses is that experi- 
 ment permits the repeated production of every fact fresh from 
 its original source in the order of nature, as often as may be 
 necessary for its full appreciation, and with such variations in 
 its circumstances and surroundings as a clear view of every side 
 of it may demand. The method of experimoiit is a tower of 
 strength in the study of the facts of science, while its applica- 
 tion to languages is usually discouraged by the teacher, and its 
 use in history is impossible. The recourse in this way to the 
 study of the thing itself for first hand information, the exactness 
 and conclusiveness with which every fact may be established, 
 the testing of every inference or hypothesis by renewed com- 
 parison with facts, form the essence of the scientific method. , ij 
 While it is employed as far as possible in all scholarly work, yet 
 it was first recognised by logicians in connection with the rapid "^ 
 growth of science which resulted from its systematic application 
 
I NT ROD UCTION 1 1 
 
 in the study of nature, and it still finds special opportunities of 
 employment along scientific lines which are lacking in other di- 
 rections. It is not too much to expect that the practice of this 
 universally applicable method on the original material will form 
 an invaluable foundation for its subsequent use in any direction 
 whatever. As Professor Jebb says : " The diffusion of that which 
 is specially named science has at the same time spread abroad 
 the only spirit in which any kind of knowledge can be prose- 
 cuted to a result of lasting intellectual value." 
 I" Amongst the possibilities which the study of a science promi- 
 nently presents is that of the exercise and control of the imagi- 
 nation.] In connection with every subject of thought Useof tte 
 it is a function of the mind to rearrange the various Imagination 
 conceptions which are presented, to recombine them 
 in new forms, and to invent hypotheses which justify the new 
 combinations. Of all the powers of the mind it is certainly 
 that which is most important in giving originality to the results 
 of thought. But in proportion to its value and activity is the diffi- 
 culty in controlling its operations. The imagination is a good 
 servant, but a bad master. ^The opportunity which is offered in 
 an experimental science to test the results of the work of the 
 imagination by comparison, again and again renewed, with the 
 concrete materials with which it has been dealing, furnishes an 
 unrivalled opportunity to practise the control of it] To parody 
 Dr. Johnson's aphorism about Richardson^ the study of science 
 must do much towards teaching the imagination to move at 
 the command of truth. 
 
 As Professor John M. Tyler says l : " The successful scientist 
 will always exercise his own imagination and that of his pupils. 
 He will not allow ' This valuable gift of nature to be repressed 
 by a bookish and wordy education.' He will encourage no day- 
 dreaming fancy. He will demand that the pictures of the imag- 
 ination shall be rigidly tested to see that they correspond to 
 
 1 The. Culture of the Imagination in the Study of Science; SCHOOL 
 REVIEW/ VI. (1898), 716. The whole article should be read. See 
 also Pearson's Grammar of Science, chapter I. 
 
1 2 IN TROD UCTION 
 
 some objective reality. But within these limits, and with these 
 restrictions, the student of science will cultivate his imagination 
 as faithfully as the student of art. And he will train it and 
 control it with far more scrupulous fidelity." 
 [_ The study of science gives training in what, for want of a 
 better name, we may designate self-eliminationj In all subjects 
 s if 11 in c ^ ear an( l unbiased judgment is the ultimate goal of 
 tion in Science the student's effort, but many branches of knowledge 
 Work ' are so filled with human opinions, permeated by 
 
 conventional standards, and all through show so strongly the 
 stamp of human workmanship, that unprejudiced judgment is 
 hard to attain. Professor Coulter, in an address delivered at 
 the University of Michigan, presents clearly the idea I wish to 
 convey : 
 
 ] " The general effect of the humanities in a scheme of educa- 
 tion may be summed up in the single word appreciation. They 
 seek so to relate the student to what has been said or done by 
 mankind, that his critical sense may be developed, and that 
 he may recognise what is best in human thought and action]] 
 To recognise -what is best involves a standard of comparison. 
 In most cases this standard is derived and conventional ; in no 
 case is it founded in the essential nature of things, in absolute 
 truth, for it is apt to shift. In any case the student injects 
 himself into the subject ; and the amount he gets out of it is 
 V measured by the amount of himself he puts into it. It is the 
 N artistic, the aesthetic, which predominates, not the absolute. 
 It is all comparative rather than actual. The ability to read 
 between the lines is certainly the injection of self into the sub- 
 ject-matter, and the whole process may be regarded as one of 
 self -injection in order to reach the power of appreciation. . . . 
 The proper and distinctive intellectual result of the sciences is 
 a formula, to obtain which there must be rigid self -elimination. 
 Any injection of self into a scientific synthesis vitiates the result. 
 The standard is not a variable, an artificial one, developed from 
 the varying tastes of man, but absolute, founded upon eternal 
 truth." 
 
IN TROD UCTION 1 3 
 
 Of course neither of these qualities of self-injection and self- 
 elimination is confined to the branch of knowledge in which it 
 is thus discovered to be a conspicuous constituent. As Profes- 
 sor Coulter points out, even in the study of science alone the 
 self-injecting tendency of the humanities must be combined 
 with the self-eliminating tendency of science, " and the power 
 of appreciation developed by the humanities must always be 
 tempered by the scientific spirit." Each method is needed in 
 the study of both. Objective and dispassionate study is the 
 result of the application of the scientific method in any field of 
 knowledge, but the material of the sciences favours the achieve- 
 ment of this ideal in an especial degree. As Huxley says, the 
 scientific mind is "a clear, cpld^Jogic^ engine, with all its parts 
 of equal strength, and in smooth working order." 
 L Other characteristics of mental discipline, such as the way in 
 which it stimulates mental rectitude, favours clear thought, leads 
 to clear expression, etc., might be discussedj They are, how- 
 ever, either implied more or less distinctly in those already 
 enumerated, or may be discussed more fitly in connection with 
 the particular parts of chemical work which call out their em- 
 ployment. 
 
 [_An argument of a different kind but of no small weight is 
 founded upon the value of the information which the study of 
 science imparts. It is at once evident that a study Value of tiie 
 which has strong claims on account of its disciplinary J^^edby 
 value must become practically indispensable if it is Science. 
 able simultaneously to furnish information which is useful and 
 can be obtained in no other way. It is one of the strong points 
 of Spencer's argument in the chapter on " What knowledge is 
 of most worth " that the information furnished by science is of 
 this kind. In learning how to live we must consider the activities 
 which make up lifej Spencer divides these into those con- 
 cerned with self-preservation, those concernetl with the gaining 
 of a livelihood, those concerned with the rearing of offspring, 
 those which minister to the regulation of conduct in social and 
 political relations, and those which minister to the gratification 
 
14 INTRODUCTION 
 
 of our tastes and feelings. He shows in great detail how all- 
 important scientific knowledge is for success in any of these 
 lines. j^Huxley has used the same argument, and puts it in a 
 very striking form.7 The memorable passage in one of his 
 essays, 1 in which, after comparing life to a momentous game 
 with complicated rules, he asks whether a parent who failed to 
 teach his son the rules of this game would not be considered 
 negligent or even cruel, is so familiar that to recall it is almost 
 superfluous. In his simile, life is like a game of chess with an 
 invisible opponent, who may be regarded if you will as some 
 calm, strong angel, who plays for love, as the saying is, and 
 would rather lose than win. The rules of the game are the laws 
 of the universe. The incompetent player is checkmated 
 without haste, but without remorse. 
 
 I Not only is this information valuable, nay, indispensable, in 
 itself, but it assists in holding the interest of the majority of 
 pupils who would not be so much attracted by a purely disci- 
 plinary study] Contact with physical science when it is pre- 
 sented in the right way must continually be felt to be contact 
 with a mighty, living, and growing reality. 
 
 There is still another consideration which cannot be left out 
 of account when the introduction of a subject into the currie- 
 History of the ulurri is proposed, and that is that we have no 
 Curriculum, reason to believe on historical grounds that the old- 
 curriculum has become so much a part of the development Of 
 the race that any change in it would produce serious organic 
 disturbance. As President Eliot has clearly shown, 2 the 
 classical curriculum is only three hundred years old, and dis- 
 placed after a severe struggle an entirely different course of 
 training, consisting of scholastic theology and metaphysics, 
 while this in turn was simply the usurper of a throne formerly 
 occupied by grammar, rhetoric and logic, with a little mathe- 
 matics, music and astronomy. Thus a complete revolution of 
 the whole list of studies might occur again without scholarship 
 
 1 A Liberal Education, and where to find it. Essays, Vol. III. 
 
 2 What is a Liberal Education. Educational Reform, 94. 
 
I NT ROD UC TION (p^ 1 5 
 
 becoming a byword or education perishing from the earth. 
 Even if science and modern languages entirely displaced the 
 classics, we could not urge that a break in the course of nature 
 had occurred, but only that history was repeating itself. This 
 displacement, however, is not demanded. All we make is a 
 plea for the fair representation of science, and this must be 
 regarded as conservative, whether we look at it in the light of 
 reason or of history. 
 
 pTo sum up, we may fairly claim that when science is employed 
 in a way which constitutes an approach to the realization of its 
 possibilities, it furnishes a field for observation along 
 a special line, that of the phenomena of nature ; 
 it exercises us in knowledge-making, and for this furnishes a 
 method of unusual power, that of the study of concrete objects 
 and of experiment ; it gives employment for the imagination, 
 and at the same time provides an especially sure means of con- 
 trolling its operations ; it trains the judgment by the way in 
 which the nature of its subject-matter favours self-elimination ; 
 and finally, the information which it yields is of a special and 
 particularly, valuable description.,, Other subjects may claim to 
 provide discipline under every one of these heads, but in each 
 case science gives a particular variety of this discipline which is 
 distinctive. It is thus an indispensable complement to other 
 branches of study, and, it may be added, is indispensable not 
 merely in the secondary school, but at every stage of education.] 
 This is the least that can be said. Many scientific men 
 claim more for it. In ascending the Brocken one sees, at 
 intervals of a few hundred feet, portions of ground fenced off 
 and used for the rearing of small trees which are afterwards to 
 be planted out at the same altitude. 1 If the same trees were 
 sprouted at the experiment station at Goettingen, and then 
 planted at the top of the Brocken, so far as even an authority 
 on forestry could see, they might appear to be perfectly 
 
 1 I have adapted this illustration from the highly suggestive presi- 
 dential address of Professor Dennis on " The School and the World " 
 delivered before the Indiana State Science Teachers' Association (1898). 
 
1 6 INTRODUCTION 
 
 adapted to the purpose, yet they would have less chance of 
 surviving in their changed environment. It is to be feared that 
 a large part of what we learn in school does not survive transr 
 plantation to the climate of the world, in spite of the demon- 
 strable value of its educational possibilities. Perhaps before we 
 have concluded our study of the teaching of chemistry, it may 
 appear that science at its best comes nearer to being a form of 
 training sprouted at the right altitude, and stands a better 
 chance of thriving in every-day life than book learning in any 
 other branch. 
 
 Some objections have been urged against the conspicuous 
 employment of the sciences as aids in education. It is said 
 Objections to tnat tne metn d of science is so rigorous and 
 the study of exact that it unfits men for dealing with human 
 the Sciences. , . . . . , . , . 
 
 questions which have not the same clean-cut qual- 
 ities. Perhaps the best answer to this is that experience has 
 not shown that men, even when they have devoted their whole 
 lives to the study of science, very generally lose the qualities of 
 sympathy and humanity. And, if there is no great evidence of 
 this in their case (and, in this connection, surely the quotation 
 of Darwin's experience has been decidedly overworked, and 
 been manipulated like a stage army until it has furnished an 
 apparent basis for generalization), there is little danger of 
 serious atrophy of the sensibilities when scientific work of an 
 elementary character occupies but a fraction of the time of our 
 youth. 
 
 It is said also that the study of science tends to lower the 
 ideals of the student, since it calls upon him to soil his hands 
 by contact with that which is commercially useful, and that its 
 general pursuit would convert us into a money-getting and 
 ease-loving people. I believe that the writing and publication 
 of books for beginners in various languages is a very lucrative 
 occupation, but I have not heard that this fact diminishes the 
 cultural value either of the instruction given by the author or of 
 the study of his books. Seriously, it is not proposed that a 
 course should be given which shall in the remotest way suggest 
 
IN TROD UC TION 1 7 
 
 how one may become wealthy by the employment of chemistry. 
 There are many teachers of chemistry who would be delighted 
 to attend such a course, however, if it were given. 
 
 Finally, it is stated that the scientific man exercises himself 
 with so limited a part of human experience, as compared with 
 that touched by the classics, for example, that the study of 
 science has of necessity a distinctly narrowing influence. This 
 argument, and the preceding one as well, simply seem to be 
 fresh cases of comparing one study at its worst with another 
 study at its best. Science at its worst under a poor teacher is 
 doubtless as narrowing, not to say dull and useless, as any 
 other study taught under the same conditions. 
 
 So far we have spoken of science in general with the thought 
 of physical science particularly in our minds. Some of the 
 arguments in its favour hold with special force in The Sciences 
 regard to the biological sciences, and indeed, if inthe Curri- 
 these sciences had been considered, at least one 
 weighty addition might have been made to the list. We are 
 not here concerned with sciences other than physical ; nor does 
 any question arise as to whether physics is to be preferred to 
 chemistry or chemistry to physics. Chemistry can be studied 
 only through physics. The latter science is more easily ap- 
 proached, furnishes a broader field and more points of contact 
 with every-day life, and is indeed a prerequisite to the study of 
 any science. If chemistry is studied before, or instead of 
 physics, about half the time at the disposal of the teacher 
 of chemistry must be devoted to the study of physics, or the 
 work in chemistry itself will be trivial and superficial. 
 
 Chemistry shares with physics all the characteristics of 
 scientific study which we have discussed. It differs from it 
 slightly, however, in respect to the degree and manner in 
 which some of them are represented. Thus in chemistry ob- 
 servation is mainly through the study of physical phenomena ; 
 chemical observation is therefore made by inference and not 
 directly. Again, the facts of chemistry which have to be taken 
 into consideration, even in elementary work, are much more 
 
1 8 INTRODUCTION 
 
 numerous than is the case in physics. The memory is much 
 more heavily taxed in their mastery, and the powers of organi- 
 zation are called more prominently into play in their arrange- 
 ment. Without unusual emphasis on organization and 
 arrangement the science disintegrates into a mass of details. 
 Finally, the study of chemistry, on account of the indirect 
 method of observation, gives more employment to the imagina- 
 tion than does physics. The theories and hypotheses of chem- 
 istry are more indispensable to the appreciation of its facts. Of 
 course, as regards information, the sciences are all distinct from 
 one another, and there is little to choose between physics and 
 chemistry in the matter of the importance of this. 
 
 II. History of the Teaching of Chemistry. 
 
 While the discussion centering round arguments like those 
 we have set forth was going on, the sciences had been slowly 
 ripening on the didactic side against the time when they 
 should gain free representation in the schools as disciplinary 
 studies. 
 
 The course of laboratory instruction in the earlier days of all 
 
 institutions of whatever kind seems to have been modelled on 
 
 that pursued by Liebig in Giessen. Here, Professor 
 
 Methods oi 
 
 instruction Perkin says, " after preparing the more important 
 in Chemistry. gaseSj the stu dent was carefully trained in quali- 
 tative and quantitative analysis." The publication of an out- 
 line of Liebig's course in qualitative analysis by Professor Will 
 in 1846 (this was the first systematic introduction to the subject 
 for the use of beginners), and its translation into English, seem 
 to have been followed by the adoption of this subject as almost 
 the sole material of elementary laboratory instruction. Even at 
 the present day the tradition still retains its influence, and the 
 importance of fuller preliminary instruction in general chemistry 
 is still righting its way to recognition in some quarters. The 
 one-sided and distorted view of chemistry which the standpoint 
 of elementary qualitative analysis gives is still unfortunately the 
 only one offered to many beginners. 
 
INTRODUCTION 19 
 
 The first really decisive step in the right direction was taken 
 by Harvard College, when, in 1888, it included chemistry for 
 the first time among the subjects that might be offered for ad- 
 mission, and, through Professor Cooke's Laboratory Practice^ 
 issued in the same year, defined the kind of work which it 
 considered to be the true educational equivalent of the other 
 and older preparatory school studies. This book practically 
 launched a new ideal in chemical instruction. It was the first 
 attempt in this country * to lay out a course of laboratory work 
 dealing adequately with the fundamental facts and laws of 
 chemistry. The result was in marked contrast to the miscel- 
 laneous experimentation with chemical substances, and the 
 dabbling in qualitative analysis which had hitherto been in use 
 and had afforded so little support to the classroom work on the 
 principles of the science. 
 
 In Great Britain the question of the best methods of teaching 
 elementary chemistry had been under discussion for some years 
 before this time. In 1889 a committee of the British Associa- 
 tion, appointed to consider the subject, submitted a report 
 which included a detailed outline of work (prepared by Pro- 
 fessor Armstrong for the Committee) that was a vast improve- 
 ment on the old schemes commonly in use. It resembled the 
 American plan in discarding analysis, but was intended for a 
 younger set of pupils, and differed from it besides in placing 
 emphasis even more strongly on the method 'of instruction at the 
 expense of the completeness of the account of the science. It 
 sought to place the pupil as completely as possible in the attitude 
 of a discoverer, and was willing to sacrifice much in the way of 
 speed and area covered to accomplish this. In their different 
 ways both were notable contributions to the didactic side of 
 chemistry, and we may trace directly to their influence the rapid 
 spread of more rational methods of teaching the science which 
 has been so conspicuous in both countries. The principle 
 
 1 Professor Ramsay's Experimental Proofs of Chemical Theory for 
 Beginners (London, Macmillan, 1884) was the corresponding "first" in 
 Great Britain. 
 
20 INTRODUCTION 
 
 underlying Professor Cooke's plan has been adopted by nearly 
 every recent work prepared for the use of secondary schools. 
 The motif ot Professor Armstrong's report has coloured, where 
 it has not controlled, a large proportion of the recent teaching 
 of Great Britain. 
 
 In Germany some work in science is given in every year of 
 the secondary school course. The instruction, however, seems 
 
 to be undertaken with a different aim from that 
 Chemistry in 
 the Schools of kept in view in the English-speaking countries. 
 
 Germany. \vhile in this country chemistry is taught as a 
 separate department of instruction, and with the object of con- 
 ferring some knowledge of the science itself, in addition to the 
 extraction of such general mental discipline as its study is able 
 to afford, in Germany the science is employed primarily for the 
 purpose of giving intelligent knowledge of things around us, and 
 as a means of training the powers of observation, reasoning, and 
 exact expression. While this is the general tendency, however, 
 there are many schools in which individual laboratory work by 
 the pupils is included in the curriculum, and in which the place 
 of chemistry is more like that which it holds in America to- 
 day. Yet even in these schools the laboratory work does 
 not call for fresh study of new problems in an independent 
 spirit, but only repetition of those already used and illus- 
 trated in the classroom. Then, too, attendance on the 
 laboratory exercises is optional and is usually very limited. 
 Promotion to the next class is in theory dependent on pro- 
 ficiency in scientific as in other studies, but in practice takes 
 place irrespective of this. Thus, in the German school, 
 science, to use the words of Spencer, is " the household 
 drudge, who, in obscurity, hides unrecognised perfections." 
 At least these perfections, if recognised, are veiled until the 
 regular study of the sciences as separate subjects begins in 
 the university. 1 
 
 1 See James E. Russell, German Higher Schools, 329-351, in which a 
 detailed outline of the work in physical science in one school is given, 
 and the methods and ideals are fully set forth. 
 
INTROD UCTION 2 1 
 
 III The Present Condition of Chemical Instruction. 
 
 The history of secondary education in America so far as 
 chemistry is concerned, has been marked by two conflicts, first, 
 the struggle for admission, and then, the struggle for x ne struggle 
 rank. The struggle for admission may be said to for Admission. 
 have been completely won, although there may be outlying 
 portions of the field which have not yet been occupied by the 
 victor. The number of pupils taking chemistry in all the 
 secondary schools in the United States is some indication of 
 this. According to the report of the Bureau of Education, 
 8.55 per cent of all the pupils were studying chemistry in 
 1897-98. When we consider that chemistry is very rarely 
 taught during more than one year, and that it is usually placed 
 in one of the later years of the course, it is probable that not 
 more than 15 per cent of all the pupils during any one year 
 have any opportunity to take chemistry. The actual number, 
 therefore, is, on the whole, encouraging. Attention may be 
 called in passing to the peculiarities, either in the opportunities 
 for taking chemistry, or in the way in which advantage is taken 
 of these opportunities, or both, in different parts of the country. 
 The percentages are 9.39 in the North Atlantic States, 12.22 
 in the Western States, 7.58 in the North Central States. 
 
 The struggle for rank may be said to have been won also, but 
 by a moral victory. The opponents are defeated, but it may be 
 doubted whether they are convinced. They cover The struggle 
 their retreat by the statement that the scientific for Rank, 
 course is possibly of equal value with the classical, but the 
 training which it gives is different. On this ground they fre- 
 quently would refuse the granting of the degree of A.B. to the 
 graduates of such a course. Unquestionably the sciences have 
 been at a disadvantage on account of their lack of that prestige 
 which three hundred years of continuous employment have 
 given to the older subjects. But, putting aside all prejudice, 
 there is perhaps still some ground for reserve in answering the 
 question whether science has actually fulfilled its promises. 
 
22 INTRODUCTION 
 
 That its present average efficiency is far below its possible best, 
 no one can doubt. So far as the feeling of which we have 
 spoken is due to a distrust of science at its best, the question 
 has already been disposed of in the first section of this chapter. 
 So far as it expresses a lack of confidence in science, and par- 
 ticularly in chemistry as it is, some further inquiry into the 
 question will be proper in this place, and before we pass to 
 the discussion of the means which in many schools at least 
 have enabled it to reach the best. 
 
 There are unquestionably some things which diminish the 
 
 effectiveness of chemistry as a means of instruction in our 
 
 schools. The first of these is a lack of organized 
 
 withwhich instruction in scientific matters running through 
 
 Chemistry every year of school work, from the first to the 
 Contends. 
 
 last. The pupils have not been brought up to the 
 
 study of nature and physical science by personal handling of 
 the objects with which these deal, and consequently their ability 
 to get the best out of the subject is hampered because their 
 capacity to employ the means of study has become partially 
 atrophied by disuse. 
 
 This state of affairs is certainly being remedied, but that the 
 
 improved conditions have yet had time to affect the average 
 
 teaching in chemistry, may be doubted. Contrast this with the 
 
 f custom of continuously employing the methods of language 
 
 / study from the earliest years, which every child has acquired, 
 
 and the disadvantage under which chemistry labours is at once 
 
 apparent. 
 
 Still another impediment may be found in the instruction in 
 chemistry in the higher institutions which are intrusted with 
 Defects in the tne ^ u ^ * tramm g tne teachers. As before, we are 
 Means af- speaking of the average and not of the best. It has 
 Training* been asserted, and with justice, that the greater 
 of Teachers. p art o f tm ' s training is essentially non-scientific in 
 its tendency. The instruction is too dogmatic, and books are 
 too largely the reliance of the instructors. The pupils are not 
 disciplined in the methods of observation and investigation, 
 
INTRODUCTION 23 
 
 and there is too much speculation substituted for the much 
 more conservative theorizing and explanation which are alone 
 permissible. The pupils are not brought in contact with the 
 spirit of the subject by the study of the original sources and the 
 memoirs of investigators, and, above all, they are scarcely ever 
 called upon to perform any original investigation, no matter 
 how simple, on their own account. Such instruction can 
 never transfuse into the minds of the pupils any notion of the 
 spirit of the subject. Take, for example, the conventional course 
 in chemistry. Even if the subject is studied for two or three 
 years, which occurs in the preparation of a small minority only 
 of the prospective teachers in secondary schools, the time is 
 largely occupied with quantitative and qualitative analysis, sub- 
 jects which should play a subordinate part in the preparation of 
 the teacher, unless he' has ample time at his disposal. It is 
 general chemistry that he must knqw^and instruction in these 
 other branches not only contributes little to his knowledge of 
 the main trunk, but even diverts his attention from it. Com- 
 parison with the training given in languages and mathematics 
 shows that, although it may be easy to point out defects, the 
 preparation is, after all, much more thorough in the directions 
 in which the work of teaching in the secondary school makes 
 the heaviest demands.' 
 
 The results of faulty training of the teacher are more serious 
 in science than in language. As Professor Macgregor says, 
 " In the making of linguistic knowledge, a pupil under an 
 incompetent teacher does not stick fast. He has the experi- 
 ence of his childhood to help him, is capable of exercising the 
 knowledge-making power without the teacher's aid, on the 
 familiar material which language affords, and in his effort to 
 make progress, cannot help exercising it to a greater or less 
 extent. Let me draw special attention to this point ; for the 
 fact that in the study of language, exercise of the knowledge- 
 making power is not only possible, but in a large measure 
 unavoidable, even under an incompetent teacher, gives to lan- 
 guage study a great advantage over science study, as a means 
 
24 INTRODUCTION 
 
 of discipline in all educational institutions, but especially in 
 those of lower grade, in which, owing to their large number, 
 the difficulty of* securing competent teachers is especially 
 great." 
 
 Still another cause of diminished effectiveness in chemistry 
 teaching is the lack of unity in the aims and methods of the 
 La k of unity teacners - This is the result of the existence of the 
 in Aim and same fault in the work of the higher institutions. 
 Some elementary courses in chemistry are devoted 
 largely to analysis. In others, the discourse is mainly of atoms. 
 These, instead of being employed as conceptions rather than 
 facts, are described with such realism that the study of the sub- 
 ject by experiment is pressed into the background, either 
 actually or in the estimation odf the pupils. This lack of unity 
 is so notorious that when, a few years ago, a set of educational 
 conferences was called at Columbia University, no conference 
 on science was held. It was considered that the opinions of its 
 advocates were so unsettled that the colleges had no basis on 
 which to fix definite requirements in science at all. We have but 
 to look at text-books on chemistry in order to see that, although 
 they are all labelled chemistry, their content and spirit differ 
 widely. We have but to compare them with the standard trea- 
 tises on languages and mathematics to see how much greater 
 the unity is which has been reached in these subjects. 
 
 In enumerating the disadvantages under which the teacher 
 labours in fitting chemistry for a place in the curriculum, we 
 
 must note that not the least of these is the difficulty 
 The Intrinsic 
 
 Difficulty of of the subject itself. To quote Professor Mac- 
 
 the Science. g regor a g am> A difficulty with which the sound 
 
 teaching of science has met, arises from the complex character 
 
 of its subject-matter. To compare different usages of words, 
 
 for example, one has but to turn over the leaves of a book ; to 
 
 compare instances of the occurrence of natural phenomena, the 
 
 phenomena must be watched for or reproduced under varying 
 
 . conditions." Or again, as Professor Cooley says, "Phenomena 
 
 ; are the symbols in which truths are written, but phenomena 
 
INTRODUCTION 2$ 
 
 abound in superficial likenesses, obscure differences and decep- 
 tive analogies. A correct translation of this language requires 
 keen perception, accurate judgment and crystalline forms of 
 expression. " It is undoubtedly harder to carry the subject to 
 a depth corresponding to that which would be reached in 
 French or Latin, or to master it with equal thoroughness. 
 
 The case is often made worse by putting chemistry before 
 physics in one of the earlier years in the secondary school. 
 The highest benefits can be got from its study only when the 
 
 time comes at which, as Professor Nicholas Murray 
 
 ~ , . j r ^ f Trivial Nature 
 
 Butler, in attempting to define the stages of psy- O f much School 
 
 chological development and ascertain their corre- ., 
 
 Chemistry. 
 spondences with the stages in our educational 
 
 system, says, the soul " demands new and more difficult prob- 
 lems to occupy it and absorb its activities." As we hope to 
 show later, the organization of the teaching of chemistry at its 
 average is in need of very great improvement before adequate 
 benefit can be conferred by it, even in the fourth year of the 
 secondary school. At present much time is wasted on the 
 study of superficial aspects of this science, when the same time 
 devoted to languages or mathematics might have gone much 
 deeper and been educationally much more effective. Much 
 testimony is available to prove that the chemistry work in 
 the average school is not a trial worthy of the powers of the 
 pupils. To use the expressive phrase of a friend of mine, 
 "There is too much chicken-feed chemistry occupying time 
 that might have been devoted to the giving of solid nourish- 
 ment." One needs but to visit a number of schools to see that 
 there is truth in this statement. I have seen work in English 
 being done by the freshmen of a high school which showed a 
 surprising grasp of the more abstract aspects of rhetoric and an 
 ability to handle problems of literature in a wonderfully effec- 
 tive manner, while the same pupils in the next year were putter- 
 ing with a kind of chemistry which, it may be said without 
 exaggeration, would not have over-taxed the ability of a reason- 
 ably intelligent infant if its physical development had permitted 
 
26 INTRODUCTION 
 
 it to attempt the work. A mode of study in a science which 
 does not take full advantage of the knowledge-making power 
 which it can call forth, not only largely wastes the time it occu- 
 pies and discredits the science itself, but diminishes the effi- 
 ciency of the whole curriculum of instruction. There is reason 
 to fear that chemistry has gained admission before the means of 
 using it most effectively have become widely known. 
 
 The work in science is also frequently hampered by the atti- 
 tude of the authorities of the school, who may not be as fully 
 Some Other convinced of its value as their introduction of the 
 Hindrances, subject into the curriculum would lead us to ex- 
 pect. They are apt to promote pupils who have neglected 
 scientific work, provided they have done well in other studies. 
 They are apt also to appease the clamour for representation 
 of science in their school by assigning classes in chemistry 
 to teachers who have had almost no preparation in the subject, 
 instead of delaying its introduction until they can afford to obtain 
 a properly prepared instructor. They are prone to load four or 
 five sciences on one teacher, regardless of the utter impossibility 
 of organizing good laboratory instruction under such circum- 
 stances, even if the preparation of the teacher should, by a 
 miracle, be not unequal to the task. They cut the day into 
 equal and often very brief periods, as if mechanical adjustment 
 of time were everything, and the essential differences between 
 laboratory work and class work, in respect to the value which 
 each can get out of thirty or forty minutes, were nothing. 
 
 To secure instruction in science of effectiveness equal to that 
 in other subjects, and to wrest from it the benefits which it ad- 
 mittedly can confer, we must have continuous in- 
 Summary. 
 
 struction in science, beginning with nature study 
 
 in the elementary schools ; we must have at the other end im- 
 provement in the chemical curricula in the highest institutions 
 \vhich furnish the teachers ; we must have unanimity, or some 
 approach to it, in regard to the aims and methods of secondary 
 school chemistry ; and we must work out the detailed organiza- 
 tion of the teaching of chemistry more fully. When these things 
 
INTRODUCTION 2/ 
 
 have been accomplished, proper respect for the subject at the 
 hands of all educational authorities will come of itself. At 
 present the average instruction in chemistry does not even re- 
 motely approach, in the benefits which it gives, the best that 
 can be given or is given. When the difficulties we have 
 enumerated have been removed, or considerably reduced, we 
 may confidently expect that chemistry, at its average, will 
 worthily fulfil the hopes which the reasons given for its study 
 awaken. It is in the earnest hope of contributing something, 
 however little, to the attainment of this end by bringing to- 
 gether the opinions of all authorities on the teaching of chem- 
 istry in secondary schools that the following chapters have been 
 written. 
 
CHAPTER II 
 
 CHEMISTRY IN THE CURRICULUM 
 REFERENCES. 
 
 Report of the Committee of Ten of the National Educational Associa- 
 tion. Washington, D.C., U. S. Bureau of Education. 1893. P P- ri 7- I2 3- 
 
 Woodhull, J. F. Sequence of Sciences in the Secondary School 
 Curriculum. High School Bulletin No. 7. Albany, N. Y., The Univer- 
 sity of the State of New York. Pp. 516-523. 
 
 THE sequence of chemistry with reference to other subjects 
 and the year in which it shall be placed are questions of great 
 importance, since they affect profoundly the manner of the 
 instruction and the amount that can be accomplished. This 
 question can hardly be said to arise except in connection with 
 the sciences. In the case of Greek the doubt lies between 
 the second and third years. In English, Latin, or mathemat- 
 ics the first year is the natural place for the beginning course. 
 In science, however, we have a choice of five or six distinct 
 subjects which may conceivably be taught in any sequence, 
 each in any year. Observation of schools shows that this 
 freedom is made use of to the fullest extent. Not to occupy 
 too much space with the discussion we may confine ourselves 
 to the question of the order in the case of chemistry and phys- 
 ics, and whether the physical sciences should be placed in the 
 earlier or later years of the high school eourse. Even with this 
 restriction, there is not the slightest approach to unanimity on 
 either of these questions, either in the opinions of school-men 
 themselves, or in the practice of the schools. Something more 
 final than the opinion of the individual teacher is required, 
 since, if he is interested in securing the best work from his 
 pupils in chemistry, he will naturally prefer to secure a place 
 
CHEMISTRY IN THE CURRICULUM 29 
 
 V 
 
 in the fourth year of the school for this work. Several of 
 the points involved in the discussion of theje questions have 
 so important a bearing on the teaching of chemistry that we 
 shall be justified in devoting some space to their consideration. 
 
 I. The Precedence of Physics. 
 
 a. The Report of the Committee of Ten : In the report of the 
 Committee of Ten perhaps the point which excited most dis- 
 cussion was the decision which they reached, that 
 chemistry should be taught before physics. It is Physics . 
 undoubtedly conceded by all that the logical order * ore Chem- 
 is just the reverse of this. The minority report of 
 Professor Waggener states, with considerable clearness, the 
 reasons which lead him to dissent from this part of the re- 
 port. In brief, these were as follows : Since in training the 
 pupil to make accurate observations and to draw safe infer- 
 ences, the more simple subject-matter should precede the less 
 simple, and that which is more obvious to the senses that which 
 is less so, and since that which derives more abundant material 
 for illustration and application from the experiences of every- 
 day life will form a better starting point, physics seems to be 
 indicated as the natural precursor of chemistry. He points out 
 that a great part of physics relates to phenomena wherein the 
 bodies concerned and their behaviour are directly perceptible to 
 the senses at every stage of the experiment. The first results 
 thus ^ome from direct perception rather than by inference, 
 and upon such phenomena the power of making inferences 
 should* first be trained. The behaviour of parts of matter con- 
 cerned in chemical changes, on the other hand, is inferred, not 
 observed ; and the conceptions we form of it are less simple 
 than those of molecular physics, since it involves a redistribu- 
 tion of more than one kind of matter, and the forces in obedi- 
 ence to which this takes place are much more complex in the 
 matter of selection and direction than cohesion. " The ra- 
 tional study of chemical phenomena is therefore of a higher 
 order of difficulty than those of physics, certainly than those of 
 
30 CHEMISTRY IN THE CURRICULUM 
 
 molecular physics, a portion of the subject to which the work of 
 the high school is largely directed." Finally he points out that 
 chemical theory depends for rationalization so completely upon 
 an intelligent conception of its many and close relations to 
 physical laws that previous training in the measurement of the 
 fundamental physical constants would seem to be indispensable. 
 
 b. Observations in Chemistry a Study of Physical Properties : 
 It appears to me that the dependence of chemistry upon 
 physical conceptions and phenomena might fitly have been 
 emphasized much more strongly. I think that a closer exam- 
 ination of the features of chemical experimentation will show 
 this, and will incidentally point out one of the directions in 
 which much of the teacher's effort may be fruitfully spent. 
 
 When any chemical operation is to be carried out, its suc- 
 cess invariably depends upon attention to matters belonging 
 
 . strictly to the domain of physics. Thus, if it be a 
 Physical Basis / 
 
 of Chemical question of dissolving a salt in water, the process 
 p a on ' will take a limitless time if the solid is permitted to 
 rest at the bottom of the vessel, along with the part of the solu- 
 tion which is slowly becoming more concentrated. Yet it is 
 seldom that a pupil will spontaneously hasten the process by 
 mixing or agitation. Again, when a gas is to be generated 
 and collected over water, the filling and inversion of the jar 
 of water and the displacement of the water by the gas all in- 
 volve many physical questions. In more difficult experiments, 
 particularly those connected with the determination of the 
 molecular weight of chemical substances by one of the many 
 simplified methods which may now be used in any high school, 
 physical principles (vapour tension, laws of gases, adjustment of 
 pressure before volume measurement, etc.) are almost the sole 
 things to be considered. 
 
 A little reflection will show in a manner still more striking 
 how. even in the study of the simplest chemical changes, the 
 interpretation of the result depends upon a knowledge of physics. 
 If the problem be to ascertain the effect of heating upon some 
 body, the pupil may observe all that takes place, but, without a 
 
CHEMISTRY IN THE CURRICULUM 31 
 
 rapid concurrent interpretation of each feature as it presents 
 itself by reference to physical principles, the experiment will 
 
 lead to no correct conclusions whatever. The sub- 
 
 Fnysical Basis 
 
 stance may melt, and the pupil must ascertain of Chemical 
 whether this is simply a physical change, or whether Observation - 
 it involves chemical change also. The substance may boil, 
 or appear to do so. The pupil must be in a position to dis- 
 tinguish between boiling and decomposition accompanied by 
 the production of a gas, for example, by the fact that the removal 
 of the source of heat interrupts boiling, but usually does not so 
 promptly affect the progress of decomposition. In heating 
 ammonium nitrate 1 we have an excellent illustration of a multi- 
 plicity of things which require physical explanation. The ex- 
 periment is full of points, such as the apparent violence of the 
 boiling while the bubbles of gas rising in the bottle succeed 
 one another but slowly, and the cloud of smoke which some- 
 times accompanies the gaseous materials and passes successfully 
 through the water, all of which require careful consideration of 
 the physical properties of matter for their explanation. 
 
 Again, suppose that the problem before the pupil is the ex- 
 amination of the action of various metals upon concentrated 
 hydrochloric acid, and that he is instructed merely Furt]ier i llus . 
 in the method of bringing the materials together, and tration. 
 is expected to observe what follows for himself. He must have 
 recourse to physics to ascertain whether the effect following the 
 introduction of zinc is boiling, and consists in the evolution of 
 steam, or is produced by the development of hydrogen. Usually 
 his first thought is to attribute the effect to boiling, and indeed 
 the reasoning of the observer must frequently consist in draw- 
 ing a trial conclusion, and then testing it by known physical 
 facts. Again, when the copper is introduced into the acid no 
 action takes place. But when the mixture is warmed, bubbles 
 of vapour are given up apparently from the neighbourhood of the 
 copper, and the pupil is likely now to conclude that hydrogen is 
 
 1 This illustration is fully discussed by R. P. Williams. New England 
 Association of Chemistry Teachers, Report of Fifth Meeting (1899), 4- 
 
32 CHEMISTRY IN THE CURRICULUM 
 
 being formed. This conclusion must be suspended, however, 
 when he realizes that the liquid being heated is a strong solu- 
 tion of a gas. He must, therefore, either ascertain whether the 
 escaping vapour contains hydrogen, or indirectly, by looking for 
 the blue colour of a salt of copper, recognise that there has really 
 been no formation of such a salt, and therefore there can have 
 been no evolution of hydrogen. 
 
 It is hardly necessary to add that when parts of physics have 
 to be drawn upon wholesale, as the kinetic theory of gases in 
 explaining Avogadro's hypothesis and its applications, or the 
 properties and employment of electricity in experiments in elec- 
 trolysis, a previous acquaintance with dynamics and electricity 
 is of the utmost value. In the contrary case, the extreme un- 
 familiarity of the whole thing interposes a tremendous drag on 
 the progress in chemistry. 
 
 A careful consideration of any chemical experiment, even the 
 simplest, thus reveals the fact that an intimate knowledge of the 
 physical properties of matter is required in carrying it out suc- 
 cessfully, and in interpreting the results. This knowledge of 
 physics must be even more intimate than that demanded of the 
 pupil of physics himself, for in the case of the latter the work is 
 outlined in such a way that the subject under investigation and 
 the method are both known beforehand. In a chemical experi- 
 ment, the physical phenomena turn up without warning, and the 
 pupil must identify them instantly and understand their whole 
 bearing if the conclusion is to be otherwise than doubtful or 
 hazy. In fact, the matters of immediate observation in a chemi- 
 cal experiment are all physical, and the data derived from these 
 depend upon physical knowledge, and thus everything but the 
 final conclusion is physical and not chemical. 
 
 It has been remarked that " each chemical experiment is a 
 
 question put to nature, and forethought and care are 
 
 nomena the *~ necessary in putting the question, and study and 
 
 Language of reflection in interpreting the answer." In view of 
 Chemistry. 
 
 the above we note that the chemical question has 
 
 to be put in a strange language (namely, by physical methods), 
 
CHEMISTRY IN THE CURRICULUM 33 
 
 and the answer is returned in the same foreign language. This 
 language must therefore be mastered before the question can be 
 put or the reply understood. The education of a chemist con- 
 sists largely in acquiring a colloquial knowledge of this language. 
 
 c. The Conclusion : Whether chemistry or physics should 
 come first is thus seen to be an idle question. Physics jpusj; 
 come first. The question really is whether it is better to furnish 
 a systematic knowledge of physics during the previous year, or 
 leave it to be picked up as it is presented, hap-hazard, in the 
 course of chemical work. When the question is put in this 
 form, there can be little doubt in regard to the answer. It is 
 true that the course in physics will probably not deal in any 
 sufficient detail with some of the phenomena most intimately 
 connected with chemistry. But the facility with which the pupil 
 who has surveyed the whole ground in outline will acquire fur- 
 ther knowledge of the same kind, will be incomparably greater 
 than that of the pupil who has no " apperceptive mass" in 
 which the fragmentary facts noted in the course of chemical 
 work may be absorbed. 
 
 It is evident that when chemistry precedes physics, the former 
 subject will furnish a more valuable introduction to the latter 
 than in recent discussion has been generally admitted. A 
 teacher of chemistry, whether he will or not, is bound to fur- 
 nish some instruction in physics, and the result, while it must 
 necessarily be unsystematic, will nevertheless assist materially 
 in the subsequent study of the same thing. The study of either 
 subject is bound to hasten the process of acquiring the other, 
 but the precedence of physics is the more economical arrange- 
 ment, since it will but little diminish the speed with which 
 physics may be acquired, while greatly accelerating the prog- 
 ress of the pupil in chemistry. 
 
 II. Arguments in Favour of the Precedence of Chemistry. 
 
 The decision of the Committee of Ten seems to have been 
 based finally upon the consideration that the greatest amount 
 of mathematical training possible should be secured before the 
 
 3 
 
34 CHEMISTRY IN THE CURRICULUM 
 
 pupils enter upon the study of physics. Authorities on this 
 subject, however, do not seem by any means to be unani- 
 Physics and mous m thinking that a course in advanced algebra 
 Mathematics, and solid geometry are really indispensable prerequi- 
 sites. In algebra the solution of simple equations is usually 
 considered sufficient, while in geometry the determination of 
 the area of the parallelogram and circle, and the volumes of the 
 sphere and cylinder can easily be given by the teacher of phys- 
 ics, and thus the postponement of the work for the whole year 
 may be avoided. It is probable that the Committee of Ten 
 was really thinking of the value of the general discipline which 
 these subjects would undoubtedly confer, rather than of any 
 considerable percentage of the subjects themselves which would 
 be required for the service of the teacher of physics. 
 
 It is frequently maintained that chemistry may and should be 
 taught more simply than physics. This is an insidious argu- 
 ment. Every subject should be taught simply, if 
 simpler than by the term we mean that it should be so carefully 
 Physics? related at every step to the previous knowledge of 
 the pupil that over-strenuous effort on the one hand, and obscu- 
 rity on the other, are avoided. But, in many cases, the simplifica- 
 tion which makes chemistry an easy study is not of this kind. 
 It involves not the careful bridging of all gaps and rational ap- 
 proach to conquest of all difficulties, but rather the mutilation 
 of the subject and the removal of most of the science along with 
 the difficulties. For example, in studying the action of a metal 
 upon hydrochloric acid, we have seen that an intimate knowl- 
 edge of the physical properties of the materials is required. 
 But we may "simplify" the experiment, heading it " Standard 
 method of making hydrogen," and direct the pupil to place 
 zinc in hydrochloric acid. By this arrangement, as he already 
 knows that hydrogen is a gas, no close observation, no knowl- 
 edge of physics, and no reasoning are demanded of him. The 
 whole pith of the exercise has been removed as an incident of 
 the simplification however. Chemistry can thus be reduced to 
 a series of cook-book receipts, and all difficulties may disap- 
 
CHEMISTRY IN THE CURRICULUM 3$ 
 
 pear simultaneously with the removal of all the discipline which 
 chemistry is most fitted to impart. A large part of the work 
 may be arranged so as to consist in the formation of precipi- 
 tates. Here the same set of physical phenomena is repeated 
 time after time without variation, and the chemical conclusions, 
 namely, that a certain substance is or is not formed, and if 
 formed is black or red, as the case may be, may be drawn with- 
 out the pupil once realizing what the physical conditions are 
 that make this possible. 
 
 When the work has thus been conventionalized, so to speak, 
 it ceases to deserve the name of chemistry. It has variously 
 been designated as " cookery " and "test-tubing." Yet scorn 
 does not seem to have much effect in appreciably reducing the 
 amount of this kind of mechanical work. There are still some 
 who seem to think that anything which deals with chemical ma- 
 terials and uses chemical terms is in some measure chemistry. 
 There are laboratory manuals that can be used with delightful 
 facility by the largest class, and with the least amount of super- 
 vision, which furnish the pupil with little work that is not of this 
 description. 
 
 The mention of text-books reminds us, that the fact that high 
 school books on chemistry appear to be simpler than those on 
 physics, has been used as an additional support of the argument 
 that chemistry is intended to precede physics. This really in- 
 volves the question of the choice of a text-book, which we shall 
 discuss in another chapter. It may be remarked, however, 
 that chemistry books are not as simple as they seem. Many 
 works intended for high school use are filled with graphic form- 
 ulae. I know no subject which is found more difficult by the 
 beginner than the comprehension of the way in which a 
 graphic formula represents the chemical properties of a sub- 
 stance. The books I refer to seem to realize this, for they 
 make no attempt to explain the formulae they employ. Per- 
 haps they leave that task to the teacher. The usual result 
 seems to be, however, that the formulae are memorized, and are 
 highly prized as the subjects of examination questions. If the 
 
36 CHEMISTRY IN THE CURRICULUM 
 
 laws and formulae found in works of physics were to be memor- 
 ized also, that subject might rival chemistry, if not excel it, in 
 simplicity. The teacher is not compelled to confine himself to 
 the most trivial treatment of chemistry. Avogadro's hypothesis 
 and its consequences, involving as it does the determination of 
 molecular weights, atomic weights, valency, and the construc- 
 tion of formulae and equations, is the most fundamental prin- 
 ciple in chemistry, and will usually be found as difficult a subject 
 as anything in elementary physics. Professor van 't Hoff, in a 
 recent lecture, stated that as a student he never had understood 
 the application of this hypothesis, and that he learned it only 
 when he became an instructor in chemistry. 
 
 The argument that the manipulation in chemistry is simpler 
 than in physics, and therefore fitted to precede the latter, is 
 based upon the same assumption as before. If we 
 Manipulation ema sculate the subject sufficiently, we can make it 
 easier than simpler than any other subject that may be named, 
 Physical? k ut ^ e ^ eac ] 1 j n g j n chemistry attempts to include 
 the fundamental principles of the science, as the teaching in 
 physics does, it need not suffer from lack of experiments requir- 
 ing skill, patience, and knowledge. The determination of molec- 
 ular weights, and the measurement of combining weights, are 
 the most fundamental things in elementary chemistry. They 
 are not, by any means, beyond the skill of the high school 
 pupil, or the equipment of the high school laboratory, but they 
 are not to be classed in simplicity with naming salts, or dis- 
 tinguishing ' silver,' ' lead/ and ' mercury ' by the use of hy- 
 drochloric acid and ammonia. 
 
 Nor need we have recourse to experiments of a quantitative 
 nature to furnish instances of difficulty in chemical work. The 
 pupil in chemistry is confronted with one difficulty in every ex- 
 periment, which it seems to me is not met with in the same 
 degree in any of the other sciences. The difficulty rests on the 
 fact that before observing, he has himself to produce that which 
 he is to study. There is doubtless important training for the 
 pupil who is called upon to examine a cockroach minutely, and 
 
CHEMISTRY IN THE CURRICULUM 37 
 
 report upon the number, location, and kinds of its appendages. 
 But if he had to create the cockroach by a definite method of 
 procedure, it is likely that his observations would less exactly 
 describe the standard animal than they do. In chemical work 
 almost every experiment will show varying results in the hands 
 of different students, all working by the same directions. Some 
 will use concentrated sulphuric acid or pure zinc, and so fail in 
 obtaining hydrogen ; a solution may be applied in too concen- 
 trated a form, or too much may be used ; a test-tube may not have 
 been thoroughly cleaned. Every teacher knows how puzzling 
 the ' sports ' are which the pupil may produce in this creative 
 work. Nor is carelessness always to blame. Directions so 
 minute as to remove all possibility of variation from the desired 
 result would frequently be so elaborate as to be impracticable. 
 Successful laboratory work in chemistry must depend largely on 
 the knowledge, forethought, and skill of the pupil. The use of 
 these is an essential part in chemical manipulation, and makes it 
 at least as difficult as anything in the other sciences. 
 
 III. In which year of the High School Course shall Chemistry 
 be taught ? 
 
 amount of work which can be given in a year, and the 
 thoroughness with which it can be given, must be influenced 
 very greatly by the general advancement of the pupil! Prob- 
 ably at least twice as much can be done in the fourm year as 
 in the first, on this account alone. The necessary absence of 
 previous training in physics, in the latter case, must greatly in- 
 crease the disproportion. Every science cannot secure a place 
 in the fourth year, and so have the advantage of reaching the 
 pupils who are most mature and have had the largest prelimi- 
 nary training in other sciences. The decision must mainly 
 depend upon whether chemistry or some other science is to be 
 selected for most elaborate treatment. If physical geography 
 or physiology secure the coveted position, either will obviously 
 be benefited greatly by the fact that it is preceded by a course 
 in chemistry. The general tendency in the secondary schools, 
 
38 CHEMISTRY IN THE CURRICULUM 
 
 however, is undoubtedly to emphasize most strongly the funda- 
 mental sciences, and to treat with less considerations those which 
 are developed largely by the application of physical and chemi- 
 cal principles. 
 
 It has indeed been said that habits of neatness, care, and 
 skill in manipulation cannot be learned after the second year of 
 Ar umentfor tne n ^S n school, and that therefore chemistry and 
 Chemistry in physics should occupy these two years. This argu- 
 irs * ment, however, seems to assume that the work of 
 the chemist requires the agility of the pianist, or the suppleness 
 of the acrobat. Surely what is needed is rather the patient, 
 intelligent, and forethoughtful variety of manipulation which is 
 favoured by maturity rather than by youth. No difficulty seems 
 to be found in training surgeons in precisely this sort of way, in 
 years much later than those just mentioned. 
 
 There seems to be good ground for the contention that 
 physics and chemistry cannot give up the fullest discipline of 
 
 which they are capable in the earlier years [ of the 
 Arguments 
 forChemistry course. Without mathematics, physics must be 
 
 in Later feeble, and without physics, the chemistry must be 
 
 considerably restricted. Then, too, the continuous 
 and minute supervision, which work in chemistry requires, must 
 be greater the earlier it appears in the curriculum, to offset the 
 slighter previous knowledge of the pupils. In practice, how- 
 ever, the much larger classes of the earlier years would entail a 
 diminution in the supervision, rather than an increase in it, and 
 thus still further reduce the efficiency of the work. 
 
 1 Although the entrance requirements of universities should not be 
 permitted to interfere with the arrangement of the work of the secondary 
 schools, if their interests conflict, it may be noted that, so far as chemistry 
 is accepted at all as an admission subject, the work done in the first or 
 second year will almost always satisfy the very indefinite requirement. 
 The work outlined by the University of the State of New York, and the 
 questions asked in their examinations, are said to pre-suppose fourth year 
 work. The requirements of the Examination Board of the colleges of 
 the Middle States and Maryland, and those of one or two universities out- 
 side of this organization which have definitely outlined admission work in 
 this subject, practically demand fourth year work. 
 
CHEMISTRY IN THE CURRICULUM 39 
 
 [^Perhaps the far-reaching relations of chemistry to commerce 
 and industry, the value of the discipline which it affords in pre- 
 paring for a business career, and its importance in preparation 
 for the study of medicine and technology are worthy of notice as 
 inclining the schools very generally to give it the most favourable 
 position among the sciencesj It is at least certain that many 
 bodies of recognised authority incline to recommend the placing 
 of it late in the course. The Committee of Ten (1892) set it in 
 the third year immediately before physics. The Committee of 
 the National Education Association on College Entrance Re- 
 quirements (1899) indicated that the last year was the most ap- 
 propriate, and the University of the State of New York makes 
 the same recommendation.' In individual schools there may be 
 good reason for departing from this arrangement. Successful 
 curricula have been devised in which the advantage of prelimi- 
 nary chemistry was secured to the teachers of biology, physics, 
 and physiography without reducing the opportunity of the pupils 
 to secure the best training in chemistry. This is done by intro- 
 ducing selected parts of the subject, along with some physics 
 and physical geography, into a course in general science which 
 occupies the first year. The regular course in chemistry which 
 comes later can only be benefited by this arrangement. In a 
 few schools a compromise with the recommendation of the 
 Committee of Ten is effected by dividing the third year between 
 physics and chemistry, and then offering a full course in both 
 of these subjects as alternatives in the fourth year. 
 
 Uniformity in the arrangement of the curricula of all secon- 
 dary schools can never be achieved, and is probably not desir- 
 able. The chief value of the discussion in this chapter to the 
 teacher of chemistry lies in the attempt to bring vividly before 
 him the great importance of a clear knowledge of the physical 
 conceptions involved in all chemical work, and the necessity 
 which is imposed upon him, wherever his work may be placed, 
 of making these conceptions clear to his pupils as necessity 
 arises. Without this the work in chemistry must be mechanical 
 and fruitless, and indeed, although dealing with the sub- 
 
40 CHEMISTRY IN THE CURRICULUM 
 
 ject-matter of the science, it cannot justly be called chemistry 
 at all. 
 
 IV. The Time to be allotted to Chemistry. 
 
 The subjects which have long been established in the cur- 
 riculum in most cases run continuously through the course, and 
 the unit of work is seldom less than a year. The sciences, 
 however, in the struggle for recognition, have had to content 
 themselves with a bare foothold, and in a majority of the 
 secondary schools of this country are each disposed of in 
 brief periods of twelve weeks. The question of the minimum 
 length of time which may be assigned to chemistry, consis- 
 tently with securing the best value for the efforts of teacher and 
 pupil, is, therefore, one of the greatest importance. 
 
 If the object in teaching chemistry were simply that of im- 
 parting a certain amount of information about the subject, the 
 A Full Year result would be considerable in proportion to the 
 for chemistry, length of the course, no matter how short it might 
 be. If, however, the task of contributing to the discipline of 
 the pupil's mind is to be assigned to it, the time factor requires 
 careful consideration. If we take into account the fact that, 
 when a subject is taken up for the first time, familiarity has to 
 be acquired with a new material of study, with a new language 
 and mode of expression, and, in the case of a science, with a 
 new mode of study by experiment in a laboratory, and a less 
 familiar form of exercise for the reasoning powers, it is evident 
 that much time will be consumed in overcoming the initial 
 difficulties. In the case of chemistry eight or ten weeks at 
 least must pass before the pupil has become accustomed to 
 the use of a laboratory and has reached the position of being 
 able to study the new subject in the new way. The effect of 
 experience, which is always cumulative, is most markedly so in 
 an elementary course in science, and even after twenty-four 
 weeks' work, the pupil is just reaching the point at which facility 
 in handling the subject will enable him to make really rapid 
 progress. The influential committees which have recently re- 
 
CHEMISTRY IN THE CURRICULUM 41 
 
 ported on this subject have been unanimous in demanding at 
 least a year for chemistry in the secondary school. 
 
 The far too common plan of teaching three sciences in a year 
 is supported by the argument that it gives more variety, but 
 when we consider that each of the sciences introduces a new 
 subject, a new variety of material, a new nomenclature, new 
 forms of manipulation, and to some extent new methods of 
 thought, it is evident that the repeated change from one sub- 
 ject to another must involve a great expenditure of time on 
 the mere machinery of each subject, and a prodigious loss of 
 power in throwing away at each transition much that had been 
 acquired, instead of using it as the foundation for still greater 
 and more rapid advances in the same direction. The names 
 of all the sciences may be included in the curriculum, but it is 
 certain that if their number reduces too greatly the time allotted 
 to each, the sciences themselves will never get within reach of 
 the pupil excepting in name. If the means of the school per- 
 mit the teaching of only one or two years of work in science, 
 then one or two sciences only should be taught. 
 
 The Committee of Ten recommends that at least two hun- 
 dred hours be devoted to chemistry, and that one-half of this time 
 should be spent in the laboratory. The Committee on College 
 Entrance Requirements of the National Education Association, 
 the most representative educational body in this country, rec- 
 ommends that at least four periods a week be given to chem- 
 istry, and that half of these be periods of double length spent in 
 the laboratory. They add that a longer time than this will 
 be required if chemistry appears before the third year of the 
 course. The Committee of Nine of the New York State Sci- 
 ence Teachers' Association, in its report published by the 
 University of the State of New York (High School Bulletin 
 No. 7, 714), recommends an even longer time. If the period 
 in the high school is forty-five minutes in length, the com- 
 mittee demands two double periods weekly in the laboratory, 
 one period devoted to an experimental demonstration, two 
 periods to prepared recitations, and suggests that three ad- 
 
42 CHEMISTRY IN THE CURRICULUM 
 
 ditional periods will be required for text-book and library 
 study. 
 
 The difficulty of securing consecutive periods for laboratory 
 work seems to be so great that particular emphasis should be 
 placed on the importance of this. When the periods are short, 
 experiments requiring construction of apparatus, and occupying 
 more than a very few minutes of time in their performance, can 
 only be accomplished under considerable difficulties. If it is 
 found impossible to secure double periods, the apparatus may 
 be prepared in advance by the teacher, and thus the exclu- 
 sion of some experiments of fundamental importance may be 
 avoided. 
 
 V. Continuous Courses in Chemistry. 
 REFERENCES. 
 
 Wilson, C. C. The Place of Science in the Preparatory Schools. 
 SCHOOL REVIEW, VI. (1898), 211-214. 
 
 Palmer, C. S. Specialization in Preparatory Natural Science, ibid., 
 659-671. 
 
 Although the extension of the courses in chemistry in secon- 
 dary schools to the length of one year has not yet been accom- 
 Arguments plished in the majority of the high schools of the 
 in Favour of country, a movement in favour of the establishment 
 lon> of three and four year courses in this subject has 
 acquired such prominence that reference to it cannot be 
 omitted. In recent articles the arguments in favour of this 
 extension have been marshalled with such earnestness, and it 
 must be admitted with some degree of plausibility. The dis- 
 ciplinary value of the old curriculum depended upon the con- 
 tinuous courses in Latin, Greek, and mathematics which it 
 contained. The disciplinary value of a similar course in chem- 
 istry, or one of the other sciences, properly taught, although 
 we have no experience of it in the secondary school period, 
 would undoubtedly be not less than that of the older subjects. 
 Differing in kind from these, as they differ from one another, 
 
CHEMISTRY IN THE CURRICULUM 43 
 
 it would be a valuable addition to the training of the pupil. 
 It would also give a wider selection of continuous studies, and 
 enable those who are unable to secure the greatest benefit 
 from the classical course to get a more congenial, and, at the 
 same time, a really worthy substitute for Greek. 
 
 The counter-argument that the study of science has a nar- 
 rowing influence may be branded at once as preposterous. Any 
 study, even Latin, may have a narrowing influence TwoYears 
 if taught by a narrow man in a narrow way. But the Maximum 
 this suggests one real difficulty, namely, that no non- 
 technical or liberal course for the second or third years of chem- 
 istry has yet been worked but. 1 The real obstacle, however, in 
 the case of chemistry, and we are not concerned with the ques- 
 tion as it affects other sciences, is that if we agree that it should 
 be preceded by physics, which in turn is preceded by algebra, 
 at least two years, and more often three years of the high school 
 course will have passed before the pupil is ready to begin the 
 subject. Even taking the possible redistribution of the work of 
 physics and chemistry into account, it does not seem likely that 
 more than two years of chemistry can in any case be secured. 
 In a few high schools this amount of instruction is given, and given 
 successfully. The question, however, of outlining the work of the 
 second year cannot become pressing as long as the preparation 
 of a majority of teachers is not sufficient for a single year. 
 
 In spite of the obvious and weighty difficulties in the way of 
 this so-called " specialization " in school science, it is surprising 
 how rapidly sentiment in favour of it seems to be de- some Favour 
 veloping. Mr. Wilson mentions ascertaining the aWe Opinions, 
 opinions of about two hundred teachers, of whom only one-third 
 were college professors, on the question whether they preferred 
 (a) to divide the time among four branches of science, or (b) to 
 give the pupil a choice of four sciences or two years' work each 
 in any two of the four sciences, or (c) to devote four years to 
 continuous study on one subject. Only forty-three per cent 
 
 1 This subject is discussed further in connection with that of the train- 
 ing of the teacher (chapter VIII). 
 
44 CHEMISTRY IN THE CURRICULUM 
 
 favoured the first plan, and many of these may have done so 
 simply because they disliked the other two still more, while forty- 
 two per cent favoured the second, and fifteen per cent favoured 
 the third. Of those preferring the last plan, eight or more were 
 teachers in secondary schools. 
 
 VI. Articulation of School and College Chemistry. 
 REFERENCES. 
 
 Palmer, C. S. Resume and Critique of the Tabulated College Require- 
 ments in Natural Sciences. SCHOOL REVIEW, IV. (June, 1896), 452-460. 
 
 Smith, Alexander. Articulation of School and College Work in the 
 Sciences. SCHOOL REVIEW, VII. (1899), 411, 453, 527. 
 
 While it is generally admitted that the work of the school 
 should be arranged exclusively with reference to the needs of 
 the pupils of the school itself, and without reference to any 
 special section of them which may harbour the intention of after- 
 wards proceeding to college, there is no question but that the 
 college has exercised a definite if subordinate influence on the 
 evolution of the school course. In some subjects, the college 
 has assisted in setting the pace and marking out the path which 
 has finally been adopted as best for the pupil, whether he goes to 
 college afterwards or not. Except in a few isolated instances, 
 the correlation between the work of the two institutions unfort- 
 unately has been confined to languages and mathematics. In 
 these subjects it is possible for the pupils who go "to college to 
 continue without interruption or loss of ground the studies 
 which they pursued in school. The achievement of a similar 
 articulation in the sciences has encountered so many difficulties 
 that it has as yet made practically no progress. 
 
 The first difficulty lies in the extraordinary diversity in length 
 and in content of the courses in the same science in different 
 School Chem- sc hl s ' In chemistry, the time varies from twelve 
 istry a Vari- to forty weeks, and the instruction may be entirely 
 able Quantity. . , , i , ,- 
 
 in general chemistry, almost entirely m qualitative 
 
 analysis, or it may dispense with the laboratory. The college, 
 
CHEMISTRY IN THE CURRICULUM 45 
 
 drawing its freshmen from a hundred different schools, cannot 
 furnish a course which will fit equally so many differing founda- 
 tions, and it does not attempt the task. President Eliot says, 
 " It would be a pity if we could not adapt our courses in college 
 to any good teaching in the schools." If Latin and mathematics, 
 however, had remained one-tenth part as full of divergencies as 
 school chemistry, the present system of co-operation would 
 never have been brought about. It is difficult to believe that 
 chemistry possesses any property which makes this divergence 
 unavoidable. 
 
 The second difficulty in the way of articulation is the con- 
 siderable diversity in the elementary courses of different colleges, 
 and therefore in the work, part or all of which, pupils Attitude of 
 in the same school in going to these different col- tte Colle s es - 
 leges must attempt to anticipate. A third difficulty is that 
 many colleges give no admission credit for chemistry, 1 and the 
 
 1 The preliminary report of the Committee on College Entrance 
 Requirements of the National Education Association, published in 
 the SCHOOL REVIEW, IV. (June, 1896), 341-412, gives some startling 
 information in regard to this subject. Of the fifty-six colleges and uni- 
 versities whose admission requirements were discussed, only thirty accept 
 chemistry at all. A further study of the relation between admission and 
 college chemistry in these thirty institutions, which I had occasion to 
 make and have fully discussed in the SCHOOL REVIEW, VII. (1889), 
 411, 53, 527, shows that only three have definite entrance requirements, 
 and provide a definite mode of handling those who offer them. A dozen 
 or so place the students who offer chemistry into the college course along 
 with beginners, and the remainder seem to attempt a rough sifting by 
 which the better prepared students go into advanced work, and the less 
 well prepared into the elementary course. 
 
 Professor Bardwell of the Massachusetts Institute of Technology 
 presented to the Sixth Meeting of the New England Association of chem- 
 istry teachers some facts which illustrate the method in the last class of 
 institutions. In the autumn of 1899, one hundred and fifty-eight students 
 offered chemistry for admission to the Institute, being 50.3 per cent of 
 the total number entering. After five weeks eighty-six of these students 
 remained in advanced courses, while seventy-two retired voluntarily into 
 the elementary course. It is evident that a majority of the eighty-six 
 were most likely only partially fitted for the work in which they found 
 themselves, while the seventy-two were all misfits in the elementary course, 
 since they had all studied more or less of it before. It is evident from 
 
46 CHEMISTRY IN THE CURRICULUM 
 
 rest, with few exceptions, give credit for anything that is 
 presented, and thus make the arrangement of a logical sequel 
 to high school work in the subject within their own walls 
 impossible. 
 
 The few universities which insist upon a definite amount and 
 kind of chemistry do not agree at all in regard to the kind, and 
 thus when the school seeks the advice of the college, as it often 
 does, the utterances of the latter in regard to chemistry lead to 
 nothing but discouragement and distraction. The Committee 
 of Ten reported definitely " that there should be no difference 
 in the treatment of physics, chemistry, and astronomy for those 
 going to college and scientific school and those going to neither." 
 The principle would have been something more than a mere 
 doctrinaire statement if it had read, "When the secondary 
 schools have decided upon the length, aim and content of their 
 course in chemistry, all colleges should accept this for admis- 
 sion." 1 
 
 The fourth difficulty in the way of articulation is that no 
 advancement is granted to pupils who offer chemistry as an ad- 
 mission subject. I have elsewhere discussed this subject more 
 fully, and may be permitted to quote a few lines. 2 
 
 " The college should grant advancement in the series of its 
 courses in each science to an extent corresponding to the ad- 
 mission credit given. In other words, it must recognise ade- 
 quately, and in a practical form, the extent to which the school 
 work may fairly claim to constitute an anticipation of its own. 
 
 " To effect this, each department in the college must adapt 
 its own courses so that one of them shall offer a suitable contin- 
 uation of the preparatory work. This will be open to those 
 
 this that the Institute has no definite requirement in admission chemistry, 
 and must, like other institutions of the same class, share with the schools 
 the blame for this chaotic state of affairs. 
 
 1 Arguments similar to the above, and leading to the same conclusions, 
 have been urged most strongly by the Committee of Nine of the New 
 York State Science Teachers' Association in its first report (University 
 of the State of New York, High School Bulletin No. 2, 478-480). 
 
 2 From the SCHOOL REVIEW, VII. 456. 
 
CHEMISTRY IN THE CURRICULUM 47 
 
 students who enter with a credit in the subject, and such stu- 
 dents should never be required to begin the science over again 
 in the same class with those who lack this credit and 
 preparation." 
 
 The course in continuation of school work will not usually be 
 the second regular college course, for the school work will not 
 be the equivalent of the first course in college. 
 
 Thip Pollpp'f 1 
 
 When the college, as it often does, attempts nothing must offer 
 
 beyond a secondary school course in elementary Two indepen- 
 J . } dent Courses. 
 
 chemistry, it deliberately throws away the advan- 
 tages which the more rigid selection of its students, the smaller 
 size of the classes, the greater maturity of the constituents of 
 these classes, and the greater amount of work which can conse- 
 quently be demanded of them, place in its hands. The college 
 introductory course should be heavier by at least a half, and a 
 distinct class should be formed for those who are not beginners 
 and desire a sequel to secondary school chemistry. This ar- 
 rangement should certainly be possible in the larger universities, 
 and especially in technical and medical institutions in which all 
 the students are required to study chemistry, and in which, 
 therefore, a sufficiently large number will have offered it for 
 admission to warrant the formation of a separate class. Where 
 no proper sequel is offered, and chemistry inside the college is 
 optional, the pupil takes an elementary course, in which much 
 that he has already studied is repeated, of his own free will. 
 Where the pupil is required to take college chemistry, however, 
 and admission credit has been granted, the institution is under 
 an obligation to furnish fit instruction to the candidates. 
 
 The movement in favour of unity in the matter of secondary 
 school chemistry will doubtless be materially assisted by the 
 recent inauguration of a college entrance examination board, by 
 the Association of Colleges and Schools of the Middle States and 
 Maryland, and the preparation by it of syllabuses l of admission 
 
 1 The requirements in all subjects may be obtained by transmitting 
 the price, ten cents, to the Secretary of the College Entrance Examina- 
 tion Board, Sub-station 84, New York, N. Y. 
 
48 CHEMISTRY IN THE CURRICULUM 
 
 work in all secondary school subjects. The syllabus in chem- 
 istry is based upon the report of the Committee of the National 
 Educational Association, and will probably be accepted not only 
 by the universities within the association, but also by the great 
 majority of the institutions of learning in the country. 
 
CHAPTER III 
 
 THE INTRODUCTION OF THE SUBJECT 
 BIBLIOGRAPHY. 
 
 Richards, T. W. Requirements in Chemistry for Entrance to Harvard 
 College. Cambridge, published by the University (1900). Pp. 4-10. 
 
 Freer, P. C. The Teaching of Beginning Chemistry. Proceedings of 
 the National Educational Association, 1896. Reprinted in SCIENCE 
 [N. 8.], IV. 130-135. 
 
 Smith, Alexander. The Value of Chemistry. Proceedings of the 
 National Educational Association, 1897. Pp. 945-951. 
 
 Report of the Committee of Nine of the New York State Science 
 Teachers' Association. High School Bulletin No. 7. Albany, N. Y., 
 The University of the State of New York, 1900. Pp. 708-721. 
 
 I. Impediments to be overcome or avoided. 
 
 WHILE the introduction of any new subject must of necessity 
 be difficult, there are special reasons which make the demand 
 for unusual tact and skill on the part of the teacher 
 of science imperative. The introduction of a new Lan uae 
 
 language, for example, does not present the same and Science 
 degree and kind of difficulty. The pupil has been 
 accustomed from his infancy to handling the problem of words, 
 their meaning, and their relations, and there is no novelty in 
 the material, or, to any great extent, in the method. The 
 operation of noting the usage of words, for example, and 
 determining their precise significance, " the formation of hy- 
 potheses . . . and repeated modification of hypotheses after 
 they have been brought to the touchstone of experience," 
 and, in general, the operation of organizing isolated facts into 
 knowledge, which Professor J. G. Macgregor has styled knowl- 
 edge-making, has, in the direction of language, become a habit. 
 Much of this work may have been unconscious, but it has none 
 
 4 
 
50 THE INTRODUCTION OF THE SUBJECT 
 
 the less resulted in education with especial application to a par- 
 ticular kind of problem. The objects of the material world have 
 not been studied with anything like the same care, for attention 
 to physical matters has not occupied almost every waking instant, 
 and there has not been the same inexorable necessity for mi- 
 nute and exhaustive organization of the phenomena which they 
 present. 
 
 Then, too, the study of language furnishes an endless suc- 
 cession of simple problems in which the same forms recur at 
 Science more short intervals an endless number of times. A 
 Difficult. science, on the other hand, presents " problems 
 with a greater range of difficulty on a material which is in 
 general more complex." 
 
 Furthermore, when a new language is presented, the assist- 
 ance which the pupil receives from the grammar and diction- 
 ary has no parallel in scientific work. The contents of these 
 aids to study are classified in such a way that the problem of 
 ascertaining the meaning of a word or phrase can be at once 
 reduced within certain narrow, clearly defined limits. The 
 laboratory directions, indeed, attempt to instruct the pupil how 
 he shall himself produce that which in science takes the place 
 of the text, the phenomenon to be studied. But unless these 
 directions play the part of an interlinear translation also, he has 
 to provide from his own previous experience the ability to sepa- 
 rate the significant from the insignificant factors among the 
 many details he may observe, and to furnish, upon the same 
 presumably rather meagre basis, the correct interpretation. 
 The teacher always has it in his power to simplify the problem 
 by affording guidance, but, if this is carried too far, the benefit 
 of learning from experience under conditions which far more 
 closely resemble those of actual life than is the case in language 
 study, is snatched from the pupil's grasp. Acquiring the ability 
 to make knowledge is education, and to shield the pupil from 
 the necessity of doing this with the material which science sup- 
 plies, is to deprive him of that element in his training which 
 science is in an especial degree fitted to furnish. 
 
THE INTRODUCTION OF THE SUBJECT 5 I 
 
 Not only, however, does the beginning work in a science 
 present an unfamiliar material for study, but it should seek to 
 cultivate an attitude which is for the most part j^^^ 
 entirely new. f The work in chemistry can be made Spirit in 
 
 4* Cpjprtpp 
 
 almost wholly inductive in method, and must be k 
 made altogether so in spiriy The pupil encounters an addi- 
 tional difficulty in the acquired mental habit which he has of 
 developing consequences by speculation. It is the hardest 
 thing in the world to compel him to stick closely to the facts 
 and to test such inferences as he may draw by renewed scrutiny 
 of the data, and perhaps the performance of new experiments, 
 before adopting them. The symmetry of an idea, and its logi- 
 cal harmony with conceptions already existing in his mind, blind 
 him to the fact that a dozen competing ideas might have arisen 
 in the same connection, and yet none of them be confirmed by 
 experience. In geometry he is accustomed to the developing 
 of a system from a few simple conceptions, and he has still to 
 lea\that in science a multitude of facts are required for the 
 foundation of one conception. Not only does the pupil suffer 
 from wft difficulty, but the teacher himself may follow the lines 
 of least resistance, and, allured by the rapid progress the pupils 
 make, conform his teaching to methods to which they are ac- 
 customed, and so throw away the opportunity of making a new 
 start which the study of a science furnishes. He may thus all 
 too easily pervert it into a continuation of the same kind of dis- 
 cipline, instead of making it the starting point of a new one. 
 The teacher must be continually on the watch lest defects in 
 his own training, which he has not later observed and remedied, 
 lead him to teach chemistry as a dogmatic system of principles 
 with which the concrete experience in the laboratory has little 
 more than a nodding acquaintance. 
 
 Still another feature of chemical work which in some ways 
 forms an impediment to the beginner, is the attitude of an 
 original observer in which he is to be placed. This attitude is 
 a strange one to him, for he has been accustomed to accept 
 facts from books or his teacher as the basis of his work, and 
 
52 THE INTRODUCTION OF THE SUBJECT 
 
 even to derive most of his opinions from sources other than 
 his own intelligence. It is difficult if not impossible to con- 
 Self-reliance ^ uct ^ ie e l ementar y instruction in a language in a 
 in the Lab- way which will have any other effect than to confirm 
 oratory. ^ e m}nd of ^ Q ^^ m th j g att j tu( j e . Before be- 
 ginning a science, therefore, he has acquired the habit of rely- 
 ing upon authority for most of what he learns. I It is the special 
 boast of work in a science, that, as it proceeds, the pupil is 
 bound to see that the facts may be derived from his own obser- 
 vation, and the conclusions may be drawn by his own unaided 
 efforts. It is held that scientific work thus furnishes an exer- 
 cise in indejDendent thought much more readily than the study 
 of language. \ 
 
 The number and subtlety of these pitfalls to which the intro- 
 ductory work in chemistry is especially liable, make it impor- 
 tant that we should devote a chapter to the discussion of the 
 most natural method of approaching the subject, and of the 
 principles which should first be the objective of the instruction. 
 
 II. What Phenomena shall furnish the Basis of the Introduc- 
 tory Work. 
 
 The course in chemistry frequently begins with a part which 
 is intended to be introductory, and is not a portion of the sys- 
 tematic presentation of the subject. There must of necessity 
 be some attempt during the earlier part of the course to mar- 
 shal before the pupil the various types of chemical change, the 
 most characteristic features of chemical action, and the constantly 
 necessary habits which he should form in doing chemical work. 
 In this chapter we shall not attempt to elaborate any novel 
 method of approach. We shall simply seek to decide which 
 are the most important generalizations, and how they may be 
 brought to the knowledge of the pupil. In concrete form our 
 conclusions will be found embodied in many of the available 
 text-books. The common statement of the nature of the 
 subject-matter of the science, which is usually to the effect 
 
THE INTRODUCTION OF THE SUBJECT 53 
 
 that chemistry deals with the changes in composition which 
 matter undergoes, and with the accompanying physical phe- 
 nomena, will furnish us with a starting point. 
 
 a. Classification of Various Principles of Arrangement : The 
 elementary study should clearly begin with familiar forms of 
 matter, and familiar phenomena should be selected. T^ Earliest 
 If any of the earlier facts are unfamiliar, they must Observations, 
 at least be closely related to those which are familiar. Then, 
 also, the selection must consider the facility with which the phe- 
 nomena can be subjected to experimental study by one who is 
 as yet untrained in the methods of the science. Thus while the 
 action of soap upon water, and the effects of the caustic soda 
 produced by it upon the skin, are exceedingly familiar, they are 
 not capable of simple experimental investigation. Finally, the 
 chemical changes studied must be of a simple nature in the 
 chemical point of view, since then alone will they form an easy 
 vehicle for the passage from the realm of simple fact to that of 
 chemical knowledge. 
 
 At this point a divergence takes place which enables us to 
 classify the ways of treating the subject roughly into three kinds, 
 and, it may be remarked, imposes upon us ulti- 
 
 Xfl6 Tnrcc 
 
 mately the necessity of deciding which is more Principles of 
 applicable to the case of any given set of pupils. Arrangement. 
 It will be noted that we are speaking at present mainly of the 
 ways of selecting the content, and not of modes of presenta- 
 tion, inductive, deductive, or otherwise. One method proceeds 
 by selecting from common materials those whose general physi- 
 cal properties must be familiar even to the youngest, namely, 
 solids, and frequently devotes a very considerable amount of 
 attention to quite a series of studies from which work with gases 
 is, as far as possible, excluded. Another variety of treatment 
 deals indeed with familiar substances to begin with, but does 
 not restrict itself to the most familiar materials physically. In 
 fact, it deliberately leads up as rapidly as possible to the prop- 
 erties of air and the chemical effects of oxygen, pursuing its 
 way after that largely through the study of other gases. 
 
54 THE INTRODUCTION OF THE SUBJECT 
 
 When the former of these methods is employed, the main 
 object is to put the pupil in the attitude of a discoverer. The 
 Nature study problems are selected therefore, not because of 
 Method. their chemical importance or their relation to the 
 
 development of an organized knowledge of the science, but 
 solely because they are simple, since thus alone is there any 
 hope of realizing the object in view with any degree of com- 
 pleteness. The facts as they are accumulated lend themselves 
 easily in this less systematic study of the subject to the con- 
 struction of the ordinary generalizations of the science. But 
 the ultimate results come more slowly than they would with the 
 more systematic treatment. 
 
 Largely different must be the arrangement of the work, if the 
 most logical presentation of the framework of the science is 
 Theoretical to ^ e rna( ^ e one f tne objects. While the same 
 Method. methods are pursued in matters of detail, this plan 
 
 seeks, as directly as possible, to reach the means of explaining 
 the basis of our modern mode of expressing the quantitative 
 relations involved in chemical change. In other words, this 
 plan handles the gases as soon as possible -in order that it may 
 quickly lead up to the explanation of Avogadro's hypothesis 
 and the consequences which follow from it. Until this hy- 
 pothesis has been discussed, everything else relating to the 
 appropriate statement of quantitative relations must remain 
 largely in suspense, unless we are willing to teach these matters 
 in an empirical manner without examining their basis or know- 
 ing the centre from which they are controlled. When the 
 attempt is made boldly thus to grapple with the foundations 
 of chemistry, the pupil must perforce be brought rapidly through 
 the most indispensable stages leading to the study of chemical 
 change in the light of Avogadro's hypothesis. His early work 
 must thus deal largely with gaseous materials, and the peda- 
 gogical advantage of greater familiarity which solid bodies afford 
 must be sacrificed. 
 
 Still a third method, which, however, is closely related to the 
 last, may be defined. In this arrangement of the material the 
 
THE INTRODUCTION OF THE SUBJECT 55 
 
 desire is, as rapidly as possible, to bend the order of study into 
 a series of chapters dealing with successive elements, arranged 
 in an order something like that which, in spite of The -g^^fa^ 
 slight variations, is in its general features com- Systematic 
 mon to most books. The second method was 
 an arrangement with reference to theory ; the third is an 
 arrangement with reference to chemical materials, with the 
 theory distributed at convenient intervals. The order here 
 seems to be determined in the first place by a desire to con- 
 form to the historical development of the subject. Oxygen, 
 air, and water thus find an early place. This motif presently 
 gives place to the impulse to arrange the elements in accord- 
 ance with the natural families. 
 
 Each of these methods of arrangement, the nature study, the 
 theoretical, and the historico-systematic, has its merits. The 
 decision as to which is more suitable will depend largely upon 
 the advancement of the pupil whose instruction is under con- 
 sideration. The first method is practically that which is adopted 
 in nature study, excepting that it may be expanded beyond the 
 limits of the familiar materials to which the latter is confined. 
 It is applicable to the youngest scholars, and in general would 
 probably be the best arrangement for pupils in the first year of 
 the secondary school. The two latter methods, suitably modi- 
 fied by importations from the former, might enter largely into a 
 course given in the later years of the secondary school, espe- 
 cially if the pupils had already studied physics. Their greater 
 maturity, as the result of continuous work in languages, mathe- 
 matics, and physics, would more than offset the more rapid 
 progress they would be called upon to make through unfamiliar 
 ground. The more highly developed intelligence required for 
 the successful accomplishment of the more difficult task should 
 be by this time available. 
 
 b. Various Arrangements Illustrated by Reference to Existing 
 Text-books : It is so important that the teacher should have a 
 clear idea of what is implied in the arrangement of the text -book 
 which he may adopt, and of the precise demands which this 
 
56 THE INTRODUCTION OF THE SUBJECT 
 
 will make upon his pupils, that it may be well to indicate books 
 which will furnish examples of each of these methods of han- 
 dling the subject. 
 
 The best example which I know of a work of the first kind 
 is An Introduction to the Study of Chemistry by Professor Perkin 
 The Nature ^ O wens College and Dr. Lean l of The Friends' 
 study Method. School, Ackworth. The study of chemical change 
 begins (p. 126) with an experimental examination of common 
 salt, chalk, sand, washing soda, iron pyrites, and other common 
 materials. This is followed by a study of the common acids, 
 and common alkalies, and this again by the relation between 
 acids, bases, and salts. The next topic is the ' fixed air ' of 
 Black, followed by rusting and combustion. The remaining 
 subjects, which are not numerous, need not be given. There is 
 no attempt to develop the science in a conventional manner. 
 The way in which ordinary knowledge of familiar materials is 
 gradually transformed into scientific knowledge of the same 
 things is worthy of careful examination. 
 
 Aside from this, which is our main reason for mentioning 
 the book, it presents other features which make it exceedingly 
 instructive. The first part (up to p. 125) deals entirely with 
 physical properties. This is doubtless done in recognition 
 of the fact that the pupils using it will be entirely ignorant of 
 physics. The selection of material, however, is naturally not that 
 which the physicist would make in presenting his subject sym- 
 metrically, but shows rather the parts of physics particularly 
 important in chemical observation. We shall revert to this sub- 
 ject presently. The reader accustomed to the decoration of 
 the pages of every chemical work with numerous equations, and 
 supposing that these are indispensable parts of the science, will 
 be surprised to find that in a course of this kind they may be 
 dispensed with entirely without appreciable loss in clearness. 
 Then, too, since the work does not pretend to be a treatise on 
 chemistry, it gains the unquestioned right to omit what it 
 
 1 Perkin and Lean. An Introduction to the Study of Chemistry. Lon- 
 don and New York, Macmillan. 1896. 
 
THE INTRODUCTION OF THE SUBJECT $? 
 
 pleases, and thus shows that much chemistry of a perfectly 
 sound description may be taught without a single mention of 
 atoms, molecules, or valency. While the presence of these is 
 doubtless demanded in a book treating the subject by the 
 second or third method, a study of the aspect which chemistry 
 presents in their absence will prove exceedingly instructive to 
 any who may think that chemistry begins with these concep- 
 tions, and it is to be feared sometimes act as if it ended there 
 also. 
 
 Much of the recent discussion of the teaching of chemistry 
 in Great Britain has been concerned with urging the moulding 
 of instruction in the subject on the lines of that Method used in 
 method of the three which we are now discussing. Great Britain. 
 A syllabus of elementary chemistry published by the Board of 
 Education, 1 described as the 'alternative elementary stage,' 
 furnishes another instructive example of what we have called 
 the nature study method. 
 
 A Committee of the British Association 2 suggested a plan 
 of study closely resembling those we have just mentioned. The 
 new Syllabuses 8 issued by the Incorporated Association of 
 Head Masters also present a well-devised and thoroughly tested 
 course of a similar kind. 
 
 As we have suggested, the plans of the first kind are not 
 accepted as the basis of such work as is usually attempted in the 
 later years of the secondary school in America. 
 They do not present that connected and complete American 
 account of the subject which in these years is gen- | e condary 
 erally demanded. Pupils trained with their assist- 
 ance would have a sound knowledge of chemistry, so far as that 
 subject had been covered, but they would not be able to pass 
 
 1 Directory, with Regulations for Science and Art Classes. London, 
 issued annually by the Board of Education and sold by Eyre & Spot- 
 tiswoode. The Syllabus of Chemistry may be had separately. 
 
 2 For references and further discussion of the nature study plan, see 
 Heuristic Method, Chapter IV., Section IV. (p. 105). 
 
 3 The Elementary ( 1900) and Advanced ( 1899) Syllabuses are published 
 by Whittaker & Co. (London). 
 
58 THE INTRODUCTION OF THE SUBJECT 
 
 examinations for admission to most colleges, since they would 
 probably know nothing of equations or the atomic theory. 
 Their work, in spite of its excellence, would lack some of the 
 conventional signs which usually mark a knowledge of chemistry, 
 and sometimes take the place of it. The study of them, how- 
 ever, will afford to the teacher a valuable demonstration of the 
 application of pedagogical principles to the study of chemistry. 
 The teacher fresh from the college or university, especially if 
 he has been highly trained in chemistry, is apt to have forgotten 
 the almost innumerable steps by which he reached his knowl- 
 edge of the science, and to give his pupils work which assumes 
 this knowledge rather than instruction which will confer it. 
 Under such circumstances their acquisition of the subject 
 becomes purely mechanical, and, in the highest sense of the 
 term, wholly uneducative. 
 
 The second of the three guiding principles in the arrangement 
 of the introductory work, the theoretical, is illustrated more or 
 Theoretical ^ ess clearly in a number of books. The idea is 
 Method. typically presented in Dr. Torrey's Elementary 
 
 Studies in Chemistry}- When he reaches the first chemical ex- 
 periments (p. 62), after introductory work dealing exclusively 
 with physical properties, he proceeds rapidly, through the study 
 of combining proportions by volume, with water and hydrogen 
 chloride as the concrete materials, to the statement of Avogadro's 
 hypothesis (p. 101) and the consequences which follow from it. 
 The intervening matter, while it does not take the shortest 
 course possible towards this goal, nevertheless is lightened of 
 much of the material usually treated in connection with the 
 chemistry of oxygen, hydrogen, and water, in order that the 
 development of the theory may not be impeded. After Avo- 
 gadro's hypothesis has been disposed of, a larger proportion of 
 general chemical work begins to appear, while at the same time 
 formulae and atomic weights are discussed. Almost all of the 
 study of the properties of the elements and their compounds 
 
 1 Joseph Torrey. Elementary Studies in Chemistry. New York. 
 Henry Holt & Co. 1899. 
 
THE INTRODUCTION OF THE SUBJECT 59 
 
 thus follows the theoretical matter. The recent work of Pro- 
 fessor Young 1 is arranged similarly on the same general princi- 
 ple so far as the theoretical part is concerned. The facts 
 employed up to the end of the development of the theory 
 (p. 89) are selected at random from various parts of the subject, 
 and in consequence solely of the readiness with which they fur- 
 nish experimental support for the theory. The systematic treat- 
 ment of the elements then follows. Professor Freer's elementary 
 work 2 resembles these books in placing the logical development 
 of the theory in the foreground, with the employment of a mini- 
 mum of selected facts, and differs from them only in that the 
 treatment of the rest of the science is much briefer, and the 
 whole ground covered much less extensive. 
 
 The third principle which has been mentioned as affecting the 
 arrangement of the work, the historico-systematic, is commonly 
 associated with the second, and the presentation of . 
 
 the elements one by one is usually found in com- Systematic 
 bination with, and as a modifying factor in, the e 
 application of the second principle. The well-known books by 
 Professor Remsen 8 and Dr. Newell, 4 however, illustrate very 
 well the continuous development of the principles along with an 
 arrangement of the material in the normal order. The two run 
 side by side, and the more theoretical portions are taken up 
 at convenient intervals without any effort to introduce each at 
 the earliest moment at which this is theoretically possible. 
 Professor Newth, in his Elementary Inorganic Chemistry;' pur- 
 sues essentially the same plan. The connection between experi- 
 ment and inference is worked out systematically with admirable 
 
 1 A. V. E. Young. The Elementary Principles of Chemistry. New 
 York, D. Appleton & Co. 1901. 
 
 2 P. C. Freer. The Elements of Chemistry. Boston, Allyn & Bacon. 
 1895. 
 
 3 Ira Remsen. Introduction to Chemistry (Briefer Course,}. New York, 
 Henry Holt & Co. London, Macmillan. 1893. 
 
 4 Lyman C. Newell. Experimental Chemistry. Boston, D. C. Heath 
 & Co. 1900. 
 
 5 G. S. Newth. Elementary Inorganic Chemistry. London and New 
 York, Longmans, Green & Co. 1899. 
 
60 THE INTRODUCTION OF THE SUBJECT 
 
 clearness. The theory is introduced at suitable intervals with- 
 out haste and at the same time without undue delay. The 
 report of the Committee of Nine of the New York State Science 
 Teachers' Association 1 contains a detailed outline of intro- 
 ductory work, in which the same combination of these prin- 
 ciples of arrangement is observed. 
 
 The combination of the second principle with the first may 
 be seen in the late Professor Cooke's Laboratory Practice? 
 Ordinarily the theory is consistently developed after certain 
 physical properties and manipulations have been studied, but 
 here the rate of its development is modified by the effort to 
 combine with this much experimental work on a variety of ma- 
 terials. The difference from the treatment last described lies 
 in the fact that this chemical experience is afforded, not by the 
 more or less systematic study of the elements, but by handling 
 a number of miscellaneously selected topics. 8 
 
 c. The Present Ideal of the Secondary School Course in Chem- 
 istry : Of the various plans outlined above, each is admirable 
 Prevailing m ^ ts wav - Each has advantages for certain pur- 
 Ideal, poses. It remains for the teacher to decide which 
 is most likely to suit the case of his particular set of pupils. Nor 
 need the choice of a book wholly determine the kind of instruc- 
 tion to be given, although it must influence it largely. At present 
 the prevailing tendency in American secondary schools seems 
 to be towards the use of the historico-systematic, if not the 
 theoretical style of book. At least the recent works seem to 
 
 1 High School Bulletin No. 7. Albany, N. Y., The University of the 
 State of New York. By post 35 cents. This bulletin contains so much 
 suggestive matter of the highest interest to the teacher of chemistry, 
 aside from this report, that the reader should not fail to obtain it. 
 
 2 J. P. Cooke. Laboratory Practice. New York, D. Appleton & Co. 
 1891. 
 
 3 Amongst the other elementary text-books whose methods are worthy 
 of study are : J. E. Reynolds. Experimental Chemistry for Junior Stu- 
 dents ; Part I., Introductory; Part II., Non-metals ; Part III., Metals. 
 Longmans, Green & Co. 1897. J. Walker. Elementary Inorganic 
 Chemistry. Bell & Sons. 1902. Henry Roscoe. Lessons in Elementary 
 Chemistry. Macmillan. 1890. Storer and Lindsay. Manual of Chem- 
 istry. American Book Company. 1894. 
 
THE INTRODUCTION OF THE SUBJECT 6 1 
 
 emphasize these conceptions in their selection of material and 
 method of arrangement. Observation of the work of many 
 schools confirms this belief. It is evidently a prominent aim of 
 
 the teacher at the present day to give his Duoils 
 
 , 3 r 1 Treatment, 
 
 a well-rounded account of chemistry as a science ; Academic and 
 
 to give him a bird's-eye view of the science as an r rmah 
 organized system of knowledge ; in fact, to show him an outline 
 plan of the results of the science as they appear to the chemist 
 himself. With this purpose in view, Avogadro's hypothesis 
 and its consequences, formulae, and equations (often even 
 graphic formulae), and many somewhat artificial experiments 
 with strange substances have to play a conspicuous part in the 
 instruction. 
 
 There can be no question of the value of a well-ordered out- 
 line knowledge of the whole science for the understanding of 
 
 its parts. But an outline or map of an extensive _ 
 
 r Course often 
 
 territory is not an end in itself. The sketch is covers too 
 chiefly useful to those who know the country first m 
 hand and can fill in from their own experience the detail of 
 many parts and so form a true appreciation of the whole. It is 
 the knowledge of this detail which constitutes a genuine ac- 
 quaintance with the subject of the outline. It is thus unfortu- 
 nate if the effort to give a systematic plan of the subject is 
 allowed to occupy the foreground, while the method and detail 
 of the science are suppressed by lack of time. It is important 
 therefore pointedly to call attention to a possible danger in this 
 direction. The extensiveness of the field covered by the book 
 tempts one to make a superficial rush through the whole subject 
 instead of taking time for a detailed study of the fundamental 
 things of the science. Thus the hypothesis just mentioned is 
 indeed fundamental, in a sense. But behind it and on every 
 side of it there is something without which it is merely an empty 
 phrase, and that is the ability to understand and reason about 
 chemical problems as they present themselves in the laboratory. 
 The behaviour of concrete substances and mixtures of substances 
 in real test-tubes and flasks and the phenomena around us in 
 
62 THE INTRODUCTION OF THE SUBJECT 
 
 nature must be understood before more abstract matters ac- 
 quire any significance. 
 
 The point is that there are few, very few, secondary schools 
 in which the time allotted to chemistry permits treating both of 
 these aspects adequately. I hesitate to quote experience in 
 higher institutions in discussing school work. What a univer- 
 sity student can do, in many cases the school pupil cannot do. 
 Yet, what a university student cannot do, with the advantages 
 of maturity and preparation which he possesses, must surely 
 be, a fortiori, beyond the pupil in the high school. I find 
 that more than a hundred hours (of 60 minutes) in class- 
 room and laboratory are required for the introduction to the 
 subject. In the course of this, a beginning, and only a be- 
 ginning, is made in learning to observe ; the theory up to 
 and including Avogadro's hypothesis is taught ; and a few ele- 
 ments and compounds are studied in a very elementary way. 
 All that can be covered in this time, besides introductory matter, 
 is the chemistry of oxygen, hydrogen, water, chlorine, hydrogen 
 chloride, air, and nitrogen (the element only). It would be 
 desirable to give even more time to this seemingly meagre pro- 
 gramme. Indeed more would be given if the imperative necessity 
 of covering the whole subject in outline within a total of 325 
 hours did not compel the adoption of a more rapid gait at the 
 expense of thoroughness. Now 100 hours is half or more than 
 half the whole time allotted to the subject in most secondary 
 schools. In giving the same extent of work with the pupils of 
 a secondary school I should be compelled to occupy an even 
 longer time, and all hope of covering the subject would have to 
 be given up. 
 
 More rapid progress through the science can be had only by 
 substituting the memorizing of results for genuine study of chemi- 
 The intensive ca ^ problems. Learning chemistry as it is and mak- 
 Method. m g a ra pid survey are two things which, under the 
 
 conditions imposed by the programmes of secondary schools, 
 are incompatible. What is meant by genuine study of chemi- 
 cal problems? Let us take an example. Suppose we learn 
 
THE INTRODUCTION OF THE SUBJECT 63 
 
 that hydrogen burns in air and forms water, and illustrate the 
 fact by burning a jet of hydrogen in the laboratory and holding 
 
 a cold beaker over the flame. This exercise has 
 
 ,, , , , r , Illustrations, 
 
 the appearance of having taught the tact, and we 
 
 go off in the belief that the pupil thoroughly understands all 
 about it. If, however, we overhaul his conceptions, we soon 
 find that we have conventionalized the experiment and the 
 result has been learned as a purely mechanical acquisition. 
 
 To test this statement, take the class after this exercise, 
 extinguish the jet of burning hydrogen, hold a cold beaker 
 against the jet of unlighted gas, and ask what the class thinks 
 of the moisture which the gas is seen to deposit even in this 
 condition. In a large class a few will suggest that the water 
 comes from the union of the hydrogen with the oxygen of the 
 air, showing that they have failed to appreciate the signifi- 
 cance of the lighting of the jet. Others will think it comes 
 from condensation of moisture in the atmosphere, although 
 they can give no explanation of how this happens. I have not 
 yet encountered a class of beginners in the university in which 
 a single member is to be found who can suggest the correct ex- 
 planation, so little are students, even well-prepared and intelli- 
 gent ones, able to apply the knowledge of physics they possess. 
 Further questioning shows that, although the whole preparation 
 of the experiment had previously been done by the pupils them- 
 selves, and attention had been drawn to the heat developed by 
 the action, not one realized spontaneously that his flask con- 
 tained a liquid which was warm and consisted, to the extent of 
 80 per cent, of water through which the hydrogen was passing. 
 The bare skeleton of the action, as it appears in the equation 
 Zn -f H 2 SO 4 -*ZnSO 4 + H 2 , seemed to be all that their minds 
 had consciously grasped of the whole paraphernalia of the action. 
 
 It is only after a thorough discussion in which attention has 
 been called to the details, that the pupil realizes that the first 
 condensation of moisture was quite inconclusive as a proof that 
 water was formed by the union of hydrogen and oxygen, sees 
 the need of drying the gas, and finally learns that chemical 
 
64% THE INTRODUCTION OF THE SUBJECT 
 
 "~'"\ 
 
 work includes far more and far more important things than put- 
 ting together the materials stated in the equation. Now this 
 sort of experience can be duplicated in almost every action 
 studied, and it must be constantly repeated in a thousand forms 
 before any intelligence about chemical work can be developed. 
 But this sort of work takes time which might otherwise be 
 devoted to passing on to the acquisition of a quasi-knowledge 
 of new actions. 
 
 It is doubtless assumed by the writers of the systematic variety 
 of treatises, that the thorough development of all sides of each 
 experiment will be brought out by the teacher. They furnish 
 the skeleton, and the teacher does the heavier share of the work. 
 The most of the real chemistry is between the lines. So, as 
 has been said, the character of the book need not determine 
 the character of the instruction. A skeleton book need not 
 lead to an attenuated, fleshless, academic treatment of the sub- 
 ject .in the class. But the inexperienced teacher, and it is for 
 him chiefly that this is written, will find that it takes much 
 thought and experience to extract the meat from the work, 
 that the skeleton in the book may be fitly clothed withal, and 
 that there is a constant temptation to treat the skeleton itself as 
 if it were the chief dish of the feast. 
 
 There must be some reason for the tendency to make school 
 text-books of chemistry more and more academic. It must be 
 Why is the that some essential element in secondary education 
 ^schools' would be lacking if the formal survey of the science 
 so Formal? were not conspicuous, or its prominence as a char- 
 acteristic of school chemistries would not be so great. Perhaps 
 the key may be found in the use to which the chemistry, or the 
 training it furnishes, is to be put in after life. This test ought 
 to furnish the explanation of all peculiarities of secondary school 
 work. Some of the pupils go to college, some become teachers 
 in grammar and grade schools, the great majority go into the 
 affairs of business or professional life. What purpose can for- 
 mal chemistry serve for each of these classes ? 
 
 To the last a knowledge of formal chemistry, which is not 
 
THE INTRODUCTION OF THE SUBJECT 65 
 
 also much more than this, cannot be of great use. On the 
 other hand, a quick perception of conditions, ability to reason 
 surely about the causes of physical phenomena, chemistry in 
 capacity to study materials and to devise means of Preparation 
 accomplishing definite ends with them and, in the 
 broader view, a confirmed habit of getting to the bottom of 
 everything that is observed, will be invaluable. It will be of 
 for more use than an array of picked information which all 
 soars a little above the plane of experience as we find it, and 
 has not been brought down to the every-day level. 
 
 Again, the teacher in the lower schools gives instruction in 
 elementary science. But here a formal knowledge of chemistry 
 only hampers her, unless she has happened to have Chemistryin 
 the opportunity to go further into the subject. The Preparation 
 chemistry of the grades, so far as their nature-study f 
 work can be said to include chemistry, must not be consciously 
 chemistry at all. A knowledge of three distinct ways of making 
 chlorine and the ability to name the fundamental laws of chem- 
 istry will not be of much assistance. The study is approached 
 from an entirely different side. TFor example, what are leaves 
 made of and where do they go when they disappear every 
 autumn ? l The high-school text-books do not tell us how to 
 lead the child to some comprehension of this latter wonderful 
 natural fact. We may take two equal heaps of leaves and 
 weigh one and keep the other for reference. Then we dry the 
 weighed leaves. For small children we condense the moisture 
 that comes off and show it. Thus we have a certain weight of 
 dried vegetable matter and a certain weight of water, both of 
 which can be handled and compared with the undried speci- 
 men. Then we burn the dry leaves and get a certain weight 
 of ash, and a loss in weight represented by the burnt mate- 
 rial. Then we treat the ash with water, and part dissolves, 
 and is recovered by evaporation. Part remains insoluble. 
 Thus we lay bare the nature of leaf material.! The child sees 
 
 1 From Jackman's Nature Study for Grammar Grades (Macmillan), 
 chapter VIII. 
 
 5- 
 
66 THE INTRODUCTION OF THE SUBJECT 
 
 also that the ash part came from the soil, the water from rain 
 or other moisture of the soil. The subject can be pursued 
 further if it seems desirable. My point is that while intelligent 
 teaching of this sort of thing will be assisted by a systematic 
 knowledge of chemistry, it will be quite impossible if the knowl- 
 edge of chemistry was of the formal, equation-loving sort and 
 nothing more. Evidently the too academic variety of chemistry 
 is not intended to help the teacher in the grades. 
 
 Finally, can it be that the teaching of chemistry in secondary 
 schools has been modelled to suit the supposed need of the 
 Chemist in P U P^ w ^ ^ s S om S to college, and that the needs 
 Preparation of the vast majority who do not go to college are 
 w College. .^ Danger of being sacrificed ? It would be a pity 
 if that were the case. There is no reason why the college 
 should demand a knowledge of formal chemistry for admission. 
 Any good chemical instruction which really teaches chemistry 
 of some kind should be gladly accepted. Of course a knowl- 
 edge of how to reason and how to work intelligently is difficult 
 to test by examination, while the presence of a knowledge of 
 formal chemistry can be readily ascertained. 1 But if the intel- 
 ligent knowledge of chemistry is more valuable for other pur- 
 poses, and at least as valuable to the college entrant, it is the 
 business of the college to find some way of testing it. It is 
 much to be feared that the college ideals of what constitutes a 
 
 1 The various existing reports describing courses in chemistry for 
 secondary schools are perhaps in part responsible for perpetuating the 
 impression that, whatever else is desirable, a formal survey of the science 
 is indispensable. It is relatively so easy to give a brief yet comprehen- 
 sive list of topics, and so difficult to describe effectively the spirit and 
 manner in which the instruction is to be carried out, that the former 
 never fails to put in an appearance, while the latter is slighted. The list 
 may be suggestive and valuable, but if it is unaccompanied by a full dis- 
 cussion of how the teaching is to be done, occupying a space which, to 
 represent the relative importance of the two parts, would have to be ten, 
 or even a hundred times more extensive, the impression conveyed by 
 the report as a whole must be misleading. The fact that preparing and 
 securing the passage of such an extensive report are well-nigh imprac- 
 ticable is the only excuse that can be found for the way in which the 
 crucial part of the task has hitherto been avoided. 
 
THE INTRODUCTION OF THE SUBJECT 67 
 
 genuine knowledge of chemistry, which are themselves much in 
 need of reformation, have been permitted to influence the kind 
 of chemistry taught in the schools to far too great an extent. 
 
 In what has been said above there is danger that I may be 
 misunderstood. No one can doubt the pre-eminent value, the 
 absolute indispensability to the chemist, of a systematic view of 
 the science. But an attempt really to give this view in any 
 genuine way, when the basis is lacking, must be futile. Along 
 with this view, the chemist has also at his command all the 
 details which have gone to the making chemistry in the past 
 and which make chemistry for him a living reality. I am there- 
 fore raising the question whether putting the broad sketch of 
 the whole in the foreground, and leaving the details to the 
 teacher and to chance, is not a reversal of the proper order. 
 Some of both must be given. But the technique of experi- 
 ment, observation, and induction, and the habit of using it 
 come first. 
 
 It was with thoughts of this sort in mind that emphasis was 
 laid on books of the nature-study variety. Much of their spirit 
 may be infused l into teaching which professes to follow one of 
 the other plans. Adaptation to the point of view of the begin- 
 ner will demand such an infusion, if the instruction is not to 
 be altogether artificial. We cannot approach a class with the 
 idea that here is a certain outline of work to be done, which 
 has been selected because its importance is evident to the 
 mature mind of the chemist, and regard the pupil as being 
 there to receive the dose. 2 The case is rather that the pupils 
 are there to be educated and assisted in development, and the 
 work must be adapted to their preparation and needs. 
 
 At the same time this book has not been written to advocate 
 a new kind of chemistry, but to assist the teacher who is giving 
 the kind of chemistry which is at present demanded. So we 
 shall assume for the most part in what follows that one of the 
 
 1 See the paragraph on the attitude to be cultivated in the pupil 
 under Instruction in the Laboratory, chapter IV., section IV. (p. 105). 
 
 2 See May M. Butler, SCHOOL REVIEW, X., (1902), 52. 
 
68 THE INTRODUCTION OF THE SUBJECT 
 
 more or less systematic texts is being used, and simply try as 
 occasion offers to show how the instruction based upon it may 
 be adapted to give the most benefit. 
 
 To sum up our conclusions, the study of chemical change, 
 the generalization of the features which it presents, and the ac- 
 Concluskms quisition of the habit of applying the knowledge 
 introfiSory thus acc l m ' red are the business of the student of 
 Work. chemistry. In assisting him to a mastery of the 
 
 science, the first thing is to lay a solid foundation in the 
 knowledge of the detail of observation. The second thing is 
 to lead him up to generalization, for without this the work will 
 not be scientific. The third thing is to exercise him in applica- 
 tion, otherwise the work will not be useful. Ordinarily the work 
 is controlled in the fourth place by an effort to approach the sys- 
 tematic arrangements of the elements, or at all events, sooner or 
 later, to reach this. Finally, it is undoubtedly useful to combine 
 these objects with the presentation of much of the early matter 
 in the historical order. 
 
 Most of these objects are readily attained by selecting for 
 early treatment actions in which air plays a part. Historically, 
 the discovery of oxygen by Priestley and Scheele, and the proof of 
 its presence in, and responsibility for the chief properties of the 
 air by Lavoisier, coming as it did at a time when chemistry was 
 just crystallizing into a science, point to experiments on the 
 action of air as particularly significant in an historical point of 
 view. The study of oxygen, a gas, enables us rapidly, if we 
 choose, to approach the theoretical portion of the science, and, 
 at the same time, the familiar nature of its chemical effects 
 makes them suitable for introductory work. 
 
 We assume then that some simple and more or less familiar 
 facts, some of them probably connected with the action of the 
 air, will be presented in the beginning to the pupil. Some of 
 these may be examined by him personally in the laboratory ; 
 others may be shown him by the teacher. It is impossible for 
 us here to describe in detail the method which the teacher will 
 pursue in bringing out the significance of what is seen by call- 
 
THE INTRODUCTION OF THE SUBJECT 69 
 
 ing attention to the detail of observation and leading the pupil 
 to the interpretation of each detail. Illustrations of the method 
 to be used will be found admirably given in Perkin's work 
 already mentioned. Professor Richards gives some instructive 
 examples in the Harvard pamphlet of requirements in chem- 
 istry. 1 Many laboratory manuals also develop the method of 
 instruction with considerable fulness. 
 
 III. Earlier Generalizations of a Qualitative Nature. 
 
 The first thing which the examination of several chemical 
 changes reveals is that a total alteration in all the physical 
 
 properties of the substance takes place. This is a 
 
 * . . . , , . . ,. First Charac- 
 
 feature requiring minute and careful instruction, teristlcof 
 
 In order that the pupil may adequately appreciate 
 this characteristic, the nature of the various physi- 
 cal properties which are interesting to the chemist must be 
 discussed more or less fully, and in each particular case the 
 properties of the body or bodies before chemical change, and 
 the new properties after chemical change, must be carefully and 
 exactly enumerated. The pupil will not do this for himself, 
 and without it his ideas must remain somewhat hazy. This is 
 advised not because the doctrinaire treatment of this conven- 
 tional sign of chemical change is particularly helpful, but be- 
 cause a keen appreciation of physical details is at the basis of 
 all chemical work. The pupil must eventually learn to recog- 
 nise materials by their physical properties, since by this alone 
 can he study chemical change qualitatively. 
 
 In many cases the study of physical properties is treated as a 
 separate topic before any chemical change is introduced, and 
 there is certainly justification for this course, even 
 if the pupils have already studied the science of of Knowledge 
 physics itself. There are many physical matters ofph y sics ' 
 important to the chemist which are not treated in elementary 
 
 1 Requirements in Chemistry for Entrance to Harvard College. Cam- 
 bridge, published by the University, 1900. 
 
70 THE INTRODUCTION OF THE SUBJECT 
 
 physics. 1 Every teacher of chemistry knows the mistakes which 
 the beginner makes when told to evaporate any substance in 
 order to attain crystals for examination. The pupil is utterly 
 innocent of any knowledge of the conditions under which crys- 
 tals are formed, and usually does not even recognise that the 
 amorphous mass he obtains by violent boiling over a naked 
 flame is not the required crystalline product. And this is only 
 one example out of many which might be adduced to show that 
 a knowledge of physical properties which remain unconsidered 
 in school physics is an indispensable part of the equipment of 
 the pupil in chemistry. The necessity of attention to this mat- 
 ter has already been emphasized (pp. 30-33 and 39), and its ex- 
 treme importance alone justifies our recurrence to the subject. 
 
 This study of physical change leads to the familiar general- 
 ization 2 that every physical property is altered, and that the 
 alteration is usually permanent. Most frequently the matter 
 is made clearer by contrast with physical change. It is advis- 
 able also to cite familiar instances of each kind of change. 
 
 The study of the facts in connection with the first few ex- 
 periments next reveals the nature of chemical change. Some 
 Second Char- ma terial has come out of combination or gone into 
 acteristic. combination. In other words, the great change in 
 physical properties is accompanied by a change in composition. 
 If the experiments on which this conclusion is founded have been 
 properly selected, they will incidentally lead to the classification 
 of changes in composition into the three common kinds. The 
 
 1 In Tilden's Teaching of Elementary Chemistry, 8 n, and more 
 especially in the work of Perkin and Lean which we have already (p. 56) 
 mentioned, 22-125, will be found laboratory instructions covering a large 
 number of experiments on those physical properties, familiarity with 
 which is most important in chemical work. 
 
 2 The two or three facts actually in the hands of the pupil do not, of 
 course, strictly speaking, justify generalization. No generalization in a 
 science deserves the name unless it is founded upon an immense range 
 of facts. The teacher must therefore indicate the direction in which 
 numerous other facts of the same kind lie, in such a way that the pupil 
 readily appreciates their nature, and feels satisfied with the general prin- 
 ciple deduced. The conscientious development of a single generaliza- 
 tion might otherwise occupy the whole year. 
 
THE INTRODUCTION OF THE SUBJECT /I 
 
 first experiments in chemical change are discussed again in 
 i this connection. 
 
 The pupil's attention may next be drawn to the production 
 or disappearance of heat in connection with some of his illus- 
 trations of chemical change. Special experiments Third char- 
 may even be introduced to show that in like man- acteristic. 
 ner light and electricity may be consumed or produced in a 
 similar way. This is not of course the place in which to dis- 
 cuss energy, but it furnishes a convenient opportunity at least f 
 for drawing the attention of the pupil to the fact that all 
 chemical change is accompanied by energy change of some 
 kind. Perhaps even the economic importance of this in con- 
 nection with the steam-engine and the storage battery may be 
 referred to. If he has already studied physics, the tendency 
 to the dissipation of energy, which a chemical system, in com- 
 mon with any physical one, exhibits, may repay notice. In any 
 case, none of the subjects touched at this stage can possibly be 
 treated fully or become a section of the subject complete in it- 
 self. Usually, recurring to the same subject at intervals, and 
 adding a little each time, will be more effective, when the ques- 
 tion is an abstract one, than a complete treatment of it at any 
 stage. The pupil becomes gradually accustomed to thought 
 about the subject, and thus does not experience the difficulty 
 and perhaps disgust with which a sudden presentation of abstract 
 ideas may otherwise affect him. 
 
 Aside from the three main features which we have men- 
 tioned, there are matters which may be described as minor, and 
 which yet are exceedingly important and soon begin Qth rMinor 
 to obtrude themselves upon our notice. There is, but Important 
 for example, the necessity for contact in order that Trutlls> 
 chemical action may occur. It is long before the pupil realizes 
 that putting two materials in the same test-tube is not the equiva- 
 lent of giving them every opportunity for interaction. If, for 
 example, the experiment is to place powdered potassium iodide 
 in a test-tube, add concentrated sulphuric acid and observe the 
 result, one pupil will fulfill the directions to the letter, while his 
 
72 THE INTRODUCTION OF THE SUBJECT 
 
 neighbour may use large crystals of the substance instead of 
 powdering them. Thus while the former obtains a violent action 
 in the cold, the latter may decide that practically nothing hap- 
 pens. It requires most persistent discussion to lead students 
 to realize that, unless means is taken to permit complete access 
 of every part of each substance to every part of the other, the 
 best conditions for chemical change have not been fulfilled, and 
 that, without thorough mixing, chemical action is as little to be 
 expected as if the substances had been in different test-tubes 
 instead of the same one. Another matter worthy of notice is 
 the great increase in the speed with which a chemical change 
 takes place when the temperature is even slightly elevated. 
 This, together with the melting or other assistance to contact 
 which heating affords, is the reason for its effect on chemical 
 change. A third point, which for the present is of minor im- 
 portance, is the fact that chemical changes are often carried out 
 with incomparably greater ease by dissolving the substances in 
 water, and that in most cases of this kind the water is not a 
 factor in the change. It is only by noting matters like these, 
 in the many various ways in which they affect chemical change, 
 that the pupils' chemical intelligence can be slowly developed. 
 
 IV. Further Generalizations, of a Quantitative Character. 
 
 The basis for the introduction of the fundamental quantita- 
 tive laws of chemistry may soon be reached. This may be 
 found partly in the very first experiments, and partly in addi- 
 tional ones designed more specifically for the purpose. If it 
 is desired, the systematic development of the subject-matter 
 may begin at this point, or at all events immediately after the 
 first of the following principles. This, following the historical 
 order, will probably begin with a more formal study of oxygen 
 and its relation to air. Or, as some writers prefer to arrange 
 it, hydrogen may precede oxygen, and water may precede air. 
 We shall not attempt to express any preference in regard to 
 the particular time for introducing this treatment or the par- 
 
THE INTRODUCTION OF THE SUBJECT . 73 
 
 ticular topic with which it shall begin. The matter is largely 
 one depending on the taste of the teacher, and the arrangement 
 of the book he uses. 
 
 The first of these generalizations arises naturally in answer to 
 the question whether, in the changes which have been noticed, 
 one body combines with another and alters the char- Fourth char- 
 acter of the latter without adding to the weight, or acteristic. 
 whether each substance takes its weight with it into combina- 
 tion. This being answered in the affirmative, the further ques- 
 tion arises whether this occurs absolutely without loss or gain, 
 or takes place with some slight abatement or modification of 
 weight. The fact, of course, is that, of all the physical prop- 
 erties of a substance, its weight is the only one which it is 
 found to have carried with it through any number of chemical 
 transformations. 1 
 
 It must be clearly explained to the pupil that this principle 
 cannot be rigidly established without an immense number of 
 experiments, and all of them would have to be of a more 
 exact character than the technical skill of the beginner could 
 furnish. 
 
 Closely associated with the question answered by the previous 
 law, is that of whether, in producing the same compounds, con- 
 stant proportions of the constituents are required. Fifth Char- 
 The answer is naturally in the affirmative. acteristic. 
 
 1 Phrases like the conservation of matter or of energy, if used at all 
 with beginners, should be defined carefully in strict harmony with their 
 particular experience, or, if they have none, at least with conceptions which 
 can most readily be pictured to the mind. The statements, for example, 
 that the " sum total of each kind of matter," or " of all the energy " " in the 
 universe " is constant are too remote from experimental examination to 
 be seen to have any relation to ordinary experience. It may be remarked 
 also that they are not in this form scientific" statements, but metaphysi- 
 cal speculations. All that we can verify by experiment is the fact that 
 in physical and chemical operations on a limited scale the matter and 
 energy can all be accounted for, and we have no evidence that any is lost 
 or gained. The more abstract mode of statement leads the pupil natu- 
 rally to think that these laws are simply dogmas. Many of us, having 
 received this false impression, have for a time wondered greatly what 
 the origin of these dogmas was. 
 
74 THE INTRODUCTION OF THE SUBJECT 
 
 As before, these generalizations will be illustrated by refer- 
 ence to every-day experience on which they have a bearing. 
 Generalization is not an end in itself. It is simply the clear 
 formulation of a fact preparatory to its employment for illumi- 
 nating our experience. Application in later work in chemistry 
 occurs as a matter of course. It is important, however, that 
 the employment should be as wide in range as possible. We 
 are all familiar with the surprise with which the obviousness 
 of an application or illustration strikes us after the relation has 
 been pointed out by some one else. Yet it is chiefly an inde- 
 pendent ability to apply what is known that distinguishes the 
 scholar from the prig. The mastery of the generalizations of 
 chemistry may constitute a part of learning in a narrow sense : 
 to have digested them and become able to see their application 
 to remoter facts within our knowledge is education. The 
 possibilities and methods of application are discussed more 
 fully under classroom instruction (chapter V., sections a and e, 
 pp. 129 and 138). 
 
 In connection with the discussion of the law of definite pro- 
 portions, the question of the actual ratios by weight in some 
 Measurement smi P^ e chemical compounds will naturally come up. 
 of Proportions The proportions in some of the actions already no- 
 ught. ^^ should be given as illustrations, and the results 
 expressed by percentage. If possible, the actual carrying out 
 of a measurement should be shown. The union of a weighed 
 amount of copper with oxygen, for instance, is a suitable ex- 
 periment, for it requires no supervision. Other quantitative 
 experiments which are available will be discussed in the chap- 
 ter on the laboratory work. 
 
 The principle of multiple proportions may fitly follow. As a 
 classroom illustration, the reduction of cuprous and cupric 
 Sixth char- oxides by hydrogen will be found easy, provided 
 acteristic. pure cuprous oxide can be obtained, 1 as failure to 
 get good results is almost impossible. 
 
 The next generalization is that relating to reciprocal propor- 
 
 1 I have found Kahlbaum's most satisfactory. 
 
THE INTRODUCTION OF THE SUBJECT ?$ 
 
 tions (law of combining weights). For its development a num- 
 ber of actual combining proportions and equivalent weights are 
 required, and may be tabulated on the blackboard. Seventh Char- 
 The study of the numbers which a suitable series acteristic. 
 exhibits brings out a very remarkable fact about chemical com- 
 bination. This may be stated as follows : If we take any ele- 
 ment as basis, and any number as the value for the combining 
 weight of that element, then the quantities of other elements 
 which combine with this amount, or are equivalent to it in 
 chemical combination, have this property, that complete com- 
 bination of the elements with one another takes place when 
 these quantities, or simple integral multiples of them, are em- 
 ployed, and no compounds are known whose composition is 
 not in harmony with this rule. 1 
 
 This relation furnishes us with a set of combining weights, or 
 rather, by varying choice of the basal element and value as- 
 signed to it, an indefinite number of such sets of weights. It 
 may therefore be indicated at this point that convenience de- 
 
 1 It is one of the most serious defects of many elementary text-books 
 that they do not formulate this principle in terms of its experimental 
 basis. It seems sometimes to be left entirely out, and its consequences 
 creep in unawares under the cloud of dust raised by the atomic theory, or 
 appear in the use of equations without any attempt at justification of the 
 prodigious logical hiatus which this involves. 
 
 The experimental fact, stated in one way, is as follows : We take a 
 definite quantity of an element A, and ascertain the quantity of an ele- 
 ment B which unites with it. Then we measure the quantity of C which 
 unites with this quantity of B ; then that of D which unites with this 
 amount of C, and so forth. We thus obtain a series of numerical re- 
 sults (equivalents) such that each quantity in the series is that which 
 unites with the neighbouring quantities of adjacent elements on each side 
 of it. Now we discover that the stated quantities of remoter elements 
 are also such as enter into combination, either as they stand or with the 
 use of the principle of small integral multiples. It is this fact which 
 enables us to assign individual combining (atomic) weights to the ele- 
 ments. Without it, chemical proportions would be a waste of unrelated 
 percentage compositions, and our much cherished formulae and equa- 
 tions would have no existence. 
 
 The matter is explained with exceptional clearness in Young's Ele- 
 mentary Principles of Chemistry, 23-26, and 242-243. See also 
 Vaughan Cornish, Practical Proofs of Chemical Laws, chapters I. and IV. 
 
76 THE INTRODUCTION OF THE SUBJECT 
 
 mands that some particular set shall be preferred. It is clear 
 that numbers less than the hydrogen equivalents will be in- 
 convenient, as they must either make hydrogen itself less 
 than unity or introduce unnecessary multiples whenever they 
 are used. The selected combining weights (atomic weights) 
 may be given, and will be seen to be frequently small mul- 
 tiples of the hydrogen equivalents. 1 The basis of selection 
 cannot be further explained without the use of the conse- 
 quences of Avogadro's hypothesis. 
 
 This point in the development of the principles forms a 
 convenient halting place, and we shall not pursue the subject 
 further at present. The results of the work we have outlined 
 suffice, if the teacher so desires, to enable him logically to 
 introduce symbols and equations. At this point, or a little 
 later, if he sees fit, he may also present the explanation of the 
 last three generalizations which the atomic theory furnishes. 
 The discussion of the relations of symbols (p. 7 7) and of the 
 atomic theory (p. 154) to introductory work will be taken up later. 
 
 It will be seen that the chief theoretical subjects affecting the 
 quantitative description of chemical change which still re- 
 Avogadro's mam fc> r consideration are : Avogadro's hypothesis 
 Hypothesis, and its application through measurement of the 
 density of gases to the determination of molecular weights, the 
 final adjustment of combining (atomic) weights, and the ex- 
 planation of valency. It might be noted at this point that 
 many teachers do not favour a complete discussion of these subjects 
 in the secondary school. They are undoubtedly difficult, and 
 must necessarily occupy a great deal of time, and, when all is 
 said and done, the pupils are little likely long to retain much of 
 the intricate reasoning which is inseparable from their discussion. 
 It is true that, like any other part of the science, the study of 
 this aspect of it must furnish admirable discipline, but it is a 
 
 1 Throughout, oxygen equivalents (O 8 and II = 1.0076) may be 
 used just as easily as hydrogen equivalents (H = i and O = 7.94), and 
 they have the advantage of leading directly to the standard atomic 
 weights (O = 16.00). 
 
THE INTRODUCTION OF THE SUBJECT 77 
 
 question whether even in this point of view a more economical 
 use of the time may not be made by substituting other and 
 simpler chemical topics. These particular things are not 
 likely to find application in every-day life, even if they are 
 retained, and, in the less usual case of the pupil who afterwards 
 attends a university or technical school, this subject will in 
 any case have to be dealt with afresh. It is on account of 
 these facts that I am inclined to justify the less rigid treatment 
 of the matter of combining weights, in order that apart from 
 Avogadro's hypothesis we may have a reasonable basis for the 
 use of equations. 
 
 V. The Relation of the Quantitative Laws to Formulae and 
 Equations. 
 
 One of the chief criticisms of the teaching of chemistry at 
 the present day is that much of it fails to make clear the place 
 of the balance in chemical work and the relation of the results 
 of measurement to the plan chemists have adopted of expressing 
 these results, namely, by the use of the combining or atomic 
 weight as the unit of quantity for each element. I am not, for 
 the moment, referring to the much debated question whether 
 the pupils can or should do quantitative work. It is the un- 
 assailably fundamental character of the quantitative data and 
 their interpretation that I would emphasize. It is this that has 
 made chemistry an exact science. Thus, even if he has no 
 balance at all, or no inclination to use it, the teacher is still 
 compelled to reach the core of the science, if he reaches it at 
 all, by explaining, in one or two actions at least, how one could 
 set about measuring the quantities concerned. 
 
 When the time comes for expressing these measurements in 
 the form of symbols and equations the pupil must be shown 
 
 clearly how the translation into the conventional 
 
 , . , - , rr , Expression of 
 
 chemical formulae is effected, i It may seem to Quantitiesby 
 
 some readers a strange statement to make, but I Formulae - 
 believe that many will bear me out, when I say, that, although 
 the modern works have included the stage of measurement, 
 
78 THE INTRODUCTION OF THE SUBJECT 
 
 there are few elementary text-books in which any attempt is 
 made to furnish the links between experiment and equation. I 
 know hardly any that I could put into the hands of an intelligent 
 person for study, with the least confidence that this connection 
 would be understood. 1 It is to be feared that the number of 
 teachers who furnish this link must be limited, for the books 
 must by all means represent the average, if not the best teach- 
 ing in the country. 
 
 A concrete illustration will make most clear what is meant. 
 Suppose the teacher deems that the time has come for the 
 An use of formulae and equations to begin, and that 
 
 Illustration. tne introduction has been conceived somewhat in 
 the spirit of the preceding section. To be specific, suppose 
 that he decides to do this in connection with the study of 
 oxygen. Let us further suppose that sulphur is the first body 
 whose union with oxygen is observed. After qualitative obser- 
 vation the question of quantity arises. It is necessary to ascer- 
 tain, or assume as known, the weights of two of the three bodies, 
 sulphur, oxygen, and sulphur dioxide. The third can then be in- 
 ferred. The simplest experimental method is that which weighs 
 the sulphur and burns it in excess of oxygen, and catches and 
 weighs the sulphur dioxide. The apparatus and general pro- 
 cedure must be sketched and described or shown. 2 The result 
 
 1 The explanation is admirable in Reynolds, ibid., 69-72 ; it is clear, but 
 too long postponed in Torrey, ibid., 315-316 ; in Young, ibid., 75-76, it is 
 satisfactory. 
 
 2 Newth, Elementary Inorganic Chemistry (Longmans, Green & Co.), 
 p. 108, describes this experiment. It will do very well for description, 
 but I do not advise its performance, as it requires careful watching, and 
 I have found that the boat, or glass of the tube, often acts catalytically 
 and sulphur trioxide is formed in such quantities that the weight of the 
 sulphur dioxide, and therefore of the oxygen, comes out much too 
 large. 
 
 Perhaps the best experiment for illustrating the making of a formula 
 is the solution of a weighed piece of iron wire in nitric acid, and the 
 evaporation and ignition of the residue (Fe 2 O 8 ). The indirect nature 
 of the oxidation is unfortunate. But the oxides which are formed easily 
 by direct union, like those of copper and magnesium, do not afford an 
 example of the use of multiples of the combining weights, while there 
 
THE INTRODUCTION OF THE SUBJECT 79 
 
 of the experiment leads to the conclusion that the proportion 
 by weight of sulphur to oxygen is 50 : 50 in a hundred parts, or 
 i : i, almost exactly. 
 
 Now chemists express this result in a system in which the 
 combining (atomic) weight of each element is the unit. There- 
 fore, what we desire next is to know the value of x, the number 
 of combining weights of sulphur, and y, the number of com- 
 bining weights of oxygen in the equation : 
 
 x X comb. wt. of sulph. : y X comb. wt. of oxygen i : i. 
 
 The combining weights must be known or the operation stops 
 here, and the equation cannot be reached until they are known. 
 We state them to be 32 and 16 respectively. The problem 
 then is to find the simplest values of x and y in the equation 
 .% X 32 : _y X 16 i : i. If the combining weights have-been 
 successfully chosen, x and y must be rational numbers, and 
 will usually be small numbers. This is the property of chemical 
 combination mentioned in last section (p. 75), in consequence 
 of which alone we possess interchangeable combining weights of 
 any kind at all. Here evidently x : y = i : 2. Now the sym- 
 bol S expresses 32 parts of sulphur, 1 the combining weight, and 
 
 are objections on the score of experimental difficulty to the use of the 
 oxides of carbon and phosphorus. 
 
 1 This statement of the meaning of the equation harmonizes with the 
 mode of approach from the experimental side which we have pursued. 
 In this point of view, S may not be used as a contraction for the name of 
 the body. Nor does it mean an atom of sulphur, since atoms are not 
 perceived in experiment. 
 
 The symbol represents, not the yellow, light solid which is indicated 
 by the word sulphur, but the part of the mass of the compound (in this 
 case, sulphur dioxide) which was originally sulphur, but now shows none 
 of its properties. Some chemists distinguish between the free body, or 
 "simple " (as opposed to compound), and the element. The latter is the 
 same material in its combined and unrecognizable form. The atomic 
 theory, in explaining the quantitative laws of combination by supposing 
 each constituent to be done up in little pieces of uniform weight, inci- 
 dentally leads us to suppose also that the pieces remain intact after 
 combination, It suggests that the pieces are stuck together without 
 losing their individuality. So the symbol SO 2 shows them to us side 
 by side. But precisely because the theory and the atomic ideas con- 
 
80 THE INTRODUCTION OF THE SUBJECT 
 
 the symbol O stands for 16 parts of oxygen, its combining weight. 
 Therefore the composition of sulphur dioxide, in terms of the 
 chemical units of quantity is i X S : 2 X O, which is equivalent 
 arithmetically to the proportion by weight, i : i, found in the 
 experiment. The formula is thus SO 2 - Since one combining 
 weight of sulphur and two of oxygen are required to form this, 
 the equation is S + O 2 = SC^. 1 
 
 Every step in this process is easily followed, and the equation 
 is seen to rest directly on experiment, as it should do in a science 
 which claims to be experimental. The only point of possible 
 obscurity is in the justification of the atomic weights. If Avo- 
 gadro's hypothesis has not been given, that difficulty cannot be 
 fully met. The pupil has seen, however, how a set of combin- 
 ing weights can be established, and may, without confusion, be 
 asked to leave in suspense the question of why these particular 
 values (such as 32 for sulphur rather than 32/2 or 32/5) have 
 been finally chosen. This whole proceeding must be repeated 
 with each succeeding equation for some little time, until it is 
 thoroughly familiar. If the teacher can actually perform one 
 
 nected with the formula prejudice us in favour of the view that the sul- 
 phur persists in the compound in this way, we are apt to forget that 
 the theory makes no attempt to explain why the product is a wholly 
 new species of matter. It simply ignores the fact that a body with a 
 powerful odour and the other familiar physical and chemical properties 
 of sulphur dioxide has appeared, and that the characteristic properties of 
 the two bodies from which it was made have been submerged (cf. Per- 
 kin and Lean, ibid., 322). In other words, we are put in the risky 
 position of trying to think that the bodies are both still there and both 
 gone at the same time. The qualitative facts are better explained by 
 supposing complete change of the sulphur and oxygen and production of 
 the compound out of the material (cf. pp. 156, 158). Thus, in the formula 
 of the compound SO 2 , at least, the material denoted by S is not free 
 sulphur (the " simple "), and the symbol and word are not interchange- 
 able, at all events, not until the atomic theory has been given, and, 
 strictly speaking, not even then. 
 
 1 The general solution of this problem consists in taking the weights 
 of the constituents found in any sample of a compound, dividing each 
 such weight by the combining weight of the corresponding element, 
 and finding the whole numbers which stand in the same ratio as the 
 quotients. 
 
THE INTRODUCTION OF THE SUBJECT 8 1 
 
 experiment before the class, the impression will be incomparably 
 more definite and lasting. If it is possible to include such an 
 experiment in the laboratory work of the pupils, the effect will be 
 still better. But my point is that the equation can never be 
 understood unless the quantitative measurement, whether by 
 description, demonstration, or individual performance makes 
 relatively little difference, is brought to the notice of the pupil, 
 its numerical result seen, and its translation into the form of an 
 equation exhibited. Without some such explanation, the equa- 
 tion is bound to be a mysterious thing, and must remain utterly 
 unconnected by any visible link with the chemistry of the lecture- 
 table and the laboratory. 
 
 It will be seen that we have treated the symbol and the equa- 
 tion as if they represented the materials, not by atoms and mol- 
 ecules but by weight. It is frequently assumed 
 that the reverse of this is the correct view. Yet the ^Represent 
 fact is that the equation is seldom used in the lat- Weights, not 
 ter sense, and there is no impropriety in treating the 
 former as its primary signification. Chemistry is primarily 
 experimental. 1 To illustrate. Marshall (JouR. CHEM. Soc., 
 Lond. LIX., 771) found a white crystalline body in a cell, 
 originally filled with a solution of potassium bisulphate, through 
 which a current of electricity had been flowing for a long time. 
 
 \ 
 
 1 The equation may therefore be used solely as a record of quantita- 
 tive data until the atomic theory has been introduced. After that has 
 occurred, the explanation that the chemical unit quantities of each ele- 
 ment are likened in this theory to atoms will naturally be given. When 
 Avogadro's hypothesis has finally defined the chemical molecule, the 
 equation comes up once more. This time it has to be changed to cor- 
 respond with the new ideas, if the items it contains are to be complete 
 molecules, and the equation is to represent the change as if it took place 
 in the physical minimum of materials. Where we can measure the molec- 
 ular weights, as in the case of volatile substances, the formulae will 
 now be adjusted so as to represent molecules (as O 2 -f2H 2 2H 2 O) and 
 the equation will embody the change in petto physically, as well as in pro- 
 portions by weight chemically. For practical purposes this form of 
 equation is preferable only when gases are concerned. With bodies 
 which, under ordinary conditions, are not gases (as P 4 ), it is a needless 
 complication. 
 
 6 
 
82 THE INTRODUCTION OF THE SUBJECT 
 
 He did not for a moment attempt to ascertain the nature of the 
 body, and the action by which it had been formed, by trying to 
 see how the molecules of the bisulphate were affected by the 
 current and what atoms were contained in the molecules of the 
 new substance. If the chemist did not think in a more con- 
 crete way in his work than he seems often to do in his teaching, 
 his mind would be so befogged with theory that he would never 
 accomplish anything. Marshall simply analysed the body, 
 found that the elements potassium, sulphur, and oxygen were 
 present in it, and determined the percentage of each. A 
 process of reasoning essentially the same as that in our illustra- 
 tion gave the formula KSO 4 . Comparison with the bisulphate 
 (KHSO 4 ) showed that hydrogen had been eliminated, and, as 
 this gas was liberated during the electrolysis, the simplest equa- 
 tion was evidently : KHSO 4 =KSO 4 +H. This was the first iso- 
 lation of a persulphate. 1 
 
 Naturally only a mere fraction of the actions studied in an 
 elementary course can be treated quantitatively. But when, 
 without exact measurement other equations are constructed by 
 the help of such data as the pupil's experiments afford, or are 
 even taken from the book, the learner will still realize that the 
 process described above was carried out by some one, and the 
 origin and meaning of the equation, once grasped, will never 
 again become obscure. 
 
 'Equation writing,' in the sense in which the phrase is com- 
 monly used, will be a necessary exercise in connection with 
 Equation tne making of the record of each experiment in the 
 Writing. note-book, but, after rational explanation like the 
 above, it will be largely a genuine exercise in chemical thought, 
 based on inferences from observation. Without any such ex- 
 planation, it is likely to be a combination of copying and illogi- 
 
 1 Subsequent study showed that persulphuric acid was a dibasic 
 acid, and that therefore the formula of the salt was K 2 S 2 O 8 . The above 
 process could not go beyond correctly expressing the proportions by 
 weight in terms of multiples of the atomic weights. Entirely different 
 means were required to furnish this improvement. 
 
THE INTRODUCTION OF THE SUBJECT 83 
 
 cal collocation of letters, accompanied by vague gropings after 
 some rule. If ' rules ' are supplied, then the last chance of any 
 chemical benefit surviving is removed and some puzzle like the 
 once popular " fifteen puzzle " would furnish more exercise for 
 the intelligence and just as much chemistry. 
 
 If the exercise is merely arithmetical like this : 
 
 " Complete the following : 
 
 CaCO 3 -CO 2 =? 
 2 KNO 2 = N 2 O 3 + ? 
 Pb + HN0 3 = Pb (N0 3 ) 2 + H 2 + NO," 
 
 a little of it may be safe and useful. Even students in universi- 
 ties can seldom count the numbers of atomic weights of each 
 element correctly. But too much of this sort of thing suggests 
 to the pupil that a chemical change can be predicted safely from 
 manipulation of the formulae of the factors entering into it, and 
 withdraws the attention from careful reasoning from observation. 
 
 This is especially likely when, as in the book from which the 
 above is taken, a large number of such truncated equations are 
 given early in the course, before the actions with which they 
 deal have been studied. We are not surprised a few pages 
 further on to read : " HC1 is the formula of an acid because 
 it 1 consists of hydrogen united with a non-metallic element," 
 followed by an exercise in selecting " from these symbols " 
 " the ones which stand for acids : " " H 2 C 2 O 4 , CaCO 3 , NaOH, 
 H 2 S." The reasons for the decision are to be given. How 
 unpleasant it would have been if the printer's devil had mali- 
 ciously added H 6 C 2 O, H 3 NO, and P(OH) 3 to the list ! 
 
 In view of the fact that equations, symbols, formulae, etc., are 
 not parts of chemistry, but of our mode of recording The Tlmc for 
 chemical facts, it seems desirable to plant the facts introducing 
 and their importance securely in the mind of the Eauations< 
 pupil before these conventions are considered. When they are 
 
 1 This reminds, one irresistibly of a pupil's answer quoted by Tilden : 
 "Metals differ from non-metals, both by ending in um and having a 
 metallic lustre." 
 
84 THE INTRODUCTION OF THE SUBJECT 
 
 given they should be clearly distinguished from the facts of the 
 science and explained as a kind of abbreviated language for 
 expressing the facts. 
 
 Since they are quantitative expressions, they cannot logically 
 appear before the method of measurement has been explained. 
 If the problem were that of explaining to a visitor from Mars 
 the system of money and exchange used on this planet, we 
 should not first invite him to memorize part of the stock ex- 
 change and commercial reports of a newspaper. He would 
 have to become familiar with the materials themselves, and 
 understand the object and machinery of exchange, before he 
 could intelligently handle the conventions by which we have 
 come to chronicle them. The introduction of equations soon 
 after the quantitative laws have been explained and illustrated 
 is desirable, because their use gives much greater precision to 
 the pupil's conception of each chemical change. On account 
 of the abuse to which they are subject, their postponement to a 
 very late stage, or even omission altogether, has been seriously 
 advised by many teachers. This, however, is surely an extreme 
 view. Why propose excision of a valuable organ when the cure 
 of the disease lies in the hands of the teacher ? 
 
CHAPTER IV 
 
 INSTRUCTION IN THE LABORATORY 
 
 WE have already, either by implication or directly, touched 
 upon many of the important aspects of instruction in the labora- 
 tory. This was unavoidable, since the purposes and results of 
 chemical instruction are so closely bound up with the practical 
 side. We must now discuss the subject in a more systematic 
 manner. The value of laboratory work offers a convenient title 
 under which we may endeavour, through the discussion of the 
 benefits it may confer, to set forth the considerations which 
 affect the attitude of the teacher, and are to be used in mould- 
 ing that of the learner, towards the science. We may" then con- 
 sider in succession, the laboratory directions, the attitude of 
 discoverer or verifier which the pupil may be induced to adopt, 
 the importance of technique, the question of quantitative ex- 
 periments, and the note-book. 
 
 In all this, of course, we assume that the teacher is provided 
 with a laboratory of some kind, and with equipment more or 
 less adequate. The construction and furnishing of a laboratory 
 will be dealt with in a chapter by itself. The importance of its 
 right employment in teaching chemistry will not require 
 separate treatment, since it will emerge very distinctly from 
 the results of our discussion of the topics immediately following. 
 
 The laboratories, in many cases magnificent, with which new 
 school buildings are nowadays usually provided, show that the 
 necessity for having them has been recognised, at LatonAmy 
 least by the architects. One would fain think that Instruction 
 their importance is equally appreciated by superin- 
 tendents and principals. The statement made by the Com- 
 mittee of Nine, however, although startling to those who have 
 
86 INSTRUCTION IN THE LABORATORY 
 
 looked into one or two of the best schools, and have not taken 
 the average of the secondary schools of a whole state into con- 
 sideration, is, it may be feared, not without justification. They 
 say : l " While the laboratory method is almost universally ap- 
 proved by the science teachers, the text-book method prevails 
 in the schools, to such an extent that laboratory work is inci- 
 dental, inefficient, and in many cases excluded altogether." 
 In their preliminary report, which deals with this phase of the 
 subject more fully, they say : 2 " It is true that attempts at labora- 
 tory work in one or two subjects are reported by the schools of 
 the State of New York almost without exception, but the com- 
 plaint is made that the laboratory study must be limited, desul- 
 tory, and subordinate to the study of books with classroom 
 exhibitions." They attribute this condition in part to lack of 
 recognition of " the great labour involved in the conduct of good 
 laboratory work," and the fact that " the reputation of the 
 teacher and the standing and financial support of the school 
 are affected by the results of examinations," while "the results 
 of laboratory study cannot be tested by the current methods of 
 examination." As this committee included representatives from 
 the high schools, as well as the normal schools and colleges of 
 New York State, and as this opinion was expressed after pro- 
 longed and minute study of the actual condition in the schools 
 of a state which is certainly not below the average education- 
 ally, it must be regarded as a serious criticism of the present 
 teaching in the whole country. Only the constant efforts of the 
 teachers of science, to awaken the minds of other school offi- 
 cers and of the public at large to the indispensability of reason- 
 able expenditures for scientific equipments, and reasonable 
 consideration of the points made by the committee, can secure 
 the gradual remedy of this state of affairs. No special benefit 
 is to be expected from the teaching of science until a far-reach- 
 ing change has been brought about. 
 
 1 University of the State of New York, High School Bulletin No. 7, 
 706. 
 
 2 JOURNAL OF PEDAGOGY, Vol. XL (1898), 119. 
 
INSTRUCTION IN THE LABORATORY 87 
 
 I. The Value of Laboratory Work for General Education. 
 
 a. For Teaching Knowledge-making by Observation and In- 
 duction: Observation in chemistry implies something much 
 more complex and difficult than we sometimes ap- Wnatisim _ 
 preciate. In its simplest terms it may consist in plied in 
 noticing the colour of a precipitate, or stating Observati011 - 
 whether bubbles of gas do or do not appear, or perhaps in 
 describing the form of a crystal. This demands what one 
 writer has described as " ocular accuracy." The process is 
 one of the mind, although the phrase suggests that the eye as 
 a physical instrument is mainly concerned. In many experi- 
 ments, however, the use of experience and reasoning in obser- 
 vation so greatly predominates, that the part which the eye or 
 the sense of touch plays becomes relatively inconspicuous. 
 We read of observation consisting in the " training of the 
 senses." The phrase is vague. It should be remembered 
 that the reactions of our sense organs are scarcely affected by 
 practice. Galton has shown that sailors' eyes, instead of being 
 more efficient physically than other peoples', are really less sen- 
 sitive than the average. It is the ability of the seaman to 
 interpret what he sees in the light of experience that makes 
 him a better observer of some things than the landsman. A boy 
 may see ten times as much as a man, yet the man will learn ten 
 times more from what he sees than the boy. Applying this to 
 the matter in hand, we see that the training of a pupil in obser- 
 vation consists really in storing his mind with suitable experi- 
 ence, all thoroughly classified and digested. Ability to observe 
 chemical phenomena is an attribute of the chemist, and teach- 
 ing observation consists really in teaching chemistry. 
 
 b. For Teaching Knowledge-making by the Study of Natural 
 Objects and Phenomena: As we have seen (pp. 10 and 49), 
 training in observation in the fullest sense of the practical 
 term may be obtained from the study of languages JJ^ato 
 and other book work. The man who is trained, Experience, 
 however, in this direction only, may remain bookish and un- 
 
88 INSTRUCTION IN THE LABORATORY 
 
 practical. The knowledge by which we live is not furnished with 
 an index, nor is it arranged alphabetically. It is thrown at us 
 much like the experience of the chemist, and, as a school of edu- 
 cation and a sphere of activity, the world is more like a labora- 
 tory than a library. The experience in chemistry quickly shows 
 the fallacies into which we continually fall, and from which ex- 
 periment and renewed observation alone can rescue us. We 
 quickly learn that the operation of thinking clearly and keeping 
 our ideas in touch with facts is not a natural attribute of the 
 untrained mind. In studying chemistry in the laboratory we 
 acquire the habit of applying to concrete things the methods 
 of observation, of induction, and of testing every hypothesis by 
 reference to facts, which are indispensable to clear thought 
 about such matters. The application of the method is a 
 quality of the scientific mind, whether that mind is employed 
 in business or in study. As Professor Remsen l says : " By 
 a scientific mind is meant one that tends to deal with questions 
 objectively, to judge things on their merits, and that does not 
 tend to prejudge every question by the aid of ideas formed 
 independently of the things themselves. 
 
 To illustrate : 2 When ammonium chloride is heated in a 
 test-tube and litmus paper shows the presence of ammonia at 
 
 illustration t ^ ie moutn ^ tne tu ^ e > ^ e stu dent instantly says 
 of Faulty that ammonia has been given off, and thinks of 
 uc on. ^ remamm g solid as containing the hydrogen 
 chloride. Presently the test paper shows the arrival of this 
 acid, and he is reminded that the other product is a gas. 
 If he is now asked why the ammonia appeared first, he will 
 invariably say that it must have been formed before the 
 hydrogen chloride ! It usually comes as a surprise when you 
 lead him to see that in the decomposition of a substance 
 
 1 Address on " The Chemical Laboratory," delivered in connection 
 with the opening of the Kent Chemical Laboratory of the University of 
 Chicago. NATURE, XLIX. (1894), 531. 
 
 2 An excellent discussion of this, with many historical illustrations, is 
 given by Tilden, Hints on the Teaching of Elementary Chemistry. Lon- 
 don and New York, Longmans, Green & Co. 1895. P P- I-I1 * 
 
INSTRUCTION IN THE LABORATORY 89 
 
 into two gaseous molecules, the products cannot be formed 
 otherwise than simultaneously. The same pupil would not 
 have made so grotesque a mistake in reasoning in geometry or 
 in translation from French. It is the reasoning about material 
 objects and phenomena which is difficult to him because it is 
 unfamiliar. 
 
 c. For Teaching Caution and Mental Rectitude : The illustra- 
 tion just given points further to the continual discipline which 
 the pupil must receive in the necessity for caution Heed of Care 
 
 in forming conclusions. No work so much as that in Drawing 
 ... . , ., r Conclusions, 
 
 in chemistry impresses one with the necessity for 
 
 distrusting preconceived notions, or furnishes a better prepara- 
 tion for tenaciously employing this principle as one of the best 
 guides in all the actions of life. The line between the mini- 
 mum inference which the facts actually justify, and the more 
 extensive one which we are continually tempted to draw, is 
 often so easily passed that the most varied experience in search- 
 ing for it and remaining on the safe side can never make the 
 process too familiar. Take, for example, the case of the Bun- 
 sen burner. When the pupil, after he has observed the dif- 
 ference which the position of the ring at the bottom of the 
 burner makes, is asked what the openings have to do with the 
 matter, he will invariably say that it is the admission of oxygen 
 which causes this difference. This statement may even be 
 found in many books, in spite of the fact that nitrogen and other 
 gases which contain no oxygen have the same effect. 1 The 
 higher temperature of the Bunsen flame is sufficiently explained 
 by its smaller size. The liberation of free carbon in luminous 
 flames is another rock of offence. It seemed to be accounted 
 for by the theory that the hydrogen of the hydrocarbons burned 
 more easily, until this was shown conclusively to be the exact 
 contrary of the fact by Smithells. 2 
 
 The custom of careful scrutiny of hypotheses and their con- 
 
 1 See Newth's, Inorganic Chemistry. London and New York, Long- 
 mans, Green & Co. 1894. Pp. 291-306, particularly 304. 
 
 2 NATURE, XLIV (1893), 8 6. For further references, see p. 215. 
 
90 INSTRUCTION IN THE LABORATORY 
 
 tinual probation before the court of experiment begets a habit of 
 mind which finally finds delight in the search for exact knowledge 
 and correct opinions for their own sake. In these days of ex- 
 aggeration and superficiality the influence of the tendency of 
 laboratory work to the fostering of mental rectitude cannot be 
 prized too highly. 
 
 d. Other Benefits of a General Nature : Laboratory work is 
 undoubtedly of value in that cultivation of the mind which is 
 expressed by care and neatness in mechanical matters, and in 
 dexterity in the manipulation of materials. This training has 
 undoubtedly a broader significance, beyond the operations 
 and objects peculiar to chemical work. Perhaps, as a substitute 
 for, or supplement to manual training, 1 it may be said to have 
 some value in a partial way. 
 
 In all instruction the personality of the teacher is held to be a 
 factor of not less importance than the nature of the subject 
 taught. The close personal contact which laboratory instruction 
 secures between the pupil and teacher, and the consequent 
 greater opportunity which his personality has to impress itself 
 upon the pupils, is not one of the least of the benefits we are 
 discussing. There are others that might be mentioned; several, 
 such as the liberation from the bondage of authority (pp. 10 
 and 51), have already been discussed in other connections. 
 The examples we have given (in b and c above), if carefully 
 thought out, will furnish a clearer insight into the value of 
 laboratory work than any mere enumeration of ours could do. 
 
 II. Value of Laboratory Work for Instruction in Chemistry. 
 
 a. For giving First-hand Knowledge : The study of chemis- 
 try, or any other body of knowledge, must be carried out by 
 direct encounter with the material of the science itself. The 
 study of what some one else has said or thought about the sub- 
 ject is an interesting, but entirely different exercise. We do 
 not study Latin by reading an English translation, or an essay 
 
 1 W. E. Bennett, Manual Training of Chemistry. University of the 
 State of New York, High School Bulletin No. 13, 926. 
 
INSTRUCTION IN THE LABORATORY 91 
 
 on the author's work. Every one understands that the study 
 of Latin means the study of the text itself. So the term " study 
 of chemistry " can be properly applied to nothing but laboratory 
 study of the subject. An author's explanations and verbal 
 statements are but a feeble and exceedingly partial substitute 
 for the facts themselves. Really to know what the facts of 
 chemistry are, they must be seen and handled directly. The 
 books are not chemistry, but literature, and, as some one has 
 said, they are mostly poor literature at that. 
 j^In order that there may be no question of the pre-eminence 
 of practical experience, the course should be arranged round 
 the laboratory work, and the latter should carry the Tne study 
 
 thread of the subject. Classroom work and other arranged 
 
 round the 
 exercises should be adjusted to this and used as Laboratory 
 
 supplements. This of course presupposes the Work ' 
 existence of certain qualities in the chosen laboratory outline 
 which shall fit it f6r furnishing the backbone and carrying the 
 burden of the workj It is evident that if the relation of the 
 other parts to the laboratory work is not that which we have 
 suggested, if, for example, the recitations from a text-book form 
 the only continuous and logical feature of the course, the atti- 
 tude of the student towards the laboratory work will be entirely 
 false. If the text-book is taken as the basis, and the impression 
 is given that experiments are thrown in like the engravings and 
 autograph letters in what bibliophiles call extra illustration of 
 some book, they are bound to suggest mere ornamentation of 
 some pre-eminently worthy nucleus, and the whole anatomy 
 of chemical instruction must be deformed. 
 
 b. For holding Interest and Attention : The whole psychology 
 of laboratory work forms an interesting study in itself. Without 
 attempting to treat the subject fully, we may draw 
 attention to one fact at least which contributes to of Laboratory 
 its value as a means of instruction. |_ During the study * 
 performance of an experiment, unless it is an exceptionally 
 tedious one, it is almost impossible for the interest 6f the pupil 
 to be withdrawn, or for his attention to flag. The operations 
 
92 INSTRUCTION IN THE LABORATORY 
 
 being performed, the changes being watched, and the legitimate 
 curiosity in regard to what will happen next, keep the whole 
 matter constantly in the centre of the pupil's field of conscious- 
 ness, and effectually prevent mind wandering. The strain on 
 the pupil's powers of voluntary attention, which book work 
 brings with it, is thus avoided in a large part of the time devoted 
 to the study of chemistry. His thought about the subject also, 
 with the activity continually prompted by this thought, satisfies 
 the psychological demand for reaction as the necessary correla- 
 tive of reception. *J 
 
 (^Professor Devvey has pointed out another advantage which 
 the laboratory possesses over the book, inasmuch as the per- 
 formance of an experiment entirely diverts the attention of the 
 pupil from the thought that he is studying, and fixes it com- 
 pletely on that which is being studied.) In other ways of learn- 
 ing, the thought that he is studying is continually in danger of 
 approaching a focal position in the field of consciousness, and 
 relegating the object of study to a less central position, and even 
 occasionally banishing it altogether. 
 
 c. For Securing Clear and Pregnant Expression: In most stud- 
 ies we begin with the expression of the fact, and seek by study of 
 the statement to reach the fact itself. In practical 
 fronfract to sc i ence > we encounter the fact first, and, having the 
 Expression fact clearly in mind, proceed to find a suitable expres- 
 and not Vice / - mi / i 
 
 Versa. sion f r rt' ^ ne former process is subject to mis- 
 
 understanjdings which are only too familiar. Even if 
 the language used is fortunately chosen, our personal equation, 
 
 1 Cf. James, Talks to Teachers, Chapter V. The pyschology of labo- 
 ratory work has been admirably discussed by Newell in a paper on 
 "More Profitable High School Chemistry." SCHOOL REVIEW, IX. 
 (1901), 286. This article contains an admirable application to chemistry of 
 the general principles discussed in Professor James' book. The criti- 
 cisms of actual features of chemical instruction in the light of psychologi- 
 cal principles will be found not only interesting but of practical value. 
 It should be added that the Talks to Teachers form the clearest presenta- 
 tion of the application of psychology to teaching in existence, and in 
 case it is not familiar to the reader its study cannot be urged too 
 strongly. 
 
INSTRUCTION IN THE LABORATORY 93 
 
 resulting from the associations we have formed with the words, 
 may result in more or less distortion when we seek to grasp the 
 meaning. We are all familiar with the game of "rumour " in which 
 the final result bears scarcely any recognisable resemblance to 
 the original. Much instruction is of this kind. The teacher 
 takes the fact he intends to present from a statement in a book. 
 It went through several stages even before it reached his eye. 
 But, leaving this out of account, we have first his conception of 
 its meaning, then the expression which he gives it in conveying 
 this conception to his class, then the interpretation they put 
 upon his statement, and finally the effort they in turn make to 
 reproduce it in their own language. The steps in this process 
 are more than sufficient amply to explain the ludicrous misap- 
 prehensions which so often arise. (_In the laboratory the pupil 
 encounters the fact directly, without the intermediate steps which 
 involve the teacher, although the latter is of course concerned in 
 assisting in the thorough exploration of the fact, and so the pupil 
 is able to express the fact with much less risk of falsificationj 
 
 Not only, however, are direct apprehension and clear expres- 
 sion of the facts of the science thus the privilege of the pupil, 
 but the statement means much more to him after this process 
 than it could have done if it had been furnished by the teacher 
 or the book. Lit is not an assemblage of words or a dead phrase, 
 
 ^rt 
 
 but a statement bristling with reminiscence and significancey 
 When we consider the limitations of language as a mode of ex- 
 pressing any idea with absolute precision and completeness, 
 and at the same time without including too much, the advan- 
 tage of this thorough grasp of the idea which has preceded the 
 expression, and must forever accompany its use, will not require 
 further justification. 
 
 Let us illustrate by referring to one of the commonest forms 
 in which the differences between related substances are ex- 
 pressed. The statement that chlorine is more An 
 active thap bromine, and bromine than iodine, is a nitration. 
 lifeless platitude to one who has no vivid experience with these 
 substances to accompany it and give it meaning. After the 
 
94 INSTRUCTION IN THE LABORATORY 
 
 elements have been handled, however, and comparison of their 
 activity has been made by studying the action of chlorine and 
 bromine on salts of bromine and iodine, for example, or by com- 
 paring the actions of sulphuric acid upon chlorides, bromides 
 and iodides, or by heating the hydrogen compounds of the 
 three elements, the word active acquires a definite experimental 
 significance, and the whole phrase becomes pregnant with 
 information. 
 
 III. The Laboratory Directions. 
 
 Since it is impossible for the teacher continually to supervise 
 every motion and thought of the pupil, his place during the 
 greater part of the work must be taken by printed laboratory 
 directions. On the completeness and adequacy of these direc- 
 tions must depend to a large extent the realization of the pur- 
 poses just discussed. If, for example, the instructions confine 
 themselves to the barest statement of what materials shall be 
 brought together, the pupil's experience will be utterly insuffi- 
 cient to furnish him with a conception of how best to perform 
 the operation, of what to look for and when to look for it, and 
 of the relations of the things he sees to one another and to his 
 previous experience. The existing laboratory manuals show all 
 sorts of directions, from the most meagre to the over-elaborate. 
 It is, at all events, necessary that the teacher should carefully con- 
 sider the directions in the book he uses, and adapt himself to 
 them by preliminary discussion of the experiment. If need be 
 he must give supplementary directions written on a blackboard, 
 or perhaps substitute a more appropriate form in mimeograph 
 sheets. The difficulty which this problem presents will be seen 
 when we consider all the demands which may fairly be made on 
 a good outline. 
 
 a. Laboratory Directions Should be Coherent : The chief fault 
 of laboratory study is its tendency to resolve itself into a series 
 of isolated, and therefore mechanical, proceedings. The phrase 
 we so commonly hear, that a pupil has performed fifty or a 
 hundred experiments, suggests that this disintegration may by 
 
INSTRUCTION IN THE LABORATORY 95 
 
 some be considered a merit rather than otherwise. Fifty ex- 
 periments may contain the material for the development of a 
 knowledge of the typical principles of chemistry, Disadvantage 
 just as fifty sleight of hand tricks may contain the basis of inconer- 
 for the study of the psychology of illusion, but in both ence * 
 cases there must be a great distance to be covered before the 
 results of the separate mechanical proceedings have been organ- 
 ized into a knowledge of either science. Evidently a long step 
 can be taken in the right direction by arranging the operations 
 in groups, with an idea running through each group, so that it 
 shall constitute a study of some element or compound, or of the 
 material for the development of some generalization. An ex- 
 ample will show how a series of experiments, by proper grouping, 
 may be converted into a systematic study. 
 
 Suppose that chlorine is the subject. The first question 
 has to do with the ways in which it may be prepared. It may 
 not be possible conveniently to illustrate all the dis- m us t r ation 
 tinct methods in the laboratory. The electrolysis Chlorine, 
 of solutions of chlorides, for example, may be reserved for the 
 demonstration. But the common general method, consisting in 
 the oxidation of some chloride, will naturally be given. It is as 
 easy for the pupil to take half a dozen test-tubes, and place in 
 them various substances, like potassium chlorate, minium, 
 barium peroxide, potassium dichromate, etc., and to treat each 
 with hydrochloric acid, as to perform the same experiment with 
 one of them. The view of the nature of the action will be 
 broadened by further comparing the effect of litharge with that 
 of minium, and of some metallic chloride and sulphuric or 
 phosphoric acid with that of hydrochloric acid. The results 
 naturally lead later to an instructive discussion of the meaning 
 and mechanism of oxidation in this case. 
 
 Following this will naturally come the main preparation of a 
 quantity of chlorine for the examination of its properties and the 
 performance of some of the usual experiments with it. It may 
 be noted that the union with phosphorus, antimony, and other 
 elements are not distinct properties, but illustrations of one 
 
96 INSTRUCTION IN THE LABORATORY 
 
 property, namely, the great activity it exhibits in uniting with 
 various elements. Other distinct properties are its tendency 
 to act upon water, forming a small amount of hypochlorous acid 
 (H 2 O + C1 2 ; HC1 + HC1O Note that the actiofl of light 
 on the solution is due to decomposition of the hypochlorous 
 acid and is not a property of chlorine), its tendency to replace 
 hydrogen in organic compounds, etc. 
 
 It will be noted that experiments giving negative results, like 
 the action of litharge above, are useful rather than objectionable, 
 ''hey are, indeed, necessary in order that a basis for comparison 
 may be furnished. 
 
 In a similar way the study of hydrates, commonly spoken of 
 as substances containing ' water of crystallization,' requires a num- 
 ber of closely related experiments in order that a 
 Illustration, . f l ,. . 
 
 Water of basis for really understanding the subject may be 
 
 Crystalliza- furnished. We have to note, first, that a body like 
 blue vitrol can be decomposed by heating and the 
 product has entirely new properties ; second, that this anhy- 
 drous material combines with water and the mixture furnishes 
 crystals like the original ones ; third, that the proportion used 
 in combination can be expressed ultimately in terms of com- 
 bining weights, proximately in terms of the formula weights of 
 water and the salt, and is therefore genuine chemical com- 
 bination ; fourth, that the same substance may have crystalline 
 form, of a different kind however, without containing water 
 (it may be crystallized from concentrated sulphuric acid) ; 
 finally, a number of crystalline substances may be examined by 
 heating in order to ascertain which are and which are not 
 hydrates in the common form in which they are sold. 
 
 There is no objection to the numbering of experiments. 
 This is indeed an advantage to the teacher when examining the 
 note-books. The point we have tried to make is, that the work 
 must be grouped, and the groups must be coherent, in order 
 that the results may be such that they furnish material for com- 
 parison, discrimination, and the arrangement in logical relation 
 of the observed facts. When the results are assembled in such 
 
INSTRUCTION IN THE LABORATORY 97 
 
 a fashion, the material is ripe for generalization. This final 
 step will not usually be taken by the pupil, even if he is invited 
 to take it. The review of the work in the quiz will be needed to 
 bring out the relations more clearly, and in this exercise there- 
 fore the first development of generalizations will usually occur. 
 
 b. Main Points in Regard to the Directions for each Experi- 
 ment: The main features which are required to constitute 
 proper direction in each experiment, and which must be fur- 
 nished either by the manual, the teacher, or the head work of 
 the pupil, may be summed up very briefly. 
 
 First, the object of the experiment must be definitely stated, 
 -r at least clearly implied in the title. Except in the case of 
 v crification of a law, however, it is obvious that the result of the 
 experiment should be carefully concealed. 
 
 Second, the apparatus must be lucidly described, and if 
 possible illustrated, in order that it may be readily constructed 
 
 without loss of time : the object of the various parts ^ 
 
 J Directions in 
 
 should be mentioned in case any of them are new, regard to 
 or are not likely to be understood at once. Manipulation. 
 
 Third, a minute and practical description of the materials 
 must be given. The quantity should be stated precisely,} to 
 avoid the tendency which the pupil generally has at the start to 
 use four or five times too much ; he should be shown that this 
 results not simply in waste of material, but, what is much more 
 important, in great waste of time. If solutions are concerned, 
 the concentration to be used should be given : it will be noted 
 that in general chemistry, unlike qualitative analysis, one 
 strength will not serve for all experiments. Inasmuch as the 
 state of many materials differs in different samples, the outline 
 should specify whether an anhydrous or crystallized variety is to 
 be used, whether the zinc is to be common granulated or 
 chemically pure, or in the form of zinc dust, and whether lumps 
 of the substance will serve the purpose, or whether it must be 
 powdered. The great difference in the results depending on 
 these things may be pointed out when opportunity offers (pp. 
 102, 131). 
 
 7 
 
98 INSTRUCTION IN THE LABORATORY 
 
 Fourth, the handling of the material and apparatus must be 
 made clear. In simple cases like precipitation, for example, 
 the very gradual addition of the reagent, accompanied by con- 
 tinual agitation, must be directed to avoid confusion. The 
 curious layers which otherwise arise may else become the 
 subject of observation and divert the attention into fruitless 
 channels. Perhaps a special exercise on this is advisable. When 
 the experiment is elaborate, minute directions are even more 
 necessary. 
 
 The three last points are concerned with the peculiarity of 
 chemical work, that the subject of observation has to be created 
 by the pupil, and the lesson it may teach cannot be reached 
 unless care is taken that the data, consisting in the phenomena 
 observed, shall be specific and identical in every repetition of 
 each experiment. 
 
 Fifth, the point at which a pertinent observation may be 
 made should be indicated by an interrogation mark, or in 
 Directions some other way. In one experiment the pupil 
 
 concerning ma y acidify a solution *and then add hydrogen 
 Observation J J 
 
 and sulphide ; in the next he may use zinc sulphate 
 
 Inference. an( j ^^ so dj um hydroxide, first in small amount, 
 and ^ then in excess. The slight alteration in the appearance 
 which the acid may produce will leave him in doubt as to 
 whether it has <any significance, and should be made a basis of 
 inference or not ; and if he decides that it should not, it may 
 happen that the first effect of the sodium hydroxide will be so 
 slight that he will neglect it also. Since the acid simply added 
 hydrogen ions, while the sodium hydroxide produced a definite 
 change, an interrogation-mark will call attention *to the latter 
 fact. 
 
 : Sixth, some indication is necessary as to what is to be ob- 
 served : for example, the use of the nose has to be enjoined 
 many times before it becomes habitual in almost every experi- 
 ment. Similarly it is sometimes necessary to draw attention to 
 a change in colour which may represent a passing stage in a 
 chemical change, or to the production of a gas which might be 
 
INSTRUCTION IN THE LABORATORY 99 
 
 overlooked, as in the addition of a soluble carbonate to many 
 salts of heavy metals. Perhaps separate exercises on these 
 details of observation would be advisable, in order that the 
 pupil may afterwards be left more completely to think for 
 himself in later experiments. 
 
 Finally, definite questions should be asked in regard to the 
 interpretation of what has been observed. These should be of 
 two kinds which should be distinguished plainly from one an- 
 other. Some it may be possible to answer from the observa- 
 tions and previous knowledge of the pupil alone ; others may 
 require reference to a book for part of the data. The pupil 
 cannot tell, without some suitable indication, of which variety 
 the question is, and will, in general, in every case make use of 
 the book, and so miss the opportunity of thinking for himself, 
 which the former variety of question would encourage him 
 to do. 1 
 
 It is evident, of course, that some mean must be struck be- 
 tween over-elaboration and too great compression of the in- 
 structions. They must not be so minute that to follow them 
 will be wearisome, or so complicated as to 4>e distracting and 
 unworkable. If too concise, they will put more responsibil- 
 ity upon the teacher and pupil than_ the size of the class 
 in the former case, or the intelligence in the latter case, will 
 stand. f 
 
 It is evident also that detailed directions will not be given in 
 connection with every problem. In many cases the question 
 will be stated and the pupil will be left to devise his own experi- 
 mental method of attacking it and to do most of the thinking 
 involved for himself. With large classes problems of this kind 
 can be given only after much carefully directed work has been 
 accomplished. With small classes, on the other hand, or when 
 trained assistance is available, the more independent method 
 may be used almost from the start and with the very best 
 results. 
 
 1 This question is discussed more fully under Use of the Text-book, 
 chapter V., section d (p. 136). 
 
100 INSTRUCTION IN THE LABORATORY 
 
 c. Selection of Experiments : - In general the selection of the 
 experiments should be made so as to afford the pupil oppor- 
 Considera- tumt y to handle and become acquainted with all 
 tions affect- important substances, and to furnish him with mate- 
 ing selection. . , r i r i 
 
 rial for systematic study of each topic m order that 
 
 some material for generalization may be available. Such chem- 
 ical changes only should be used as may surely be brought 
 about when the conditions are definitely specified. The inclu- 
 sion of a fact should be determined by its value for the pur- 
 pose in view, and not because it is easy to show, or because 
 its presentation is sanctioned by custom. The experiment 
 should reach the point to be illustrated as directly as possible. 
 Thus measurement of substances by observing the volumes of 
 solutions is less direct than weighing, since the latter is the mode 
 of measurement in terms of which chemical quantities are de- 
 fined. Gravimetric experiments should therefore precede volu- 
 metric. Artificial methods should be replaced by natural when 
 possible. For example, making sulphuric acid from sulphur 
 dioxide obtained from sulphuric acid does not illustrate the 
 commercial process, and is in itself stultifying. It is equally 
 easy to burn pyrites (in a hard glass tube) in a stream of air 
 drawn or driven over it. 
 
 Above all, the numerous limitations of the pupil, both in gen- 
 eral and in view of his particular state of advancement, must not 
 be forgotten. The apparatus which can be furnished by the 
 laboratory or handled by the pupil must be thought of. ] The 
 degree of skill and the knowledge which the pupil has acquired 
 must be borne in mind. The length of the periods available 
 for work must frequently lead to the exclusion of some val- 
 uable experiments. In discussing the results, the precautions 
 taken by the pupil must be considered in the light of the much 
 greater precautions which scientific work of permanent value 
 demands. The small number of data he obtains, as compared 
 with the mass of data tvhich alone can furnish a basis for confi- 
 dent generalization, must be remembered. We shall presently 
 discuss more fully the incompleteness of much of the pupil's 
 
INSTRUCTION IN THE LABORATORY IOI 
 
 work in consequence of these limitations, and the necessity for 
 leading him to realize precisely how far he contributes to the 
 result, and how far the book is to be called upon for furnish- 
 ing an adequate foundation for the conclusion (p. 136, cf. also 
 p. 99). All this will be made much clearer if some oppor- 
 tunity is taken to explain in Detail some particular chemical 
 investigation, with all the laborious purification of materials and 
 analysis of multitudes of specimens which must be accomplished 
 before even comparatively limited conclusions can be reached. 
 Almost any account of inorganic research l will furnish material 
 for this. 
 
 (The chief general rule is that the work should be, as far as 
 possible, intensive rather than extensive. _J A sufficient sample 
 of the whole ground covered by the science must 
 be included, for there are many reasons which rather than 
 
 make this desirable in the course given in the ^* ive 
 secondary school. But it must be remembered 
 that a thorough knowledge of one small portion really implies 
 the ability to master other and different portions more rapidly, 
 and is therefore, from every point of view, a thing desirable of 
 attainment. The intensive method means also that the total 
 acquisition must be greater, for it is only after we know some- 
 thing about some chemical substance that we are able to do 
 the most intelligent work with it. Nor is intensive work more 
 difficult than the other. On the contrary, it is much easier to 
 enlarge our knowledge of a group of closely related things, than 
 to enlarge it by passing rapidly from one group to another of 
 things which are strange and less closely related. This instruc- 
 tion may tax the power of the teacher more, but it must be less 
 difficult for the pupil. A Cook's excursion covering ten cen- 
 turies of time and ten square miles of area in a single day is 
 notoriously not the best means of studying the history and soci- 
 ology of a people and its institutions. Laboratory work which 
 resembles a personally conducted glance at many different things, 
 
 1 For list of papers, see chapter VIII., section III. (p. 214). 
 
102 INSTRUCTION IN THE LABORATORY 
 
 may leave a confused sense of many more or less interesting 
 impressions, but it cannot furnish an opportunity for learning 
 chemistry. 
 
 It is this superficial quality which much school work possesses 
 that prevents its recognition by the colleges. If the study of 
 Latin in the school were of the same flimsy nature, and included 
 no genuine investigation of the text, no mastery of the thing 
 itself, and no adequate acquaintance with it in all its complexity 
 as a medium of communicating thought, it would receive no 
 recognition either. Both subjects must submit to the same 
 test of educational value, or the whole work must be done over 
 again in college. As Professor Bard well says, 1 speaking of chem- 
 istry, " ingenuity and initiative power . . . come to the student 
 not ... by looking through experiments to greater things be- 
 yond, but by looking into experiments to find the simpler things 
 which are near at hand." The same may be said of any of the 
 benefits the study of the subject may confer. The limit of in- 
 tensive study is to convert the whole work into research 'and 
 give up the idea of covering much ground. My point is that 
 both features must be preserved, and that of the two the former 
 is the more important. 
 
 d. An Illustration : In a well-known laboratory outline 
 I find the following : " Treat a few small crystals of potassium 
 iodide with concentrated sulphuric acid. What 
 iodide and do you notice? Compare with the results ob- 
 Suiphuric tained when potassium bromide and sodium chlo- 
 ride were treated in a similar way." This brief 
 statement constitutes the whole directions for the experiment. 2 
 I have found this apparently simple experiment, at least at the 
 stage at which it naturally appears in the course, by far the most 
 difficult of the whole series for the year. In the first place, if 
 
 1 New England Association of Chemistry Teachers, Report of the 
 Sixth Meeting, 3. 
 
 2 It ought to be said that the author of the book does not profess to 
 offer the sort of directions combining instruction with direction which we 
 have advocated. He says expressly that everything has been omitted 
 tliat " does not serve to insure the success of the experimental work." 
 
INSTRUCTION IN THE LABORATORY 103 
 
 rather large crystals are taken, with much acid, and heat is not 
 applied, no noticeable amount of gas may be given off at all. 
 To get uniform results, the salt must be powdered and simply 
 moistened with acid, and heating must be suggested in case 
 the pupil does not get more results than he can take care of 
 without this. In the second place, the pupil observes fuming 
 in the air outside the mouth of the tube, a violet-coloured 
 vapour in the tube, a brown film on the walls of the tube, an 
 odour (sulphur dioxide or hydrogen sulphide, or both), and 
 often a yellow sublimate (sulphur). Unless he is warned, he 
 supposes that one body has all these properties. Without 
 guidance he will never realize that from three to five distinct 
 products are concerned. In the third place, he may not have 
 yet met with free iodine, sulphur dioxide, or hydrogen sulphide, 
 or, if he has studied them, he will have forgotten the properties 
 of the last two. He certainly must have encountered hydrogen 
 chloride, but he has probably forgotten that it fumed in moist 
 air, and in any case he will not reason that, the halogens being 
 similar elements, the new fuming gas must be hydrogen iodide. 
 In the fourth place, he will try to put the whole of the products 
 into one equation, and involve himself in an arithmetical puzzle 
 of some difficulty, as well as a chemical absurdity. In the last 
 place, he will fail to infer the oxidizing power of sulphuric acid 
 and the easy oxidizability of the iodides, unless he is invited to 
 do so. 
 
 I question the advisability of giving this experiment in ele- 
 mentary work at all. But in college work, to prevent the pupils 
 being hopelessly muddled and discouraged, I have been led 
 gradually to elaborate the directions. They have reached the 
 following form, which will serve as an illustration of the sort of 
 thing which is required to secure intelligent practical study of 
 any problem : 
 
 " Place about a gram of powdered iodide of potassium in a 
 test-tube and moisten it with concentrated sul- Model of 
 phuric acid (?). Warm, if necessary. Investigate Directions, 
 the result as follows : 
 
104 INSTRUCTION IN THE LABORATORY 
 
 " a. Breathe across the mouth of the test-tube to ascertain 
 the effect of the gas on moist air. What gas previously made 
 showed the same behaviour? Remembering the similarity 
 between the halogens and between their corresponding con> 
 pounds, what do you infer in this case? To confirm this con- 
 clusion, lower a glass rod dipped in ammonium hydroxide 
 solution into the test-tube ( ?) : also a strip of filter paper dipped 
 in lead nitrate solution [R] (?). x 
 
 " b. What is the colour of the gas, or any part of it ? What 
 is the coloured body ? (This assumes that iodine has been han- 
 dled before.) Was there any corresponding product when 
 sulphuric acid acted on a chloride ? By what kind of chemical 
 action could this coloured substance be formed from the one 
 identified in a? 
 
 " c. Study the odour of the gas and describe it (?). Was 
 there any effect on the lead nitrate which remained unex- 
 plained in #? Can you now explain it [R]? (This [R] as- 
 sumes that hydrogen sulphide has not yet been studied.) 
 
 " The work in a and b leads to the recognition of two distinct 
 gaseous products. That in c will yield one, and perhaps two 
 others. Still another distinct solid product may be observed 
 on the walls of the tube (?). Construct separate equations 
 representing the formation of the first product from the orig- 
 inal materials, and of each of the others from this product and 
 sulphuric acid. What two properties of sulphuric acid and 
 what property of hydrogen iodide are illustrated by this set of 
 experiments." 2 
 
 1 [R] indicates that the pupil, in understanding what he is asked to do 
 or in interpreting the result, needs information he cannot have gained in 
 previous work, and must therefore refer to some book or to the instructor. 
 Here he is ignorant of the action of iodides on lead salts. 
 
 2 For examples of coherent directions and thorough working out of 
 a problem, see the treatment of hydrates in Richardson, 6-8, of 
 mechanical mixture and chemical combination in Remsen and Randall, 
 7-10, and of chalk in Perkin and Lean, chapters XIX. and XXX. 
 A large proportion of the work in E. F. Smith and Kellar (Experiments 
 in General Chemistry, Philadelphia, Blakiston) and Volhardt and Zim- 
 
INSTRUCTION IN THE LABORATORY . 105 
 
 IV. The Pupil and his Attitude. 
 BIBLIOGRAPHY OF HEURISTIC TEACHING. 
 
 Second Report of the Committee of the British Association on The 
 Present Methods of Teaching Chemistry. Report of the British Asso- 
 ciation, 1889. Also published separately by the Association. London. 
 1889. 
 
 Third Report of Same Committee, with additions by Professor H. E. 
 Armstrong. Report of the British Association, 1890. Reprinted in 
 NATURE, XLIII. (1891), 593. 
 
 Armstrong, H. E. On the Heuristic Method. Special Reports on 
 Educational Subjects, vol. II. Printed for H. M. Stationery Office, Lon- 
 don, and sold by Eyre & Spottiswoode. 1898. 
 
 The 46th Report of the Department of Science and Art. Printed 
 for H. M. Stationery Office, London, and sold by Eyre & Spottiswoode. 
 1899. Abstract in NATURE, LX. (1899), 381. 
 
 Picton, Harold. The Great Shibboleth. SCHOOL WORLD, London, 
 vol. I., Oct. and Nov., 1899. 
 
 Perkin, W. H. Vice-Presidential Address before the Chemical Sec- 
 tion. Report of the British Association, 1900. Reprinted in NATURE, 
 
 LXII.477- 
 
 Discussion in THE SCHOOL WORLD, II. (1900), 358,396, 437, 476. The 
 last letter, by C. M. Stuart, gives an instructive illustration in detail. 
 
 Syllabus of an Elementary Course in Physics and Chemistry, issued by 
 the Incorporated Association of Headmasters. London, Whittaker & Co. 
 1900. 
 
 Syllabus of an Advanced School Course in Physics and Chemistry, 
 issued by the Incorporated Association of Headmasters. London, Whit- 
 taker & Co. 1899. 
 
 Whether we consider the best means of awakening and sus- 
 taining interest, or of fostering the scientific habit of thought, 
 it is evident that leading the pupil to adopt the attitude of a 
 discoverer will be most likely to accomplish the result desiredjf 
 At the same time there are parts of the subject to which this 
 method of approach is inapplicable. If, for example, we sug- 
 gest that the pupil should discover the fundamental laws of the 
 subject for himself, we are putting upon him an impossible task, 
 and indeed deceiving him in regard to the nature of the foun- 
 
 mermann (Experiments in General Chemistry, Baltimore, The John 
 Hopkins Press) illustrates these qualities admirably. 
 
106 INSTRUCTION IN THE LABORATORY 
 
 dation of a law. Verification is the term more applicable to 
 work in this direction. Nor would we even suggest that the 
 whole of the ordinary facts should be approached by the 
 method of " find out for yourself," for the progress by this plan 
 would be too slow for the purposes of a secondary school 
 course. Much may be furnished in the class room, but 'the 
 laboratory work should be divided between a small amount 
 of verification and a large amount of what may be called 
 investigation. ) 
 
 a. The Verification of Laws : When the purpose of an 
 experiment is the verification of a law, it will naturally be 
 preceded by a careful study of the facts which the law covers. 1 
 While this necessarily carries with it full knowledge of the re- 
 sult of the experiment, it does not deprive the experiment of 
 any of its value. Practical illustration will be required in order 
 to make the understanding of the law more vivid, the recollec- 
 tion of its content more lasting, and, above all, to show by 
 means of a sample, admittedly rough, what the general nature 
 of its experimental basis is. 
 
 b. 2 he Attitude of Discoverer : the Heuristic Method : 2 It is 
 evident that the nature of the directions will have much to do 
 
 with the attitude of the pupil towards his work. 
 Outline of . 
 
 Heuristic In the ideal application of this method, however, 
 
 Work ' no book and no directions are used. The ques- 
 
 tions to be solved are suggested as far as possible by the pupils 
 themselves in the course of the examination of materials given 
 to them. Naturally the demands made upon the pupil must 
 be graduated, and at first the questions must be very simple. 
 An outline prepared by Professor Armstrong (Second B. A. 
 Report) will serve for illustration. Natural objects are ex- 
 amined, their origin, manufacture, and uses discussed, their 
 appearance described. This is the first stage. Next, measure- 
 ments of length, area, weight, density, temperature, and so forth 
 
 1 Report of the Committee of Nine. University of the State of New 
 York, High School Bulletin No. 7, 710. 
 2 Cf. pp. 19, 54 and 56. 
 
INSTRUCTION IN THE LABORATORY IO/ 
 
 are made. This is the second stage. Then the effect of heat 
 on many things is examined for the purpose of gaining experi- 
 ence. Metals are heated in various ways ; wood is dried and 
 then burned for examination of the ash ; minerals, such as sand, 
 clay, sulphur, etc., are also heated. This is the third stage, and 
 prepares for the fourth or problem stage in which the study of 
 some chemical change may first be taken up. 
 
 The first chemical problem is that of determining what happens 
 when iron rusts. The pupils must not only " find out for them- 
 selves," but as far as possible be led to imitate the detective's 
 method, and find out how to find out for themselves. The ques- 
 tion of the relative progress of rusting in moist and dry filings may 
 suggest itself. Or air without water (dry) and water without 
 air (boiled) may be tried. Then the iron may be weighed be- 
 fore and after rusting, and the search for the extra material begun. 
 The question will be whether air or water furnishes the material. 
 Moist iron tied up in muslin may be rusted in a pickle bottle 
 inverted over water. The disappearance of part of the air leads 
 to the treating of the same air with fresh filings, and of the same fil- 
 ings with fresh air, to see whether the change in either substance 
 reaches a limit. The experiments may include other metals, 
 and be extended in various ways according to the questions 
 which suggest themselves to the pupils. 
 
 With a little care a series of interesting problems of this kind 
 can be arranged in such a way that the solution of the preced- 
 ing problems brings the pupil within measurable Nature, 
 
 distance of the solution of the next. When suffi- Limitations, 
 
 and Results of 
 cient skill has been acquired, the quantitative stage Heuristic 
 
 will be entered upon. Work * 
 
 While in this way a large amount of chemistry may be 
 learned, the object is not to teach chemistry, but to teach the 
 pupils how to learn, to confer ability and not knowledge. The 
 progress in one sense will be slow, but the work, as long as 
 interest is maintained and rational thinking and experimenting 
 goes on, is fulfilling its mission- It cannot be objected that 
 this kind of study is too difficult, for experience shows that it 
 
108 INSTRUCTION IN THE LABORATORY 
 
 can be done even by young children. Picton ( The Great Shib- 
 boleth ) has outlined a course of this kind in chemistry for boys 
 about twelve years old which he finds to work admirably. He 
 says (SCHOOL WORLD, II., 397), "My experience is that 
 the young boy of nine or ten can be readily got to think ; the 
 boy who has had considerable school training on ordinary lines 
 can only rarely be got to think at all." 
 
 Illustrating the really remarkable way in which children, to 
 whom text-books are quite unknown, will prove successful in the 
 solution of intricate problems, a correspondent in the SCHOOL 
 WORLD (II., 397) mentions four boys who, after two terms' 
 work in a physical laboratory, investigated the rate of expansion 
 of water when heated from o upwards. They used two 
 methods, and got good curves for the apparent expansion. 
 They saw clearly, however, the relation between this and the real 
 expansion, as it would have been in the absence of the glass vessel. 
 They tried first to measure the expansion of the glass with cal- 
 lipers between o and 60, but, finding the results not exact, 
 were at a loss how to proceed. When it was suggested that 
 some Frenchman had determined the expansion of mercury 
 independently of the vessel containing it, the boys ransacked 
 the library and found a description of Regnault's apparatus and 
 results. After being dissuaded from repeating his experiments, 
 they corrected their own measurements by employment of his 
 table. The writer adds, " undoubtedly the method has its draw- 
 backs. The 'investigation' above mentioned occupied the 
 better part of a term, during which, no doubt, the boys might 
 have read through some little text-book, or pottered through a 
 course of ready-made * experiments ' on * heat.' It also 
 cost the master ... a good deal of labour. But he finds that 
 a very little of this sort of work goes a very long way. ... It 
 seems to confer a power that is not acquired in any other way. 
 The pupil's mind gains a freedom, a power of seeing things for 
 itself, an alertness and adaptability in turning to fresh matter, 
 which make great gaps in methodic knowledge of comparatively 
 little importance. I have more than once been astonished at 
 
INSTRUCTION IN THE LABORATORY 109 
 
 the ease with which boys, who have worked on this plan within 
 a very small range, have been able to grasp the bearings of ex- 
 perimental work in quite another department, .... their eyes 
 [seemed] to see things and processes in themselves, and not 
 through the mists of conventional terminology." 
 
 Since the course of the pupil's inquiries must be as inde- 
 pendent as possible, the direction which it may take cannot be 
 foretold. The teacher must assist and guide with judgment, 
 and, in general, as little as possible. A severe tax, however, will 
 frequently be put upon the breadth of his knowledge of the sub- 
 ject, upon his time, and upon his mechanical skill. 
 
 While work exclusively on these lines, although pre-eminently 
 suited to the needs of young pupils in the nature work of the 
 grammar school and below it, does not furnish the Application 
 knowledge of chemistry which is expected in the ifl Teaching 
 secondary school, it is evident that this attitude is 
 the one to be cultivated when chemistry itself is being taught. 
 I imagine that, when hydrogen is being studied, in nine hun- 
 dred and ninety-nine cases in a thousand the pupil is informed 
 directly or indirectly that it comes from the acid. Suppose 
 that, instead of this, the question were raised whether the hydro- 
 gen came from the metal, the hydrogen chloride, or the water. 
 If the pupil's experience had dealt with the last of these three 
 substances only, the problem would be difficult to solve. If 
 other metals were tried, many would be found to give hydrogen. 
 Do these all contain it? Other acids would give hydrogen. 
 Are they the source of the element? Substituting another sol- 
 vent such as toluene prevents the appearance of hydrogen. 
 Was water therefore the source of it ? A little thought will 
 show that a large amount of careful original work would be re- 
 quired to demonstrate that the acid was the source. In our 
 teaching we are continually thus skimming airily over gaps 
 which conceal not one or two steps, but whole flights of steps, 
 all of which would have to be taken in a scientific study of the 
 subject, although they are superfluous when memorization of 
 the results is the only object. 
 
IIO INSTRUCTION IN THE LABORATORY 
 
 Practically, the effort will be to include as much heuristic work 
 as possible in the secondary school course. The spirit of it 
 should certainly be of this kind. Now and then problems of a 
 simple nature can even be given, after the material needed for 
 their solution has been furnished, and the pupil may be left to pro- 
 vide his own directions for their solution. Thus, after equiva- 
 lents have been measured, the pupil might determine the 
 proportion of zinc oxide in zinc dust. Again, he might be 
 instructed to find a solvent for some material ; he might be 
 told to make some salt in a pure form from an impure mineral, 
 such as manganous chloride from manganese dioxide ; or again, 
 he might be asked to demonstrate the presence of one or more 
 of the elements in ammonium carbonate. The exercises in the 
 recognition of unknown substances (p. 178) are problems of 
 the same order and are of the highest value. 
 
 c. Summary : It is safe to say that much chemical instruc- 
 tion does not reach the ideal sketched in this and the preceding 
 
 sections of the chapter. Yet chemistry will never 
 The Ends of 
 Instruction be recognised, nor will it deserve to be recognised, 
 
 and Means^' as Latin and other olcler studies are > either as an 
 Attaining element in sound secondary education, or in work 
 preparatory to college, until it is better organized 
 along lines like these. We are only beginning to recognise 
 this. It is not sufficient to suggest more thorough work. The 
 pupil will be lost in details without the instruction which must 
 go with it. Yet if the work is not made more elaborate, the 
 result must be superficial. To fit the science for its place with 
 the older studies, we must have guidance of a restrictive nature, 
 which shall confine the possibilities of experiment, observation, 
 and inference within limits somewhat like those set by the text, 
 the grammar, and the dictionary. We must have guidance of 
 an analytical kind to assist in the finding and study of all the 
 points to be considered in each experiment. We must have 
 guidance of a synthetic nature to stimulate the inter- relating of 
 various facts and views brought out by present and past experi- 
 ments. All this is necessary in order that the instruction may 
 
INSTRUCTION IN THE LABORATORY III 
 
 be an imparting of organized knowledge and not a jumble sale, 
 and that, with the acquirement of an ever- tightening grip on the 
 inner spirit of the science, rather than an ever-growing collec- 
 tion of rag-bag odds and ends, the pupil may advance in the 
 profundity as well as the area of his knowledge. This alone 
 can make chemistry a genuine means of culture and a discipline 
 of real benefit in the later work of life. ( We need more detail, 
 and at the same time more perspective. I The Latin language 
 cannot be studied by any other method ; in this lies its strength. 
 It seems to be possible to think that a study of chemistry which 
 is not of this kind may still be a study of the science ; in this 
 lies its weakness. The purpose of scientific education is the 
 application and higher cultivation of the critical powers by com- 
 parison, discrimination, and reasoning. It must also exercise 
 and cultivate the power of scientific imagination, for, without 
 this, no clear conception of the chemical tendencies of matter, 
 and the conditions which influence their results, can be 
 formed. That criticism and imagination are required in and 
 are strengthened by its study, when this is prosecuted in the 
 proper way, may be claimed for chemistry at least as confidently 
 as for any other study. 
 
 V. Laboratory Technique. 
 
 One of the failings of chemistry teaching is the neglect of 
 laboratory technique. The obvious value of neat and careful 
 work, and of knowing how to adapt means to ends in mechani- 
 cal matters, is so great, not only on account of its general edu- 
 cational value, but more especially because it is absolutely 
 indispensable in really instructive chemical experimentation, 
 that this neglect may well seem astonishing. It can be ex- 
 cused in any given case only on the ground that adequate 
 supervision of a large class was impossible. In handling large 
 classes of pupils who have already studied chemistry for a year 
 in the secondary school, I have, for example, rarely found one 
 who had any idea of how to ascertain whether a piece of 
 apparatus was air tight or not. They usually blow into it as if 
 
112 INSTRUCTION IN THE LABORATORY 
 
 it were a pair of bagpipes, oblivious of the fact that a hole 
 nearly as large as their own throat would be necessary before 
 the defect would be noticeable. The rational way of arranging 
 the test, so that in some fashion the eye is the instrument used, 
 forms an instructive lesson in itself. 
 
 A good deal of attention is required in teaching proper 
 manipulation. It is long before the pupil discovers that the 
 
 stop-cock is meant for lowering the eras-flame, as well 
 Manipulation. I . . . . , , 
 
 as for extinguishing it, yet he has continual oppor- 
 tunity to observe the risk in boiling a small amount of liquid 
 in a large vessel with a large flame. It seems impossible 
 to impress upon the minds of some pupils the proper method 
 of folding a filter paper, of cutting it to circular form, and 
 making it invariably smaller than the funnel. The clever use 
 of the test-tube is a small art in itself. The pupil should 
 learn the reason for the employment of different kinds of 
 apparatus, such as retorts, flasks, test-tubes, etc., and in some 
 exercises should be left free to select or devise apparatus for 
 himself. The pupil is slow in learning the difference between 
 thick and thin glass vessels in connection with the application 
 of heat. Repeated misfortunes seem never to teach him that 
 careful boring of corks and fitting of tubes takes no longer than 
 making a funnel-shaped or ragged opening, and sometimes 
 saves hours of time in subsequent work. The laboratory in- 
 structions, no matter how minute, will not secure the desired 
 result without supervision and criticism by the teacher. 1 
 
 Weighing, unless it has already been learned in the physical 
 laboratory, requires careful preliminary instruction, if damage 
 
 to the balance and discouragement in the work 
 
 are to be avoided. The most frequent mistakes 
 seem to arise from failure to count the weights correctly. 
 Special emphasis should be laid on the necessity of ascer- 
 
 1 These general operations are well described by Newth, Elementary 
 Inorganic Chemistry, 15-34, by Young, Elementary Principles of Chem- 
 istry, Part II., 91-104, by Newell, Experimental Chemistry, 1-9, 329-353, 
 and 365-369, by Peters, Modern Chemistry (Maynard, Merrill & Co.), 
 355-380, as well as by many other authors. 
 
INSTRUCTION IN THE LABORATORY 113 
 
 taining the weight, first by examination of the vacant places in 
 the box, and then checking by counting the weights themselves 
 as they are replaced. The working of glass, even <ji ass _ wor k- 
 if it go no further than the bending or drawing out tog. 
 of glass-tubing and fire-polishing of the sharp edges, requires a 
 separate exercise. A Bunsen burner on which was inscribed in 
 large letters, " do not use me in bending tubing," would be a 
 boon to the teacher. 1 
 
 VI. Quantitative Experiments. 
 REFERENCES. 
 
 Newell, Lyman C. Quantitative Experiments in Chemistry for High 
 Schools. SCHOOL SCIENCE (Monthly. Chicago, 138 Washington St.), 
 I. 12. This new journal has already published several valuable articles 
 on subjects of interest to teachers of chemistry. 
 
 Ramsay, Wm. Experimental Proofs of Chemical Theory for Begin- 
 ners. London and New York, Macmillan. 1893. 
 
 Tilden, W. A. Hints on the Teaching of Elementary Chemistry. 
 London and New York, Longmans, Green & Co. 1895. 
 
 Cornish, Vaughan. Practical Proofs of Chemical Laws. London and 
 New York, Longmans, Green & Co. 1895. 
 
 Smith, Alexander. Laboratory Outline of General Chemistry. Chi- 
 cago, The University of Chicago Press. 1900. 
 
 We have already referred to the emphasis which is neces- 
 sarily laid in chemistry upon quantitative measurement and the 
 interpretation of the results. Imaginary examples, as we have 
 hinted (p. 80), may serve when actual ones are not available, but 
 the ease with which properly chosen measurements can be 
 
 1 Clear instructions in regard to glass-working are given by Newth, 
 ibid., 35-39, by R. P. Williams, Elements of Chemistry (Ginn & Co., 
 Boston, 1897), 384-387, and by G. M. Richardson, Laboratory Manual 
 and Principles of Chemistry (Macmillan, 1894), 225-229. The teacher 
 will find some accomplishment in this art invaluable. It is best acquired 
 from direct instruction by some glass-blower. Much may be learned, 
 however, by the study of works like Shenstone's Methods of Glass Blowing 
 (Longmans, Green & Co., 1897), or Threlfall's On Laboratory Arts (Mac- 
 millan, 1898), chapter I. 
 
 I I ft I I \ 1 1~ r- r+ 
 
114 INSTRUCTION IN THE LABORATORY 
 
 carried out leaves little excuse for their omission, either from 
 the demonstration or from the laboratory work of the pupil. 1 
 
 a. Limitations : 2 It is clear that the experiments chosen 
 must be such that they are easily performed, and furnish 
 fairly good results in the hands of beginners. They should 
 employ no complicated or expensive apparatus. They should 
 be capable of performance by a single pair of hands within the 
 laboratory period. There is no disadvantage, however, in per- 
 mitting two pupils to work together, provided they figure out 
 the results separately. The most important condition is that 
 it should be possible to furnish the pupil with instructions 
 which will relieve the teacher of the burden of continuous 
 supervision of each individual. 
 
 The chief misunderstanding which seems to arise in connec- 
 tion with this work is a confusion of it with quantitative analysis. 
 
 The latter has for its object the learning of tech- 
 The Degree of ... - , , . . rr ,. 
 
 Exactness nique of the most refined description. 1 he present 
 
 Required. experiments have for their use the comprehension 
 of how quantities in chemistry are determined. Of course 
 sufficient precautions must be taken to insure results which are 
 approximately correct, or are at least concordant. It is 
 frequently objected that results which are not exact are not 
 only without value, but are misleading. This seems to rest on 
 a misapprehension. No chemical work is absolutely exact. 
 The conclusion always takes into consideration the sources of 
 error, "and the probable magnitude of the error, in applying the 
 numerical value obtained. There is no reason why this should 
 not be done in the experiments of beginners also. Indeed 
 it should be one of the most instructive features of the work. 
 Nor is there any reason why inexact results, within certain 
 
 1 Their use is recommended by the Sub-Committee of the Committee 
 of Ten, by the Committee of Nine, by the Committee on College Entrance 
 Requirements, and, most recently, by the College Examination Board 
 of the Middle States and Maryland. 
 
 2 The whole subject of quantitative experiments is admirably treated 
 by Dr. Newell in SCHOOL SCIENCE (see References). 
 
INSTRUCTION IN THE LABORATORY 115 
 
 limits, should fail to point to a law expressed in mathematically 
 exact terms. 
 
 It is instructive to notice that most of the laws of chemistry 
 were accepted long before they were confirmed by work show- 
 ing any degree of exactness. Black {Experiments upon Mag- 
 nesia Alba?- 1782), for example, converted 120 grains of chalk 
 into quicklime and from this recovered 1 18 grains of the original 
 material, showing an error of 1.6 per cent. Lavoisier decom- 
 posed mercuric oxide and ascertained the weight of the mer- 
 cury and oxygen formed. The error appears to have been 
 about one per cent, yet these results were held to furnish 
 support to the law of conservation of mass. Proust ultimately 
 triumphed in his controversy with Berthollet, although his own 
 measurements of definite proportions showed errors varying 
 from .5 to 5.5 per cent. The law of equivalent proportions 
 was supported by Dalton by data which, in the light of modern 
 work, are seen to be affected by inaccuracies sometimes amount- 
 ing to 15 per cent. Dalton {New Chemical Philosophy, 318) 
 quoted, in support of the law of multiple proportions, values 
 for the ratios of nitrogen to oxygen in two oxides of nitrogen 
 which show an error of 8 per cent. 2 
 
 The ideal of quantitative work for beginners is i per cent 
 accuracy. That this may easily be attained with suitable ex- 
 periments, may be seen from the actual results of pupils' work 
 in many schools where they are used. 8 
 
 b. Equipment for Quantitative Experiments : No elaborate 
 equipment is needed for these experiments. Usually the same 
 pieces of apparatus which are used in ordinary work will serve 
 for them. The few special articles required may each be 
 employed in several if not all of the experiments. A sufficient 
 
 1 Alembic Club Reprints, No. i. Edinburgh, W. F. Clay. Easton, Pa. 
 Chemical Publishing Co. P. 29. 
 
 2 This subject is discussed in detail by Vaughan Cornish. Practical 
 Proofs of Chemical Laws, \ 5, 26, 43, 68, 79. 
 
 3 Sample results are given by Newell in SCHOOL SCIENCE, I. 16, 
 and on his Teachers' Supplement, 13, 14, 17, etc., and by Benton, SCHOOL 
 SCIENCE, I. 148. 
 
Il6 INSTRUCTION IN THE LABORATORY 
 
 equipment for a large class does not imply that each mem- 
 ber should be furnished with a complete outfit, since all need 
 not do the same or any quantitative experiment at the same 
 time. 
 
 The chief item is the balance. Using an expensive instru- 
 ment, however, is not only unnecessary, but wasteful. A bal- 
 ance with case, such as Becker No. 31, costing 
 The Balance. 
 
 $15, and sensitive to one centigram, will serve all 
 
 purposes. A set of weights (50 gr. i cgm.), costing in a 
 box $1.50, will also be needed. Newell {Experimental Chemis- 
 try, 347) describes a mode of enclosing common horn-pan 
 scales, costing originally $1.25 to $2.25, which makes them 
 applicable in this ' work, and other teachers confirm this 
 statement. 
 
 One source of trouble lies in the rusting of the balance. This 
 is reduced to a minimum in a form of the instrument which 
 is manufactured entirely of aluminium and glass/ and is rec- 
 ommended and figured by Benton (SCHOOL SCIENCE, I. 
 148). Another source of annoyance is the continual loss of 
 the smaller weights. This becomes impossible with the use of 
 the Chaslyn balance, 2 figured on the back of the same number 
 of SCHOOL SCIENCE (May ist, 1901), in which rings which can- 
 not be removed from the apparatus take the place of weights. 
 I have found this balance very satisfactory. 
 
 The only other more or less special pieces of apparatus re- 
 quired are burettes (graduated, and holding 50 c.c.), porcelain 
 
 crucibles (No. o), porcelain boats, large bottles 
 Apparatus. ( one ntre bottles, or five-pint mineral-water bottles), 
 
 a barometer, and thermometers. Rubber stoppers 
 save the loss of much time, and indeed are in the end cheaper 
 than corks. Platinum ware is never needed, but clean crucible 
 tongs will be found useful. 
 
 1 Made by The Crowell Apparatus Co., Indianapolis. 
 
 2 Made by The Chicago Laboratory Supply and Scale Co. Another 
 form, "the triple beam balance," sensitive to 8 mgm., is made by the 
 Apfel-Murdock Co. (82 Lake St., Chicago). A similar instrument is 
 sold by Richards & Co. also. 
 
INSTRUCTION IN THE LABORATORY 1 1/ 
 
 c. Suitable Quantitative Experiments: So many of these 
 have been employed in recent text-books and laboratory manuals 
 that detailed description is unnecessary. We may Quantitative 
 refer to a few which have been tried and found Experiments, 
 trustworthy. They are arranged according to the subjects in 
 connection with which they are used. 
 
 Definite Proportions : Action of hydrochloric acid on varying 
 quantities of ammonium hydroxide or sodium carbonate (A. 
 Smith/ 8). 
 
 Combining Weights : By direct union of copper and oxygen, 
 or direct formation of cuprous sulphide (Tilden, 15). In- 
 directly by action of nitric acid on copper, zinc, iron, tin, or mag- 
 nesium, and ignition leaving the oxide (Tilden, 14; A. Smith, 
 18). Indirectly by union of iodine and magnesium and for- 
 mation of the oxide by ignition of the iodide (Young, 2 34). 
 By decomposition, mercuric oxide (Nevvth, 3 105), silver 
 oxide (Ramsay, 4 97). The composition of water is some- 
 what difficult to measure on account of the small weight of the 
 hydrogen (Newell, 5 97 ; Tilden, 34 ; Perkin & Lean, 286). 
 
 Hydrogen Equivalents : By measuring the volume of hydro- 
 gen displaced by zinc, magnesium, aluminium, sodium, etc. 
 (Remsen, 6 47; A. Smith, 19; Perkin & Lean, 204; Torrey, 7 
 147). By measuring the weight of the hydrogen lost (Perkin & 
 Lean, 206 ; Reynolds, 8 23). 
 
 Inter-Equivalents of Metals : Zinc and copper (Cornish, 
 91), zinc and silver (Newth, 140), magnesium and silver 
 
 1 The names in parenthesis in this section refer to books listed in the 
 Bibliography or described already in other connections. 
 
 2 A. V. E. Young. Elementary Principles of Chemistry. Part II. 
 
 3 Newth. Elementary Inorganic Chemistry. 
 
 4 Ramsay. Experimental Proofs of Chemical Theory. 
 
 5 Lyman C. Newell. Experimental Chemistry. 
 
 6 Remsen & Randall. Chemical Experiments. New York, Henry 
 Holt & Co. 1895. 
 
 7 James Torrey. Studies in Chemistry. 
 
 8 J. E. Reynolds. Experimental Chemistry. Part I. London and 
 New York, Longmans, Green & Co. 1897 (7th ed.). 
 
Il8 INSTRUCTION IN THE LABORATORY 
 
 (Reynolds, 17), iron and copper, magnesium and silver (Per- 
 kin & Lean, 302 and 305). 
 
 Multiple Proportions: Reduction of cupric and cuprous 
 oxides (A. Smith, 17). Reduction of nitrous and nitric oxides 
 and collection of the nitrogen (Ramsay, 82-86). The reduc- 
 tion of lead monoxide and dioxide will be found suitable if the 
 pure substances can be obtained. Note that the former takes 
 up carbon dioxide from the air. The monoxide is difficult to 
 reduce. 1 
 
 Solubility of Salts : Measurement at different temperatures 
 (Richardson, 9). 
 
 Raoulfs Laws : Depression of freezing point and elevation 
 of boiling point of solutions (Young, Part II., 54-57). 
 
 Gas Density : Several excellent methods are described by 
 Professor Ramsay (Ibid., 26, 34, 39, 45). These have been 
 borrowed freely, and many of them will be found in the other 
 books we have quoted. Another method, that of Regnault 
 (Perkin & Lean, 234), gives good results. 
 
 Volumetric : This takes the form usually of titration of solu- 
 tions of acids and bases. Volumetric experiments with gases, 
 illustrating Gay Lussac's law, we owe chiefly to Hofmann. 
 These are concerned with the volumetric composition of steam, 
 ammonia, and hydrogen chloride ; they are described in many 
 works. The combination of oxygen and nitric oxide (Tilden, 
 252; Young, 40), the volumetric composition of nitric oxide 
 (Tilden, 25 1) of ammonia (Ramsay, 59), and of the air (Cooley, 2 
 61) will be found useful. 
 
 Special ': A very instructive experiment, in which a weighed 
 amount of silver foil is converted first into the nitrate, then into 
 the oxide, and finally back to silver, is used by Benton 
 (SCHOOL SCIENCE, I., 157). It has the advantage of enabling 
 the pupil to check his result, since the silver is weighed at the 
 
 1 Other instructive illustrations are given by Young (Ibid., Part II., 
 30), W. R. Smith (SCHOOL SCIENCE, I., 87), A. Smith. 18. 
 
 2 Le Roy C. Cooley. Laboratory Studies in Elementary Chemistry. 
 New York, American Book Co. 1894. 
 
INSTRUCTION IN THE LABORATORY 119 
 
 beginning and end. The reduction of silver nitrate by hydro- 
 gen (Cornish, 34), measurement of water in hydrates (' water 
 of crystallization/ A. Smith, 21), and the proportion of the 
 carbon dioxide in a carbonate (Newth, 228; Newell, 215) 
 will also be found applicable. The determination of the com- 
 position of zinc chloride (Torrey, 140), when taken in con- 
 nection with the measurement of the hydrogen equivalent of 
 zinc, permits a complete investigation of the action of zinc on 
 hydrochloric acid to be made. 
 
 d. The Application of Quantitative Experiments : There is 
 one danger to which the use of exact measurement is liable, 
 and that is, that the pupil may be misled into thinking that the 
 operation of measurement is an end in itself. The scientific 
 mechanic who cannot see beyond the cross wires of a telescope 
 is not the person we are trying to train. Measurement is a tool 
 and should be used, aside from a preliminary exercise or so, 
 only in the solution of some definite problem. As Professor 
 Perkin 1 says, " measurements should, in fact, be made only in 
 reference to some actual problem which appears to be really 
 worth solving, not in the accumulation of aimless details." It 
 is in this respect that these experiments resemble investigation 
 rather than quantitative analysis. 
 
 The time at which the first quantitative experiment may be 
 given naturally depends upon many things, particularly the pre- 
 vious experience of the pupil. Some practice in Time of j^,,. 
 ordinary chemical work will be needed by way of duction ' 
 preparation. The experiments should be used, however, not later 
 than the laws which they illustrate, and measurements of com- 
 bining weights must certainly be introduced before equations 
 are used. To leave them to the end of the course is practically 
 to postpone them until they become superfluous. Their early 
 introduction is particularly desirable, in order that the pupil, in 
 spite of the laws he may have learned, may not acquire from 
 
 1 Vice-Presidential address already mentioned. See on this point 
 Picton, The Great Shibboleth ( SCHOOL WORLD, October and November, 
 1899), and also Lean (Ibid., II. (1900), 78). 
 
120 INSTRUCTION IN THE LABORATORY 
 
 his practical experience the impression that chemical propor- 
 tions are after all purely matters of chance. The teacher can 
 only find out by trial the earliest point at which, with his par- 
 ticular class, they may be introduced. 
 
 When obviously inexact results are presented, they should 
 never be dismissed abruptly and with contempt.^ Sometimes a 
 
 Treatment of discussion of these very results, and how he got 
 Poor Results. ^ Qm> w j tn tne pupil, w jn teac h more t } ian jf 
 
 they had turned out well, and had been accepted without criti- 
 cism. \ The fact must be continually impressed on the mind of 
 the pupil that it is the conscientious performance of the experi- 
 ment that is wanted, and not a certain result.) If the reverse 
 impression is given, the pupil may resort to ' cooking ' his 
 figures, and the exercise may do harm instead of good. The 
 teacher should always ascertain for himself, by trial with the 
 same apparatus, the limits within which results may be accepted 
 as representing good work. 
 
 In all cases the pupil should be warned not to throw away 
 the product, in case the result seems to be bad, until he has sub- 
 mitted it to the teacher. Sometimes the result may be corrected, 
 and repetition of the experiment be avoided, as when through 
 misunderstanding the pupil gets a result, correct, but different 
 from that which he had expected ; when the product has been 
 insufficiently dried ; or when some arithmetical error has been 
 made in the calculation. Pupils rarely feel any reluctance to 
 repeat experiments of this kind, a fact which in itself testifies 
 strougly to the interest they feel in them. 
 
 e. Benefits and Objections : The general benefits which 
 these experiments confer scarcely need enumeration. They 
 
 teach the necessity for care, exactness, patience, 
 Benefits. J 
 
 and cleanliness, by themselves demonstrating too 
 
 often the effects of lack of application of these elementary 
 virtues. They give the pupil a confidence in the exactness of 
 the experimental basis on which the science rests, and a respect 
 for exact experimental work, which he could not otherwise at- 
 tain. They take time, but their very slowness is in some ways 
 
INSTRUCTION IN THE LABORATORY 121 
 
 an advantage. The laboratory should be a place for thinking 
 as well as for seeing. I have found that questions often suggest 
 themselves to the minds of the pupil during the leisure which 
 some stages of these experiments permit, the effort to answer 
 which teaches them much they might not have otherwise 
 learned. The arithmetical problems arising out of these ex- 
 periments, founded as they are on their own data, are worked 
 by the pupils with an amount of interest, not to say eagerness, 
 which artificially made problems can never inspire. 
 
 Some of the objections l which have been urged against their 
 use have already been noticed incidentally. The statement 
 
 that high school pupils lack skill to carry out 
 
 3 Objections. 
 
 these experiments is either a commentary on the 
 
 selection which the teacher has made, or a piece of rather ob- 
 scure humour. It is in the effort to gain skill which they call 
 forth that part of their value lies. The argument that in colleges 
 quantitative analysis usually does not appear until the third year, 
 and that quantitative experiments are not given in general chem- 
 istry, may be a criticism of college teaching, but it is not an 
 argument against the use of these experiments. Finally, the 
 suggestion that historically chemistry was qualitative before it 
 was quantitative, and that the historical order should be fol- 
 lowed, seems to misapply an important principle. The history 
 of modern chemistry begins with Priestley, Lavoisier, and Cav- 
 endish, but it was the quantitative part of their work which 
 alone really deserved the designation fundamental. It is diffi- 
 cult to see why a pupil should be dragged through a fog- 
 bank of alchemy and empiricism simply because the rest of 
 the world lost its way and wandered in such a fog for hundreds 
 of years. 
 
 1 An extended treatment of a long list of objections, including all that 
 have been urged with the exception of two, is given by R. P. Williams, 
 New England Society of Chemistry Teachers, Report of the Fifth Meeting, 
 3-6. Some of the arguments in their favour are well put by Young, 
 Suggestions to Teachers, designed to accompany his Elementary Principles 
 of Chemistry^ 2-4. 
 
122 INSTRUCTION IN THE LABORATORY 
 
 VII. The Role of the Teacher in the Laboratory. 
 
 One of the most serious faults of much chemistry teaching is 
 that the pupils are allowed to work by themselves in the labo- 
 ratory in the absence of the teacher. \ None of the 
 
 Continuous benefits we have enumerated above, or of the re- 
 Attendance 
 in the suits anticipated from the methods of laboratory 
 
 ory ' instruction just described, can possibly be realized 
 in the smallest degree when this course is pursued. The pupils 
 cannot be expected to teach themselves chemistry any more 
 than they could give themselves instruction of the slightest 
 value in Latin or mathematics under the same circumstances. 
 The Latin room cannot teach Latin, and the chemical labora- 
 tory is not more fit than any other apartment to take the place 
 of the instructor. The natural result of neglect of continuous 
 and strenuous supervision is that the pupils think that the per- 
 formance of prescribed mechanical operations constitutes a study 
 of chemistry. This tendency of all laboratory work is exceed- 
 ingly difficult to combat, and continual questioning by the 
 teacher can alone keep the work on the level of an intellectual 
 exercise. No laboratory outline, however, carefully prepared, 
 can take the place of the living teacher. His questions are 
 directed to the particular features of the particular way of doing 
 each experiment and to the particular misconceptions or short- 
 comings of each pupil. No two cases are ever precisely alike, 
 and therefore no printed questions can ever meet the difficulty. 
 The disastrous blunder of permitting or encouraging unsuper- 
 vised work seems to be commoner in colleges than in secondary 
 schools. But, until it is recognised and remedied, we can 
 never secure either culture or a knowledge of chemistry, either 
 for the ordinary student or the prospective specialist, merely by 
 including of the science in our curricula. 
 
 Chemical manipulation is an art. It cannot be acquired 
 without models to copy and trenchant criticism as the work 
 proceeds. The latter must be applied the moment occasion for 
 it arises, or hours may be wasted in trifling with unimportant 
 
INSTRUCTION IN THE LABORATORY 123 
 
 features of an experiment, or in using an imperfect or inade- 
 quate piece of apparatus. Supervision of the technique is as 
 necessary in chemistry as in drawing or shopwork. ) Teaching 
 Some pupils seem naturally to possess the ' knack ' Technique. 
 of working neatly and successfully with little assistance, but 
 these are very few in number. The great majority are utterly 
 incapable of giving concrete expression to the directions with- 
 out frequent suggestions and warnings. 
 
 At the beginning, one teacher cannot handle successfully 
 more than fifteen students. The more the number assigned 
 to him exceeds this, the less thorough the instruc- j^ f 
 tion and the longer the time taken in reaching the instructors 
 same degree of proficiency must be. When once topup s> 
 a good start has been made, equally efficient work may be done 
 with a larger proportion of pupils to each instructor. If a 
 sufficient force of instructors is not available, the work can be 
 simplified and more time can be taken in covering the same 
 ground. 
 
 VIII. The Note-book. 
 REFERENCES. 
 
 Arey, A. L. A Paper on the Management of Laboratory Classes in 
 Chemistry, and the discussion following its reading. Albany, N. Y., The 
 University of the State of New York. High School Bulletin No. 7 ( 1900), 
 678-684. This covers almost all phases of the subject. 
 
 Cooke, J. P. Laboratory Practice. Pp. 6-8. 
 
 Keeping a note-book is a valuable aid in laboratory study. 
 The notes should be provided with prominent headings indicat- 
 ing the part of the subject which is being studied 
 and the Object of each experiment. Following this 
 should appear a statement of what was done, including the mate- 
 rials used, a description of the apparatus (with a sketch, if it seems 
 called for), and the procedure adopted. When all this is de- 
 tailed in the laboratory directions, however, it does not seem 
 necessary that it should be repeated, unless perhaps in an ab- 
 breviated form. Next, the observations which have been made 
 
124 INSTRUCTION IN THE LABORATORY 
 
 should be stated, then the inferences drawn from these, and in 
 most cases the chemical equations representing the changes 
 should be given. 
 
 Care should be taken in regard to the form in which the 
 
 notes are presented, but the lavishing of too much time upon 
 
 the unnecessary copying and beautifying should be 
 
 discouraged. The use of concise yet clear English 
 
 should be imperatively demanded. But a too formal division 
 
 of the notes into columns containing " requirements, conditions, 
 
 observations, conclusions," is not sufficiently elastic, represses 
 
 the individuality of the student, cultivates a mechanical view of 
 
 the subject, and should be avoided. 
 
 ( The majority of teachers favour the writing up of the notes in 
 final form in the laboratory rather than at home. This is un- 
 doubtedly the better method. Inasmuch as attainment of the 
 best form cannot be reached in this way at once, it is well to use 
 the even folios of the book for memoranda and ciphering, and 
 to write the notes in more formal fashion on the odd folios 
 opposite, and to do this immediately after the experiment has 
 been performed. 
 
 It is indispensable to the success of the system that the note- 
 book should be examined periodically by the teacher, and all 
 Examination blunders in English, errors in observation and mis- 
 of Note-books takes in chemistry marked distinctly. The correc- 
 tions themselves, however, should by no means be 
 made by the teacher. In discovering the truth and making the 
 necessary change himself, the attention of the pupil is called to 
 the matter much more forcibly. The note-book should be ex- 
 amined immediately after the first exercises, in order that by 
 criticism and suggestion the best way of making the notes may 
 be most quickly communicated. Later they should be examined 
 at regular intervals. Some teachers require that the note-books 
 be left in the laboratory at all times, and provide a shelf near 
 the door on which they may be filed as the pupils pass out. 
 They are thus available for examination during any moments of 
 leisure which the teacher may find. 
 
INSTRUCTION IN THE LABORATORY 12$ 
 
 The reading of note-books when the class is large is the most 
 laborious and least attractive task of the teacher. Indeed, in 
 many cases, systematic examination of all the books by one per- 
 son is impossible without assistance. Sometimes a classroom 
 hour may be devoted to the reading of notes by some of the 
 pupils and criticism by the other members of the class. Often 
 former pupils may be induced to take a share in the work. In 
 Normal Schools, in fact, the students will receive distinct benefit 
 from an opportunity to assist, to some small extent, in the in- 
 struction by examining note-books and taking part in the super- 
 vision of the laboratory work. 
 
 The extreme value of keeping a note-book in a suitable style 
 cannot be doubted. It impresses the facts ten times more 
 strongly on the memory than would be the case value of the 
 without its use. It gives practice in accurate and N te-l>ook. 
 clear expression. As an incident to the writing, the pupil usu- 
 ally finds his thoughts on the subject were not so perfectly 
 organized as he had supposed. In framing written answers to 
 the interrogation points and questions in the directions, he is 
 stimulated to group the facts in new ways, and is assisted in 
 studying the subject by the discovery of gaps in his thought and 
 in his observation which otherwise would have passed unnoticed. 
 If the note-making is to be perfunctory, it had better not be 
 attempted at all, for, instead of yielding the benefits we have 
 mentioned, it will simply waste the time of both pupil and 
 teacher. 
 
 IX. Emergencies. 
 
 Guarding the pupils from injury by specific laboratory direc- 
 tions, 1 due and pointed warning, and continuous oversight is one 
 of the most serious responsibilities of the teacher of p^ger from 
 chemistry. When, in spite of this, slight accidents Injuries, 
 occur, as they frequently do, he must be prepared to treat the 
 
 1 As prevention is better than cure, the pupils should be positively 
 forbidden to make any experiments of their own devising without first 
 consulting the teacher. 
 
126 INSTRUCTION IN THE LABORATORY 
 
 injury properly. Aside from damage to the eyes, burns are the 
 most serious injuries with which he is called upon to deal. They 
 are to be regarded very seriously, because, through the destruc- 
 tion of the protective power of the skin, infection will almost 
 always occur unless the burn is very small indeed. This will be 
 followed by suppuration, and the resulting wound will leave an 
 exceedingly ugly scar. In such cases, therefore, careful disin- 
 fection should never be omitted. 
 
 Burns through contact with hot bodies, or from burning liquids 
 like alcohol, should be treated first with an emulsion of linseed 
 oil and lime water. Burns produced by corrosive 
 liquids like bromine, sulphuric acid, and nitric acid 
 should be washed with water, and then the part should be 
 rubbed gently with a paste made of sodium bicarbonate and a 
 little water (the normal carbonate is alkaline and, having an 
 irritating effect, should not be used). In all these cases, to pre- 
 vent infection, carbolated vaseline or powdered boracic acid 
 should be applied liberally to every part of the surface burned, 
 and a bandage should then be wound around the whole. A 
 " wet dressing " is often used. Saturated boracic acid solution, 
 (i : 20) diluted with an equal volume of water, is employed. 
 The piece of lint, large enough to extend some distance beyond 
 the burn in every direction, is soaked with this solution, and cov- 
 ered with a sheet of oiled silk or " protective" to restrain evap- 
 oration. Burns caused by phosphorus are the most difficult to 
 heal. They should be first cleansed by washing with a brush 
 dipped in water containing a little carbolic acid. If necessary 
 carbon disulphide may be applied. The best results seem to be 
 obtained when the wound is then powdered over with picric 
 acid and wrapped in a wet bandage. When the injury includes 
 the contact of acid with the eyes, washing with water and a solu- 
 tion of sodium bicarbonate projected from a wash bottle should 
 be applied, and the victim of the accident sent at once to a com- 
 petent physician. 
 
 Cuts should be washed out with water, and, after certainty has 
 been reached that any glass they may contain has been removed, 
 
INSTRUCTION IN THE LABORATORY 1 27 
 
 they should be covered with court-plaster. A solution of ' iron 
 persulphate,' or, in an emergency, ferric chloride will arrest 
 bleeding. If the cut is otherwise than small, a dis- 
 infectant will be required. A dry mixture of sali- 
 cylic acid, one part, and boracic acid, two parts, applied liberally 
 and held in place by a bandage, is a suitable dressing. In case 
 of faintness, inhalation of ammonium hydroxide, or administra- 
 tion of five drops of ammonium hydroxide in a little water will 
 usually be effective. The irritation caused by inhaling acid 
 fumes will be relieved by inhalation of ammonia, and that from 
 chlorine and bromine by the inhalation of vapour of alcohol. 
 
 Fires caused by burning liquids like carbon disulphide are not 
 affected by water, and should be put out by liberal use of 
 
 sand. Burning clothing can be extinguished best 
 
 . r Fires. 
 
 by means of a wet towel. 
 
 The various materials mentioned above, along with a pair of 
 scissors, should be kept on hand in some special cupboard, in a 
 conveniently accessible position, and they should never be used 
 for any other purpose than that for which they are intended. 
 
CHAPTER V 
 
 INSTRUCTION IN THE CLASSROOM 
 
 IN order that the purposes which we have so far explicitly 
 discussed, or implicitly assumed, may be realized, several dis- 
 tinct means of instruction are at the disposal of the. teacher 
 and should all be used. Of these the individual laboratory ex- 
 perience of the pupils is the most important. The utilization 
 of this experience, however, will never occur spontaneously. 
 The results will remain largely incoherent and meaningless 
 without discussions, ' quizzes' in which they are infused 
 with life, experimental demonstrations in which they are am- 
 plified, problem-working in which they are made more definite 
 and are driven home, and book study and reference work in 
 which they are brought into relation with the rest of the 
 science. 
 
 a. Oral and Written Quizzes: The oral quiz naturally 
 follows the laboratory work and deals mainly with this, because 
 The Services ^ * s ^ ie notm f tne significant facts and their 
 Rendered by translation into chemical knowledge which gives 
 t e ^ " most difficulty to the beginner. It will draw out 
 much that was unheeded at the time, but remains accessible to. 
 careful questioning, and so will prepare the way for more adequate 
 observation in the future. It will also relate this work to the 
 statements of the book and keep the two from remaining two 
 different things, as they have a tendency to do. Through 
 criticism of loose expressions, by the teacher and by other 
 members of the class, it will bring out lack of clearness of 
 thought and at the same time teach discrimination in the use 
 of language. 
 
 Aside from these, there are assigned to it three services 
 which would remain entirely unrendered if the quiz did not 
 
INSTRUCTION IN THE CLASSROOM 129 
 
 undertake them. ^One is that of developing the generalizations 
 of the science from the facts, of which those observed in the 
 laboratory are samples. Thus the pupil may have treated zinc 
 with half-a-dozen acids, yet will almost never even speculate on 
 the probable generalization unaided. The second service is in 
 practising the application of the generalizations to chemical 
 questions and, when possible, to those of every day-life. Gen- 
 eralizations are the tools of thought, and unless they are put to 
 some use the labour involved in their manufacture will have 
 been largely wasted. The third service is in exercise of the 
 scientific imagination, without which attainment of even the 
 slightest degree of chemical intelligence is impossible. This 
 furnishes one form of the so-called 'explanations' (cf. p. 147) 
 which, when legitimately used, are so helpful. 
 
 To sum up, the object of the quiz is to lead the pupil to gain 
 the scientific habit of mind by practice in the scientific treat- 
 ment of a specific science. 
 
 Of these features of the quiz, only the two last seem to 
 demand special discussion. 
 
 When a generalization has been stated it will find immediate 
 application. Frequently some little time will have to be de- 
 voted to making the application plain. For ex- 
 
 _ . Service in 
 ample, the law of conservation of matter finds showing Ap- 
 
 illustration in the results of raising the same crop plication of 
 , - , , .. , f . Conclusions, 
 
 on the same |)iee~of midyear after year. If the 
 
 product is one which is cut and carried off entirely, the constit- 
 uents of the soil which are essential parts of the food of the plant 
 are effectually removed. Analysis of the soil and of the plant 
 show at once what stock of plant food is available, and how long 
 it will last. The use of fertilizers and other expedients replaces 
 or brings within reach of the plant the phosphates, for example, 
 which are indispensable to its growth. If it is the law of de- 
 finite proportions which is under discussion, illustrations are 
 abundant. In its absence we could not regulate the heating of 
 our houses, because with the same draft and supply of oxygen 
 the combustion would be more fierce at some times than at 
 
 9 
 
130 INSTRUCTION IN THE CLASSROOM 
 
 others : we could not make a contract for the supply of iron 
 because we could not foretell what amount of coal would be 
 required to reduce our ore, and therefore what the expense 
 of producing the metal was likely to be : we could not offer 
 photographs at so much a dozen, because the second half of 
 the dozen might cost a thousand times as much to print, de- 
 velop, or tone as the first. Commercial analysis, by the results 
 of which values were to be determined, would be made utterly 
 in vain. In fact, the conduct of all industries depending on 
 chemistry would be impossible as business enterprises. Even 
 life itself would cease, since its continuance depends on the 
 assumption that approximately constant quantities of food will 
 give approximately constant results in the way of nourishment. 
 A little thought will show that similar illustrations of almost all 
 the generalizations of chemistry may be found. Visits to fac- 
 tories will usually furnish many opportunities for pointing out 
 applications of facts noted in the classroom. 1 
 
 By inference is meant a rigidly logical process in which no 
 steps are omitted and no gratuitous or surreptitious additions 
 Service in are made to the conclusion to which the data fairly 
 Furnishing lead. For example, when hydrogen chloride is 
 lon ' formed by the action of sulphuric acid on salt, we 
 infer that under the circumstances the hydrogen of the acid 
 could unite with the chlorine and the sodium with the sulpha- 
 nion (SO 4 ) ; that is, that affinity between these materials exists. 
 We may not infer that this affinity was much greater than that 
 which held the original compounds together, nor that sulphuric 
 acid is more active (' stronger ') than hydrochloric acid. 2 Nor 
 may we infer that a tendency to the formation of gases accounts 
 for the action. ' Accounting for ' and * explaining ' chemical 
 changes is a risky proceeding. It is usually beyond the be- 
 ginner. In this illustration, a knowledge of mass action is 
 needed for the purpose. Supposing causes should never be 
 
 1 This subject is discussed farther in par. e, p. 138. 
 
 2 As a matter of fact, both these conclusions would be completely 
 erroneous. 
 
INSTRUCTION IN THE CLASSROOM 131 
 
 indulged in. Explanations are very satisfying, but we must 
 be careful to avoid incorrect ones as they are much worse than 
 none. An illustration of the use of the imagination will help to 
 show how far the attempt may safely go. 
 
 The imagination (cf. p. n) must be applied to everything in 
 chemistry. For example, why is the generation of chlorine such 
 
 a leisurely process ? It is not for lack of affinity 
 
 . . . . i Service in 
 
 that the interaction of the manganese dioxide and Employment 
 
 hydrochloric acid refuses to be hurried even by a blast- of the imag- 
 
 J ... ination. 
 
 lamp ! To answer the question, we have to imagine 
 
 the whole affair in detail. The molecules of the substances must 
 meet to act. The acid is in solution, and from six to twelve 
 molecules of water encounter a lump of dioxide for every one 
 of acid that reaches the goal. After the one acts, another has 
 to come up by diffusion, a slow process. Again, the dioxide is 
 insoluble and does not go to meet the acid. How great is the 
 contrast between the action of hydrochloric acid on similar 
 pieces of marble and of sodium carbonate on this account. 
 The molecules of dioxide have to be sought, and only the surface 
 ones, the merest infmitesimally small fraction of the whole, are 
 within reach. Contrast this with the rapid action in the ' Seidlitz' 
 powder,' where both bodies are dissolved. Then the manganous 
 chloride formed has to diffuse away to expose a new surface. And, 
 when we try heating, we cannot raise the temperature much, 
 because aqueous hydrochloric acid boils at 110 or lower. 
 Contrast this with our custom of raising the temperature to a 
 red heat in making oxygen. Here, to avoid distilling over 
 some of the acid, and so wasting it and rendering the chlorine 
 impure at the same time, we may not go even as high as 100. 
 It will be noted that we are not accounting for the chemical 
 action, or supposing causes for it. We are simply considering 
 the details and trying to explain how the conditions affect the 
 change. The tremendous role which the imagination plays in 
 this hardly needs to be pointed out. 
 
 " Imagination is thought by means of images " (Wundt). It 
 gives new form or grouping to the relations of the contents of 
 
132 INSTRUCTION IN THE CLASSROOM 
 
 the memory and the percepts of the senses. In the above illus- 
 tration it uses the pictorial imagery of the molecular theory, a 
 multitude of facts, and some ideas about molecular forces for 
 the production of a rationalized kinetoscope picture of the 
 whole proceeding. 
 
 The quiz will fitly occupy a large portion of the whole time 
 near the beginning, when all is new, and again during the last 
 half of the course. As the subject advances, earlier matters, 
 already partly forgotten, receive fresh light from and reflect val- 
 uable light upon each successive topic. 
 
 Some of the objects of the quiz enumerated above will be\ 
 especially well served by occasional written exercises or informal 
 written examinations. These are particularly valuable inas- 
 Exercises. mu ch as they give the pupils practice in making 
 connected statements, such as accounts of the properties of 
 substances and extended discussions of chemical questions, 
 and so train them in the chemist's way of classifying his 
 facts and expressing his conclusions. They also furnish oc- 
 casion for that continual reviewing which is so indispensable. 
 
 The nature of the questions asked in a written exercise shows M 
 more clearly than any other one thing the kind of instructionV 
 they are testing. Questions such as : What are the colours of 
 the precipitates when such and such substances are mixed ? or/ 
 Give the graphic, semi-graphic, and empirical formulae of the 
 following substances, are tests of memory and show serious 
 misdirection of the pupils' energy. The questions should test ' f 
 the powers of reasoning, discrimination, and co-ordination, as j 
 well as the knowledge of the pupil. They should be con- 
 structed so as to demand reference to laboratory experience 
 for correct answer. 
 
 For example, if we ask what the action of hydrochloric acid 
 on quick-lime is, the answer may be given by rote. If we ask, 
 How would you show the presence of oxygen in quick-lime? 
 the pupil's thought, disciplined by laboratory experience, alone 
 can furnish the reply. The answer, " I don't know," or " I 
 don't remember," which we often receive, is a pointed com- 
 
INSTRUCTION IN THE CLASSROOM 133 
 
 mentary on the habit of mind our educational methods seem 
 to engender. The question invited the pupil to think, and this 
 was so unusual that he did not even recognise the fact. 
 
 The Committee of Ten recommended that examinations 
 should be practical as well as oral or written. They referred 
 to college admission examinations, but the idea is practical 
 equally applicable to any test of acquirement what- Examinations, 
 ever its purpose. 1 
 
 b. Experimental Demonstrations : Some teachers prefer 
 this work to precede, others to succeed the laboratory exercise 
 on the same topic. In the latter case the desire is to let the 
 pupil examine the subject first entirely by his own efforts. This 
 is, doubtless, as a general rule, the best plan. But, while the 
 pupil is still ignorant of the handling of apparatus and the kind 
 of phenomena to be expected, it must involve slow progress and 
 much supervision. After some experience has been gained, it 
 is undoubtedly more instructive as well as more interesting than 
 the other arrangement. 
 
 The first of the uses of the demonstration is, in connection 
 with the earlier exercises, to show simple experiments, to point 
 out the matters of observation and to indicate the Usesof th 
 inferences to be drawn. These in fact will be Demonstra- 
 model laboratory studies, showing something of 
 the nature and use of the apparatus, and intended to save' 
 the pupil much needless bungling in his first efforts. The 
 experiments need not be the same as those performed in the 
 laboratory. Yet even if they are, the whole affair seems so 
 
 1 Perkin and Lean give a large number of simple problems (ibid., 
 324-326) to be solved by practical work in the laboratory, which, even 
 if they are not used for examination purposes, will nevertheless afford 
 hints that may be utilized in other ways. The recent examination 
 papers of the University of the State of New York will assist in show- 
 ing what are deemed the most important things in the science. Ellis' 
 Papers in Inorganic Chemistry (London, Rivingtons ; New York, Long- 
 mans), containing eight hundred questions and problems, with numer- 
 ical answers to the latter, and a volume of Questions on Chemistry, by 
 Jones (Macmillan), maybe found useful. Sets of questions in chemistry 
 are published every month in the SCHOOL WORLD (London). 
 
134 INSTRUCTION IN THE CLASSROOM 
 
 different in one's own hands from what it appears with an 
 expert at the helm that more than enough remains to be learned 
 to repay the repetition. There will be so many physical con- 
 siderations of a strange kind connected with the apparatus and 
 the chemical substances, that these alone, quite apart from the 
 chemical facts, make the first laboratory exercises sufficiently 
 hard in spite of the utmost assistance the teacher can give. 
 
 Experiments requiring special skill will usually be shown by 
 the teacher. } To put these in the hands of beginners would be 
 to invite failure and discouragement. Of this nature are the 
 experiments of Hofmann 1 on the law of volumes. 
 
 Experience is nowhere more needed than in this work. 2 Yet, 
 whatever his experience, the teacher should never show an ex- 
 Hever show P ei "i ment ne nas n t tried with precisely the same 
 Untried Ex- apparatus and materials he intends to employ. 
 Different lots of the same substance are not al- 
 ways identical, and even a lot previously used will deteriorate 
 and cease to be trustworthy. Care in these matters is usually 
 learned only after several humiliating experiences. The teacher 
 will also find it difficult at first to see the experiment as his 
 pupils view it, to put himself back in their place and omit noth- 
 ing essential in making clear the construction of the apparatus 
 and its working, to draw attention to every feature in the pro- 
 gress of the whole operation, and finally to wring from it the 
 lessons it teaches to the last drop. In all this, the interest of the 
 
 1 See Smith, Laboratory Outline of General Chemistry, pp. iii-iv. It 
 is a great pity that the English edition of Hofmann's delightful Introduc- 
 tion to Modern Chemistry (London, 1865) * s out f print and difficult to 
 procure. It contains the best models of experimental lectures, both as 
 regards presentation and illustration, extant. The German translation 
 (Einleitung in die moderne Chemie, Braunschweig, Vieweg, 1877) has 
 reached its 6th edition. 
 
 2 See Newth's Chemical Lecttire Experiments (Longmans, Green & 
 Co., London and New York, 1899). Also Benedict's Chemical Lecture 
 Experiments (Macmillan, London and New York, 1901). These works 
 will be found indispensable, even to the practised experimenter. 
 
 With few exceptions, the apparatus used in demonstrations should be 
 the same as that used by the pupils in similar laboratory experiments. 
 
INSTRUCTION IN THE CLASSROOM 135 
 
 class, which never flags when anything is going on, may be 
 utilized and directed so that, in response to questions put by 
 the instructor and by themselves, most of the points just men- 
 tioned are covered. 
 
 The preparation of experiments consumes much time and 
 requires some ingenuity. Keeping the demonstrations up to the 
 highest standard that the equipment of the school Demandollt j ie 
 permits demands heroic effort, and often some Time of the 
 self-sacrifice on the part of a busy teacher. School Teacher - 
 authorities have for the most part still to learn that a teacher of 
 science "cannot carry as many hours of classroom appointments 
 with efficiency as teachers of most other subjects. As Dr. 
 Newell says, 1 he " needs time to arrange the workshop of his 
 class ; time to consult with individual pupils ; time to repair, 
 clean, arrange, and replace apparatus ; time to clean up what 
 pupils and janitors will not do ; time to mix solutions, put them 
 in properly labelled bottles, and the bottles in the customary 
 place ; time to correct laboratory notes and see that the pupils 
 understand the corrections ; time to arrange lecture experi- 
 ments and remove the unsightly results before the room is 
 again used ; time to visit with classes the neighbouring shops 
 and manufactories which illustrate the industrial phases of chem- 
 istry ; time to read current scientific literature ; time to rest 
 physically and mentally, so that he may come daily to his 
 classes with that mental poise which is essential to successful 
 teaching." Reasonable time within school hours for most of 
 these tasks is as necessary for good teaching of chemistry as 
 the materials and laboratory themselves. 
 
 c. Stoichiometric Problems : The working of problems in 
 considerable numbers by individual pupils seems to be an ex- 
 ercise too often neglected. This is acknowledged 
 to be a valuable aid in enforcing the quantitative 
 character of every chemical change, and in holding the pupil's 
 attention on, and making him familiar with combining weights 
 and their use. More difficult problems, concerned with the 
 
 1 SCHOOL REVIEW, IX. (1891), 288. 
 
136 INSTRUCTION IN THE CLASSROOM 
 
 calculation of molecular and atomic weights, and other allied 
 subjects using the laws of gases, form the readiest means of 
 clinching what may otherwise remain a mass of loose and 
 ephemeral ideas. Sample cases should be worked in the 
 classroom. After the pupil's exercises have been corrected, 
 it will be found adv'sable to discuss them with the class. 1 
 
 d. Use of the Text- Book : Some teachers prefer to use no 
 regular book, and instead refer their pupils to certain passages 
 in works contained in the school library. Their pupils, how- 
 ever, generally lack fulness in knowledge of the subject. To 
 throw the pupil on his own resources is an excellent idea, but 
 this plan seems to carry it too far. Reading in other books, 
 however, is also highly advisable, if there is opportunity for it. 
 In any case, turning of the work into humdrum preparation of 
 so many pages of printed matter daily is easily avoided. 
 
 It is well to have some familiar source to which the pupil 
 may turn for assistance in recalling old matters. There is some 
 advantage also in the pupil's becoming perfectly acquainted 
 with the arrangement of one book, which shall employ approxi- 
 mately the order followed in the laboratory. This helps him in 
 getting a more definite grasp of the relations of the parts of the 
 science. 
 
 The chief reason for the use of books, and preferably in the 
 main, one book, lies in the fact that there will hardly be a single 
 A Text-Book chemical change of which the pupil can make a 
 necessary. complete study, if he is thrown absolutely on his 
 own resources. His own work furnishes him with a part only 
 
 1 A graduated series of problems, with answers, is given in Whiteley's 
 Chemical Calculations (London and New York, Longmans, Green & Co.). 
 Waddell's Arithmetic of Chemistry and Lupton's Elementary Chemical 
 Arithmetic (London and New York, Macmillan) are similar books. 
 Many problems will be found also in Newell's and in Perkin and Lean's 
 books already mentioned, in E. F. Smith and Kellar's Experiments in 
 General Chemistry (Philadelphia, Elakiston) and in Tilden's Introduction 
 to the Sttidy of Chemical Philosophy (London and New York, Longmans, 
 Green & Co.). The teacher will find an admirable series of problems 
 in physical chemistry in Brauer's Aufgaben aus der Chemie und der physi- 
 kalischen Chemie (Leipzig, Teubner, 1900). 
 
INSTRUCTION IN THE CLASSROOM 137 
 
 of the information necessary for reaching the chemical con- 
 clusion to which his experiment points. If, for example, he 
 burns phosphorus in oxygen, he sees a white cloud. He may 
 succeed in showing that this is a solid, that the gas is used up, 
 and that the solid is the only product. These things are within 
 his powers of observation, although the experiment seldom seems 
 to be carried even as far as this. But even so, he can only in- 
 fer that a solid compound of the two elements has been formed. 
 His study of the problem has been suspended before it could 
 be clinched, on account of the difficulty in measuring the com- 
 position of the product. Even if he could do this, however, 
 he would still require to get the combining weights from the 
 book. Usually he gets both, in the formula, from this or the 
 teacher. I have seen many note-books in which the observa- 
 tion of white smoke and the inference that the " product was 
 P 2 O 5 " were the sole entries. It is worse than waste of time to 
 encourage the pupil to make sham inductions like this from 
 ridiculously inadequate data. When he has been told explicitly 
 that his laboratory work is not expected to furnish all the neces- 
 sary information, he appreciates the possibility of extending this 
 information by more elaborate experiments. If, on the con- 
 trary, he is left in doubt on this point, and yet is asked to write 
 the equation for every chemical change (*'. e. to draw a quan- 
 titative conclusion from qualitative data) he will perceive the 
 existence of an imposture, even if he cannot point out where it 
 lies. 
 
 This is not criticism of an unreal state of affairs. Much 
 chemistry teaching is like setting out to invite a man to test a 
 stair, and then almost carrying him up bodily. He not only 
 learns nothing about the soundness of its construction, but he is 
 led to suspect that it was unsound because he was continually 
 juggled out of the chance to test it. Our laboratory manuals 
 too .often give no definite indication of how far induction may 
 go, and they seldom draw the line sharply between the knowl- 
 edge obtainable from this, and that which must be obtained 
 from some other source, if it is to be obtained at all. It seems 
 
138 INSTRUCTION IN THE CLASSROOM 
 
 to me that, unless the laboratory work is all reduced to pluck- 
 ing unopened buds, for mere practice in plucking, the practical 
 work and the book must go hand in hand. The laboratory 
 work is indispensable. It gives real knowledge of a kind no 
 book can furnish. But the book must be employed also unless 
 the instruction is to progress with the leisure and resources of 
 original discovery (cf. Heuristic Method, p. 105). 
 
 e. The Importance of keepi?ig the Stibject in Contact with 
 Eve.ry-day Life : * There are two dangers into which the 
 teacher of chemistry may fall. One is that of so circumscrib- 
 ing the view which he gives of the science that it is shut in by 
 a high fence which precludes even a glimpse of the world be- 
 yond and its chemistry; the other is that of digression into 
 various attractive and more or less famjliar subjects, which 
 may thus be allowed to interfere with the systematic teaching 
 of the science. While avoiding the real danger of excessive 
 digression > we must at all hazards save the subject from the 
 former abuse by the judicious employment of legitimate means 
 of illustration and vitalization. 
 
 This procedure is helpful to the instruction in the science 
 itself. A strange subject, dealing entirely with foreign material, 
 Unfamiliar can never be interesting to the majority of pupils. 
 Materials. Their natural craving for a tinge of human interest I 
 in everything is starved. Surely the study of a subject which / 
 is as intensely interesting historically and industrially as chem- 
 istry is, need never suffer from this limitation. On the other 
 hand, we cannot possibly confine ourselves to common ma- 
 terials in attempting to teach the science. In speaking of 
 oxygen, we immediately encounter barium peroxide, mercuric 
 oxide, and potassium chlorate. If we were to attempt to avoid 
 strange bodies like these, we should be bound to leave our- 
 selves without means of systematically building up and rounding 
 out the architecture of the science. We simply cannot summon 
 it forth from a mass of information about cooking, agriculture, 
 rusting, and photography by any legerdemain. The chemistry 
 
 1 See pp. 68, 74, 129, 138, and 177. 
 
INSTRUCTION IN THE CLASSROOM 139 
 
 of many of these things, and the experimental work involved in 
 studying it, are too difficult for beginners. But when we speak 
 of the three bodies just mentioned, for example, we can refer 
 to Erin's oxygen process, to Priestley and his work, and to 
 matches, so as to facilitate the introduction, on a friendly foot- 
 ing, of these barbarous materials, and so break down the shy- 
 ness and reserve, if not distrust, with which new acquaintances 
 will naturally be formed by the beginner. 
 
 An illustration will help still further in showing what is meant. 
 Suppose we state that aluminium is made by decomposition of 
 the oxide by means of electricity, and that the equa- 
 tion is 2A1 2 O 3 ->4A1+3O 2 . Bald teachifig-Tjf^this^ 
 kind is not uncommon. Sometimes, in a misdirected attempt to 
 animate the subject, tee operation is explained in terms of the 
 atomic theory. This, however, inevitably renders it more in- 
 animate than before, and transfers it at once to a ghostly and 
 unreal world. How much better to show the materials ; to 
 describe the plant, its location, and the water power it uses ; to 
 explain the process with its exciting details from the bath of 
 molten cryolite to the blazing block of carbon at which the 
 oxgen is liberated. The action of the electricity will be better 
 appreciated if electrolysis of a dilute acid, or better still of cupric 
 sulphate, is shown. All this need not be given, and certainly 
 nothing like as much as this in connection with every chemical 
 action. But once or twice in every lesson something is needed 
 to revive the drooping imagination of the pupil, and give him a 
 vivid stereoscopic view of chemistry as it is. Again, when we 
 deal with the preparation of nitric acid, the method will be for- 
 gotten infallibly if some precautions are not taken. Reiteration 
 is not a remedy ! Why not contrast it with sulphuric acid, which 
 cannot be made from the sulphates, found in great quantities in 
 nature, for easily explained reasons. On the other hand nitric 
 acid, although natural nitrates are expensive, cannot be made 
 economically from the elements. In connection with its syn- 
 thesis we have Cavendish's work on the investigation of the 
 residual gas in air, then, and for long afterwards, supposed to be 
 
140 INSTRUCTION IN THE CLASSROOM 
 
 all nitrogen, and Lord Rayleigh's recent success in obtaining 
 argon by use of Cavendish's principle (this, by the way, is 
 an admirable illustration of the effect of removing one factor 
 in a reversible action). Finally, the sources of the natural 
 nitrates and their production under the influence of bacteria are 
 available for lending colour and interest to the subject. It must 
 be repeated that giving all of this would take time which cannot 
 be spared, but something may be picked out in connection with 
 almost every action in chemistry which will be helpful in mak- 
 ing it comprehensible or memorable. 
 
 The employment of illustrations from things outside the labo- 
 ratory also increases the usefulness of the instruction. The teacher 
 in the secondary school, in view of the fact that his pupils are most 
 of them receiving from him their sole preparation for life, has a 
 certain responsibility in this direction which he cannot avoid. 
 In a later section (p. 177) we shall have occasion to suggest a 
 number of questions, for reply to most of which the basis at 
 least is to be found in elementary chemistry. There is no use 
 claiming that chemistry is a study of real things and not an arti- 
 ficial discipline, unless we show that it is so. It is not suggested 
 that the applied chemistry should be taught, but only that its 
 existence should be made plain in the most pointed manner. 
 We need not and must not make too much of this aspect. 
 Without there being any necessity for turning aside to teach 
 domestic science, for example, and leaving chemistry altogether, 
 there are illustrations of all sorts from various more or less every- 
 day matters which must suggest themselves continually to the 
 thoughtful teacher. 
 
 Take, for example, oxidation. Aside from the hackneyed 
 illustrations connected with rusting, life, and decay, the subject 
 Still Other suggests the way in which blue clay becomes brown 
 Illustrations. w hen exposed to the air through the change of the 
 iron it contains from the ferrous to the ferric condition ; the way 
 in which paint ' dries ' through absorption of oxygen by the 
 solidifying oil ; the way anglesite (PbSO 4 ) and cerussite (PbCO 3 ) 
 are formed from galena (PbS) and are commonly found en- 
 
INSTRUCTION IN THE CLASSROOM 141 
 
 crusting the veins of the latter ; and the fact that deposits of 
 ores of copper are mainly carbonate and oxide at the surface, 
 and pass into sulphide as the exploration of greater depths pro- 
 ceeds. Reduction is illustrated by the various photographic de- 
 velopers and by the genesis of native copper from cuprite ; 
 adsorption by dyeing of cloth, the action of mordants, the for- 
 mation of ' lakes/ and the effect of heating a glass bulb after it 
 has just been evacuated to the point at which it begins to show 
 the X-rays. 1 Reversible actions are illustrated by the storage 
 battery ; osmotic pressure by the root pressure in plants; 2 pre- 
 cipitation of calcium carbonate by the formation of coral and 
 shells through the action of ammonium carbonate excreted by the 
 organism inter-acting with the calcium sulphate in the sea-water ; 
 the subject of the lowering of vapour pressure in solutions by the 
 spontaneous way in which impure table salt becomes moist, and 
 ice is melted by contact with salt ; dissociation of the true or 
 reversible kind by lime burning ; the displacement of metals by 
 toning in photography ; solution in the broader sense by refer- 
 ence to alloys and to gems like the sapphire or yellow diamond. 
 The judicious use of this sort of illustrations involves not a 
 loss but a saving of time, and it fixes points of real chemical 
 value in the memory. The mention of things which other Benefits 
 are natively interesting in connection with other of illustration, 
 things which are not so is one of the best means of lending in- 
 terest to facts that might otherwise seem dry. The practice is 
 useful so long as it is employed with this end in view. It ceases 
 to be so when the chemistry becomes secondary, and that which 
 should be simply an illustration is dwelt upon to such an extent, 
 or in such a way, that it displaces the chemical fact from the 
 field of view entirely. Another advantage of this procedure is 
 that it relates the subject continually to the physics, geology, and 
 biology which the pupil may have already studied or may be 
 
 1 Air adhering to the glass is liberated, and the X-rays vanish, to re- 
 appear only when the pump has been started again. 
 
 2 Applications of the theory of solutions to physiology will be found 
 in Jones' Theory of Electrolytic Dissociation (Macmillan), Chapters II. 
 and IV. 
 
I4 2 INSTRUCTION IN THE CLASSROOM 
 
 about to study. It is at least as important that the teacher in 
 the secondary school should give a general view of science, and 
 of the relations of the sciences, as that he should give a sharply 
 focused view of one. 
 
 Many chemists are conscientiously and systematically opposed 
 to encouraging the introduction of anything which is in the least 
 Danger in degree likely to divert the attention of the pupils 
 the Abuse of from the science. They state, and probably with 
 
 justice, that there is far too much so-called chemi- 
 cal instruction in the schools which is perverted into the teach- 
 ing of odds and ends about various domestic and industrial 
 applications of chemistry. I fear greatly, therefore, that what 
 has just been said may be open to misconstruction, and may 
 be taken as advocating, or in some way countenancing such a 
 misuse of illustrative material. To be perfectly clear, let me 
 say that the object of the references to every-day life will be 
 defeated if they give occasion for long descriptions of these 
 matters. It is a continual but brief reference to these matters 
 in their chemical aspect, which shall show that the chemistry of 
 the laboratory and the classroom is the same as that of the 
 universe, and that there is such a thing as chemistry in the uni- 
 verse, that is suggested, and not such prolonged tours of super- 
 ficial inspection of the chemical universe as will prevent that of 
 the laboratory and classroom from taking definite form. The 
 use of judgment of the sanest description is imperatively 
 needed. 
 
 The facts cited for the purpose of illustration must be sub- 
 jected to careful scrutiny before currency is given to them. The 
 
 reader may recall the statement in a familiar work 
 Scientific that "throwing water upon conflagrations results 
 
 in the dissociation of the compound into the gases 
 hydrogen and oxygen, which, in reuniting, add fury to the flames 
 and increase the devastation." There are many popular notions 
 about the scientific aspect of common things which contain fal- 
 lacies more difficult to trace than is the absurdity in this. Then, 
 too, the chemistry of many common things is but little known. 
 
INSTRUCTION IN THE CLASSROOM 143 
 
 The contradictory statements about the reason of the harmful 
 effects of the atmosphere of overcrowded rooms, for example, 
 suggests that more knowledge of the subject is necessary before 
 it can be admitted to the elementary classroom. Again, the 
 chemistry of many familiar things is hard. Domestic science 
 and agriculture are difficult to relate intelligibly to elementary 
 chemistry. Soap-making can be explained, but the view of the 
 facts connected with cooking and digestion afforded by the 
 standpoint of the pupil in the elementary school must be too 
 superficial and distant to make it suitable for incorporation in 
 the elementary course. The treatment of these subjects must 
 for the most part degenerate into the giving of mere miscella- 
 neous information. 
 
 At the risk of repetition let it be said again that teaching the 
 chemistry of every-day life is not the end of the course in the 
 secondary school. Its object is the giving of discipline through 
 a knowledge of chemistry in a broad but strictly scientific sense. 
 Reference to the chemistry of matters of common knowledge 
 is suggested simply as one means of attaining the main end of 
 the course, by making the subject memorable, attractive, and 
 digestible. 
 
 f" f. Necessity for Unification of the Whole : Although the 
 necessity for unification has been more than hinted at already, 
 too much emphasis cannot be laid upon this point. 
 In a multitude of details there is no wisdom. The Science 
 
 mastery of the science consists not so much in steady 
 accumulation of knowledge as in building up habits of Habits. 
 of observation and thought, and cultivating a chemical intelli- 
 gence. No point in technique, observation, or generalization is 
 ever past or disposed of. The pupil is slow to appreciate the 
 universality of the ultimate constituents of chemical thought and 
 work, and requires to have them brought to his attention again 
 and again. The teaching of a science is a weaving process. 
 The same warp runs through all, and, while the pattern develops 
 and no strand is precisely like the preceding one, the result 
 should be an harmonious development of the design as a whole. 
 
144 INSTRUCTION IN THE CLASSROOM 
 
 Each new fact is centrifugal in tendency and at first introduces 
 a foreign element. The important thing is not the adding of 
 new facts, but their utilization in the creation of that more 
 recondite entity, the pupil's general grasp of the science. The 
 quality of the result depends not on the amount or variety of 
 the material, but on the perfection with which it has been 
 assimilated^ 
 
 g. Some Misleading Words : One of the most fruitful 
 sources of misconception lies in the ordinary phraseology of 
 Strong' chemistry. Thus the word strong is very much 
 Acids. overworked. It is used for active in reference 
 
 to the chemical tendencies of oxygen, chlorine, certain acids, 
 and so forth. It is used in connection with solutions when 
 great concentration is meant. It is even used for stable. It 
 will be found most satisfactory to use the proper one of these 
 three terms in the classroom and to exclude the word strong 
 altogether. 
 
 The words stable and, the converse, unstable are used in two 
 ways. Thus sodium chloride and nitrogen iodide are respec- 
 4 Stable' tively styled stable and unstable, in consequence of 
 Bodies. their behaviour when heated, and properly so. 
 
 Phosphorus trichloride is exceedingly stable by this test, but is 
 often spoken of as unstable because moist air decomposes it. 
 In this sense everything might be considered unstable, since 
 everything undergoes change when treated with a suitable chem- 
 ical agent. 
 
 The pupil eagerly learns a word and forgets the fact it was 
 used to describe, and our words are often so badly chosen that 
 
 _ . afterwards, when the learner tries to reproduce the 
 4 Water of 
 Crystalliza- idea from the word, he makes the most egregious 
 
 blunders. He will say that water of crystallization, 
 for example, is water needed to make the particular substance, 
 or all substances, take the crystalline form. He will say it is 
 not chemically combined, because the word suggests a physical 
 condition simply. It would be better to use the term hydrates 
 exclusively (p. 96). At the end of the course, he will still say 
 
INSTRUCTION IN THE CLASSROOM 145 
 
 that oxidation is combination with oxygen regardless of the 
 many other phenomena it covers. He will say a metal 1 is 
 a metallic-looking substance and call arsenic a oxidation.' 
 metal, regardless of the fact that the term has a ' Metal.' 
 use of its own in chemistry. He will say that a saturated solu- 
 tion contains all that the liquid can hold of the dissolved body, 
 and a supersaturated one more than it can hold ( !) , < satura- 
 
 reirardless of the fact that the terms have nothing to tion *' 
 
 ' Super- 
 do with what the liquid can hold, but concern only saturation.' 
 
 what it can take up from a given sample. A solution of a cer- 
 tain concentration may be saturated, unsaturated, and supersat- 
 ured all at the same time toward different forms of ' sodium sul- 
 phate.' 2 Our ideas in chemistry have so often been labelled 
 wrongly that we must discredit the label while teaching the 
 idea ; our terms often obliterate and obscure the very distinc- 
 tions they are intended to record. In examinations we must 
 ask for illustrations, to make sure that the word has not been 
 learned and its definition memorized without comprehension 
 of what it really covers. 
 
 Some words are as yet without definite signification. Oxygen 
 and ozone, rhombic and monoclinic sulphur, red and yellow 
 phosphorus are called pairs of allotropic modifi- 
 cations. Yet the first pair, and probably the last, 
 are chemically distinct substances, while the second is a pair of 
 physical states of the same body, like ice and water. 
 
 Absurdities, like the description of a metal as " brittle and 
 ductile," are so common that we must heed the warning and 
 make sure that even the definite terms are not being used as if 
 they were a meaningless jargon. 
 
 h. Some Common Fallacies : There are a few blunders, that 
 have long since been recognised to be such by chemists, which 
 still hang pertinaciously round elementary instruction. For 
 example, the formation of hydrogen chloride by the action of sul- 
 phuricacid upon common salt does not prove the superior activity 
 
 1 Cf. Tilden, Hints on the Teaching of Elementary Chemistry, 63-66. 
 Cf. Walker, Introduction to Physical Chemistry (Macmillan), 50. 
 
 10 
 
146 INSTRUCTION IN THE CLASSROOM 
 
 (' strength ') of sulphuric acid. Under other conditions hydro- 
 chloric acid displaces sulphuric acid from sodium bisulphate 
 almost as completely. 1 
 
 The so-called law of Berthollet in regard to the formation 
 of precipitates, even in its least objectionable form of statement, 
 is a half truth or less. So distinguished a chemist 
 Precipitation ' as ^ ie ^ ate P r fe ssor Cooke makes something like 
 nonsense of it when he says, 2 " When materials 
 are brought together in solution there is always a tendency to 
 make such a transfer of their constituent parts as will produce 
 insoluble compounds." It must be remembered that the prin- 
 ciples of chemical equilibrium 3 alone, and not a tendency to 
 produce insoluble substances, or, above all, any superior 
 ' affinity ' can explain this behaviour. 
 
 The current explanations of the heat produced when sub- 
 stances like sulphuric acid and caustic potash are dissolved in 
 water are almost all of doubtful correctness. The 
 Solution.' present condition of the science does not permit us 
 confidently to offer any explanation and in elemen- 
 tary instruction it is safest to say so. 
 
 The early misconceptions produced by injudicious teach- 
 ing in matters like those just cited are wonderfully lasting 
 and can only be eradicated afterwards with great difficulty, if 
 at all. 
 
 i. T/te Grammar of Science : The ordinary treatises on the 
 sciences omit all explanation of the fundamental conceptions 
 of the scientific method. Indeed it would be fortunate if they 
 also avoided introducing confusions of thought and blunders of 
 the grossest kind when they touch the subject indirectly. The 
 teacher of science must make up for this lack, and perhaps 
 correct these misconceptions, by the study of some work dealing 
 with the subject. We have space to mention two or three 
 examples only. 
 
 1 A. Smith, Laboratory Outline, p. 26. 
 
 2 Laboratory Practice, p. 41. 
 
 8 See Carnegie, Law and Theory in Chemistry (Longmans, Green & 
 Co.) chapter VII., particularly p. 205. 
 
INSTRUCTION IN THE CLASSROOM 147 
 
 Explanation, 1 its nature and correct use seem to be frequently 
 misconceived. An explanation never attempts to state the 
 reasons for, or causes of scientific facts. We can , Ex lana 
 give no reason for chemical behaviour, nor do we tion in 
 regard it as proceeding from ultimate causes (in 
 the sense of active originators which do things). ,An explana- 
 tion is simply a description which relates a thing or idea to 
 other more familiar things or ideas. In this way we explain 
 the hastening of the evolution of hydrogen, when a little cupric 
 sulphate is added, by reference to what we know about electric 
 couples. An illustration fully worked out in detail has already 
 been given in connection with the discussion of the use of the 
 imagination (p. 131). The employment of terminology is not 
 explanation. For example, to call an action 'catalytic,' clas- 
 sifies, but does not explain it. Note also that to call the 
 tendency to chemical action ' affinity 7 simply substi- 
 tutes the one word for the four. It also classifies, 
 in so far as it distinguishes this tendency by name from cohesion 
 and other forces. It most emphatically does not explain, for, 
 instead of relating a fact to a closely allied but more familiar 
 fact, it deliberately relates the simple fact to a complex set of 
 entirely foreign ideas connected with the word affinity (namely, 
 those of kinship, sympathy, and attraction), which are pure 
 importations, and so the word confuses instead of explaining. 
 Thinking that these ideas are germane to the thing itself, is, to 
 apply a sentence of Wundt's, " one of those numerous self- 
 deceptions which are no sooner stamped in verbal form than 
 they forthwith thrust non-existent fictions into the place of 
 reality." As a name for a thing and a means of classification, 
 affinity is a good term ; as an explanation, it is a failure, for, 
 in the language of the schoolmen, at the best it is simply 
 a case of explaining idem per idem, and at the worst of ob- 
 
 1 See W. K. Clifford. Aims and Instruments of Scientific Thought in 
 his Lectures and Essays, particularly pp. 101-103 (2nd ed. 1886). Also 
 Stallo, Concepts and Theories of Modern Physics, chapter VIII., particu- 
 larly pp. 104-110. 
 
148 INSTRUCTION IN THE CLASSROOM 
 
 scurum per obscurius, for it only adds greatly to the total to be 
 explained. 
 
 The meaning of law in natural science seems far from being 
 generally known. My own recollection as a student shows that 
 
 Law 'in for a lon S time * was in utter confusion as to the 
 Natural origin and meaning of the laws of physics and chem- 
 istry, because the meaning of the word Maw 7 had 
 never become clear to me. Its usage was frequently so confus- 
 ing that its significance could not be inferred. This experience 
 I am convinced is not exceptional. The use of the word 
 even in scientific books is so often incorrect that it would be 
 astonishing if teachers were not in danger of misleading their 
 pupils. The word is commonly accepted as applying to some 
 dogma which requires no defence and must be accepted with- 
 out question, or some belief, like that in our own existence as 
 conscious beings, which is more easy to accept as an intuition 
 than to support by argument. Another misuse of the term adds 
 additional confusion. We find it stated that some gases do 
 not obey Boyle's law ; again, we learn that Boyle discovered this 
 law, about a century and a half after Columbus discovered 
 America. One writer speaks thus : " Nature . . . follows laws 
 which are always operative under the same conditions. Vary 
 the conditions of an experiment, and new laws are liable to in- 
 tervene and change the result. The essence of law is uniformity 
 of action under like conditions." The italics are in the original. 
 Of the various senses tn which the word is used, two only 
 seem to be legitimate in science. In the narrower of these 
 two senses, 1 a law is simply an exceedingly brief statement 
 which embraces an immense range of separate facts. In a 
 broader sense the term may be used of the uniform behaviour 
 itself which is described in the statement of the law. It is 
 therefore either the statement of a fact or it is a fact. In the 
 latter sense it is pre-eminently a fact of the highest order. 
 Thus the so-called law of falling bodies, for example, is either 
 
 1 Karl Pearson, Grammar of Science, chapter III. See also The Duke 
 of Argyle, The Reign of Law. 
 
INSTRUCTION IN THE CLASSROOM 149 
 
 that which tells us in one brief statement all about the fall of 
 every sort of material, whether it be a feather, a bullet, or the 
 moon, and whether it falls towards the earth or some other 
 celestial body, or it is the uniform behaviour itself of bodies left 
 free to move under each other's influence. In the former and 
 stricter sense this law was not discovered, however, for, unlike 
 the New World, it did not exist previous to its ' discovery ' 
 and does not now exist objectively in nature. It was a state- 
 ment invented or made from the comparison of multitudes of 
 single observations. Laws in this sense are thus true only so 
 long as they express successfully the facts with which they deal. 
 When we discover by more careful observation that gases do 
 not change their volume exactly in the inverse proportion of 
 the pressure, it is not the gas which 'disobeys' the law, but 
 the law which fails to express the facts exactly. Laws are not 
 active agents ; they do not ' operate ' under any conditions, 
 nor do they ' act ' either uniformly or otherwise, and new laws 
 do not ' intervene ; ' the humble law-maker has to change his 
 law when he finds that the facts do not support it in its existing 
 form. In the latter sense the law is the fact itself, the fashion 
 of behaving. This was discovered, but it is not of the order of 
 a mandate of some recognised authority, and the word l dis- 
 obey ' is inapplicable. It is not supported by a police force, 
 like legislative law, and therefore does not ' operate,' 'act,' 
 or ' intervene,' even in the figurative sense in which these 
 terms are used of the law of the land. 
 
 These unfortunate conventional modes of expression make it 
 exceedingly desirable that the teacher should guard himself, 
 first in his own mind, and then in the language he uses, most 
 carefully against putting the idea of law in a wrong light. No 
 single thing can do more than the misuse of this term to per- 
 vert completely the pupil's whole idea of scientific method and 
 perspective, and to undo on a large scale what observation and 
 induction are trying to do on a small one. 
 
 Of the matters coming up in elementary chemistry, the princi- 
 ples of definite and multiple proportions and combining weights 
 
150 INSTRUCTION IN THE CLASSROOM 
 
 are laws because they state facts, and facts of the widest bearing. 
 On the other hand, Avogadro's statement, while it is frequently 
 called a law, is not a fact of the same order as the others at 
 all, 1 It is a part of the molecular theory of matter. If it be a 
 fact, as it probably is, it is reached remotely by inference, and 
 not directly by experiment. 
 
 Misconception is particularly liable to occur in connection 
 with the use of the word cause. When anything unusual or 
 unfortunate occurs in every-day life, we immediately 
 Natural ask whose activity or negligence ' caused ' the occur- 
 
 Science. rence. We thus acquire the habit of looking for 
 
 some active agent whose intervention is indispensable for the 
 production of certain results. We have no justification for the 
 use of the word cause in this sense in the scientific study of 
 nature. We note occurrences, such as those connected with 
 certain motions of bodies, and we sum up the nature of these 
 occurrences in brief statements, of which the most condensed is 
 known as the law of gravitation. Observation, however, leads us 
 to the discovery of no active agent whose intervention brings the 
 phenomena about. We do not know that the heavenly bodies 
 will move to-morrow as they do to-day, or that iron will rust in 
 the future under the same conditions as in the past. We regard 
 it as probable in the highest degree that these occurrences will 
 repeat themselves, but the relation is one of probability and not 
 of necessity. We know the fact of each occurrence as a 
 separate thing, and our general statement in regard to the 
 occurrences has no power of enforcement for the future. In 
 science, causes, in the sense of active agents which originate 
 occurrences, do not exist. It is useless, therefore, to permit 
 our minds to search for causes of this description. 
 
 Yet we have a tendency to furnish the link, which our habit 
 of thought suggests as needful, by attaching the name of cause 
 to something, and sometimes in doing this the term is grossly 
 misused. For example, we sometimes hear the law of gravi- 
 
 1 See Ostwald, Outlines of General Chemistry (Macmillan), chapter 
 VII., in which the terms hypothesis and postulate are used. 
 
INSTRUCTION IN THE CLASSROOM 151 
 
 tation spoken of as the cause of the behaviour of falling bodies. 
 The mere statement which in one phrase epitomizes all the be- 
 haviour of falling bodies, should surely be the very msnae of 
 last thing to which we should ascribe the power the Word 
 of bringing about occurrences which it simply de- 
 scribes. Even if we apply the term law to the uniform be- 
 haviour itself, this uniform behaviour may explain future 
 occurrences, but it is not the cause of them. 
 
 A study of occurrences scientifically shows that they may be 
 related in two ways. In the first place, certain phenomena are 
 observed always to appear simultaneously. Occurrences con- 
 nected in this way are described technically as being related 
 by co-existence. The word cause cannot be employed in con- 
 nection with any of them. 
 
 The other relation which may exist between phenomena is 
 that of sequence. We pass hydrogen over a heated oxide and it 
 
 is reduced, or we subject a match to friction and a , 
 
 Correct use 
 
 chemical change occurs. The same phenomena of the Word 
 are observed every time the same treatment is use ' 
 used. We do not know anything further than that this relation 
 of sequence obtains. The result is a continual coincidence 
 and nothing more. Its repetition on the next occasion is 
 highly probable, but we perceive in the phenomena nothing j 
 which makes the consequence a necessity. In such cases we 
 employ the word cause, and by this term we describe some one 
 occurrence which always precedes some other. Pearson l says : 
 " Cause, in this sense, is a stage in the routine of experience, 
 and not one in a routine of inherent necessity." The term 
 cause is misused when it is applied to phenomena which are 
 related by co-existence, or when it is applied to gravity or affinity, 
 which are facts simply, not causes at all. 
 
 The teaching of science consists in establishing a point of 
 view and not merely conveying a knowledge of facts. We 
 should, therefore, avoid the misuse of words like cause and 
 effect. When, through misuse of words like these, the rules of 
 
 1 Karl Pearson, Grammar of Science, chapter IV. 
 
152 INSTRUCTION IN THE CLASSROOM 
 
 the Grammar of Science are broken, obsession by false points 
 of view ever afterwards distorts the victim's whole conception 
 of the method of description and classification in which the 
 study of science consists. 1 
 
 Not to prolong our list, we may mention finally the words 
 matter and energy. There is much difference of opinion as to 
 'Matter' tne definition of these terms. It is certain, how- 
 
 and ever, that some of the current statements are de- 
 
 cidedly misleading. For example, it is sometimes 
 said that the universe is made up of matter and energy. Again we 
 learn that matter is the vehicle of energy. Still again we find 
 the statement that energy is the cause 2 of change in matter. 
 Each of these statements suggests an entirely different relation, 
 and all are more or less misleading. Our whole knowledge 
 of the universe is obtained by the study of our sense im- 
 pressions. In describing these, we employ two conceptions. 
 The idea of matter gives account of much that we perceive. 
 Since, however, matter may be at rest or in motion, hot or 
 cold, electrified or neutral, and the same specimen can change 
 its state of motion, or of electrification, or its temperature, we 
 separate these phases of the data of our experience, and employ 
 a second conception, that of energy, for the purpose of describ- 
 ing them. Now we cannot logically describe one conception 
 as the vehicle of another, any more than we can say that 
 one axis in co-ordinate geometry is the vehicle of the other. 
 
 1 It may be well to emphasize the fact that the discussion of topics 
 like those handled in this section is by no means to come before the 
 pupil. He could not understand their import and would only be confused. 
 The teacher can convey correct ideas concerning ' law ' and ' cause,' and 
 'energy' as readily as incorrect ones, if he is aware of the danger which 
 lies in the employment of careless forms of expression, without openly 
 discussing the terms themselves. 
 
 2 In many actions the employment of some form of energy is an- 
 tecedent to chemical change, in others the chemical change seems to be 
 antecedent to the production of some manifestation of energy. There is 
 evidently here no constant order of sequence. We have as frequent 
 reason for saying that change is the cause of energy as that energy is the 
 cause of change. 
 
INSTRUCTION IN THE CLASSROOM 153 
 
 The conceptions must be kept independent, or they cannot 
 subserve the purpose of describing the complex phenomena of 
 experience. Matter and energy are not parts of the universe, 
 but constituents of our mode of thinking about it and describing 
 it. Philosophically they are best classified as conceptions of 
 the mind and not things of an objective nature. 1 
 
 1 See Karl Pearson, Grammar of Science, chapter VII. and Stallo, 
 who seems to use the terms force and energy as equivalent, Concepts 
 and Theories of Modern Physics, chapter X. 149. Cf. James Ward, 
 Naturalism and Agnosticism, Lecture VI., passim. 
 
 Karl Pearson's Grammar of Science gives an admirably clear account 
 of many of the matters discussed in this section, and will be found to 
 throw a flood of light upon the foundations of scientific thought. The 
 whole contents of this book are bound to be a surprise to the student 
 who has read only treatises on the individual sciences. The same sub- 
 jects, in part, are treated with great clearness and philosophic insight in 
 the first volume of James Ward's Naturalism and Agnosticism, chapters 
 I.-VI. The teacher will also derive much benefit from reading Clifford's 
 Seeing and Thinking and Mach's Popular Scientific Lectures, as well 
 as Clifford's Essays and Stallo's Concepts and Theories of Modern 
 Physics^ to which reference has already been made. 
 
CHAPTER VI 
 
 SOME CONSTITUENTS OF THE COURSE. 
 
 THE reader will have observed that a number of topics usually 
 treated in chemistry have not yet received recognition in our 
 discussion of the subject. Some of these are of very great im- 
 portance, and some of them have a prominence in chemical 
 instruction which is perhaps somewhat out of proportion to 
 their intrinsic value. Our first section naturally treats of the 
 atomic theory. This might perhaps have demanded a place in 
 the chapter on "The Introduction of the Subject" at least as 
 potently as the question of equations. Other topics of the 
 same kind are valency, physical chemistry, and qualitative 
 analysis. The order in which we take them is the order of 
 their logical relation, rather than that of their importance as 
 features in elementary instruction. If we had adopted the 
 latter principle, the arrangement might have been different. 
 
 I. The Atomic Theory, its Nature and Place in Elementary 
 Instruction. 
 
 a. The Atomic Theory not a Fact : A theory is often formed 
 by imagining a simple mechanical system, which would behave 
 like some very complex subject of experiment in 
 call for this respect to certain clearly defined features in the 
 Theory. phenomena presented by the latter, and to these 
 
 features only of all the bewildering properties it may possess. 
 The atomic theory is of this nature : it professes to explain 
 certain features of chemical change. When we have found 
 that each compound has a constant composition, there is no 
 particular necessity for a theory to explain a fact in itself so 
 
SOME CONSTITUENTS OF THE COURSE 155 
 
 simple. When, however, we learn that the compositions of 
 several compounds containing the same constituents are related 
 by the rule of multiple proportions, and that irregular quanti- 
 ties are never observed, we feel a certain satisfaction in thinking 
 that if the constituents were done up in definite packets of 
 uniform size, such a rule would be the inevitable consequence 
 of the formation of several kinds of compounds. When later 
 we reach the principle of combining weights (p. 75), and find 
 that certain weights may be assigned to the elements, which, if 
 they have been correctly chosen, will, in combination with the 
 use of small multiples when necessary, express the weight in 
 which the elements enter into all kinds of combinations, we feel 
 an impulse to suppose that we are dealing with materials which 
 are constructed, physically, like the interchangeable parts of a 
 number of machines. The idea suggests itself that matter is 
 so made that, if we could reach the ultimate parts of which a 
 quantity of an element consists, by simply shutting our eyes 
 and taking one or two pieces we should find that they would 
 associate themselves with precision with other pieces of other 
 elements to produce any number of different structures. 
 
 We should note, however, that, convincing as the theory 
 seems, the facts which it explains do not in any sense consti- 
 tute a proof that matter is really constructed as the _. 
 theory demands. An illustration will make this not Inevitably 
 clear. If we had never observed wheat or gold a Factt 
 close at hand, and depended entirely upon the market quota- 
 tions for our information about them, we should naturally infer 
 that wheat was always done up in bushels, and gold in ounces. 
 Yet the fact is that these substances have no such structure. 
 They assume the forms of the bushel and the ounce only at 
 the moment of measurement. So there might be imagined 
 properties, at present unknown to us, which directed the quan- 
 titative selection of material for chemical change, and rejected 
 the excess, without the existence of any permanent segregation 
 into pieces of unalterable dimensions. The only bushels and 
 ounces which we have are in the measuring apparatus and not 
 
156 SOME CONSTITUENTS OF THE COURSE 
 
 in the material measured ; so the only atomic weights may be 
 in the properties controlling chemical combination, and not in 
 the matter combining. 1 
 
 b. Its Limited Application : The atomic theory has been 
 invented because of the difficulty we have in forming any 
 mental image of the complex phenomena of chemical change 
 as it takes place in large masses of matter. It furnishes a very 
 fortunate suggestion of a mechanism which would exhibit some 
 of these properties. 
 
 But the habit which chemists have acquired of speaking in 
 terms of the atomic theory as if it described objective realities 
 
 has obscured to some extent the fact that it does 
 'What the 
 Theory does n t attempt to account for everything in chemical 
 
 and does not change. It explains to us why 200 parts of mer- 
 cury is the most convenient chemical unit, and 
 describes the formation of mercuric iodide by the union of this 
 amount with 254 parts of iodine in terms of the packet theory. 
 It also accounts for the persistence of the masses of the inter- 
 acting bodies, the only properties of the original materials which 
 survive chemical change. In other words, it explains the 
 quantitative relations. It makes no attempt, however, to pic- 
 ture to us the mechanism which would account for the disap- 
 pearance of a shining, liquid, heavy, metallic substance, and 
 another black, or perhaps we should say violet body, each with 
 a definite set of physical properties, and the appearance of a 
 scarlet solid with a totally different array of properties. That 
 the mere placing of a particle of mercury very close to a par- 
 ticle of iodine, and in such a way that separation can still be 
 effected at will, should lead to the production of a composite 
 particle having properties markedly departing from the average 
 of those of the constituents is inconceivable. For the explana- 
 
 1 Cf. Stallo, loc. cit., chapter VII. An entirely different mode of show- 
 ing that the laws of combination might hold, even if the same identical 
 little pieces of matter were not attached and detached in the course of 
 chemical changes, is suggested by Karl Pearson (loc. cit., chapter VII. 6). 
 Cf. also James Ward, loc. cit., Lectures IV. and V. passim. 
 
SOME CONSTITUENTS OF THE COURSE 157 
 
 tion of the complete transformation actually observed, a much 
 more complex theory would be needed (cf. foot-note to p. 75). 
 To mention the atomic theory as furnishing such an explana- 
 tion is to perpetrate a palpable absurdity. Even the youngest 
 pupil must recognise the total inadequacy of the explanation, 
 and only the submissive spirit produced by prolonged dog- 
 matic instruction can prevent the criticism and rejection of so 
 pretentious a claim. The use of the theory must therefore 
 be confined at first to the explanation of the quantitative 
 relations. 
 
 When valency is reached, the atomic theory finds once more 
 useful application. Later still, in college work, when the rela- 
 tions of the constituents of a complex compound 
 are described, the same theory becomes practically 
 indispensable. Here, in the region of molecular in Later 
 constitution, it reaches the zenith of its success. 
 But still, it is only so long as we hold it to the role of a theory 
 and restrict its application to certain aspects of chemical change 
 that it is of assistance. Nobody thinks that the molecules are in 
 reality at all like our graphic formulae. This application of the 
 theory simply helps us to form a mental image of the gener- 
 alized relations which subsist between the facts of chemical 
 behaviour. 
 
 The fact is, then, that in elementary chemistry the atomic 
 theory attempts primarily to explain only the properties of com- 
 bination by weight and volume, and it succeeds in this only 
 because it leaves out of consideration the multitude of other 
 less easily classified relations which make the actual phenomena 
 so difficult to conceive and describe. When we thus relieve 
 the atoms of the necessity of explaining the whole marvel of 
 chemical change, they begin by being simply counters repre- 
 senting the combining weights ; and, just as counters are not 
 money, but have a numerical value, and assist in keeping account 
 of transfers of money, so atoms may be regarded at first as pri- 
 marily a fictitious medium of exchange, in terms of which we 
 chronicle the account-keeping side of chemistry. It is only 
 
158 SOME CONSTITUENTS OF THE COURSE 
 
 in the later application that the atoms become more and more 
 concrete. 1 
 
 c. The Place of the Theory in Elementary Instruction : 
 Having now cleared the way by pointing out the limitations of 
 Untimely ^ ie atormc theory, we are prepared to take up the 
 Employment much-debated question in regard to the proper 
 eoiy ' time for, and manner of its introduction in an ele- 
 mentary course. One would fear being accused of uttering a 
 platitude when stating, in the first place, that the use of a theory 
 is to explain facts, and that it must, therefore, follow the facts to 
 be explained, if it were not the most conspicuous feature of the 
 situation that the atomic theory alone, of all the theories of 
 science, seems to have gained a kind of prescriptive right to 
 take precedence of the phenomena. The most cursory study 
 of the text-books and the methods of the teachers of chemistry 
 will show that this is the case to a predominating extent. And 
 yet in the work which leads up to the noting of the qualitative 
 characteristics of chemical change there is nothing which the 
 atomic theory can explain or attempts to explain. Not only 
 does it fail to explain the transmutation of iron and sulphur 
 into ferrous sulphide ; it is even flatly discredited by an un- 
 biased consideration of the superficial features of the occur- 
 rence. Iron and sulphur, no matter how finely we divide 
 them, and how closely we put them side by side, always remain 
 iron and sulphur. The natural inference so far, therefore, is 
 that the union must consist in something entirely different 
 from a juxtaposition of minute fragments which retain their 
 identities. If, therefore, we force the conventional so-called 
 explanation on the pupil at this stage, he is bound to see that 
 the doctrine is incapable of immediate assimilation with the 
 experimental facts, that it is thus not of the nature of an expla- 
 nation, and so he is driven to suppose that it is itself an inde- 
 
 1 The most recent discussion of the atomic and molecular theories is 
 in Professor Riicker's address before the British Association. The 
 Structure of Matter: NATURE, LXIV. (1901), 470, or SCIENCE [N. S.], 
 XIV. 425- 
 
SOME CONSTITUENTS OF THE COURSE 159 
 
 pendent fact. It seems to be unverifiable by experiment, so 
 he infers that the science must include dogmatic teachings 
 which are beyond verification. Long-formed habit makes the 
 appreciation of oracular statements of this kind very keen, and 
 so the dogma is at once given the place of honour in his esti- 
 mation, and he starts his career as a student of the subject with 
 a totally false view of the science and of the scientific method 
 in general. 
 
 It is after the laws of multiple proportions and combining 
 weights have been observed to hold true of chemical changes, 
 that the opportunity for the explanation of these facts by the 
 use of the atomic theory occurs. Its presentation at any time 
 after this point is logically justifiable. It is very helpful in 
 giving definite form to the conception of combining weights. 
 It is not imperatively needed for the purpose of furnishing a 
 concrete basis for thought and expression until Avogadro's 
 hypothesis is introduced. It is exceedingly unlikely that, if the 
 consequences of this hypothesis are to be developed at all, they 
 can be made clear to a beginner in any other than the tradi- 
 tional manner. At this point the molecular and atomic theories 
 will usually be employed frankly, although Professor Ostwald 
 (in his Outlines of Inorganic Chemistry] has recently endeav- 
 oured to avoid them even at this stage. 
 
 The ever-present dangers seem to be those of forgetting that 
 the atomic theory is a theory, and of permitting the limitations 
 discussed above to slip out of view. There is also Dangers to be 
 a tendency to treat the subject too realistically, and Avoided - 
 as if the behaviour of the atoms was the subject of direct obser- 
 vation. The latter tempts us, after we have observed the burn- 
 ing of magnesium, to say, without more ado, that the action 
 takes place by the union of one atom of the metal with one atom 
 of oxygen. If the pupil makes no measurement, we should tell 
 him that weighing gives the proportion of the elements in this 
 compound; that elaborate experimental investigation has as- 
 signed 24.36 and 1 6 as the most convenient combining weights 
 of the elements concerned ; that the proportion here turns out 
 
160 SOME CONSTITUENTS OF THE COURSE 
 
 to be that of one combining weight of each element ; and that 
 hence, in terms of the atomic theory, one atom of each element 
 is used. Without these esseniial links, all implied in the origi- 
 nal statement, of course, but incapable of extraction from it by 
 the inexperienced imagination of the beginner, the pupil cannot 
 perceive the basis of our description of the action, or understand 
 what it means. [ It would be better to avoid the term atom as 
 much as possible in the every-day language of the classroom, 
 and to substitute atomic weight * or combining weight for it. 
 These terms at once recall the experimental method which is 
 the true basis of every statement. 2 
 
 I remember being present at a conference at which the sub- 
 ject of the present section was being discussed. The leader 
 Consequence was mcnne( ^ to favour explaining the very first 
 of Misuse of chemical change as an operation involving atoms, 
 eory * and leading the pupil to think of everything that 
 happened in terms of the atomic theory from the very start. 
 I had just interposed some remarks expressing views similar 
 to those defended here, and had wound up by pointing out 
 that the science of chemistry dealt practically with the behaviour 
 of gross matter and not with the vagaries of atoms, when a 
 young man near me, who apparently had difficulty in restrain- 
 ing his impatience, burst out with the exclamation, " If chem- 
 istry is not all about atoms, what is it about?" He was 
 a pupil of the leader of the conference and seemed never to 
 have been led to realize, that, in the great department of 
 knowledge which constitutes the science of chemistry, the com- 
 plex processes of nature which it describes, the magnificent 
 industries which it has founded and still guides, the services 
 to the community which it renders in a thousand applications 
 of analysis, and the multitude of distinct bodies and their rela- 
 
 1 For the definition of the expression 'atomic weight' in terms of 
 experiment, see footnote to p. 164. 
 
 2 For the most satisfactory treatment of the atomic theory, see 
 ITofmann, Introduction to Modern Chemistry (London, 1865), chapters 
 X.-XIT. ; Ostwald, Outlines of Inorganic Chemistry (Macmillan), chap- 
 ter VII. ; Remsen, Chemistry (advanced course), chapter VI. 
 
SOME CONSTITUENTS OF THE COURSE l6l 
 
 tionship with which it deals, there is scarcely ever any mention 
 of the atomic theory, except as in so far as it may furnish an 
 occasional figure of speech in their discussion. 
 
 The elementary chemistry of the classroom is, or should be 
 obtained by a careful reduction of the whole subject to a smaller 
 scale, and a careful elimination of the parts which The ^ and 
 
 in the microcosm have become inconspicuous de- Practice of 
 
 . , Condensation 
 
 tails. This process cannot be carried out by any app ii e d to 
 
 one who is not a chemist with a broad knowledge Chemistry, 
 of the subject in the unreduced form. Too many writers of 
 text-books have not the necessary qualifications for their task. 
 In the process of eliminating all that can be left out in the most 
 elementary work, and in arranging the remainder with a view 
 to what is supposed to be a simple and pedagogically correct 
 method of presentation for the use of the beginner, a good deal 
 of distortion sometimes occurs, and the result of this severe 
 banting process is in danger of becoming a mere phantom, if 
 not a caricature of its former self. It is as difficult to recognise 
 the ox in the beef extract, even when the latter is genuine, as 
 the science itself in some of the epitomes which are placed 
 at the service of the teacher. In theory, the elementary course 
 in chemistry should represent the main features of the science in 
 petto, and show it, as it were, viewed through the wrong end of 
 an opera-glass. When the reduction has been carried out faith- 
 fully, the microcosm, if once more expanded, should reproduce 
 in outline the image of the original. It is to be feared that were 
 this re-enlargement attempted with much of the tabloid chem- 
 istry of the schoolroom, a monster of terrifying and most un- 
 natural form would be hatched forth. It may be possible to 
 introduce the atomic theory at an early stage without causing con- 
 fusion, and to talk to beginners of atoms, when combining weights 
 are intended, without obscurity, but I do not know any text-book 
 in which this has been done successfully, and I could name many 
 in which it has been attempted with disastrous results. 
 
 In conclusion, and at the risk of being accused of over- 
 insistence, let us look at the matter from still another point 
 
 ii 
 
1 62 SOME CONSTITUENTS OF THE COURSE 
 
 of view. If we reflect upon what has been said in the opening 
 section of the chapter on "The Introduction of the Subject," 
 we may get additional light upon the question 
 Theory and before us. We enumerated three distinct char- 
 chemistry to act eristics of chemistry, which, while they offer 
 
 a Place in the impediments at the beginning of the pupil's course, 
 Curriculum. . f. . . . 
 
 at the same time constitute the precise reasons for 
 
 introducing a fresh study and a new kind of discipline. There 
 was first the fact that it accustomed the student to knowledge- 
 making with material objects and phenomena as the basis of 
 this exercise. Atoms are not material objects whose presence 
 and properties he can perceive by his senses, and thus do not 
 furnish concrete material for the knowledge-making process. In 
 the second place, the treatment of the subject was to be induc- 
 tive, and was to start from a large body of facts, and, by the 
 study of these, to lead to the elaboration of more general truths 
 and more abstract conceptions. Now the atomic theory does 
 not constitute a part of the fundamental data of the science. In 
 the third place, the pupil was to be taught to rely upon his own 
 powers of observation and inference, and to learn to discount 
 the teachings of authority. If at the very outset we state that 
 matter is composed of atoms, we ask him to accept on faith 
 something which he cannot observe, and could never have 
 found out for himself. Instead of asking him to exercise his 
 own powers, we treat him to a dogma, and we cannot even ren- 
 der the dose palatable by furnishing convincing reason for our 
 belief, for we have none. Thus the teacher who dogmatically 
 introduces the theory of atoms, violates every one of the condi- 
 tions imposed by the nature of the subject, and proceeds treach- 
 erously to undermine the foundations of the very claims which 
 have secured for the science admission to the curriculum. 1 
 
 II. The Treatment of Valency. 
 
 When chemistry is treated in a mechanical fashion valency is 
 a most important topic since chemical union is the subject of the 
 1 See also pp. 79, 8r, and 164, footnotes. 
 
SOME CONSTITUENTS OF THE COURSE 163 
 
 science and, in this view, is effected by the hooking together of 
 atoms. The number of hooks which each possesses is naturally 
 
 one of the first things we wish to know about. 
 
 Can Valency 
 When, on the other hand, this burlesque mode of be Explained 
 
 treatment is avoided, valency is still recognised toBe ^ iimers ' 
 as highly significant, but trouble is encountered, in trying 
 to introduce it at any early stage, on account of the difficulty 
 of explaining its experimental basis. I am inclined to think, 
 however, that, if the way in which it arises out of experimental 
 work is made sufficiently clear, there is no reason why valency 
 should be quarantined as a thing which is unteachable without 
 lapse into over-realistic atom mechanics. It is certainly not 
 primarily 'the capacity 1 of an atom for holding other atoms in 
 combination.' This is simply its interpretation according to the 
 atomic theory, and ranges it along with the other facts of the 
 science in harmony with the rest of this great conception. 
 
 Valency arises, of course, experimentally, after we have chosen 
 the values for our combining weights which shall be elected to 
 the proud position of atomic weights, and this choice, _ 
 in its turn, comes after the explanation of Avogadro's Origin of 
 hypothesis, the consequences of which determine ency * 
 the choice uniquely. An illustration will make clear exactly 
 what is meant. Take, for example, the action of zinc upon 
 hydrochloric acid (Zn + 2HC1 -+ ZnCl 2 + H 2 ). Before we 
 have settled the atomic weight of zinc, we simply find that 32.5 
 grams of it displace i gram of hydrogen. After we have fixed 
 the atomic weight of zinc as 65, that of hydrogen as i, and 
 that of chlorine as 35.5, by analysis and the application of 
 Avogadro's hypothesis (cf. footnote, p. 164), our measurement 
 tells us that 65 grams of zinc displaces 2 grams of hydrogen 
 and combines with 7 1 grams of chlorine. One chemical unit 
 of zinc therefore plays the part of two chemical units of hydro- 
 
 1 The word 'power,' frequently substituted for 'capacity,' in this 
 phrase is inadmissible. Valency is not in any way a measure of the 
 force with which atoms are held together, but only of the number of 
 atoms that can be held by one. 
 
1 64 SOME CONSTITUENTS OF THE COURSE 
 
 gen and unites with two chemical units of chlorine. In conse- 
 quence of this, we say that the chemical unit of zinc is bivalent. 
 Valency is thus simply a consequence of the choice, amongst 
 possible combining weights, of the final atomic weight. There 
 is no new addition to the theory of the subject, no so-called 
 ' theory of valency ' involved. 
 
 Valency may be placed on a sound experimental basis, even 
 before Avogadro's hypothesis has been discussed and atomic 
 weights have been settled, by the device, which may have been 
 used already for other purposes, of stating that the chemical 
 unit has been settled on grounds to be discussed later, and that 
 its value in the case of zinc is 65. The logical necessities of 
 the case are satisfactorily met by plain indication of the experi- 
 mental basis and perfectly clear delimitation 1 of any assumption 
 which may have to be made. 
 
 1 The nature of valency is so continually referred to as an exceedingly 
 obscure subject that there must surely be some lack of clearness in the 
 explanation commonly given. We may be pardoned therefore for a 
 brief statement, in harmony with the above paragraph, of its nature and 
 origin. 
 
 If gases had no properties which suggested Avogadro's hypothesis, 
 how would the composition of chemical compounds be represented by 
 formulae, and what would be the values of the atomic weights (and there- 
 fore of the symbols) ? We should find by experiment the composition of 
 aluminium chloride to be AIC\ (Al = 9 instead of Al = 27), of zinc chlo- 
 ride to be ZnCl (Zn = 32.5 instead of Zn = 65), of carbon tetrachloride 
 to be CC\ (C 3 instead of C = 12), of arsenious chloride to be AsCl 
 (As 25 instead of As = 75), and arsenic chloride to be^Cl (As = 15 
 instead of As = 75), and every chemical unit would have the 
 same valency, that is, would be univalent. Where there were two 
 different units used by one element, as in the case of arsenic, heavy 
 type might be made use of for the larger equivalent, or formulae like 
 as^Cl and as$C\ (as = 5) might be employed. 
 
 Now what effect has the application of Avogadro's hypothesis upon 
 this ? We weigh equal volumes of the vapours of all the compounds of 
 every element, so far as we can volatilize them, and record the weights of 
 volumes equal to that occupied by two grams of hydrogen (or rather 32 
 grams of oxygen. If O = 16, the volume is 22.39 litres, the gram-molec- 
 ular volume) under the same conditions. On inspecting the quantities 
 of the constituent elements found by analysis in these weights (now molec- 
 ular weights) of all the compounds, we find that no compound of alu- 
 minium contains less than 27 grams of the element in the molecular 
 
SOME CONSTITUENTS OF THE COURSE 165 
 
 III. Use of the Results of Physico-chemical Investigation. 
 
 Some of our works on physical chemistry have given so mathe- 
 matical an aspect to this subject that the ordinary chemist has 
 
 weight, no compound of zinc less than 65, and no compound of arsenic 
 less than 75, and that when the numbers are larger they are always 
 integral multiples of these numbers. If we retain our old equivalents, 
 but adapt our formulae so that they represent molecular weights, we shall 
 find Al z (Al^), or some multiple of this, in every formula of com- 
 pounds containing aluminium and Zw 2 (Zw = 32.5) and C 4 (C = 3) in 
 every formula of the compounds of zinc and carbon. The chlorides 
 would therefore be Al z Cl& Zn z C/ 3 , and (7 4 CV 4 . To avoid this complica- 
 tion, we write Al = Al& (=27), getting the formula A1C1 3 and we adjust 
 the other cases similarly. 
 
 Thus in applying Avogadro's hypothesis, we have ourselves, in a 
 manner, brought valency about. It is not a complication but a simpli- 
 fication of our way of representing chemical composition, particularly 
 in the case of elements having more than one equivalent. It has 
 the additional advantage that, when the atomic theory is introduced, 
 it then suggests the consideration of different elements as having 
 various capacities for holding chemical units of other elements, and 
 leads to the use of graphic formulas. The inestimable value of substitu- 
 ting a formula like CC1 4 
 
 Cl 
 
 i 
 
 Cl - C - Cl, 
 
 I 
 
 Cl 
 
 for C 4 C1 4 is seen in the marvellous results which the study of organic 
 compounds has yielded. to 
 
 Experimentally, valency is the number of grams of hydrogen (or the 
 multiple of 8 grams of oxygen) which are displaced by or combine with 
 one gram-atomic weight of the element, when the gram-atomic weight is 
 the least quantity found in the gram-molecular weights in all compounds 
 of the element. 
 
 It may not be out of place to add that experimentally the atomic 
 weight of an element is in general the smallest weight of the element 
 which is found in the gram-molecule of any compound containing the 
 element. The larger weights of the same element found in gram-mole- 
 cules of many compounds are always integral multiples (in accordance 
 with the principles of combining weights and multiple proportions) of 
 this smallest weight. If, as may happen in rare cases, they are not in- 
 tegral multiples, a molecule containing one atom of the element has not 
 been encountered, and the greatest common measure of the weights 
 
1 66 SOME CONSTITUENTS OF THE COURSE 
 
 been inclined to give it a wide berth. It is very certain that 
 this side of physical chemistry has no prospect of admission to 
 
 the school course, and may possibly not have been 
 Teacher! if not included in the training of the teacher. Its terrify- 
 to the Pupil, ing aspect, however, should not prevent us from 
 
 recognising that many of its results are of the great- 
 est interest and importance in connection with the study of 
 the most elementary chemistry, and that we are also at liberty 
 to help ourselves to the conclusions and leave the more theo- 
 retical portions untouched, if we so desire. Perhaps the most 
 important use of these results is in the general influence which 
 they will have on the teacher's point of view in all his instruction, 
 if he keeps them prominently in mind, rather than in the extent 
 to which they may be expressly imparted to the pupil. Many 
 teachers, however, are even in favour of teaching some of the 
 facts and theories of physical chemistry when occasion offers, 
 and when there seems to be a prospect that they will really 
 assist the pupil without putting upon him any fresh burden. 
 There are certainly some parts of general chemistry in which 
 this would seem to be possible. 
 
 found is taken as the atomic weight. This smallest weight passes un- 
 divided from compound to compound as far as chemical experiment can 
 discover. Whether it is incapable of subdivision is another question. 
 In all probability it is. For one thing we cannot conceive of a piece of 
 rtfetter incapable of subdivision. Then, too, J. J. Thomson's work (see 
 his very interesting resume in an article on Bodies Smaller than Atoms, 
 POPULAR SCIENCE MONTHLY, August, 1901) seems to have shown the 
 actual existence under certain conditions of particles much smaller than 
 the chemist's atomic quantities. The atomic weight is not that of the 
 smallest particle that exists, but is simply the smallest subdivision of 
 which there is chemical evidence. It will perhaps lead to clearness if the 
 idea of a chemical atom being a round indivisible mass is given up, and 
 there is substituted for it the idea of a bunch of smaller fragments 
 which moves as a whole through chemical transformations. 
 
 Passing over from the atomic weight of experiment to the atom of 
 theory, we consider the latter a chemical unit, and not necessarily a 
 structural unit, certainly not the smallest particle that can be conceived 
 (an absurd phrase). It is the smallest mass of a particular element of 
 which we have chemical knowledge. 
 
SOME CONSTITUENTS OF THE COURSE 1 6; 
 
 Most of the recent elementary books for secondary schools 
 seem to pay some attention to the experimental side of osmotic 
 pressure, and of freezing point and boiling point Kg Rejmlts ^ 
 phenomena. These subjects form one of the links capable of 
 between chemistry and physics on the one hand, and A PP llcatlon ' 
 between these two sciences and physiology on the other, and on 
 account of the important strategic position which osmotic Phe- 
 they occupy, it would seem that any attention they nomen a- 
 may receive can be fully justified. 
 
 The decomposition of electrolytes by electricity is illustrated 
 in several chemical experiments which are never omitted from 
 
 any course. It seems not unnatural, therefore, that 
 
 . Electrolysis, 
 
 some explanation of the phenomenon should be 
 
 given. The electrolysis of dilute sulphuric acid cannot be called 
 a decomposition of water by electricity, unless the electrolysis 
 of a solution of potassium nitrate is to be described in the same 
 way. The statement leaves too much out of account. The 
 fact, for example, that pure water and dry hydrogen chloride, or 
 dry potassium nitrate, separately, are practically non-conductors, 
 and are not affected by the current, shows that solution is 
 something more than a mere mixture of the two. Perhaps 
 carefully prepared demonstration experiments, with a limited 
 amount of explanation, will be found to give more insight into 
 this matter than long discussion could do, and effect a great 
 saving in time. The drifting of the ions through the liquid, 
 for example, can be shown in several ways. 1 The formation of 
 the ions can be observed when cupric bromide (cf. Richard's 
 Harvard Outline of Admission Requirements, 31), whose mole- 
 cules are deep brown or black, is dissolved in water. As the 
 
 1 It is so important that the teacher, at least, should be thoroughly 
 familiar with this subject, that he should not fail to assist his own 
 study of it by trying experiments for himself. A number of admirably 
 devised experiments, most of which are easy to carry out, are fully de- 
 scribed by A. A. Noyes in a most instructive paper (JOURNAL OF THE 
 AMERICAN CHEMICAL SOCIETY, XXII ( 1900), 726 : reprinted in the ZEIT. 
 FUR PHYSIKAL. CHEM. XXXVI. i). Their performance will throw a flood 
 of light on the whole subject for any one who is not already familiar with it. 
 
1 68 SOME CONSTITUENTS OF THE COURSE 
 
 liquid is diluted, the dissociation of the molecules leads to the 
 change of the brown colour of the latter to the blue colour 
 characteristic of the copper ions. 
 
 Two additional reasons for some attention to this subject 
 readily occur to us. Its relation to physics, and the light which 
 the chemical aspect of the matter throws on the knowledge the 
 pupil has already gained in the physical laboratory, suggest 
 the closer inter-relating of the chemical and physical views of 
 the same phenomena by means of the theory which explains 
 both. Then, too, the most startling recent improvements in 
 the chemical industries have been in the direction of the em- 
 ployment of electricity for many purposes. Many manufactures, 
 formerly carried out in other ways, are already, or are rapidly 
 becoming, largely electrolytic. The preparation of aluminium, 
 alkalies, bleaching agents, and chlorates are examples of this. 
 We cannot now teach chemistry and avoid frequent mention 
 of electrolytic operations, and we cannot well make these 
 operations intelligible without some explanation of the theory. 
 
 Double decomposition is an old subject. So familiar is it 
 that we do not always realize that it is after all rather remark- 
 able. If we cause two salts to interact by heating them, the 
 chances are that a most complex action takes place. When we 
 mix their solutions the action is almost always simplicity itself. 
 The solvent, far from being a mere bystander, has control of, and 
 directs the action, so that it takes place rapidly and consists in 
 a neat exchange of certain groups. Some explanation of this 
 would certainly seem to be not out of place. 1 
 
 The treatment of acids, bases, and salts is a difficult problem 
 in chemistry. It is difficult even to define the terms (cf. Til- 
 Acids, Bases, den, Hints on the Teaching of Elementary Chem- 
 and salts. ' istry ^ 66-68). To define a salt, for example, as 
 a substance which is made in such and such a way, is to shirk 
 the task of defining it altogether. We shall probably have to 
 
 1 In this connection, however, see the work of Kahlenberg, JOURNAL 
 OF PHYSICAL CHEMISTRY, V. (1901), 339-392, or abstract in NATURE, 
 LXV. ( 1902), 305. 
 
SOME CONSTITUENTS OF THE COURSE 169 
 
 say that a salt is a substance which enters into double decompo- 
 sition readily and whose solution is an electrolyte. An acid will 
 then be a salt of hydrogen, and a base an hydroxyl salt. The 
 theory of ionization throws a flood of light on the behaviour of 
 these substances (see, for example, "neutralization," in any 
 recent work, on theoretical chemistry, such as Dobbin & Walker's 
 Chemical Theory for Beginners, chapter XIX.). 
 
 In the battery we have again a collection of phenomena which 
 are as interesting to the chemist as to the physicist. The duty 
 
 of furnishing correlation between the different sub- 
 
 - , ..... . , The Battery. 
 
 jects of study, which is imperative in secondary 
 
 school-work, suggests again the desirability of some use of the 
 theory of ionization. This subject, too, is closely related to 
 chemistry on account of the way in which the electro-motive 
 force produced by various combinations forms a numerical 
 measure of the intensity of chemical action taking place in the 
 cell. 1 The order of the elements according to the electro- 
 motive series (p. 202) has many applications in chemistry. 
 
 Chemical equilibrium cannot be counted amongst the new 
 developments of theoretical chemistry, for its beginnings were 
 coeval with the discovery of oxygen, and its prin- chemical 
 ciples were clearly understood forty years ago or Equilibrium, 
 more. A strange reluctance, however, has been shown in 
 regard to the recognition of its laws, both by investigators and 
 instructors in chemistry. The blunders which have been 
 made through failure to pay attention to them are only too 
 familiar. The importance of these principles in explaining 
 many of the commonest chemical changes may well awaken 
 surprise at this strange neglect. The class of actions in which 
 they find their chief application, and which must be misunder- 
 
 1 Liipke, in his Elements of Electro-Chemistry (Lippincott), describes 
 and figures a large number of experiments illustrating this subject, and 
 this feature of his book makes it most interesting and instructive to the 
 reader who has not himself any experimental acquaintance with electro- 
 chemical phenomena. A series of experiments in the same subject is 
 described by Dr. Lash Miller in the JOURNAL OF PHYSICAL CHEMISTRY, 
 IV. 599. 
 
I/O SOME CONSTITUENTS OF THE COURSE 
 
 stood without recourse to them, namely, reversible actions, form 
 a majority of the changes which the pupil encounters in elemen- 
 tary chemistry. The contrary statement, which one so often 
 sees, is so palpably incorrect that one can but wonder what limi- 
 tation the author was thinking of when he made it. The Brin 
 method of preparing oxygen (cf. Newth, Inorganic Chemistry, 
 162) by means of barium peroxide and the chemical decom- 
 position of mercuric oxide furnish examples at the very outset. 
 Most of the chief changes at the beginning of the course are 
 reversible, and actions of this class predominate more and more 
 as the course progresses. Whether it is judicious to point this 
 out to the pupil, or to discuss the consequences of the fact, may 
 be matter for discussion. But there is no question that if the 
 teacher is not familiar with this fact, and with the whole subject, 
 he is likely to fall into egregious blunders, such as stating that 
 sulphuric acid is stronger than nitric acid, and enunciating 
 quasi-principles of a misleading kind, like the so-called ( princi- 
 ples ' of precipitation and volatilization. Almost the only way 
 to get clear ideas on this subject is to read the treatment of it in 
 several different books, and to make some experiments illustrat- 
 ing the principle of chemical equilibrium for one's, self. An 
 admirable series of experiments, which, for the most part, 
 may be performed with simple apparatus, is described by Dr. 
 Lash Miller. 1 
 
 On the whole, perhaps, after this discussion of some of the 
 bearing of physical chemistry upon elementary chemistry, it 
 
 may be a question whether, in the average course, 
 Conclusions. ...,, , r J . , 
 
 time will be found for anything more than a touch 
 
 of the subject here and there. The conclusion is inevitable, 
 however, that the teacher himself must be thoroughly familiar 
 with the results of physical chemistry and its application to 
 
 1 Lash Miller, Experiments Illustrating Chemical Equilibrium. JOUR- 
 NAL OF THE AMERICAN CHEMICAL SOCIETY, XXII. (1900), 291. For 
 a simple account of the subject, see Carnegie's Law and Theory in 
 Chemistry (Longmans), chapter VII. Cf. references to chapters in Muir 
 and Carnegie's Practical Chemistry, dealing with this subject, footnote 
 to p. 216. 
 
V 
 
 SOME CONSTITUENTS OF THE COJI&9E 1 71 
 
 ordinary chemical phenomena, if the instruction he gives is to 
 be thoroughly sound. A knowledge of this subject is one of the 
 most indispensable parts of the equipment of the teacher of 
 general chemistry, whether in school or college. Whatever ideas 
 along this line may be communicated to the pupils will certainly 
 be given in a very elementary fashion, and will be made 
 thoroughly concrete by careful experimental illustration. In 
 this way the keenest interest may be awakened. The theories 
 will not be given for their own sake as separate topics, but 
 strictly in explanation of phenomena that have been encoun- 
 tered, and only so far as they simplify and explain these 
 phenomena. The teacher who has not had an opportunity of 
 studying the subject, however, would do well to omit it from 
 his instruction entirely, as there is nothing more dull and valu- 
 less than a theory which is not lucidly explained and adequately 
 enforced by 'pat' application and experimental illustration. 
 
 IV. Shall Qualitative Analysis be Included, and if so in "What 
 
 Form ? 
 
 REFERENCES. 
 
 Armstrong, H. E. Presidential Address before the Chemical Society 
 of London. JOURNAL OF THE SOCIETY, LXV. (1894), 361. Reprinted 
 in part, NATURE, L. 211. 
 
 Brace, Geo. M. An Article on Qualitative Analysis. THE SCIENCE 
 TEACHER (New York), II. 173 (March, 1899). 
 
 There is perhaps no question in connection with chemistry 
 as a study in the secondary school which has called forth opin- 
 ions so sharply opposed to one another as this. The head of 
 the department in one of our State Universities says : " If it is 
 advisable to have lecture and recitation work, let it be at the 
 end of the course, and have the two earlier terms taken up with 
 qualitative analysis. ... If the fortunate state of affairs exists 
 that physics precedes the subject of chemistry, I think the 
 lecture work as such is of little importance." This appears to 
 
1/2 SOME CONSTITUENTS OF THE COURSE 
 
 suggest distinctly that even classroom work in general chem- 
 istry may be dispensed with, under certain conditions, and that 
 the whole introductory course may consist in qualitative analysis. 
 That, on the other hand, analysis should be excluded entirely is a 
 view expressed with equal definiteness by a large number of com- 
 mittees and single authorities. What the argument in favour of 
 making qualitative analysis the first and almost exclusive subject 
 of instruction may be, it would be difficult to say. The statements 
 supporting this view seem always to be of the nature of obiter 
 dicta. The fact that analysis must at best give but a restricted 
 knowledge of chemistry is so obvious that those who hold this 
 opinion must do so either from lack of reflection, or on 
 account of the influence of tradition, or perhaps they hold 
 their belief simply quia absurdum est. Leaving this extreme 
 view out of consideration, however, there are strong arguments 
 presented by both parties, and we shall attempt to' consider 
 both sides. It is assumed, of course, that, in what follows, by 
 qualitative analysis we mean the ordinary treatment which 
 seems almost invariably to begin with the tests for the ' metals ' 
 and to confine itself for the most part to wet reactions. 
 
 a. Arguments in Favour of Qualitative Analysis : There is, 
 in the first place, the consideration that the school course may 
 in its absence do little towards suggesting the variety of topics 
 which is studied under the name of chemistry. The introduc- 
 tion of analysis tends to give a somewhat more complete view 
 of the science by presenting another aspect of it. 
 
 It furnishes an excellent training in observation. Even if we 
 admit that the phenomena of precipitation are not in themselves 
 EasyObserva- exceedingly important, the facility with which they 
 tion - lend themselves to study by young students gives 
 
 them a certain value. This argument is extremely instructive, 
 for the satisfaction with which this sort of observation is made 
 depends upon the limitations which the selection of phenomena 
 useful for analysis has imposed. The possibilities are strictly 
 limited in advance. This assimilates the work to that in Latin 
 and mathematics, in which the pupil has become accustomed 
 
SOME CONSTITUENTS OF THE COURSE 173 
 
 to similar guidance, and he welcomes the opportunity to study 
 something which has similar characteristics. 
 
 The work exercises the reasoning powers and furnishes 
 material for simple and sure inductions. 
 
 Analysis furnishes a review of certain parts of the subject 
 which have been studied before, and thus assists in crystallizing 
 the pupil's ideas. 
 
 The properties of the substances encountered may be studied 
 in connection with the building-up of the analytical scheme, in 
 such a way that genuine additions are made to the pupils' 
 knowledge of chemistry and the bald enumeration of precipi- 
 tates and colours is avoided. 
 
 Finally, it is well known that analysis is a subject capable of 
 practical application. There is just a touch of something use- 
 ful about it which awakens interest on the part of A , Practi . 
 the pupils, and inclines parents and outsiders to cal ' Subject. 
 approve its inclusion in the high school curriculum. Of course 
 this rests on the mistaken notion so commonly held that chem- 
 istry consists in analysing things, and that the scientific chemist 
 spends his time in examining groceries for adulterations and 
 advising his neighbours in regard to the purity of their drinking 
 waters. But it none the less creates a feeling of sympathy with 
 the work of the school which has a value of its own. The in- 
 terest of the pupil is natural, for, although the fact that silver 
 chloride dissolves in ammonium hydroxide, while lead chloride 
 does not, possesses no native interest whatever, the suggestion 
 that this can be used for distinguishing the substances, or as- 
 certaining the presence of lead or silver, gives it a powerful 
 derived interest and awakens the attention of the scholar at 
 once. 
 
 b. Arguments against Qualitative Analysis : There may 
 be some arguments against qualitative analysis in any and every 
 form. There are certainly strong arguments against some types 
 of instruction in it, especially those of a mechanical kind. We 
 shall assume, however, for the most part, that the topic in its 
 best and most rational form is alone to be considered, and that 
 
1/4 SOME CONSTITUENTS OF THE COURSE 
 
 an inadequate basis in knowledge of the facts and theories of 
 the science is the chief defect from which the instruction 
 suffers. 
 
 To the first of the arguments just given it is replied that 
 chemistry as a science has nothing to do with analysis. 
 Analysis is an application of chemistry and an art practised 
 with commercial ends in view, or a tool used in the prosecu- 
 tion of strictly scientific work. A little of it may enlarge the 
 ideas of the pupil, but a greater amount must have a decidedly 
 narrowing influence. 
 
 The strongest argument in favour of analysis is certainly that 
 which points out the practice it gives in observation, guarded 
 
 by such restrictions that complete and satisfactory 
 The * Obscr- 
 
 vationArgu- study is within the powers of beginners. The inter- 
 ment, ence from this, however, is that other parts of the 
 subject should be systematized in the same way, in order that 
 gaining a fuller and more complete knowledge of them may be 
 put within the reach of the student of the elements. A system- 
 atic yet simple arrangement of certain facts has been made for 
 the purpose of analysis ; an equally simple and systematic 
 working out of all aspects of the subject should be made for 
 the purpose of instruction. The commercial impulse has 
 caused the former development. The teacher does not yet 
 seem to have learned the lesson which this plainly inculcates, 
 and, instead of imitating the principle and applying it to the 
 whole science, he has simply borrowed the fragment which the 
 analyst has worked out for his own purposes, and saved himself 
 much trouble by making up from it a large part of his course. 
 There is an obvious risk that too much system may lead to 
 mechanical work, but it certainly would seem that some im- 
 provement of this nature might be made without trespass on 
 the zone of danger. 
 
 There is no question that analysis furnishes good exercise in 
 reasoning, at least when it is taught in a rational manner and 
 not by the mechanical use of tables. Mr. Brace, in the paper 
 referred to at the head of this section, explains in an admirable 
 
SOME CONSTITUENTS OF THE COURSE 175 
 
 way how the best use may be made of its aptitude for cultivating 
 the inductive powers. As the study of the science progresses, 
 
 a record may be made of the solubility or insolubility 
 
 The ' Exer- 
 of each substance, and in the latter case of the ciseinRea- 
 
 colour and other properties of the precipitate. 
 When the table has been completed, the pupils 
 themselves can pick out a method of analysis. They note, for 
 example, that three chlorides only are insoluble, and that there- 
 fore the addition of hydrochloric acid will lead to the recogni- 
 tion of the presence of one of the metals concerned. With but 
 little assistance from the teacher or book they may be led to 
 work out a complete system of analysis applicable to simple 
 cases. There is, as we have said, no question of the rational 
 exercise which this procedure gives, but we may be pardoned 
 for asking what the subject is on which the reasoning is being 
 expended. It is the solubility or insolubility of a large number 
 of bodies. Now this question is of but slight interest to the 
 chemist as a chemist, for so far we have not been able to 
 explain most of the eccentricities of solubility. This sort of 
 study puts calcium chloride and calcium fluoride in diametri- 
 cally opposite classes. It assimilates arsenic and tin, nitrates 
 and acetates. 
 
 Suppose that after a complete study of this had been made, 
 the class were next invited to distinguish sticky substances from 
 brittle ones. Glue and phosphoric acid would adjust them- 
 selves in one group, while salt and napthalene (moth balls) 
 would find themselves accommodated in another. Or suppose 
 that substances were classified by their colours, iodine and potas- 
 sium iodide would part company at once, and sulphur and sul- 
 phuric acid would know each other no more. In the same way, 
 liquids might be distinguished from the solids. Mercury and 
 copper would be no longer classed together as metals, and in this 
 remarkable course ice and water would belong to different groups. 
 Similarly, if the year was not yet exhausted, odours and specific 
 gravities might afford opportunity for careful observation and nice 
 discrimination. Devising systems of analysis based on these facts, 
 
176 SOME CONSTITUENTS OF THE COURSE 
 
 and using them, would unquestionably furnish admirable exercise 
 for the reasoning powers. The fact is that there are a great 
 many ways of making hodgepodge of the chemical relations of 
 substances by classification according to physical properties, 
 but the study of chemistry itself cannot possibly be assisted by 
 anything which makes havoc of chemical similarities, no matter 
 how admirable the exercise it may furnish for the reasoning 
 faculties. 
 
 The reasoning of analysis, that by which we distinguish salts 
 of silver, lead, and mercury, for example, is exactly like that by 
 which, in whist, we infer the contents of our neighbour's hand. 
 Whist might with advantage be substituted for qualitative analy- 
 sis, so far as training of the reasoning powers goes. The mere 
 use of chemical bodies and chemical language in a study does 
 not make it, ip so facto, chemistry. The valid reasons for study- 
 ing qualitative analysis, without a foundation far broader than 
 any fraction of a year's work can give, amount to showing that 
 it gives good discipline, whether it contains any chemistry or 
 not, and that, while being administered to the pupil, it may also 
 be so liberally basted with a chemical sauce as to become a 
 good imitation of a part of the science itself. Whist could be 
 enriched by incorporating with it some study of the chemistry 
 of cellulose and black and red ink, but this would not greatly 
 advance its claims to inclusion in a course in the science 
 intended to be systematic. 
 
 The argument that analysis may be employed to furnish a 
 review of the previously acquired knowledge of the science is 
 true to a limited extent only. There are other ways of effecting 
 this review which cover the ground much more completely. 
 
 The final argument l that the analysis of the high school has 
 
 1 There is still another consideration which affects some schools more 
 than others, and some pupils in all schools. It concerns the pupils who 
 are preparing for college. If some schools give much analysis, some 
 little, and others none, some much general chemistry, some little, and 
 others perhaps almost none, the various pupils from these schools can- 
 not possibly be provided by any college with a fit course in continuation 
 of their previous work. Only those who have devoted a year to general 
 
SOME CONSTITUENTS OF THE COURSE 177 
 
 a possible practical application, and teaches something useful, 
 is plausible, but will hardly bear examination. In after-life the 
 graduate of the high school hires an analyst if he ^^^3^ 
 
 wishes any work of this nature to be done. If he 'Practical' 
 
 Subject 
 tries his own hand at it, he will quickly discover 
 
 that the course given in the high school is of almost no assist- 
 ance in the solution of any practical problem. The subject 
 is far too difficult to be treated adequately in a part of an ele- 
 mentary course. The fact is that the pupil whose time has 
 been taken up with analysis will only begin to discover after 
 graduation the utter valuelessness of the supposedly practical 
 instruction of which he has been the victim. It will not help 
 him in the least to understand what is wrong with the battery 
 that works his electric bell when it gets out 'of order, the way in 
 which the dye adheres to his clothes, how mortar and plaster of 
 Paris harden and cement sets, why his city dilutes its sewage 
 with water to render it innocuous, why writing is more apt to 
 fade than printing, how baking powder and yeast act, how 
 photographs and fireworks are made, why 'tin plate' rusts so 
 rapidly when it has started in one spot while galvanized iron 
 does not, why hard water uses so much more soap than soft, 
 whence and how iron, copper, and other metals are obtained, 
 what becomes of all the soda and sulphuric acid that are manu- 
 factured, and a hundred other matters which are of interest to 
 
 chemistry can be considered, for they alone can have anticipated any 
 appreciable and easily definable portion of college work. The others 
 may have anticipated, partially and feebly, portions of several college 
 courses, and will perforce have to go without recognition of this antici- 
 pation. 
 
 A vigorous discussion of the subject of instruction in chemistry, with 
 special reference to the place of qualitative analysis, by Professor Arm- 
 strong in the presidential address already mentioned QOUR. CHEM. 
 Soc. LXV. 361, or NATURE, L. 211), will be found particularly instruc- 
 tive. He seriously advises the postponement of the detailed study 
 of qualitative analysis to the very end of the college or university 
 course, after most of the other topics which usually succeed it have been 
 taken up. See also Professor Perkin's vice-presidential address before 
 the British Association (Report of the Association, 1900), reprinted in 
 NATURE LXII. (1900), 479-480. 
 
 12 
 
1/8 SOME CONSTITUENTS OF THE COURSE 
 
 everybody, the basis for whose explanation might have been 
 furnished in the high school course if the time had been better 
 employed. 
 
 If such analysis as can be given prematurely furnishes no 
 more chemistry than whist (aside from special efforts more or 
 
 less artificially to graft chemical knowledge into 
 Conclusions. , J 
 
 its study), is no more or less capable of practical 
 
 application than Latin, and positively tends to confuse what of 
 settled order the previous work in general chemistry may have 
 brought about, why cherish it on account of the opportunities 
 for exercise in observation and reasoning it offers when a study 
 of chemistry in a broader sense might give the same opportuni- 
 ties and be a support instead of a stumbling block in the acqui- 
 sition of a knowledge of the science. 
 
 The choice of proper subjects of instruction places a great 
 responsibility on the secondary school. The subjects, to speak 
 figuratively, should be fit to form little bases of supplies for use 
 in after-life, and the treatment should make plain the main 
 lines of travel in each subject. If the chemical base is placed 
 eccentrically with reference to the science as a whole, and the 
 roads with which the pupil is familiarized turn out to have been 
 by-ways instead of thoroughfares, the knowledge obtained will 
 have been useless, if it does not even prove a burden, in the 
 subsequent campaign of life. 
 
 In all this it will be understood that we are speaking of the 
 trivial form of analysis, which is the only one it can assume in 
 the hands of pupils not possessed of a broad and thorough 
 training in general and theoretical chemistry extending over 
 one or two years. After such a training, the questions of 
 genuine chemical interest with which it is replete can be appre- 
 ciated, and its study becomes in the highest sense a study of 
 chemistry. 
 
 c. Exercises in Identification : The satisfaction and apparent 
 success attending the use of qualitative analysis in an elementary 
 course show the need of some exercises which shall, if possible, 
 possess similar characteristics, while confirming and amplifying 
 
SOME CONSTITUENTS OF THE COURSE 1J9 
 
 the knowledge of the subject as a whole rather than harming it 
 by the introduction of a side issue. * We must have exercises 
 furnishing opportunity for observation and reason- 
 ing, limited by suitable restrictions; exercises, if ^Analysis, 
 possible, with an object in view that will awaken the 
 detective instincts of the pupil ; and exercises that will at the 
 same time review and enlarge the knowledge of chemistry. Can 
 a study devoted more largely to chemical properties and less 
 largely to physical ones than analysis be devised? Some 
 teachers are beginning to think so. The attempt to commence 
 with the wet reactions for the ' metals,' however, must be 
 abandoned. 
 
 Suppose we give a pupil at some suitable opportunity some 
 substance like red phosphorus or powdered charcoal, and ask 
 him to discover what it is by employing any ex- 
 perimental means that occur to him, and to make T] 16 ^ 110 ^ * 
 
 laentuication. 
 
 a report showing conclusively that it is the sub- 
 stance he determines it to be and no other. In a simple case 
 he may guess what the body is from its appearance, but the 
 furnishing of a logical proof will nevertheless give him much 
 exercise, and result perhaps in repeated rejections of the report. 
 Suppose, next, that he is given powdered sodium carbonate, 
 common salt, calcium nitrate, or sodium hydrogen sulphite for 
 examination in the same way, his task being to discover the 
 acid radical solely. Suppose again that later he gets more 
 difficult cases, such as potassium chlorate, sodium iodate, 
 ammonium iodide, potassium sulphite, or zinc acetate. Familiar 
 substances like glycerine, alcohol, soap, and so forth may even 
 be given if the chemistry of carbon compounds has received 
 much attention. The particular substances employed must natu- 
 rally depend upon the elements and compounds that have been 
 studied. In each case he is instructed as before to discover 
 what the substance is, and prove its identity conclusively by ex- 
 periment. It will probably be necessary to give him a start by 
 a little discussion of the experiments most likely to give the 
 largest amount of information. It will soon be agreed that 
 
180 SOME CONSTITUENTS OF THE COURSE 
 
 heating a substance by itself in a hard glass test-tube, and again, 
 in the case of inorganic materials, in a common test-tube with 
 concentrated sulphuric acid, are likely to furnish most quickly 
 a considerable amount of information. 
 
 When heated alone, few bodies fail to change in some way. 
 Sublimation, melting, boiling, and evidence of decomposition 
 
 are all significant and will be noted. If gases or 
 Heating* vapours appear to come off, the pupil will have to 
 
 reflect on proper means of recognising by their 
 properties whether they consist of oxygen, carbon dioxide, 
 water, sulphur dioxide, etc., or contain more than one of these. 
 Then he must decide, when the gas has been identified, what 
 substances could have furnished it, and, if possible, taking the 
 other facts into consideration, decide what the unknown body 
 was. The pupil should be warned to keep the residue from this 
 experiment, since, for example, any one of many kinds of 
 bodies may be the source of oxygen, and examination of the 
 residue to determine what it really was may be the quickest 
 way to limit the choice. 
 
 When the body is heated with concentrated sulphuric acid, 
 similar observations will be made. Oxygen, carbon dioxide, 
 Action of sulphur dioxide, etc., may be recognised by specific 
 Sulphuric properties. Dense clouds of fumes will usually 
 
 indicate the halogen hydrides or nitric acid. 
 Coloured solids like iodine and free sulphur may be seen. A 
 few salts, such as phosphates and sulphates, will give no visible 
 action. Of course everything noticed and the inferences drawn 
 will be recorded. If these two experiments do not lead to a 
 definite conclusion, the examination of the residue of the former 
 will usually assist very materially. For example, it may itself 
 be treated with concentrated sulphuric acid. 1 
 
 Naturally the reports first presented will almost always be 
 
 1 An account of the inferences which maybe drawn from the results of 
 these and similar dry way tests will be found inW. A. Noyes' Qualitative 
 Analysis (1898), 54-56, in Valentin's Qualitative Analysis (1898), 213 and 
 231, and other similar works. 
 
SOME CONSTITUENTS OF THE COURSE iSl 
 
 inconclusive. If a gas is given off which burns, it will be desig- 
 nated hydrogen. When the pupil is asked how he knew it 
 was not hydrogen sulphide, he will probably not 
 be able to recall any reason. On returning with 
 a definite report, say, to the effect that it had no 
 odour, he will then be confronted with the suggestion that it 
 might have been carbon monoxide, and so a fresh investigation 
 will be started. Or if he reports oxygen, and has not excluded 
 the possibility of its being nitrous oxide, the fact should be 
 pointed out. If he reports potassium chlorate, he is asked how 
 he knew it was not the perchlorate or hypochlorite. Each of 
 these questions at once appeals to him, his pride is stimulated, 
 and he rushes off to renewed experiment and to investigation of 
 his laboratory notes, or, if these fail, of the books provided for 
 reference. Of course the success of the system depends upon 
 the neighbours in the laboratory receiving different substances, 
 and upon the alertness of the teacher in suggesting means of 
 making the report more logical and conclusive. This sort of 
 work invariably arouses the interest of the pupils to the highest 
 pitch, and a single exercise in identification will teach them 
 more about chemistry than they have learned in months of 
 ordinary instruction, and they will be the first to draw attention 
 to this fact. Of course it would have had neither interest, nor 
 object, nor possibility of success without the previous drudgery. 
 This work is not capable of being arranged in a system so 
 simple that its employment becomes mechanical. The range 
 of observation is wider than in wet way tests, and Benefits of 
 chemical knowledge is demanded continually. That this Work, 
 it furnishes exercise in observation and reasoning, however, 
 does not require to be pointed out. That it takes advantage of 
 the various qualities of human nature which hold the attention 
 and even awaken enthusiasm, is one of its most conspicuous 
 characteristics. That it must furnish a review of most of the 
 chemical properties and modes of preparation of the non- 
 metals and their compounds, and this in the most practical 
 way, is evident. Above all, after one or two attempts at in- 
 
1 82 SOME CONSTITUENTS OF THE COURSE 
 
 vestigation of this kind, the pupil experiences a feeling of self- 
 reliance and of ability really to do something with his chem- 
 istry, which is necessarily stronger and more gratifying than it 
 would be in the use of a cut and dried system that left little 
 room for variety of procedure and independent thought, like 
 the common scheme of wet way analysis. It may be added 
 that a pupil with but little training will be as successful in this 
 work, provided, of course, no cases of exceptional difficulty are 
 presented to him, as another who has been prematurely trained 
 in formal analysis, and he will usually reach his results more 
 quickly, and what is much better, will know precisely how he 
 reached them. I have heard of students of analysis spending 
 two days in looking for the acid radical in an alloy. Students 
 of analysis are in danger of being slaves to the system and of 
 using the whole of it every time. They are often like the 
 guides to show places in Europe, who get on nicely if they 
 are allowed to deliver their accustomed harangue without any 
 appeal to their intelligence, but who are paralyzed if they 
 allow themselves to be interrupted to answer a common-sense 
 question. 
 
 Work of the kind we have described takes a good deal of 
 time, but its extreme instructiveness far more than makes up 
 for this. If any time remains at the end of the year, there is 
 no reason why the process of identification should not be 
 extended to the metallic part of the compounds given for 
 examination. 
 
 V. The General Content. 
 
 It would be needless to attempt to suggest what other mat- 
 ters should make up the course in chemistry aside from the 
 Principles of topics we have discussed. Facts, and many of 
 Selection. them, are needed for the foundation of general- 
 ization and theory, and for the illustration of the chemistry of 
 the important elements and compounds. The selection of facts 
 for this purpose must differ in different institutions according to 
 the capacities and needs of the pupils, the taste of the teacher, 
 
.SOME CONSTITUENTS OF THE COURSE 183 
 
 and a hundred other circumstances. As a general suggestion, 
 however, a statement of the Committee on College Entrance 
 Requirements may be recalled, as it is sufficiently important in 
 this connection to justify quotation": " Facts incapable of cor- 
 relation should be avoided as far as possible, " u and again : "The 
 facts should be given as examples from various classes, and not 
 as isolated things. Thus to speak of a ' standard method of 
 preparing hydrogen,' whereby the action of zinc on hydro- 
 chloric acid is meant, shows narrow and infertile teaching. It 
 should be shown that all acids are acted upon by a certain class 
 of metals to produce hydrogen. Examples of both classes of 
 metals should be given and the general principles derived. The 
 reason for using zinc and hydrochloric acid in the laboratory 
 can then be stated." 
 
 The outline of work for a secondary school course in chem- 
 istry, which is most fully worked out in detail, is that prepared 
 by the Committee of Nine, to which repeated refer- outlines Sug- 
 ence has been made already. They show what, in fjjf^jj^ 
 their estimation, is a proper content and order for Bodies. 
 presenting the subject, and by useful comments point out the 
 relations of the theoretical topics to one another. They indi- 
 cate also the way in which experimental illustrations should be 
 distributed between the laboratory and classroom. It seems 
 to me to be the best outline of what the American high school 
 can and should be expected to do. Excellent scientific judg- 
 ment and practical knowledge of the condition of the schools 
 are shown at every point in the report. 
 
 The syllabus of the Examination Board of the Association of 
 Colleges of the Middle States and Maryland is founded upon 
 the report of the Committee on College Entrance Require- 
 ments. It is much less detailed than the above, but the scope 
 of work which it indicates is practically the same. A useful list 
 of laboratory experiments, which is well selected and represen- 
 tative, has been appended by the Examination Board. 
 
 The syllabus issued by the Regents of the University of the 
 State of New York cannot be commended without reserve. 
 
1 84 SOME CONSTITUENTS OF THE COURSE 
 
 The laws of chemistry seem to receive too little consideration. 
 The only one of the quantitative laws mentioned is that of 
 definite proportions, yet they presently ask for a knowledge 
 of the "theory of valency" which cannot be obtained without 
 the study of Avogadro's hypothesis, and all that it implies. 
 They include also the atomic theory, although there is noth- 
 ing which calls for the use of this theory so long as the sub- 
 jects of multiple proportions and of equivalent proportions are 
 omitted. The laboratory work which is suggested is too brief. 
 It contains also nothing on the chemistry of the metals and 
 their compounds, and none of the fundamental principles of 
 the subject are illustrated in it with the exception, strange to 
 say, of the law of mass action. Even this is referred to, how- 
 ever, in so questionable a way (see Experiments 15 and 24), 
 that it might better have been omitted. Of course every- 
 thing depends on the use which a teacher may make of any 
 outline, but this one certainly does little to discourage dis- 
 jointed work and the neglect of the principles for accumulation 
 of facts. 
 
 The detailed statement of the admission requirements to 
 Harvard College contains much theory in proportion to the 
 number of facts. It is exceedingly well put together and 
 highly instructive. Probably the explanation of the emphasis 
 upon theory may be found at least as much in the nature of 
 the instruction in the college itself as in consideration for the 
 needs of the pupils in the secondary school who may never go 
 to college at all. 
 
 VI. The Selection of the Text-Book and Laboratory Manual. 
 
 This subject is closely connected with the last, and the choice 
 of books must depend on so many circumstances that definite 
 recommendations cannot be made. It may be useful here, 
 however, to recall the points bearing on this question which 
 have been discussed in the present volume, and to summarize 
 them in their application to the choice of books. Naturally 
 
SOME CONSTITUENTS OF THE COURSE 185 
 
 these statements are intended to apply to the average case 
 only, and in common with all statements on difficult questions 
 like this, must be subject to numerous exceptions. 
 
 In general, a book which gives a plain account of the sub- 
 ject without t$o much pedagogical pretence will be best suited 
 to the use of the teacher who knows his subject. ^ e Text- 
 It is unnecessary to say that it should be accurate, Book - 
 and not only accurate in its statements, but it should present a 
 view of the science as close to that occupied by the scientific 
 chemist as is consistent with its elementary character. It 
 should deal almost exclusively, so far as facts go, with the com- 
 mon elements, and a not too numerous selection of their 
 prominent compounds. Works of reference can be used for 
 amplifying the information which it gives. 
 
 The spirit of the book should be inductive ; the laws should 
 be carefully explained as summaries of facts which have been 
 given and in close relation to them. Theories should likewise 
 be closely related to facts and should follow them. The gen- 
 eral treatment should be connected, logical, and lucid, and 
 should make the unity, rather than the diversity, of the sub- 
 ject apparent. 
 
 The book should treat of general chemistry in a sound 
 fashion and as a pure science. It should not, for example, 
 be arranged as an introduction to analysis. 
 
 Formulae should be kept in their proper places, and shown to 
 be receptacles for the results of the study of each action. They 
 should not in any sense appear to be themselves the end of 
 study in chemistry. The way in which the facts are translated 
 into formulae, as a sort of language or shorthand for expressing 
 them, should be explained clearly, that no misunderstanding 
 may arise. 
 
 The outline of laboratory work or laboratory manual should 
 fulfil the requirements which we have discussed in Chapter IV. 
 It should plainly exhibit coherence in the study of The Labora. 
 each topic, or at least should be capable of yielding tor y Manual, 
 results in which this coherence may be brought out. The out- 
 
1 86 SOME CONSTITUENTS OF THE COURSE 
 
 line of each experiment should be a thoroughly sufficient guide 
 to the pupil, without being overburdened with detail, and with- 
 out foretelling the result ; the manner of presentation should 
 encourage and assist thought ; the selection should be judicious ; 
 and, above all, the principles of the science should be illustrated, 
 as well as the facts. 
 
CHAPTER VII 
 
 THE LABORATORY, EQUIPMENT AND ILLUSTRATIVE 
 MATERIAL 
 
 REFERENCES. 
 
 Whitney, E. R. Equipment of Secondary School Laboratory. High 
 School Bulletin No. 7. Albany, N. Y., The University of the State of 
 New York. Pp. 665-675. The whole of the paper is valuable and has 
 furnished many suggestions for this chapter. 
 
 Arey, A. L. Management of Laboratory Classes in Chemistry. Ibid. 
 Pp. 676-678. 
 
 Gibson, James H. Selection and Care of Apparatus. High School 
 Bulletin No. i. Albany, N. Y., The University of the State of New 
 York. Pp. 362-366. 
 
 Catalogues of dealers in laboratory supplies. 
 
 THE attempt should not be made to give instruction in chem- 
 istry in any school which is not provided with a laboratory 
 fairly well equipped for the purpose. It should certainly never 
 be taught without laboratory work, and a poorly furnished lab- 
 oratory means prodigious loss of time both to the pupil and to 
 the teacher, and many difficulties in discipline and class manage- 
 ment. If, however, the authorities insist upon the teaching of 
 the subject when no laboratory exists, a strenuous effort should 
 be made to provide some tentative arrangement of an inexpen- 
 sive kind in order that this indispensable feature may not be 
 entirely omitted. 
 
 I. Accommodations required. 
 
 First in order comes the laboratory itself, which should be 
 large enough to hold the necessary furniture and provide plenty 
 of space for the moving about which the work entails. 1 Close 
 
 1 For full discussion of the arrangement of benches with reference to 
 space and light, see Minot, SCIENCE [N. S.J, XIV. (1900), 412. 
 
1 88 THE LABORATORY 
 
 to this should be the store-room, which should not be made too 
 small, if perfect order is to be kept amongst the material it 
 contains. A large well lighted closet may per- 
 haps serve this purpose in a small school. The 
 classroom will probably be shared by other classes in physics 
 and perhaps biology. A private room for the teacher is indis- 
 pensable. A balance room, with shelves resting on brackets 
 attached to the walls, is extremely desirable, as the distraction of 
 attempting to weigh in a crowded laboratory interferes with 
 care and exactness. The fumes of the laboratory also damage 
 the instruments. A dark room for photographic work is a 
 convenience. 
 
 It is needless to say that all the rooms should be well lighted, 
 provided with sound-proof floors and partitions, and perfectly 
 ventilated. Artificial ventilation by fans is the best, if it can be 
 had. Aside from the ordinary heating arrangements, live steam 
 for the production of distilled water and for the steam baths 
 will be required. The rooms should be furnished with gas 
 connections for lighting, and the tables and hoods with light- 
 ing or fuel gas for experimental work. Water should be pro- 
 vided on "all the tables and in the hoods, and electrical connec- 
 tions are desirable. 
 
 One of the prime necessities is a willing and intelligent jani- 
 tor, and the maintenance of perfect cleanliness through his 
 efforts. Mr. E. R. Whitney puts this exceedingly 
 well when he says : " The activities of the pupil 
 are largely influenced by his surroundings. There is an 
 intimacy between environment and conduct, and character is 
 the outgrowth of conduct. A dirty, poorly lighted, inconven- 
 ient room, though designated as a laboratory, containing broken 
 apparatus and dilapidated furniture, breeds slovenliness, disorder, 
 and degradation. Bright, cheerful rooms, kept neat and tidy, 
 supplied with good apparatus and inspiring pictures, will be a 
 powerful aid toward the formation of high ideals and the 
 arousing of noble aspirations.'* 
 
THE LABORATORY 189 
 
 II. Laboratory Furniture. 
 
 a. The Desks : These should be three feet in height with 
 tops two feet wide, and the working places should be three feet 
 six inches long. The total length of a desk will de- 
 pend on the size of the room, but should in no case 
 contain more than four or five places. The desks may be 
 placed back to back in pairs. The tops may be made of some 
 hard wood. Paraffin should be ironed into them. This fur- 
 nishes almost perfect protection from damage. Plate glass 
 (three-eighths of an inch thick, resting on rubber), slate, and 
 tiling, are frequently employed. Perhaps the best material is a 
 form of soapstone, made by the Alberene Stone Co., Chicago. 
 It is indestructible. Glass apparatus is not more liable to break- 
 age where it is used than when wood is employed. The tops of 
 the tables should be clear, the shelves and connections being 
 carried sufficiently high above them to make cleaning easy. 
 
 As more than one section may occupy the room, the space 
 under each place should be divided vertically. For two sec- 
 tions, two cupboards with one or two drawers above each will 
 provide accommodation for the apparatus. If there are more 
 sections than two, or if economy in equipment is desired, one 
 cupboard containing the less breakable materials may be used 
 by all the occupants in common, and from four to six drawers, 
 occupying the other side, may be assigned to different indi- 
 viduals, according to the number of sections. Combination or 
 ordinary locks or padlocks, to which the teacher carries a 
 master key, will be necessary on all cupboards and drawers. 
 
 A shelf running down the centre of each double desk will 
 hold a few reagents. Glass shelves with iron supports are ad- 
 mirable. They obscure the light less than wood, and are not 
 harmed by acids. Six bottles containing the three 
 common acids in diluted and concentrated form, 
 and three containing solutions of sodium and ammonium 
 hydroxides and sodium carbonate will usually suffice for 
 general chemistry. The stoppers of the last three bottles should 
 
190 THE LABORATORY 
 
 be covered with paraffin, or rubber stoppers should be substi- 
 tuted for them. Ordinary glass stoppers continually become 
 fast in the mouths of the bottles, which are broken in large 
 numbers in the attempt to open them. 
 
 The fuel gas may be led in a horizontal pipe under the shelf, or 
 vertical pipes may rise to the surface of the table and terminate 
 Gas and * n a piece carrying four narrow exits for rubber tube 
 
 water. connections. The sinks of alberene may either be 
 
 placed in the corner between two adjacent and two opposite 
 places, thus serving for all four pupils, or at the ends of the 
 desks. In the latter case, an open trough, lined with lead or 
 alberene, running down the centre under the shelf, is useful. 
 Narrow exits for water placed over the trough furnish means 
 for attaching condensers, and should be threaded for carrying 
 water pumps. In any case the water faucet over the sink 
 should be placed somewhat high, to prevent breakage of appara- 
 tus. It is exceedingly important that the exit of each sink 
 should be provided with a cap perforated at the top, in order 
 that at least an inch and a half of water may always remain 
 standing in the sink. Thus strong acids are diluted before 
 entering the lead pipe, and solids have an opportunity to settle. 
 With this arrangement, ordinary lead and iron pipes will serve 
 for the drainage of the laboratory, and will last for years. 
 Without these caps the pipes are quickly eaten away, and be- 
 come plugged up as well. 
 
 If they can be accommodated, recesses for the stools and 
 the waste jars, 1 of which there should be at least one to every 
 Other fo ur working places, may be provided under the 
 
 Fittings. desk. Sometimes economy in equipment may be 
 effected with little loss in convenience by the use of projecting 
 strips of wood perforated with two or three holes to serve as 
 filter stands, and by fixing iron rods in the table to take the 
 
 1 Buckets, " Buggy pails," made by the Indurated Fiber Co., Water 
 Street, Chicago, are cheaper than stone-ware jars, look better, and last 
 as long. The same firm makes " Keelers," circular, flat-bottomed, shal- 
 low vessels, which make excellent pneumatic troughs. 
 
THE LABORATORY 19 1 
 
 place of ring stands. Rods eighteen inches long and three- 
 eighths of an inch in diameter will cost little, and will serve the 
 purpose very well. The invention of some form of accommo- 
 dation for the laboratory directions and note-books, which would 
 not interfere with the use of the drawer or cupboard, or with 
 the work being performed, would confer a boon upon the stu- 
 dent in chemistry. 
 
 When gas can be obtained, the Bunsen burner will naturally 
 be used for heating. In the absence of this great convenience, 
 a small apparatus for making gasoline gas is a substi- 
 tute, which, however, is only moderately satisfactory. 
 A convenient acetylene generator, and a special form of Bunsen 
 burner for use with it, are made by J. B. Colt & Co., Boston. 
 The alcohol lamp is feeble and expensive ; it may be supple- 
 mented by the use of a gasoline blast 1 when higher tempera- 
 tures are required. For many purposes, ordinary small kero- 
 sene stoves (see figure in Cooke, ibid., 193) will be found 
 useful in the absence of gas. 
 
 b. The Hoods : For the performance of experiments in- 
 volving the evolution of noxious vapours, well-ventilated hoods 
 should be provided. One section of a hood will 
 be required for every four or five workers. In 
 some cases, the hoods are placed on the desks, in others, along 
 the side of the room. Flues, in the lower openings of which 
 gas jets can be lighted, will serve the purpose in the absence of 
 better means of ventilation. If connection with a fan is pos- 
 sible, however, it should be made. The floors of the hoods 
 should be clear in order that they may be easily cleaned. Gas 
 and water connections are best placed below the floor of the hood, 
 close to the front, and the rubber tubing for attachments is passed 
 through a small hole opposite each stop-cock. One or two 
 pipes for waste water should rise at the back of the hood and 
 open flush with the surface. At least one sink should be ac- 
 
 1 Convenient forms of this, which work satisfactorily, are listed and 
 figured by the Chicago Laboratory Supply and Scale Company, 39 W. 
 Randolph St. 
 
192 THE LABORATORY 
 
 commodated in a hood in order that ill-smelling liquids may be 
 disposed of without discomfort to the occupants of the room. 
 It should be fitted in the same way as the other sinks. 
 
 c. The Side-Shelves : Conveniently accessible shelves 
 should be placed against the wall for the accommodation of 
 chemicals. The solids used in considerable quan- 
 tities may be placed in large stoppered bottles 
 (say one litre). For most of the chemicals smaller bottles 
 (say 200 c.c.) will be sufficient. The liquids may be accom- 
 modated in half-litre bottles. The reagents should be carefully 
 labelled and arranged in alphabetical order, according to some 
 definite system, upon the shelves. The bottles and their places 
 on the shelves should be numbered 'consecutively with asphalt 
 paint. The labels should be painted with melted paraffin to 
 prevent defacement. It will be found that the books of 
 printed labels usually employ an unsystematic and often incor- 
 rect nomenclature, while the formulae they give are frequently 
 erroneous. 
 
 The solutions should always be made of a fixed concentration, 
 which is marked plainly on the label. It is better to furnish 
 ready-made solutions than to direct the student to make them, 
 except in the case of special exercises, as the latter method 
 gives uncertain results, and always entails great waste of mate- 
 rials. It should be noted that more than one solution of the 
 same substance, differing in concentration, is sometimes re- 
 quired, and that in general the best concentrations are not the 
 same as those used in qualitative analysis. 
 
 A list of the chemicals required can hardly be given, as it 
 must vary somewhat with the work. Many text-books 1 furnish 
 a list of materials needed. As regards special substances, it 
 should be noted that red phosphorus can almost always be 
 
 1 For example, Williams, Elements, 398 ; Perkin and Lean, 327 ; Newell, 
 381 ; Young, Suggestions to Teachers, 42 ; Cooley, Laboratory Studies, 139; 
 Shepard, Elements of Chemistry, 343 ; Nicholson and Avery, Laboratory 
 Manual, 125. Torrey, 47 5, and Arey, Elementary Chemistry, xi, give lists 
 of apparatus only ; the others, apparatus and chemicals as well. 
 
THE LABORATORY 193 
 
 employed as well as the yellow variety, and is much safer to 
 handle. A solution of ferrous sulphate had better not be fur- 
 nished, as it rapidly oxidizes. In place of solid ferrous sulphate, 
 ammonium ferrous sulphate is preferable, as it keeps much bet- 
 ter, and is not, therefore, so liable to give misleading results. A 
 solution of this double salt containing a little sulphuric acid will 
 keep for months without much oxidation (Noyes). A solu- 
 tion of tartaric acid should be made immediately before use, 
 as moulds grow in it when the attempt is made to keep it on 
 the shelf. 
 
 d. Other Laboratory Furniture: A cabinet containing 
 drawers divided into compartments and filled with corks of 
 various sizes is necessary. In the same place 
 accommodation may be found for pliers, files, neous Fur- 
 copper wire (thick and thin, say Nos. 16 and mture> 
 22), and cork borers, all for general use. 
 
 A broad shelf attached to the wall, or a small table, furnished 
 with gas connections and covered with a sheet of asbestos board, 
 will serve for the blast lamp. 
 
 An ordinary table for readers and a book-shelf for the most 
 necessary works of reference should not be omitted. The books 
 will be used ten times more, if placed in the laboratory, than if 
 they are to be found in a separate room only. The carrying of 
 the books to the working places, however, should be forbidden, 
 as otherwise they are sure to be damaged. 
 
 A blackboard, and, if the method of filing note-books in the 
 laboratory is adopted, a shelf near the door, complete the 
 furniture of the room. 
 
 III. Laboratory Equipment. 
 
 For the general service of the laboratory, an apparatus for the 
 preparation of distilled water will be needed. If the steam is 
 sufficiently clean, any tinner can make an appara 
 tus for its condensation at small cost. The worm 
 should be made of tin pipe, as this metal is least affected by 
 
194 THE LABORATORY 
 
 water and air. If steam is not available, the necessary boiler, 
 preferably of copper, can be made to the order of the teacher. 
 Many different varieties are on sale. A very compact one is 
 made by Richards & Co., New York. It should be placed near 
 a sink with running water, in order that the supply of cold water 
 for condensing the steam may be readily attached. 
 
 As each pupil is provided with but one burner, it is a great 
 convenience to have a large steam bath for general use. In 
 
 quantitative experiments some kind of steam bath 
 Steam Baths. . j- vi i ^ i 
 
 is practically indispensable, and a large one is less 
 
 expensive than many separate small ones. After trial of many 
 forms, I have found that the following arrangement is perfectly 
 effective, runs practically without any attention, and can never 
 dry up, and so suffer damage from overheating. It consists of a 
 rectangular box of sheet copper, four inches in depth, and of 
 size according to the needs of the class and the space in which 
 it is placed. The cover is carried upon feet projecting to the 
 bottom of the box, and reaches to within a fraction of an inch of 
 the top. It is perforated with openings one and three-fourths 
 inches in diameter for the accommodation of the evaporating 
 dishes. An ordinary iron pipe, one-half inch in internal diam- 
 eter, closed at one end and perforated at intervals of an inch 
 and one-half, rests diagonally on the bottom. At the open end 
 it rises vertically and projects through a hole in one corner of 
 the lid. At this point it is connected with the supply of steam. 
 The outflow pipe for the accumulating water is attached so that 
 its lower side is about an inch below the lid. This bath should 
 be situated in one of the hoods, with the overflow discharging 
 into one of the pipes provided for waste wate'r. The whole 
 apparatus can quickly be taken apart if cleaning is required. 
 The steam connections should include a suitable valve to pre- 
 vent the return of the water into the steam-pipe, if the supply 
 of steam in the building should be shut off. Large sand baths 
 are sometimes used in laboratories, but they become filthy from 
 the spilling of material into them, and are difficult to clean. 
 Luxuries, like electrically heated plates, are usually beyond the 
 
THE LABORATORY 1 95 
 
 reach of the school laboratory. They are very convenient, 
 however. 
 
 A pair of scales and weights for rough weighings will be 
 needed. The platform variety, with a sliding weight which 
 
 takes the place of the ordinary weights up to five 
 
 / r XT 11 \ i_ Scales, etc. 
 
 grams (see figure in Newell, 12), is the best. 
 
 The small weights up to five grams will infallibly be lost, prob- 
 ably during the very first exercise, if the common form of 
 scales is used. 
 
 Foot bellows and a blast lamp, a barometer and a thermom- 
 eter, are among the other necessary articles. In experiments 
 which require large quantities of certain gases, much time is 
 saved by the use of generators, or by furnishing the gases in 
 the liquid or compressed form. Kipp's generators l are the 
 most commonly used. Oxygen compressed in cylinders, and 
 liquid sulphur dioxide in glass bottles resembling siphons in 
 appearance are also obtainable. 
 
 The balances have already been discussed (p. 116). The 
 chief source of trouble is the tendency which the pupils have to 
 lose the small weights. If a sufficient number of sets of weights 
 can be afforded, each pupil should receive one, and thus be 
 held individually responsible for its return in complete form. 
 If a more delicate balance is required for any special purpose, 
 the Sartorius balance, No. 3 (the less highly finished pattern), 
 will be found sufficiently delicate for all quantitative work. 
 
 IV. Apparatus and Chemicals and the Store-Room. 
 While the labour of managing this necessary accompaniment 
 of the teaching of chemistry is exceedingly irksome, there is 
 nothing which contributes to making the work suc- 
 cessful more than a businesslike organization of Distribution 
 the way in which the materials are handled. Each of Apparatus - 
 pupil should be furnished with a set of the apparatus of which 
 
 1 For an inexpensive generator, modified from a design of Ostwald's, 
 see AM. CHEM. JOUR., XXI. (1899), 70. Another form is described 
 in SCHOOL SCIENCE, I. 88 ; a chlorine generator is described by Cornish, 
 loc. cit., 21. See also Peter's Modern Chemistry, 373. 
 
196 THE LABORATORY 
 
 he stands most commonly in need. Apparatus which he re- 
 quires but seldom may be drawn from the store-room, and its 
 prompt return should be exacted. In order that the pupil 
 may feel his complete responsibility for the preservation of the 
 materials, and may use them with care and lock them away 
 systematically after work, it is a good plan to furnish him at the 
 beginning with a printed or mimeographed list of the mate- 
 rials he has received. This may also show the price at. which, 
 when the apparatus is checked up, all articles missing, whether 
 through having been broken, lent, or left lying about, will be 
 charged. After comparison of the list with the apparatus, the 
 former may be signed by the pupil and returned to the store- 
 room, where it is kept as a receipt. At the end of the year, if 
 everything is returned undamaged, no charge will be made. 1 
 There are, however, some pieces of apparatus, such as towels, 
 files, and wire gauze which, if furnished at all, necessarily can- 
 not be issued again after they have once been used. The 
 Bunsen burner and clamp, also, usually become corroded dur- 
 ing a year's use, and, if given out again uncleaned, any damage 
 which may occur to them will be attributed to the previous 
 user. It is a good plan, therefore, to have these articles com- 
 pletely renovated during the summer vacation in order that 
 nothing but fresh apparatus may be given out. 2 
 
 On the opposite page is shown, on a reduced scale, a sheet 
 like that whose use has been suggested. The lower portion 
 Lists and contains materials which are unreturnable, and are 
 Blanks. p a i c ] for at once if not furnished by the pupil him- 
 
 self. In filling this sheet, all the items which could possibly be 
 
 1 Since the handling of money by the storekeeper is inconvenient, 
 the best mode of securing payment for broken apparatus and for non- 
 returnable materials is to require a deposit with the treasurer of the 
 institution. In exchange for this the pupil receives a breakage ticket 
 arranged so that the storekeeper may cut off the value represented by 
 each transaction. Any balance is redeemed at the end of the year after 
 the set of apparatus has been turned in and checked up. 
 
 2 The Chicago Laboratory Supply & Scale Co. makes a special 
 business of this renovation. 
 
THE LABORATORY 
 
 197 
 
 OUTFIT FOR GENERAL CHEMISTRY STUDENT. 
 
 Laboratory Desk No Locker No.. 
 
 Date- 
 
 190 
 
 ARTICLES RETURNABLE. The articles on the following list are loaned to 
 the student and they must be returned at the end of the course clean, dry, and 
 in good condition. If any article is observed to be missing, broken, or in poor 
 condition, report same to storekeeper immediately ; and if any such article can- 
 not be replaced at store-room, a line should be drawn through the name of article, 
 for no allowance will be made after sheet is signed. Other supplies may be had 
 as needed at store-room, where posted rules should be read. After checking this 
 list carefully, sign your name in full and return this sheet to store-room as 
 soon as possible. 
 
 Sand Bath 
 Pneumatic Trough 
 
 @ 
 
 So 
 45 
 25 
 
 .10 
 
 .20 
 
 45 
 45 
 .06 
 
 .20 
 
 35 
 
 .12 
 
 25 
 
 !o8 
 1.50 
 .10 
 
 .20 
 .12 
 .12 
 .10 
 IS 
 .18 
 
 35 
 57 
 
 .05 
 
 Burette, 50 c c . 
 
 @ 
 
 $ -75 
 
 So 
 .48 
 
 .10 
 
 .14 
 
 .18 
 .07 
 
 75 
 .06 
 .08 
 .09 
 
 45 
 
 .02 
 
 '.06 
 .OI 
 
 45 
 
 1. 00 
 
 05 
 .10 
 .26 
 03 
 .06 
 .10 
 .08 
 .10 
 25 
 
 M 
 5 
 So 
 
 
 Graduated Cylinder, 100 c.c. . 
 
 Iron Stand, small 
 Iron Rings, 3 sizes 
 Clamp Holder 
 Burette Clamp 
 Universal Clamp, small . . . 
 
 
 Flask, 500 c.c 
 Distilling Flask, 30 c.c. . . . 
 
 
 Hofmann Screw Clamp . . . 
 Crucible Tongs, iron .... 
 Deflagrating Spoon .... 
 Iron Crucible 
 
 Funnel, 75 mm 
 Funnel, 100 mm 
 Funnel Stand 
 Squares of Glass, 5X5 cm. . 
 Side Neck Test Tubes . . . 
 Hard Glass Test Tubes . . . 
 i Test Tubes, 130 mm. . . . 
 i Test Tubes, 180 mm 
 Test Tube Rack 
 
 Test Tube Holder 
 
 Set Weights 
 
 Horn Spatula 
 Sponge . . 
 
 Thermometer 
 Thistle Tube 
 Hard Glass Tube, 10 inches . 
 Marchand's CaCl, Tubes . . 
 Watch Glass, 58 mm. . . . 
 Watch Glass, 75 mm. . . . 
 Watch Glass, 100 mm. . . . 
 File, round 
 Cork Borer 
 
 Porcelain Crucible, No. o . . 
 Evaporating Dish, No. oo . . 
 Evaporating Dish, No. i. . . 
 Evaporating Dish, No. 3 ... 
 Porcelain Mortar . . . 
 Nest Beakers, without lip, 
 
 $8 t& A 1*3 T 6 S 
 
 Bottles, Narrow Mouth, 250 c.c. 
 Bottles, Wide Mouth, 250 c.c. . 
 
 Pair Shears 
 
 Clay Triangle 
 Gas Tubing, 2 feet .... 
 Desk Key and Padlock, No. 
 Locker Key and Padlock, No. 
 
 Rubber Stopper, 2-holed . . . 
 
 Local address- 
 Home address- 
 
 (Sign here). 
 
 ARTICLES NON-RETURNABLE. The articles on the following list must be 
 paid for at once, with Chemical Laboratory breakage ticket, which must be ob- 
 tained from . The student may return any of these articles when he 
 
 takes the desk, if he already has them, or if he cares to get them elsewhere^ 
 
 
 4 08 
 
 
 3 
 
 
 
 
 * 02 
 
 
 06 
 
 5 Feet Glass Tubing . 
 
 
 
 
 5 Feet Glass Redding . 
 
 
 4 Sheets Filter Paper, No. 595, 
 
 .05 
 
 Total 
 
 .48 
 
 
 
 
 
 Date. 
 
198 THE LABORATORY 
 
 furnished for use in general chemistry have been included. 
 Many of the articles, while adding to the convenience of the 
 worker, or of the teacher, as in the case of the weights, may be 
 omitted, in order to save expense, without damage to the effec- 
 tiveness of the work. Indeed, all the ordinary purposes of the 
 secondary school course may be served by a list little more than 
 half as long. Another much smaller form may be used when 
 single articles are obtained from the store-room. These signed 
 slips being filed, the location of the various pieces of apparatus 
 is always readily ascertainable, and the responsibility of some 
 pupil for their return is fixed. 
 
 The teacher, unless his class is an exceedingly small one, 
 should not be burdened with the task of attending to the store- 
 room. His place is in the laboratory, and his presence can 
 never be dispensed with for a moment. The loss will be not 
 so much to the teacher as to the efficiency of his work. An 
 attendant for the few hours during which the laboratory is most 
 in use will probably not be difficult to find. 
 
 The store-room should contain a key-board for the keys of 
 
 all desks, lockers, and rooms in the building, unless this is kept 
 
 in the teacher's private room. It is convenient 
 
 also to have in it some articles which are useful in 
 
 preparing the materials used in the laboratory, such as a pair 
 
 of tinner's shears, an iron mortar, and sieves with meshes of 
 
 various sizes. 
 
 In the matter of apparatus, the chief necessity is to have an 
 ample supply of the smaller articles which are most used. 
 Sources of Expensive pieces of apparatus can always wait until 
 Apparatus. the stock of the other more necessary articles has 
 reached a sufficient size. Most of our glass apparatus is made 
 in Germany or Bohemia, but recently the manufacture of very 
 good articles at reasonable prices has been begun by Whit- 
 all, Tatum & Co., of Philadelphia. In ordering apparatus for 
 general chemistry, care should be taken to secure flasks with 
 relatively wide mouths, and, if possible, to have the glass tubing 
 and the stems of thistle tubes, etc., all of the same size, in order 
 
THE LABORATORY 199 
 
 that constant boring of new corks may be avoided. In general, 
 apparatus of thin glass should be preferred. Clamps, burners, 
 and other hardware convenient in form and economical in price 
 are made by the Chicago Laboratory Supply & Scale Co. 1 
 
 Unless very large quantities are needed, chemicals may be 
 bought without disadvantage in this country. Baker & Adam- 
 son of Easton, Pennsylvania, make chemically pure 
 articles for analytical work. Except in the case of 
 the common acids, and a few materials which may be bought of 
 a wholesale grocer, it is better to buy chemically pure materials 
 for all purposes. 
 
 The teacher of chemistry must be a person who is not simply 
 interested in learning, but must be willing to give a good deal 
 of time to the management of the material equip- careof 
 ment of his department. The utmost system and Equipment. 
 order which circumstances permit should always be maintained. 
 Articles of metal should be watched to see that they do not 
 corrode, and proper measures should be taken for their pro- 
 tection if the fumes inseparable from the laboratory seem to 
 have reached them. 3 
 
 While, for the reasons stated at the opening of this chapter, 
 a good equipment is exceedingly desirable, it should not be 
 forgotten that much may be accomplished at very little expense 
 when more means cannot be obtained. The teacher is more 
 important than the laboratory, for a good teacher will know 
 how to use and improve even a poor equipment. A good 
 
 1 The following are amongst the prominent dealers who furnish 
 apparatus and chemicals of all kinds : Eimer & Amend, New York ; 
 Richards & Co., New York; Queen & Co., Philadelphia; Henry Heil 
 Chemical Co., St. Louis ; Sargent & Co., Chicago ; L. E. Knott Apparatus 
 Co., Boston ; Bausch & Lomb, Rochester. The catalogues of these and 
 other firms, which are usually illustrated, give much information in 
 regard to apparatus. These firms, as well as the Chicago Laboratory 
 Supply & Scale Co., undertake duty-free importation of apparatus and 
 chemicals. 
 
 2 A valuable article on the care of apparatus by Inspector James H. 
 Gibson is published by the University of the State of New York. High 
 School Bulletin, No. i, 362-366. 
 
200 THE LABORATORY 
 
 deal may be done with ordinary deal tables, a few bottles, and 
 domestic substitutes for some apparatus. Some suggestions 
 on this head will be found in Cooke's Laboratory Practice, 9 
 and 10. 
 
 V. Classroom and its Fittings. 
 
 This room will probably be used in common with teachers 
 of other sciences. It should, therefore, be provided with a 
 The Lecture- large desk on which there shall be room for the 
 Table. apparatus and specimens required for illustrating 
 
 the work of more than one class. The top of the desk should 
 be for the most part perfectly clear, in order that an uninter- 
 rupted view may be had of everything upon it. The gas and 
 water supply may run along the under side of the edge next to 
 the teacher, and small holes through the top opposite the various 
 stop-cocks will furnish means of making connections through 
 the use of rubber tubes. There should be a sink at one end of 
 the table, at least, and several water faucets should be provided, 
 one being used for the attachment of a water pump arranged 
 so as to produce a vacuum or to furnish compressed air. 
 Underneath the table convenient cupboards and drawers for 
 the apparatus used in demonstrations will be required. For 
 most purposes a pneumatic trough with glass sides, so that every- 
 thing may be visible, is preferable to one lined with lead and 
 sunk in the table. Shelving for acids and other chemicals 
 should be placed in a convenient position. The hood, which 
 should be connected with the ventilating system, may be placed 
 behind the blackboard. The latter can be raised when the 
 hood is in use. Openings in the table provided with a down 
 draught and proper means of securing the removal of gases 
 generated in the course of experiments are almost indispensable. 
 In order that no time may be lost in preparing the apparatus 
 for demonstrations, or in exhibiting the experiments, no con- 
 veniences which can be obtained should be omitted. 
 
 The seats may be placed on steps three feet in width, and 
 each rising six or eight inches above the one in front of it. 
 
THE LABORATORY 2OI 
 
 Chairs with tablets facilitate the taking of notes. The windows 
 should be provided with grooves and opaque shades in order 
 that the room may be darkened when necessary, Lecture 
 and some arrangement should be provided for the Experiments, 
 exhibition of charts. Most of the apparatus used in demon- 
 strations will be the same as that employed in the laboratory, 
 excepting that everything must be on a larger scale. The 
 nature and use of the necessary apparatus is described and the 
 apparatus itself is figured in the works of Newth and Benedict 
 already mentioned (cf. p. 134). The more important special 
 articles will be a number of cylinders of various sizes, chiefly 
 used in experiments on gases, large test glasses, which are use- 
 ful in showing precipitations, and Hofmann's apparatus for 
 exhibiting the volumetric composition of various substances. 1 
 For class experiments with electricity, the storage battery is 
 much more convenient than any other, and is in the end much 
 cheaper, if means of charging it is available. Seven cells, with 
 plates five and a half inches square, will be found sufficient for 
 all ordinary experiments, and the whole of these will not always 
 be employed. A stereopticon for projecting lantern slides and 
 some experiments is very convenient. The growth of crystals, 
 for example (ammonium oxalate is a good substance), is diffi- 
 cult to make clear without this means of exhibiting its progress. 
 
 VI. Illustrative Material. 
 
 Charts and collections of various kinds add much to the 
 interest and value of the instruction. Articles which will serve 
 the purpose just as well, however, may be made or 
 picked up in various ways if a little trouble is taken. 
 Charts, for example, made from good illustrations in books 
 which are up to date, will be better in many cases than the 
 
 1 Simplified forms of this apparatus are sold by the L. E. Knott 
 Apparatus Co., Boston. The best arrangement for demonstrating the 
 equality of the volumes of hydrogen and chlorine given off in the electrol- 
 ysis of hydrochloric acid is that devised by Lothar Meyer, and figured 
 in the BERICHTE D. DEUTSCH. CHEM. GESELL., XXVII. (1894), 850. 
 
202 THE LABORATORY 
 
 antiquated and clumsy productions which are still sold. Fre- 
 quently a pupil will be found who has talent for this kind of 
 thing, and the collections of the school may be enriched with- 
 out much expense through his assistance. They should be 
 made on some material which will not be damaged by handling, 
 such as stout tracing linen, or paper backed with linen. 
 
 A list of the elements with their atomic weights, compiled 
 from the latest data by F. W. Clark (O= 16), mounted on linen 
 measuring 41" X 61", is sold by Eimer & Amend at $2. A 
 similar chart of the periodic system, using the same data, 
 measuring 58" X 42" is obtainable at the same price from the 
 same firm. An excellent series of twenty-four Chemical Lecture 
 Charts is published by Sampson, Low, Marston & Co., London. 
 They are mounted on linen, measure 40" X 30" and cost about 
 $13. They include the plant employed in many chemical in- 
 dustries, and some illustrations of theoretical matters, such as 
 curves of solubility and the apparatus for measuring freezing- 
 point depressions. A set of twelve charts illustrating industrial 
 processes, mounted on linen and measuring 170 X 125 cm. 
 is sold by Kaehler & Martini, Berlin, at 20.50 marks. Some 
 other charts are mentioned in Eimer & Amend's catalogue. 
 
 The teacher will find it convenient, frequently, to prepare 
 charts illustrating his own way of presenting the subject. A 
 list of the metals in the order of the electro-motive force they 
 show when arranged in conjunction with some other metal in a 
 battery, known also as the order of solution tension, if hung in 
 the classroom will find frequent application. 1 This order rep- 
 
 1 This order is not the same as that of the old list of Berzelius, which, 
 although hopelessly out of date, still appears in some works, but is the 
 result of modern electro-chemical (cf. Le Blanc, Electro-Chemistry, chapter 
 VI.) investigation. Omitting the less common metals, and arranging 
 the others in order of decreasing solution tension, it is as follows : 
 
 Alkali metals Nickel Bismuth 
 
 Alkaline-earth metals Tin Antimony 
 
 Magnesium Lead Mercury 
 
 Aluminium Hydrogen Silver 
 
 Manganese Copper Platinum 
 
 Zinc Arsenic Gold 
 Iron 
 
THE LABORATORY 203 
 
 resents at once the tendency of the element to form ions, the 
 potential it acquires when placed in a solution of one of its salts, 
 and its chemical activity, all in decreasing order. Thus each 
 metal displaces those following it when placed in a solution of 
 any salt. Note the place of hydrogen. The metals before it ( 
 displace this gas from water and dilute acids, those following it 
 do not. The latter are found free in nature, while the former, if 
 they existed, would eventually become oxidized by replacing the 
 hydrogen of water or weak acids. The stability of the oxides 
 is exhibited also in some measure. As far as manganese, they 
 are not completely reducible by hydrogen ; after manganese, 
 they are easily reducible. The stability of other compounds 
 under the influence of heat follows approximately the same 
 order. 1 
 
 Portraits of chemists of historical prominence are attractive 
 additions to the classroom, and frequently the remembrance of 
 important matters in chemistry will be assisted by 
 association with the appearance of the man. The 
 NATURE series (London and New York, Macmillan) includes 
 some very artistic likenesses, although they are perhaps too 
 small for use in a large room. Kaehler & Martini publish a 
 series of portraits including forty-eight scientific men, with bio- 
 graphical text by Siebert (size 29 X 39 cm.). Portraits of Hof- 
 mann and Victor Meyer suitable for framing may be obtained of 
 the Pharmaceutical Review Publishing Co., Milwaukee. 
 
 In this connection it may be pointed out that photographs 
 made by the teacher, or some friend, from actual objects of chem- 
 ical interest, such as parts of chemical factories, may 
 
 Photographs. 
 
 be enlarged or made into lantern slides and furnish 
 a valuable means of illustrating many things. Many of the 
 charts and illustrations in books are so diagrammatic in their 
 nature, not to say so completely out of date in many cases, that 
 they give an exceedingly inadequate impression of the chemical 
 
 1 A chronological chart exhibiting certain historical data is given by 
 Tilden (Hints on the Teaching of Elementary Chemistry, 42-43) and may 
 be found useful. 
 
204 THE LABORATORY 
 
 industries as they are. Authentic representations of the real 
 thing, therefore, have great value in holding before the mind of 
 the pupil the fact that chemistry is on one side a great industrial 
 reality. They also assist in keeping the subject in touch with 
 matters of every-day life which may, in many cases, have more 
 or less close connection with the future business of some of the 
 pupils. It is needless to say that visiting factories, so far as they 
 are accessible, will be of the highest value. The managers are 
 usually willing to allow a teacher to take his class to visit their 
 plants, and will usually furnish a conductor more or less capable 
 of answering questions intelligently and explaining the machinery 
 and processes used. 
 
 The illustration of classroom work by exhibition of speci- 
 mens of minerals is also desirable. This strengthens the link 
 connecting chemistry both with geology and with 
 industry. Good specimens can frequently be found 
 by the teacher or obtained as gifts. They may also be pur- 
 chased from many dealers. Large cabinet specimens are not 
 required. The most instructive specimens to purchase, when 
 limited means only are available, are single crystals showing 
 common and typical forms of the various substances. These 
 may be obtained in almost all cases for ten or fifteen cents each. 
 A set of typical minerals fulfilling these requirements need not 
 be extensive. 1 
 
 1 List of 36 Minerals which furnish good crystals, are important ores, 
 or are conspicuous constitutents of rocks [cr. (= crystal) and mass. ( = 
 massive) indicate the best forms for our purpose]. 
 
 Copper (ramifying) Malachite (pseudom. from cuprite, 
 
 Arsenic (scales) cr.) 
 
 Sulphur (cr.) Selenite (Gypsum, CaSO 4 , 2H 2 O, cr.) 
 
 Halite (NaCl, cr.) Barite (BaSO 4 , cr.) 
 
 Fluorite (CaF 2 , cr.) Corundum (A1 2 O 3 , cr.) 
 
 Cryolite (3NaF, A1F 3 , mass.) Specularite (Fe 2 O 3 , cr.) 
 
 Calcite (CaCO 3 , cr.) Haematite (Fe 2 O 3 , mass.) 
 
 Dolomite (CaMg(CO 3 ) 2 , cr.) Limonite (Fe 2 O 3) hydrated. Pseu- 
 
 Siderite (FeCO 3 , cr.) dom. from pyrite, cr.) 
 
 Arragonite (CaCO 3 , cr.) Pyrolusite or manganite (MnO. 2 , 
 
 Malachite (CuCO 3 , basic and hy- hydrated, mass.) 
 drated, mass.) Magnetite (Fe 3 O 4 , cr.) 
 
THE LABORATORY 205 
 
 One of the subjects strangely neglected both in schools and 
 colleges in this country is the study of crystals. Their treatment 
 here is in marked contrast to that in Germany, 
 where a pretty extensive knowledge of crystallog- 
 raphy is required of teachers in secondary schools, and a large 
 part of the work in science 1 deals with the study of crystalline 
 forms geometrically and with physical crystallography. It is 
 not suggested that the time available in the secondary school 
 course is likely to permit the introduction of much of this subject. 
 Some trouble should be taken, however, to give the pupils an 
 intelligent knowledge of how crystals grow, and of some of the 
 common forms. The chemist depends very largely on the 
 making of crystals for purification, and on the form of them for 
 identification in his work, and both of these features appear in 
 elementary chemistry, whether particular attention is paid to 
 them or not. The pupils will always take great interest in 
 growing large crystals for themselves, and will learn much from 
 the exercise. Common alum and chrome-alum give beautiful 
 octahedra; nickel sulphate (NiSO 4 , 4H 2 O), illustrates the 
 square prismatic system; cupric sulphate (CuSO 4 , 5H 2 O), the 
 asymmetric ; double potassium cupric sulphate, made by mixing 
 the two salts in equi-molecular proportions, the monoclinic, etc. 
 Models made of wood or of cardboard to show the com- 
 mon forms on a large scale may be purchased or made very 
 readily. 
 
 Chromite (FeCr 2 O 4 , cr.) Garnet (cr.) 
 
 Cassiterite (Sno 2 , cr.) Apatite (cr. Ontario) 
 
 Quartz (SiO 2 , cr.) Cyanite (mass. Illustrates two hard 
 
 Sphalerite (ZnS, cr.) nesses) 
 
 Stibnite (Sb 2 S 3 , cr. Japan) Analcite (cr.) 
 
 Cinnabar (HgS, mass.) Hornblende (cr.) 
 
 Galena (PbS, cr.) Orthoclase (cr.) 
 
 Pyrite (FeS 2 , cr.) Topaz (cr. Japan) 
 
 Zircon (cr.) 
 
 Prominent dealers in minerals are G. L. English & Co., New York ; 
 
 E. A. Foote, Philadelphia ; Roy Hopping, New York ; and Ward, 
 Rochester. 
 
 1 See Russell, German Higher Schools, chapter XVIL, particularly 
 p. 364. 
 
206 THE LABORATORY 
 
 VII. The Teacher's Private Room. 
 
 A private work-room should be provided for the teacher in 
 order that he may have a place in which to pursue his own 
 work undisturbed. He may there try new experiments for de- 
 monstrations, and perhaps devise better means of illustrating 
 important points in chemistry for himself. He will also thus be 
 enabled to continue his study of the subject by experimental 
 work, for no one can afford simply to rest upon what he knows : 
 such a course must really involve retrogression. If his appli- 
 ances and time permit, and his previous training has been suffi- 
 cient, this room will furnish opportunity for carrying on research 
 in some direction. 
 
 The room, like the laboratory, should have connections for 
 gas, water, and electricity, and, in addition to the usual ap- 
 paratus, should perhaps be furnished with a bench fitted with 
 a small anvil and vice, and provided with a few tools. 
 
CHAPTER VIII 
 
 THE TEACHER, HIS PREPARATION AND DEVELOPMENT 
 
 Nichols, E. L. Paper on the Training of Science Teachers for Sec- 
 ondary Schools, and discussion thereon. High School Bulletin No. 7. 
 Albany, N. Y., The University of the State of the New York. 1900. 
 Pp. 630-650. 
 
 Russell, J. E. German Higher Schools. London and New York, 
 Longmans, Green & Co. 1899. Chapters XVIII. and XIX. 
 
 Bolton, F. E. The Secondary School System of Germany. New 
 York, D. Appleton Co. London, Edward Arnold. 1900. Chapter II. 
 
 THIS chapter naturally divides itself into three parts which 
 treat of the training of the teacher, the best means for securing 
 his continued development, and the literature which will be 
 most useful in connection with the latter. It would be useless 
 to discuss the qualities of sympathy, tact, alertness, force of 
 character, etc., which are indispensable in the teacher of chem- 
 istry as in the teacher of any other subject. These depend 
 largely on the natural aptitude of the aspirant to the profession 
 of teaching. It is rather the strictly professional part of the 
 preparation of the teacher which primarily concerns us. 
 
 I. The Training of the Teacher. 
 
 LThe indispensable acquisition of the teacher is a well-rounded 
 and sound knowledge of the subject. Nothing can possibly 
 make up for the absence of a preparation which will give thisj 
 It is to be feared that the attempt is often made to teach chem- 
 istry without this prerequisite. Often, as we have already re- 
 marked, a teacher who is conscious of incompetence is required 
 by the principal of his school to teach this subject, simply be- 
 cause its representation in the curriculum is desired. Often the 
 
208 THE TEACHER 
 
 student in a college whose curriculum is of the old stamp does not 
 discover until late in his course the natural bent which he may 
 possess towards physical science. He may thus, while lacking 
 the proper preparation, find that his taste leads him in the 
 direction of science, if his inclination or circumstances induce 
 him to become a teacher at all. Often, too, the college student 
 may have pursued the study of chemistry pretty extensively 
 during his course, but the nature of the instruction may have 
 been such that, in spite of his acquaintance with many phases 
 of the subject, he is little better prepared to teach it than the 
 members of the two other classes. For these and many other 
 reasons, it is to be feared that the teachers of chemistry in our 
 secondary schools, as a class, are not so thoroughly fitted for 
 their work as they should be. Yet, as Professor Bennett says, 
 we cannot " pass judgment on the mass of the incompetent. 
 They are almost without exception men and women of charac- 
 ter, of serious and earnest purposes, and faithful even to the 
 detriment of .. their health in the performance of their tasks. 
 They are, nevertheless, endeavouring to achieve the impossible, 
 to perform a work involving the employment of large re- 
 sources without ever having secured the necessary preparation." 
 (_The first constituent of this necessary knowledge of chem- 
 istry is general chemistry.! If we ask what the second ingredient 
 must be, we should be compelled to say again gen- 
 
 Generai^hem cra ^ cner str y> anc ^ tne same answer must be given 
 istry the at every repetition of the question, fit is a knowl- 
 Prime Essen- edge of the sc i ence as a w h o le and not of any 
 
 special section of it which will count in elementary 
 instruction. \ Only in so far as other branches may contribute 
 to this knowledge are they to be considered a specially desir- 
 able part of the training of the teacher of elementary chemistry. 
 It is a delusion to suppose that general chemistry can be dis- 
 posed of in three months, and that the next thing to be done is 
 to study qualitative analysis. A whole year of general chem- 
 istry will not confer anything like sufficient knowledge of the 
 subject for our purpose. 
 
THE TEACHER 209 
 
 Taking the matter in detail, we require first an introductory 
 course. This must be thoroughly sound and fairly extensive. 
 How rare courses possessing these characteristics First Tear of 
 are, only those who have studied the instruction Preparation. 
 in many institutions know. General chemistry cannot be 
 taught by a public analyst in his spare moments, by a phy- 
 sician with limited professional practice, or by a " sticket 
 minister" with a taste for science. The instructor must be a 
 man himself engaged in productive chemical work and thor- 
 oughly abreast of the times. He must be, so to speak, a 
 self-luminous body, for, the more he plays the part of a re- 
 flector or a refractor of borrowed information, the less truly 
 will the image represent the nature of the science. The intro- 
 duction should be a year in length, it should be accompanied 
 by much laboratory work, and its whole scope should be much 
 greater than that of the corresponding course in the secondary 
 school. 
 
 Beyond this, the knowledge of the subject must be deepened 
 in various directions. More acquaintance with the ordinary 
 facts of the science, more knowledge of theoretical and physi- 
 cal chemistry by study and by practical work, more ability to 
 handle the literature of the subject, and a far broader grasp of 
 the ramifications of the science in the directions of industry, 
 agriculture, geology, physiology, and hygiene are needed. And 
 all this will be valueless if the theory, the literature, and the ap- 
 plications are not treated in a thoroughly modern manner. 
 
 It might be suggested, as a tentative plan, that the second 
 year, following general chemistry, should begin with a study in 
 classroom and laboratory of such topics as chemical ... 
 equilibrium, the methods of measuring chemical General Chem- 
 affinity, and the boiling point, freezing point, elec- y ' 
 trolysis, and other properties of solutions which are of such im- 
 portance in the chemistry of qualitative analysis. Without these 
 preliminaries, the last-named subject can contribute nothing 
 worth mentioning to the student's knowledge of general chem- 
 istry. This might be followed by an elementary study of quali- 
 
210 THE TEACHER 
 
 tative analysis itself, care being taken to use the light which the 
 recent study of solutions has thrown upon their chemical nature 
 in explaining the rationale of the processes used, and in general 
 so to employ the subject as to deepen and broaden the pupil's 
 knowledge of general chemistry as far as possible. 1 Following 
 this, exercises in the determination of molecular weights, the 
 measurement of equivalents and combining weights, in which 
 the refinements of quantitative analysis are employed and the 
 results are used for working out atomic weights, will probably 
 occupy the remainder of the year. 2 Throughout the course, 
 
 1 OstwalcTs Scientific Foundations of Analytical Chemistry (Macmillan) 
 shows in detail how the operations of analysis may be rationalized. 
 
 2 Experience shows that students gain but a feeble grasp on the sci- 
 ence until they have done some exact quantitative work. It is prefer- 
 able on many grounds even to begin the second year with three months 
 of quantitative analysis, to follow this with theoretical chemistry, and to 
 place elementary qualitative analysis last. Of course the benefit derived 
 from the reversal of the ordinary arrangement will depend entirely on the 
 method and spirit of the instruction. 
 
 Quantitative analysis should be used to train the prospective teacher 
 in, and make him familiar with that accuracy of work and refinement of 
 method, which are not only characteristic of the subject-matter of the 
 science, but which also, in some shape or other, are the ultimate basis of 
 all advance in the knowledge of chemistry by experimental methods. 
 Such training is not only necessary if the teacher is to add to our knowl- 
 edge of chemistry (see p. 216), but is equally indispensable if he is to un- 
 derstand, without hiatus or distortion, how our knowledge has been de- 
 veloped (seep. 77). To achieve these ends the quantitative analysis 
 should not only deal with the separation and determination of a certain 
 number of bodies, but should develop as far as possible a sense of the 
 ultimate exactness and rigidity of the proofs of those theories to which 
 in the previous work in general chemistry (and, when the old order was 
 followed, qualitative analysis) constant reference has been made (see 
 p. 72). 
 
 At the same time the previously acquired knowledge of chemistry in 
 the broader view (general chemistry, as we have called it) should be 
 used and increased as far as possible, e.g., by exact determinations of 
 combining weights, by testing the law of the conservation of mass, and 
 by applying the laws of chemical equilibrium to the methods used. 
 Certain phases of general chemistry can be considered profitably at some- 
 what greater length at this stage, e.g., isomorphous mixtures, the prep- 
 aration of chemically pure substances, and the growth of crystals of 
 difficultly soluble salts such as barium sulphate. 
 
 Finally, in quantitative analysis students should take up some prob- 
 
THE TEACHER 211 
 
 the reading in various works of reference, in selected original 
 papers, and along historical lines, should be arranged with great 
 skill, so as, on the one hand, to strengthen the pupil's grasp on 
 the topics taken up in the laboratory, and, on the other, to fill 
 out the gaps between these topics, and render the whole study 
 more symmetrical. Indispensable as extensive reading is at 
 this stage, it is almost wholly neglected in most institutions at 
 the present day. It is left to the initiative of the pupils who 
 have special interest in the subject, precisely at the time when 
 guidance and stimulus from the teacher are most needed. 
 
 The difficulty in endeavouring to give a course like the above 
 is that no text-books or laboratory outlines of the sort which 
 would harmonize with this ideal are available, excepting per- 
 haps in organic chemistry. 
 
 The third year of work will contain organic chemistry and 
 inorganic preparations on the lines of Lengfeld's Inorganic 
 Preparations l (Macmillan). The final prepara- organic 
 tions made should be of a more difficult order, Chemistry, 
 to the end that the pupil, by examination of the literature for 
 himself, may make some approach to realizing the conditions 
 of original research. During this year reading and inorganic 
 study are again indispensable. Seminar work in Preparations. 
 which reports on recent discoveries are presented, and topics 
 of vital interest in the point of view of general chemistry are 
 discussed, will serve for reviewing and deepening 
 the knowledge of the subject. There is far too 
 much so-called instruction in chemistry in our higher institutions 
 
 lems from the standpoint of semi-original investigation with the rigid 
 criteria applied in real research. 
 
 Work having these characteristics serves to clinch the impression 
 made when the corresponding topics were discussed in the introductory 
 course. On the other hand, the common kind of quantitative analysis, 
 which devotes itself exclusively to technique, and can be fairly defined by 
 the number of determinations it includes, is of little value at any stage. 
 It may give some mechanical skill, but it will teach no chemistry. 
 
 1 F. H. Thorp, Inorganic Chemical Preparations (Ginn & Co.), and 
 Erdmann-Dunlap, Introduction to Chemical Preparation (John Wiley & 
 Sons), are similar works. 
 
212 THE TEACHER 
 
 which consists solely in technical guidance of experimental 
 work, and neglects entirely the development of the scientific 
 knowledge of the pupils. Experimental work without reading, 
 and exercises which call for no thought, are as useless as food 
 without the intervention of the digestive fluids. 
 
 It need not be added that during this time physics and 
 mineralogy, at least, and if possible other sciences, should be 
 pursued, not only on account of their indispensability as sources 
 of illustration in the teaching of chemistry, but also because the 
 future teacher may have to give instruction in some of them. 
 The other studies should include a sufficient amount of German 
 to give a reading knowledge, since it is difficult to pursue the 
 study of chemistry without reference to articles and books in 
 this language. 
 
 It seems to me that three years, properly spent, will furnish a 
 knowledge of the science which, considering the demands of 
 the secondary school, will be approximately equivalent to that 
 expected in other subjects. The time, however, must be spent 
 as largely as possible in acquiring, adding to, and throwing side- 
 lights upon general chemistry. Long courses in analysis, while 
 they must be included, at some stage, in the training of techni- 
 cal chemists and investigators, are a misapplication of precious 
 time so far as our purpose is concerned. This adequate train- 
 ing cannot be obtained quickly or without expense. It will 
 require almost continuous work throughout the college course, 
 or an equivalent of this. 
 
 The question is, where can the teacher in training secure the 
 needful instruction. Not of a surety in the departments of 
 The Present chemistry of our colleges and normal schools as at 
 
 Condition present conducted. The chemical curricula of our 
 
 of Higher 
 
 instruction higher institutions, largely through the influence of 
 
 in Chemistry. tra( jjtion, are so filled with a mass of specialized 
 work in stereotyped grooves that proper instruction for teachers 
 is difficult to obtain. 1 Their arrangements seem to be made for 
 
 1 For a highly interesting discussion of this subject, see Professor 
 Armstrong's Presidential Address before the Chemical Society of Lon- 
 
THE TEACHER 21 3 
 
 the purpose of training chemists for agricultural stations or com- 
 mercial work. The conventional order of general chemistry, 
 followed by qualitative and then quantitative analyses, is unfortu- 
 nate. The two latter subjects, as ordinarily taught (cf. pp. 173, 
 210), contribute practically nothing to the student's knowl- 
 edge of the science of chemistry in the broader view. They 
 are almost always, for the most part, purely technical applica- 
 tions of a single aspect of the subject, and during their study 
 so much general chemistry is forgotten that the student really 
 acquires a narrower view of the subject in some respects than 
 he had at the end of the first year. The analyst turned out by 
 this training can do the routine work of a factory. His stand- 
 ing is the same as that of a bookkeeper, and his work requires 
 no more extensive training. His preparation does not fit him 
 to assist in advancing chemical industry, any more than that of 
 the mere bookkeeper fits him to manage an extensive business 
 successfully. The student who intends to become a teacher of 
 chemistry has to pick up the nourishment for the growth of a 
 broad knowledge of the subject from what must be admitted to 
 be a rather sparse vegetation in this point of view, and it is at 
 present only the exceptional student who gets it. I should 
 certainly be at a loss to mention any institution in which an 
 ideal course for teachers is given. Yet, as Professor Nichols 
 says, in his admirable paper on The Training of Science Teach- 
 ers : " No institution, whether it calls itself normal school, col- 
 lege, or university, that does not offer the student opportunities 
 of the kinds just indicated [Nichols' course in physics was on 
 the same lines as that outlined above for chemistry], is fitted for 
 the training of the modern science teacher. No institution, the 
 members of the faculty of which are not bonafide men of science, 
 
 don. JOURNAL OF THE SOCIETY, XLV. (1894), 361 ; reprinted in NA- 
 TURE, L. 211. See also Professor John H. Long's address on the 
 Teaching of Chemistry in the Medical Schools of the United States. 
 SCIENCE [N. S.], XIV. 360. Mr. Lachman, in an address on the Im- 
 provement of Instruction in Technical Chemistry, utters some very sug- 
 gestive criticisms of the present methods and sketches a substitute. 
 JOUR. Soc. CHEM. INDUSTRY, XX. (1901), 546. 
 
2/4 THE TEACHER 
 
 devoting themselves quite as seriously and continuously to re- 
 search as to routine teaching, can hope to produce in its students 
 those qualities and habits of thought that ... are essential to 
 the highest type of teacher." 
 
 II. The Development of the Teacher during Professional Life. 
 
 The teacher cannot afford to settle down and dole out his 
 instruction from the slowly petrifying deposit with which his 
 college provided him. He must follow the new developments of 
 the subject, and continually change his mode of presenting every 
 part of it, in order that it may harmonize with the best thought 
 of chemists. Not only this, however, but he must continually in- 
 crease his own attainments. The best preparation always seems 
 to have been wonderfully meagre compared to the mass of knowl- 
 edge which we, as teachers, find indispensable in our work. 
 
 The reading of the latest text-book is useful, but the most 
 productive method of study is to take up some topic of inter- 
 Whatto est and pursue it to its limits. A subject like nitric 
 Read> acid and the oxides of nitrogen, for example, when 
 
 studied first in all the general works, then in the larger books 
 of reference, and finally in the original literature, will be found 
 exceedingly interesting. The study of the various determina- 
 tions of the ratio of hydrogen to oxygen in water, in spite of 
 the somewhat dry aspect which the mere statement of the subject 
 presents, will be found truly fascinating. The determinations 
 of the atomic weights of aluminium, zinc, and other elements, 
 are highly instructive on account of the precautions employed 
 in their execution. These are mentioned as examples, and the 
 catalogue might be prolonged almost indefinitely without going 
 outside the list of subjects upon which many important papers 
 have been published in the English language. 1 
 
 1 References to books treating fully or with especial clearness of many 
 chemical questions will be found scattered through the present work. A 
 large number are given in Newell's Teachers' Supplement. The follow- 
 ing are a very few references to important and interesting original 
 articles in English. 
 
 Action of metals on nitric acid. Freer, Inorganic Chemistry, chap- 
 
THE TEACHER 21$ 
 
 Not only is the reading of original papers easy after such 
 preparation as the examination of the text-books gives, but, 
 contrary to the popular impression, it is vastly more interesting 
 and incomparably more valuable than the study of books 
 alone. If we want to know about a plant, we must consider the 
 whole structure, and the whole course of development from the 
 seed to maturity. The structure of a few dead chips is as little 
 enticing or useful in this connection, as the study of text-books 
 is in giving a genuine knowledge of what constitutes the science 
 of chemistry. Only the examination of the literature can show 
 us the growth of each fragment of the science and how ad- 
 ditions to human knowledge of permanent value are really 
 made. The atmosphere of the text-book suggests the museum 
 or the tomb to one who has breathed the air of the workshop 
 and of life in the original reports of the investigator. 
 
 ter XXVI. AM. CHEM. JOUR., XV. 71 ; XVII. 18 ; XVIII. 587 ; XXI. 
 378. 
 
 Atomic weight of oxygen. Cooke and Richards, AM. CHEM. JOUR., 
 X. 81 and 191. Keiser, ibid., X. 249 ; XX. 733. Noyes, ibid., XII. 441. 
 
 Atomic weight of zinc. Morse, AM. CHEM. JOUR., X. 311. Clarke, 
 ibid., III. 263. 
 
 Molecular weight of hydrogen fluoride. Mallett, AM. CHEM. JOUR., 
 III. 189. 
 
 Persulphates. Marshall, JOUR. CHEM. Soc., LIX. 772. JOUR. Soc. 
 CHEM. INDUSTRY, XVI. No. 5. 
 
 Nickel carbonyl. Mond, Langer, and Quincke, JOUR. CHEM. Soc., 
 LVII. 750. 
 
 Allotropic forms of silver. Carey Lea, AM. JOUR. OF Sci., [3], 
 XXXVII. 476. Barus, ibid., XLVIII. 451. 
 
 Absence of chemical action in absence of water. Baker, JOUR. CHEM. 
 Soc., LXV. 611. Shenstone, ibid., LXXI. 471. 
 
 Argon. Rayleigh and Ramsay, AM. CHEM. JOUR., XVII. 225. 
 
 Helium. Ramsay, JOUR. CHEM. Soc., LXVII. 684 and 1107. 
 
 Urea and ammonium cyanate. Walker, JOUR. CHEM. Soc., LXVII. 
 746; LXIX. 193; LXXI. 489; LXXVII. 21. 
 
 Perchloric anhydride. Michael and Conn, AM. CHEM. JOUR., XXIII. 
 444. 
 
 Adsorption. Walker, JOUR. CHEM. Soc., LXIX. 1334. 
 
 Flame. Smithells, JOUR. CHEM. Soc., LXI. (1892), 204; LXVII. 
 (1895), I0 495 NATU-RE, XLIX. (1893), 86, also correspondence on pp. 
 100, 149, 171, 172, 198; CHEMICAL NEWS, LXVI. (1893), J 39 I o- 
 Lewis, CHEMICAL NEWS, LXV. (1892), 112, 125; LXVI. (1893), 99. 
 
216 THE TEACHER 
 
 Reading, however, is not sufficient ; there should be con- 
 tinual experimental work adapted to the previous training of 
 Experimental tne teacher. Making recently discovered corn- 
 Work, pounds, and repeating new ways of making old 
 ones, will furnish opportunities for work of any degree of ease 
 or difficulty. The persulphates, nickel carbonyl, the allotropic 
 forms of metallic silver, and many other interesting bodies can 
 be made with the resources of any laboratory. Some of 
 Baker's experiments on the absence of chemical union in 
 dry materials will give opportunity for the use of experimen- 
 tal skill. If the teacher lacks preparation for this kind of work, 
 he may add to his knowledge by a systematic course of experi- 
 ments and reading in inorganic preparations, in organic chem- 
 istry or in some of the experimentally simpler parts of physical 
 chemistry, such as the observation of the boiling point and freez- 
 ing point of solutions, the measurement of vapour densities, 
 etc. 1 
 
 For the teacher who has the necessary qualifications, the very 
 best exercise of his powers will be in making simple original 
 investigations. I should hesitate to mention this 
 if it were not that Professor Nichols 2 insists upon 
 it as an indispensable feature in the life of every teacher, and 
 that Professor Ganong, in his Teaching Botanist (48), makes 
 a strong plea of the same kind. It is well known that the time 
 of the teacher is very fully occupied, and that his equipment is 
 often far from adequate, even for the needs of elementary in- 
 struction. It must be admitted, however, that, as Professor 
 Nichols explains at great length, these objections are not con- 
 clusive. The professor in the college or university, when we 
 
 1 Much highly instructive work of a kind a little above the ordinary 
 laboratory course in general chemistry is described in Muirand Carnegie's 
 Practical Chemistry (Cambridge University Press, 1887), particularly in 
 Part I., Chapters XVI., XVIII. ; Part II., Chapters IV.-VII. ; Part 
 III., Chapters II.-IV. Most phases of physical chemistry, with the ex- 
 ception of the theory of solutions, are illustrated in these chapters. 
 
 2 Loc. cit. See also, for subjects of research in physics, SCHOOL SCIENCE, 
 I. 10. 
 
THE TEACHER 21J 
 
 consider the burden of laboratory teaching and of executive 
 work which he must carry, is on the average no better off than 
 the teacher in the secondary school, and he is expected to 
 pursue research continuously. Nor is elaborate outfit or ap- 
 paratus necessarily required. There are problems, possibly of 
 a minor nature, which can be solved with nothing beyond the 
 material used in teaching elementary chemistry, unless it be 
 a balance. Even this, however, is not always indispensable. 
 Above all, we must remember that some of the best scientific 
 work has been done, in secondary schools as well as in colleges, 
 by men who had neither time nor appliances which would 
 have encouraged us to expect any productive work whatever. 1 
 
 The other means which are available for assistance in the 
 development of the teacher may be mentioned more briefly. It 
 is not often possible for him to take graduate work Summer 
 in some university, but the summer schools, which Schools, 
 are now so numerous as to be readily accessible to every one, 
 are taken advantage of by teachers, in some instances, to so 
 remarkable an extent that their power to aid them cannot be 
 doubted. Even if little knowledge, measured by some stand- 
 ards, can be acquired in six or eight weeks, the stimulus and 
 inspiration received by contact with some master of the subject 
 may, even in a brief time, bring forth new life in the teacher who 
 was dying from isolation, and give new vitality to his whole 
 thought and work. 
 
 The word isolation reminds us that no efforts of a single in- 
 dividual can ward off for a long time the inevitable petrifaction. 
 Contact with other people with like interests is indispensable. 
 For this reason the meetings of local scientific and educational 
 societies, and the conventions of the American Association 
 for the Advancement of Science and the American Chemical 
 
 1 For the encouragement of this work amongst its teachers, the Board 
 of Education of Chicago pays the expenses of any investigations they 
 may make, provided the results on whose accomplishment the claims are 
 based are certified by some competent authority to be genuine additions 
 to knowledge. This most enlightened policy might be with advantage 
 imitated by other school authorities in the country. 
 
2l8 THE TEACHER 
 
 Society furnish opportunities of receiving help which should 
 not be missed. Visiting other schools and watching the work 
 of other teachers should also be indulged in as frequently as 
 possible. 
 
 As has been said before, the teaching of beginning chemistry 
 is the most difficult task which the chemist, no matter what his 
 NoPrepara- training, can undertake. Teaching it in a secon- 
 
 tion too Great dary school is more difficult than teaching it in a 
 for the Task. / . , . ,. & , , 
 
 university, and incomparably more difficult than 
 
 giving instruction in some advanced branch of the subject, or, 
 assuming proportionate preparation of the teacher, even super- 
 vising the work of students engaged in research. These tasks 
 are all different and require perhaps somewhat different quali- 
 fications, but the delicate operation of dealing with a young 
 pupil who is beginning the study of a science, so as to impart 
 to the small change of the subject the ring of the genuine 
 metal and the stamp of truth and authority, requires a breadth 
 and at the same time a minuteness of knowledge which only 
 long training and experience can give. The maturity and 
 resourcefulness which are born of a thorough control of the 
 subject cannot be communicated. They are the fruit of un- 
 remitting and long continued labour. 
 
 III. Literature for the Teacher. 
 
 It is impossible here to mention all even of the important 
 works dealing with every branch of chemistry. In the following 
 bibliography the titles have been selected in the main with 
 reference to the needs of the teacher. There are included, 
 however, a number which are adapted also to the use of pupils. 
 A few volumes should be added yearly to the reference shelf in 
 the laboratory, in order that encouragement to excursions out- 
 side the narrow limits of the regular text-book may not be 
 wanting. The books have been classified and, under each 
 head, after some remarks in regard to sources of information 
 on the particular branch of the subject, the bibliographical 
 description of commendable works is given. In the case of 
 
THE TEACHER 2 19 
 
 many topics the appropriate references have appeared already 
 in earlier chapters. 1 
 
 Dictionaries , etc : Watts' Dictionary contains articles varying 
 in length from a few lines to many pages on every chemical sub- 
 stance and every topic in scientific chemistry. Technological 
 subjects have been relegated to Thorpe's Dictionary. Exten- 
 sive tables including much indispensable information will be 
 found in the Chemiker Kalendar and Meade's Pocket Manual. 
 The articles in the Encyclopedia Britannica and other works 
 of the same class frequently treat subjects hardly noticed in text- 
 books. In using them due regard must be paid to the time at 
 which the articles were written. 
 
 Watts. Dictionary of Chemistry. Edited by Morley and Muir. 
 4 vols., half leather. London and New York, Longmans, Green & Co. 
 1894. 
 
 Thorpe, T. E. Dictionary of Applied Chemistry. 3 vols., half leather. 
 London and New York, Longmans, Green & Co. 1894-95. 
 
 Biedermann. Chemiker Kalendar. Berlin, Springer. Annually. 
 
 Meade. The Chemists' Pocket Manual. Easton, Pa., Chemical Pub. 
 Co. 1900. 
 
 Inorganic Chemistry, Larger Works : The most useful, ex- 
 tensive work of reference is the inorganic portion of Roscoe 
 and Schorlemmer's Treatise. It has recently been brought up 
 to date. The other works, which may be classed as university 
 text-books, have each well-defined merits of their own. Rem- 
 sen is notable for lucidity ; Newth, for attention to industries ; 
 Freer, for the treatment of certain chapters ; Richter, for the 
 remarkable amount of information it gives for its size ; Ramsay, 
 for the arrangement of the material. Ostwald's Outlines is an 
 attempt to apply the latest developments of physical chemistry 
 to inorganic chemistry, and is highly suggestive. The small 
 
 1 The reader is referred for references on the following topics to the 
 appropriate parts of this book : Elementary text-books on inorganic chem- 
 istry, pp. 55-60; Laboratory manuals, pp. 104, 113, 115-119, 192, 216; 
 Questions and problems, pp. 133, 136; Inorganic preparations, p. 211 ; 
 Lecture experiments, pp. 134, 167, 169, 170 ; Glassworking and technique, 
 p. 113. Fundamental conceptions of the scientific method, pp. 147-153. 
 
220 THE TEACHER 
 
 Modern Chemistry of Ramsay is a highly successful attempt to 
 give a bird's-eye view of the same aspect of the subject. The 
 teacher should have as many of these books as possible at his 
 command. 
 
 Roscoe and Schorlemmer. Treatise on Chemistry. Vols. I. and II., 
 Inorganic. London, Macmillan. New York, D. Appleton & Co. 1898. 
 
 Mendeleeff-Greenaway. Principles of Chemistry. 2 vols. London 
 and New York, Longmans, Green & Co. 1897. 
 
 E-emsen. Chemistry, Advanced Course. New York, Henry Holt 
 & Co. London, Macmillan. 1898. 
 
 Newth. Text-Book of Inorganic Chemistry. London and New York, 
 Longmans, Green & Co. 1897. 
 
 Freer. General Inorganic Chemistry. Boston, Allyn & Bacon. 1894. 
 
 Richter-Smith. Inorganic Chemistry. Philadelphia, Blakiston. 
 London, Kegan Paul, Trench & Co. 1900. 
 
 Ramsay. A System of Inorganic Chemistry. London, Churchill. 
 1891. 
 
 Bloxam. Inorganic and Organic Chemistry. London, Churchill. 
 Philadelphia, Blakiston. 1901. 
 
 Ostwald-Findlay. Principles of Inorganic Chemistry. London and 
 New York, Macmillan. 1902. 
 
 Ramsay. Modern Chemistry. Part I., Theoretical ; Part II., Syste- 
 matic. London, J. M. Uent. New York, Macmillan. 1901. 
 
 Theoretical: Walker's Physical Chemistryis generally held 
 to give the clearest account of the subject which has so far 
 appeared. Lehfeldt's is less well known. It is wonderfully 
 comprehensive for its size, and well balanced in the relative 
 space given to different topics. Dobbin and Walker is ele- 
 mentary. The teacher is advised to study several works on this 
 subject, including some on special parts of the subject like those 
 appended to the list, as it is in this way only that a clear under- 
 standing of the theory can be obtained. The second and third 
 last books are reprints of original papers, and the last contains 
 a description of some laboratory methods. 
 
 "Walker. Introduction to Physical Chemistry. London and New 
 York, Macmillan. 1899. 
 
 Lehfeldt. Text-Book of Physical Chemistry. London, Edward 
 Arnold. New York, Longmans, Green & Co. 1899. 
 
 Nernst-Palmer. Theoretical Chemistry. New York and London, 
 Macmillan. 1895. 
 
THE TEACHER 221 
 
 Dobbin and Walker. Chemical Theory for Beginners. London and 
 New York, Macmillan. 1892. 
 
 Morgan. Elements of Physical Chemistry. New York, John Wiley 
 & Sons. 1899. 
 
 Jones. The Elements of Physical Chemistry. New York and 
 London, Macmillan. 1902. 
 
 Jones. The Theory of Electrolytic Dissociation. New York and 
 London, Macmillan. 1900. 
 
 Ostwald-Muir. Solutions. London and New York, Longmans, 
 Green & Co. 1891. 
 
 Le Blanc- Whitney. Elements of Electro-Chemistry. New York 
 and London, Macmillan. 1896. 
 
 Liipke-Muir. Elements of Electro-Chemistry. London, Grevel & 
 Co. Philadelphia, Lippincott. 1897. 
 
 PfefTer-Van 't Hoff-Arrhenius-Raoult-Jones. The Modern Theory 
 of Solution. New York, American Book Co. 1899. 
 
 Faraday-Hittorf-Kohlrausch-Goodwin. Fundamental Laws of Elec- 
 trolytic Conduction. New York, American Book Co. 1899. 
 
 Jones. The Freezing Point, Boiling Point, and Conductivity Methods. 
 Easton, Pa., Chemical Pub. Co. 1897. 
 
 Of an entirely different character are the three following 
 books. They do not profess to give much or, in the cases of 
 the two last, any attention to the theory of solutions. They 
 discuss the atomic theory, the constitution of chemical sub- 
 stances, the periodic law, and other subjects, with a strong 
 infusion of the historical method in their mode of treating them. 
 They will be found exceedingly valuable. 
 
 Tilden. Introduction to the Study of Chemical Philosophy. London 
 and New York, Longmans, Green & Co. 1902. 
 
 Kemsen. Principles of Theoretical Chemistry. Philadelphia, Lea 
 Bros. & Co. London, Bailliere, Tindall & Cox. 1892. 
 
 Lothar Meyer. Outlines of Theoretical Chemistry. London and 
 New York, Longmans, Green & Co. 1899. 
 
 Historical: The works named below divide themselves into 
 four sets : the general treatises on the history of the science, 
 histories of special periods or special parts of the science, bio- 
 graphical works, and reprints of memoirs of historical interest. 
 Of the books in the second set, Ramay's Gases of the Atmos- 
 phere is a useful supplement to the treatment of the air, and 
 particularly of oxygen, as it is found in the text-books. Car- 
 negie treats some selected topics in a very suggestive manner. 
 
222 THE TEACHER 
 
 The Alembic Club Reprints, the last set, supply some papers 
 of historical interest in a neat and inexpensive form. Study of 
 these documents gives a vivid impression of the attitude and 
 methods of the early workers which cannot be obtained except- 
 ing by reading their own descriptions of their labours. 
 
 Tilden. A Short History of the Progress of Scientific Chemistry 
 in Our Own Times. London and New York, Longmans, Green & Co. 
 1899. 
 
 von Meyer-McGowan. History of Chemistry. London and New 
 York, Macmillan. 1891. 
 
 Ladenburg-Dobbin. Lectures on the History of the Development 
 of Chemistry Since the Time of Lavoisier. Edinburgh, The Alembic 
 Club, Wm. F. Clay (Agent). 1900. 
 
 Venabie. A Short History of Chemistry. Boston, D. C. Heath & Co. 
 1894. 
 
 Muir. The Alchemical Essence and the Chemical Element. London 
 and New York, Longmans, Green & Co. 1894. 
 
 Kodwell. The Birth of Chemistry. London and New York, Mac- 
 millan. 1874. 
 
 Thorpe. Chemistry in Britain in the XIX. Century. London, JOUR- 
 NAL OF THE CHEMICAL SOCIETY, LXXVII. (1900), 562. 
 
 Ramsay. The Gases of the Atmosphere. London and New York, 
 Macmillan. 1896. 
 
 Carnegie. Law and Theory in Chemistry. London and New York, 
 Longmans, Green & Co. 1894. 
 
 "Wurtz. The Atomic Theory. London, Kegan Paul, Trench & Co. 
 New York, D. Appleton & Co, '1891. 
 
 Venabie. The Development of the Periodic Law. Easton, Pa., 
 Chemical Pub. Co. 1898. 
 
 Thorpe. Essays in Historical Chemistry. London and New York, 
 Macmillan. 1894. 
 
 Tyndall. Faraday as a Discoverer. London, Longmans, Green & Co. 
 New York, D. Appleton & Co. 1894. 
 
 Muir. Heroes of Science, Chemists. London, S. P. C. K. New 
 York, E. and J. B. Young & Co. 1883. 
 
 Thorpe. Humphrey Davy. Century Science Series. London and 
 New York, Macmillan. 1896. 
 
 Roscoe. John Dalton. Century Science Scries. London and New 
 York, Macmillan. 1895. 
 
 Thompson. Michael Faraday. Century Science Series. London and 
 New York, Macmillan. 1899. 
 
 Shenstone. Justus von Liebig. Century Science Series. London 
 and New York, Macmillan. 1895. 
 
THE TEACHER 22$ 
 
 Mallett. Memorial Lecture on Stas. London, JOUR. CHEM. Soc., 
 LXIII. (1893), l > JOUR. AM. CHEM. Soc., Sept. 1892. 
 
 Playfair-Abel-Perkms-Armstrong. Memorial Addresses on Hof- 
 maun. London, JOUR. CHEM. Soc., LXIX. (1896), 575-732. 
 
 Japp. Memorial Lecture on Kekule. London, JOUR. CHEM. Soc., 
 LXXIII. (1898), 97. 
 
 Roscoe. Memorial Lecture on Bunsen. London, JOUR. CHEM. Soc., 
 LXXVII. (1900), 513. 
 
 Chemical Society of London. Twelve Memorial Addresses (col- 
 lected). London, Gurney & Jackson. 1901. 
 
 Alembic Club Keprints. Edinburgh, Wm. F. Clay (Agent). Easton, 
 Pa., Chemical Pub. Co. 
 
 1. Black. Experiments upon Magnesia Alba, etc. 
 
 2. Dalton, Wollaston, and Thomson. Foundations of the Atomic 
 Theory. 
 
 3. Cavendish. Experiments on Air. 
 
 4. Dalton, Gay-Lussac, and Avogadro. Foundations of the Molec- 
 ular Theory. 
 
 5. Hooke. Extracts from Micrographia. 
 
 6. Davy. The Decomposition of the Alkalies and Alkaline 
 Earths. 
 
 7. Priestley. The Discovery of Oxygen. 
 
 8. Scheele. The Discovery of Oxygen. 
 
 9. Davy. The Elementary Nature of Chlorine. 
 
 10. Graham. Researches on the Arseniates, Phosphates, and Modifi- 
 cations of Phosphoric Acid. 
 
 11. Jean Rey. On an Enquiry into the Cause Wherefore Tin and 
 Lead Increase in Weight on Calcination. 
 
 12. Faraday. The Liquefaction of Gases. 
 
 13. Scheele, Berthollet, Morveau, Gay-Lussac, and Thenard. The 
 Early History of Chlorine. 
 
 14. Pasteur. Researches on the Molecular Asymmetry of Natural 
 Organic Products. 
 
 1 5. Kolbe. Papers on the Electrolysis of Organic Compounds. 
 Reprints of Science Classics. Chicago : The School Science Press. 
 No. i. Lavoisier. The Analysis of Air and Water. Tr. by C. E. 
 
 Linebayer. 1902. 
 
 Organic : The chemistry of the carbon compounds is 
 treated most comprehensively in the new edition of Richter's 
 Organic Chemistry. Remsen's work gives an elementary ac- 
 count of the subject and describes illustrative experiments. 
 Hjelt gives a survey of the generalizations of organic chemistry. 
 
 Ritcher-Smith. Organic Chemistry. 2 vols. Philadelphia, Blakis- 
 ton. London, Kegan Paul, Trench & Co. 1900. 
 
224 THE TEACHER 
 
 Bemsen. Introduction to the Study of the Compounds of Carbon. 
 Boston, D. C. Heath & Co. London, Macmillan. 1895. 
 
 Perkin and Kipping. Organic Chemistry. 2 vols. Edinburgh, 
 Chambers. Philadelphia, Lippincott. 1894. 
 
 Hjelt-Tingle. Principles of General Organic Chemistry. London and 
 New York, Longmans, Green & Co. 1895. 
 
 For laboratory work in organic chemistry, the collections of 
 selected preparations by Noyes and by Gattermann are excellent. 
 Of a more elementary character are Garrett and Harden, Orn- 
 dorrT, and Turpin. A compendium of all organic methods of 
 work, with copious illustrations of their application, and numer- 
 ous references to the original literature, will be found in Lassar- 
 Cohn. Noyes and Mulliken's book gives a different and highly 
 instructive view of the subject. 
 
 Noyes. Organic Chemistry for the Laboratory. Easton, Pa., Chemi- 
 cal Pub. Co. 1897. 
 
 Gattermann-Shober. Practical Methods of Organic Chemistry. 
 London and New York, Macmillan. 1901. 
 
 Garrett and Harden. Elementary Course of Practical Organic Chem- 
 istry. London and New York, Longmans, Green & Co. 1897. 
 
 Orndorff. Laboratory Manual of Organic Chemistry. Boston, D. C. 
 Heath & Co. 1893. 
 
 Lassar-Cohn-Smith. Laboratory Manual of Organic Chemistry. 
 London and New York, Macmillan. 1895. 
 
 Noyes and Mulliken. Laboratory Experiments on the Class-Reac- 
 tions and Identification of Organic Substances. Easton, Pa., Chemical 
 Pub. Co. 
 
 Industrial: Thorp's is the most recent work on the sub- 
 ject. It includes all industries excepting the metallurgical. 
 Borchers' work gives an excellent account of the recent appli- 
 cations of electricity in technological chemistry. 
 
 Thorp, F. H. Outlines of Industrial Chemistry. London and New 
 York, Macmillan. 1899. 
 
 Huntington and McMillan. Metals. London and New York, Long- 
 mans, Green & Co. 1897. 
 
 Borchers. Electro-Smelting and Refining. London, C. Griffin & Co- 
 Philadelphia, Lippincott. 1897. 
 
 Wagner. Manual of Chemical Technology. London, Churchill. 
 New York, D. Appleton & Co. 1895. 
 
THE TEACHER 22$ 
 
 Analytical: The standard works of reference on this sub- 
 ject are those of Fresenius. The most satisfactory treatment of 
 both branches in one volume is represented by Newth's book. 
 Perkin's work gives special attention to organic analysis. Ost- 
 wald's Scientific Foundation is indispensable, whatever other 
 works are employed, as none of the treatises on analysis pay 
 sufficient attention to the theory, and most pay no attention to 
 it whatever. 
 
 Ostwald-McGowan. Scientific Foundations of Analytical Chemistry. 
 London and New York, Macmillan. 1900. 
 
 Fresenius. Manual of Qualitative Analysis. London, Churchill. New 
 York, John Wiley & Sons. 1890. 
 
 Fresenius. Quantitative Chemical Analysis. London, Churchill. 
 New York, John Wiley Sons. 1881. 
 
 Newth. Chemical Analysis, Qualitative and Quantitative. London 
 and New York, Longmans, Green & Co. 1898. 
 
 Noyes, W. A. Elements of Qualitative Analysis. New York, Henry 
 Holt & Co. 1901. 
 
 Perkin, F. M. Qualitative Chemical Analysis. London and New 
 York, Longmans, Green & Co. 1901. 
 
 Noyes, A. A. Qualitative Chemical Analysis. London and New 
 York, Macmillan. 1899. 
 
 Clowes and Coleman. Elementary Quantitative Chemical Analysis. 
 London (4th ed. 1897), Churchill. Philadelphia, Blakiston. 
 
 Sutton. Handbook of Volumetric Analysis. London, Churchill. 
 Philadelphia, Blakiston. 1890. 
 
 Thornton and Pearson. Notes on Volumetric Analysis. London 
 and New York, Longmans, Green & Co. 1898. 
 
 Hempel-Dennis. Elements of Gas Analysis. London and New 
 York. Macmillan. 1891. 
 
 Mason. Examination of Water. New York, John Wiley & Sons. 
 London, Chapman & Hall. 1899. 
 
 Blair. The Chemical Analysis of Iron. Philadelphia, Lippincott. 
 1902. 
 
 Smith, E. P. Electro-Chemical Analysis. Philadelphia, Blakiston. 
 1894. 
 
 Classen. Quantitative Chemical Analysis by Electrolysis. New York, 
 John Wiley & Sons London, Chapman & Hall. 1898. 
 
 Landauer-Tingle. Spectrum Analysis. New York, John Wiley & 
 Sons. London, Chapman & Hall. 1898. 
 
 Chemistry of Daily Life : Information about the chemistry of 
 common things is scattered through an immense range of litera- 
 ture. Works on special branches of analysis and on special 
 
226 THE TEACHER 
 
 industries, works on botany, physiology, etc., and many others 
 can contribute much to a knowledge of this. The following pro- 
 fess to deal with such matters in a popular way. 
 
 Johnston. Chemistry of Common Life. London, Blackwood. New 
 York, D. Appleton & Co. 1879. 
 
 Lassar-Cohn-Muir. Chemistry of Daily Life. London, Grevell & 
 Co. Philadelphia, Lippincott. 1898. 
 
 Martin. Story of a Piece of Coal. London, Geo. Newnes. New 
 York, D. Appleton & Co. 1896. 
 
 Faraday. Chemical History of a Candle. London, Chatto & Windus. 
 New York, Harper & Brothers. 1862. 
 
 "Williams. The Chemistry of Cooking. London, Chatto & Windus. 
 New York, Appleton & Co. 1885. 
 
 Richards and Elliott. Chemistry of Cooking and Cleaning. Boston, 
 Home Science Pub. Co. 1897. 
 
 Richards. Food Material and their Adulterations. Boston, Home 
 Science Pub. Co. 1886. 
 
 King. The Soil. London and New York, Macmillan. 1899. 
 
 Roberts. The Fertility of Land. New York and London, Macmillan. 
 1897. 
 
 Miscellaneous : From the works on the many branches of 
 chemistry which have not been treated separately, a few titles 
 have been selected. The bibliography of ^ the New England 
 Association of Chemistry Teachers, to which I am indebted for 
 some of the data in these lists, gives a brief description of the 
 nature of each of the books contained in it. It will be found 
 very useful. 
 
 Williams. Elements of Crystallography. New York, Henry Holt & 
 Co. 1892. 
 
 Bauerman. Descriptive Mineralogy. London and New York, Long- 
 mans, Green & Co. 
 
 Dana, E. S. A Text-Book of Mineralogy. New York, John Wiley 
 & Sons. London, Chapman & Hall. 1898. 
 
 Abney. Treatise on Photography. London and New York, Long- 
 mans, Green & Co. 1901. 
 
 Meldola. Chemistry of Photography. London and New York, Mac- 
 millan. 1889. 
 
 Halliburton. Essentials of Chemical Physiology. London and New 
 York, Longmans, Green & Co. 1901. 
 
 Hueppe- Jordan. Principles of Bacteriology. Chicago, Open Court 
 Pub. Co. London, Kegan Paul, Trench & Co. 1899. 
 
THE TEACHER 
 
 Frankland. Our Secret Friends and Foes. London, S. P. C. K. 
 New York, E. & J. B. Young & Co. 1897. 
 
 Schiirtzenbreger. On Fermentation. London, Kegan Paul, Trench 
 & Co. New York, D. Appleton & Co. 1889. 
 
 New England Association of Chemistry Teachers. List of Books in 
 Chemistry. Boston, L. E. Knott Apparatus Co. 1900. 
 
 Periodicals : The best way to keep in touch with chemical 
 work is to read at least one journal regularly. The first five on 
 the list publish original articles. In addition to this, the second 
 contains reviews of all the chemical research done in America. 
 The third contains reviews of all chemical memoirs, wherever 
 published. The fourth is admirably edited, and furnishes 
 excellent abstracts of a large amount of work, even when it 
 is mainly of scientific interest and has little actual bearing on 
 industry. Numbers six to eight publish articles on all the 
 sciences, including chemistry. The last three frequently con- 
 tain articles dealing with the teaching of chemistry. 
 
 American Chemical Journal. Baltimore, Md., The Johns Hopkins 
 University Press. Monthly. 
 
 Journal of the American Chemical Society. Easton, Pa., Chemical 
 Pub. Co. Monthly. 
 
 Journal of the Chemical Society. London, Gurney & Jackson. 
 Monthly. 
 
 Journal of the Society of Chemical Industry. London, Eyre & 
 Spottiswoode. Monthly. 
 
 Chemical News. London, E. J. Davey. Weekly. 
 
 Science. New York, Macmillan. Weekly. 
 
 Nature. London and New York, Macmillan. Weekly. 
 
 Popular Science Monthly. New York, McClure, Phillips & Co. 
 
 School Science. Chicago, 138 Washington Street. Monthly. 
 
 School Review. Chicago, The University of Chicago Press. Monthly. 
 
 Zeitschrift fur den physikalischen und chemischen Unterricht. 
 Berlin. 
 
THE TEACHING OF PHYSICS IN 
 THE SECONDARY SCHOOL 
 
 BY EDWIN H. HALL, PH.D. 
 PROFESSOR OF PHYSICS IN HARVARD UNIVERSITY. 
 
Prefatory Note 
 
 IN writing the first four chapters on the teaching of physics 
 the author has had in mind especially the school-teacher, from 
 the time when, perhaps only a boy, he is making choice of a 
 profession to the time of his full career in charge of a well 
 appointed school laboratory and class room. The motives 
 and considerations which should influence the choice of this 
 career, the academic and other preparation which the prospec- 
 tive teacher should make for it, the means by which he may 
 keep himself in continual progress as a teacher, and the kind 
 of practical problem in which he, without undertaking what is 
 commonly called original research, may find profitable em- 
 ployment for any amount of energy in the improvement of his 
 work, are all touched upon in these four chapters. 
 
 In the next chapter the change of aim and method in school 
 physics teaching during the past twenty years is briefly dis- 
 cussed in connection with changes in text-books. This leads 
 naturally to a consideration, in Chapter VI., of the proper 
 general spirit and method of laboratory instruction in schools. 
 The next two chapters deal, respectively, with technicalities of 
 laboratory management, and with the very important functions 
 of lectures and recitations in connection with laboratory work. 
 
 In Chapter IX. the possibilities of physics teaching in pri- 
 mary and grammar schools are taken up. In the next chapter 
 attention is given to physics in secondary schools, and the 
 question is raised whether, after all, in view of their probable 
 difference in scholarly quality, the boy who is going to college 
 and the boy who is not going to college should follow the 
 same course of physics in school, or, rather, whether the dis- 
 
232 PREFATORY NOTE 
 
 tinctively preparatory school on the one hand and the high 
 school on the other hand should have just the same kind of 
 physics teaching and work. 
 
 Chapter XL, On The Presentation of Dynamics, is the only 
 chapter in the book which is devoted to any one part, exclu- 
 sively, of physics, the exception in this case being justified, in 
 the opinion of the author, by the exceptional difficulty and 
 importance of the subject of dynamics. 
 
 Chapter XII. gives a plan of rooms and fittings for a school 
 department of physics, and Chapter XIII., the last, gives some 
 account of the state of physics teaching in the schools of 
 Germany, England, and France. 
 
 The book assumes throughout that the system of physics 
 instruction by combined laboratory and class room w6fk is 
 now permanently established for the better class of American 
 secondary schools ; and the author believes it to be the especial 
 privilege and duty of American teachers of physics so to 
 develop and perfect this system as to make it not only a great 
 benefit and advantage to ourselves, but a model for imitation 
 by the schools of Europe, most of which, on the Continent at 
 least, have hardly ventured as yet upon the experiment which 
 we are here working out to a successful conclusion. 
 
 In the bibliography which is distributed among these chapters 
 the author has certainly not included all the good books, and 
 he does not feel sure that he has left out all the bad ones. 
 Comments on the various text-books named are given in very 
 few cases, the fact being that, according to the autlp-'s experi- 
 ence, no one knows thoroughly the possibilities of a book for 
 good or evil till he has taken a class through it. 
 
 Writing these chapters has interested the author and has 
 improved his own teaching. He hopes that reading them may 
 be equally beneficial to others. 
 
 EDWIN H. HALL. 
 
 CAMBRIDGE, MASS. 
 March, 1902. 
 
The 
 
 Teaching of Physics in the 
 Secondary School 
 
 CHAPTER I 
 
 WHETHEK TO BE A TEACHER OF PHYSICS 
 REFERENCES. 
 
 Eliot, C. W. What Is A Liberal Education ? The Century, June, 
 1884. Educational Reform. New York, The Century Co. 1898. 
 
 Fitch, Sir Joshua. Thomas and Matthew Arnold, Great Educators 
 Series. London, W. Heinemann, Charles Scribner's Sons. 1897. Pp. 277. 
 
 Hart, A. B. The Teacher as a Professional Expert. SCHOOL REVIEW, 
 I. 4-14. 
 
 Huxley, T. H. Science and Education, Vol. III. of the Essays. Lon- 
 don, Macmillan & Co. New York, D. Appleton & Co. 1894. 
 
 Spencer, Herbert. Education. London, Williams & Norgate. New 
 York, D. Appleton & Co. 
 
 \Velldon, J. E. C. The Teacher's Training of Himself. Contempo- 
 rary Review. March, 1893. P P- 369-386. 
 
 As in every other department of pedagogic art, there is in 
 physics the teacher who is born and the teacher who is made. 
 The latter, if successful, is the product of infinite labour, of long- 
 suffering patience with himself, of constant courage, of never- 
 dying willingness to learn ; but all this is equally true of any 
 man who aspires to excellence in any art for which his native 
 talent is not conspicuous. By all means, let every man find 
 the thing he can do best, and then do it at his best. 
 
 Why should a man be a teacher of any kind? First, the 
 negative reasons, which may be somewhat as follows : Purely 
 
234 WHETHER TO BE A TEACHER 
 
 manual or clerical work is too limited in its mental scope and is 
 paid too little. The practice of medicine would be too painful 
 Why be a or to critically responsible. The pulpit requires 
 Teacher? one to ta jk w h en one may have nothing to say. 
 The bar imposes a professional and mercenary contentiousness 
 for which one may lack both taste and talent. Business success 
 is too doubtful, or is obtainable at too great a price. 
 
 The positive reasons. The profession of teaching is safe, it 
 is honourable ; it is, it may be, pre-eminently, absolutely, honest. 
 It brings contact with and influence on young minds in a plastic 
 and growing condition. Viewed with regard to society at large, 
 to civilization, to government, instruction is construction. To 
 use the phrase of President Eliot, the profession of teaching 
 gives a man a chance to " build himself into " the great fabric 
 of the most beneficent and enduring human institutions. 
 
 And so we have chosen to be teachers. But what shall I 
 teach? Shall it be one of the ancient languages? The chil- 
 whatshaiii dren of the American public are not likely to suffer 
 Teach ? f rom too muc h Latin or Greek. We, perhaps more 
 
 than any people of Europe, need to be told and shown that it 
 is possible to go too fast straight ahead, that the beautiful, 
 the true, the desirable, may be 'behind us, that the most whole- 
 some, rational, happy living is consistent with, nay, requires, a 
 certain leisureliness of mind which takes occasion to learn how 
 men have lived, and what they have done that is worth remem- 
 bering and imitating. On these or similar grounds one may 
 amply justify the choice of any great language, or literature, or 
 history, as the sphere of his life-work as a teacher, provided he 
 be not incompetent for the task to which he devotes himself. 
 
 Why then should we turn from the " humanities," from the 
 study, in its various phases and achievements, of " this pleasing 
 anxious being," human life, to experimental and mathematical 
 science, for which so few have any further interest than a desire 
 to enjoy its material benefits and to be entertained by its occa- 
 sional spectacular displays. Putting aside for the moment the 
 question of individual and special talents, we can see that phys- 
 
WHETHER TO BE A TEACHER 235 
 
 ical science has for some minds, or some temperaments, a 
 peculiar charm in this, that it holds out to every devotee the 
 possibility of making by himself some positive, absolutely new, 
 addition to the sum total of permanent useful knowledge, the 
 certainty of moving forward into regions of thought and of 
 power which no previous generation of men has ever pene- 
 trated since the world began. This motive appeals to the 
 north-pole spirit, of which every true follower of science must 
 have a dash, the spirit which can find pleasure in places where 
 the air is cold but pure, where the footing is rugged but forward. 
 Contrasted with the study or teaching of any language, as such, 
 the study and teaching of science offers, as the object of espe- 
 cial attention, substance instead of form ; and though the form 
 in the one case be the expression of human thought, while the 
 substance in the other case is that of things not made by man, 
 yet we who are of the school of science cannot admit, because 
 we do not feel, that we are on lower ground. He only should 
 make such a confession who follows science for its mere 
 utilities. 
 
 But, given the intellectual predisposition in favour of science, 
 what special tastes or talents should prompt or justify the 
 choice of physics? 
 
 The most desirable qualities are, in my opinion : First, capac- 
 ity for clear, sustained, correct thinking, most conveniently 
 tested by capacity for some common branch of 
 mathematics. It is true that Faraday, who was a neededfor 
 very great scientific thinker and discoverer, de- 
 clared, after turning the handle of a calculating ma- 
 chine, that he had now for the first time in his life performed a 
 mathematical operation. It is true that Edison, who is a great 
 scientific man of a different kind, has said that he never could do 
 much with algebra, being bothered by the plus and minus signs. 
 But it is not to be supposed that either of these men was really 
 lacking in mathematical faculty. The fact is that neither of them 
 had, as a boy, much regular education. Each of them was 
 carried by native talent early in life into conspicuous achieve- 
 
236 WHETHER TO BE A TEACHER 
 
 ments in science, and after that each probably felt, consciously 
 or unconsciously but in either case rightly, that to go back and 
 try to educate himself as others are educated, would be to throw 
 himself off the track of already assured success. 
 
 Moreover, even if we admit that mathematical ability is not 
 absolutely essential to success as a teacher or investigator in 
 physics, we must find that the literature of physics, as shown 
 in text-books and in periodicals, is so permeated with the ideas 
 and the symbols of mathematics, that a person who at the out- 
 set must confess to a weakness with respect to such ideas and 
 symbols would enter the advanced study of this literature under 
 a heavy handicap. 
 
 The question remains whether it is indispensable that the 
 prospective school-teacher of physics shall look forward to what 
 would be called, among physicists, advanced study. This ques- 
 tion may be frankly answered in the negative. One can get 
 enough of physics without knowing anything of the calculus to 
 be a good school-teacher of this science. No energetic man 
 who wishes to be such a teacher need be deterred by lack of 
 interest in mathematics, provided he has the endowment, which 
 I put second, with some doubt whether it should not be put 
 first, of capacity for a quick understanding of machinery. This 
 may show itself in achievements ranging from the easy mastery 
 of a mouse-trap to the easy mastery of a compound steam- 
 engine. I dwell upon facility here, for the reason that with 
 facility goes liking, and with liking goes knowledge, and a wide 
 acquaintance with machinery and apparatus is useful, not only 
 in equipping and maintaining a laboratory, but also in awaken- 
 ing the interest and holding the attention of pupils, who, whether 
 mechanically competent or otherwise, always admire mechanical 
 proficiency in others. The man who is slow to think out the 
 relations and working of a machine may in time acquire a com- 
 petent knowledge of such apparatus and machinery as comes 
 within his range of habitual vision, but he is sure to have an 
 occasional bad five minutes in the presence of his class during 
 the early years of his teaching. 
 
WHETHER TO BE A TEACHER 237 
 
 I assume, although this is not always true, that a considerable 
 degree of manual skill and proficiency in the use of tools will 
 accompany the instinct for machinery. 
 
 No other qualities than the two now briefly discussed need 
 be mentioned as important for physics especially, though of 
 course all the intellectual virtues count here, as they do in 
 other teaching. A great memory for facts in detail, such as 
 the chemist needs, the habit of minute general observation, so 
 nearly indispensable to the naturalist, these traits are certainly 
 useful to the physicist, but he can do without them. Inventive- 
 ness, constructive imagination, is eminently desirable ; but a 
 reasonable measure of it is pretty sure to be associated with 
 the mechanical faculty already spoken of, and an unreasonable 
 measure of it, which we sometimes find, makes its possessor 
 troublesome, because he will not be content to do anything as 
 other people do it, but must invent his own methods for every 
 operation, out of a mere wantonness of originality. Necessity 
 is not the only mother of inventions. 
 
CHAPTER II 
 PREPARATION FOR TEACHING 
 
 REFERENCES. 
 
 Barnett, P. A. Common Sense in Education and Teaching. London 
 and New York, Longmans, Green & Co. 1899. Pp. 321. 
 
 Cajori, Florian. A History of Physics. London and New York, 
 Macmillan. 1899. Pp. 322. 
 
 Lodge, O. J. Pioneers of Science. London and New York, Mac- 
 millan. 1893. Pp. 404. 
 
 Monroe, Will S. Bibliography of Education, International Educa- 
 tional Series. New York, D. Appleton & Co. 
 
 Munroe, James P. The Educational Ideal. Boston, Heath & Co. 
 1895. I D P- 2 ^ 2 - 
 
 Osborn. From the Greeks to Darwin. London and New York, 
 Macmillan. 1896. Pp. 259. 
 
 Venable, W. H. Let Him First Be a Man. Boston, Lee and Shepard, 
 Pp. 274. 
 
 The "Scientific Memoirs " issued by the American Book Company 
 (New York), under the general editorship of Professor J. S. Ames, are 
 historically interesting and valuable. They are reprints of the original 
 papers announcing great discoveries or important general laws, and are 
 accompanied by biographical sketches of the authors. 
 
 THE first thing to be considered under this heading is how 
 to get a competent knowledge of the subject-matter and the 
 Knowledge of methods of the science. This cannot be done with- 
 the Subject. ou t m uch text-book study and much laboratory ex- 
 perience. The best arrangement of work combines these two 
 methods of training, from the school days on to the attainment 
 of the final degree, and even through all of one's professional 
 life ; for the two relieve and supplement each other, and the time 
 never comes when the aspiring teacher can say, I know enough 
 for my work, I will be a student no more, or when he can, to 
 the best advantage, learn by print alone. 
 
PREPARATION FOR TEACHING 239 
 
 But there is no one necessary arrangement and order of 
 preparation in science. The young man whose undergraduate 
 days are spent in a small college, where the oppor- (Mer and 
 tunities for laboratory work may be very limited, Extent of 
 should make the most of his general course in 
 physics, which will probably give him the reading of a good 
 text-book, and the seeing of a greater or less number of instruc- 
 tive lecture-table experiments, should attend faithfully to his 
 mathematics, carrying this study as far as circumstances will 
 permit, and should get what he can of chemistry. If he has 
 done all this, though he may not yet be a specialist in physics, 
 he will be in excellent condition to appreciate and to profit by 
 the opportunities which he should seek later in the graduate 
 school of some university. 
 
 But how long should the period of formal study last, how far 
 should it carry the prospective teacher before he begins the 
 practice of his profession? How much, for example, of mathe- 
 matics is necessary? Must one take the calculus? Without 
 unduly magnifying the importance and solemnity of our profes- 
 sion, without imitating the ambitious example of those who 
 introduce the study of psychology into the curriculum of a cook- 
 ing-school, we are compelled to pause before answering these 
 questions, and frame some brief philosophy of the objects of 
 education and of the functions of the teacher. 
 
 The objects of education in science are, on the one hand, 
 to make men capable, self-sustaining, physically comfortable, 
 on the other hand, to increase their capacity and Ob j ectsof 
 opportunities for intellectual enjoyment. Each of Education in 
 these objects has an ethical aspect ; for men who S 
 are materially well-to-do, and intellectually happy, can hardly 
 help being good men and good citizens. 
 
 If all communities were alike, and all youths in each commu- 
 nity alike, if all text-book makers wrote with perfect apprecia- 
 tion of and care for the needs of these young people, providing 
 information, training, stimulus, in due proportion and quantity, 
 if all school boards made ample provision for the use of such 
 
240 PREPARATION FOR TEACHING 
 
 books, if all these conditions held, any one who had learned 
 the text-book and the apparatus described by it, could be a 
 successful teacher, and the profession of teaching would be 
 honoured and paid accordingly. But no one of the condi- 
 tions mentioned does hold. Communities and schools in 
 America range from large to small, from rich to poor, through 
 many fold, from rural to metropolitan, from the racially homo- 
 geneous to the polyglot, from those having traditions of schol- 
 arship to those having no traditions at all. As to the individual 
 members of any class in school, some have capabilities for the 
 theoretical side of physics, some for the practical side, some 
 for neither. School boards and school principals may be 
 incapable of making a wise choice of text-books, which vary 
 greatly, not simply from good to bad but in method and 
 purpose. 
 
 Accordingly, the competent teacher is not a mere piece of 
 machinery, made, like an elevator, to run with safety and des- 
 The Teacher P atcn > carrying its load of passengers through a 
 must be a certain fixed distance along fixed lines and then 
 discharging them, without responsibility or care for 
 their future fate and their ultimate destination. He is, or is 
 prepared to be, a guide, an adviser. However narrow his habit- 
 ual horizon, he must know what lies beyond it. He must ask, 
 What is the best kind of training, the best kind of information, 
 the best kind of stimulus, for this particular class, for these par- 
 ticular individuals, before me? How can I make this year they 
 spend with me count most toward their life-long efficiency and 
 happiness ? How can I best develop their capabilities, correct 
 their worst tendencies, influence their careers ? Of course every 
 teacher who attempts all this will fail -in much of his endeavour ; 
 but it is better that he should try, and that he should make in 
 his student days a preparation adequate to the responsibility 
 which will rest upon him. v This means that he must know well 
 all that he will be called upon to teach directly, and have a 
 good general knowledge of much more. He may not be, 
 probably will not be, in active teaching, able to keep up his 
 
PREPARATION FOR TEACHING 241 
 
 more advanced studies, if they have ever extended far ; but he 
 will, if he has done his work faithfully and intelligently, retain 
 at least an enduring reminiscence, a sustaining memory, that 
 will be a source of strength to himself and of inspiration to 
 his pupils. 
 
 I am not prepared, as some others may be, to advise that 
 every prospective school-teacher of physics should take the 
 degree of Doctor of Philosophy ; for this, requiring 
 ordinarily three or four years of study beyond the 
 baccalaureate course, a high degree of specialization, and much 
 labour devoted to research, is a luxury, a superfluity of prepara- 
 tion for his work, which the school-teacher cannot usually afford. 
 The degree of Master of Arts, with the meaning it is now com- 
 ing to have, as the certificate of one or two years of graduate 
 study, usually devoted to some specialty, but with little or no 
 original research, seems to me the reasonable goal of the school- 
 teacher in preparation at present. 
 
 I have said elsewhere that one can be a good school-teacher 
 of physics who knows no more of the science than one can get 
 without the calculus, but my advice to the teacher Wee( i O f 
 who wishes to realize the possibilities of his pro- Mathematics. 
 fession is strongly against this limitation. Without the calculus 
 one can read almost every page of an ordinary general English 
 treatise on physics, such as Barker, Deschanel, Ganot, Hastings 
 and Beach, Watson, etc., all of Faraday's writings, Maxwell's 
 Heat, Tait's Recent Advances, Lodge's Modern Views of Elec- 
 tricity, and a great deal more excellent literature of physics. 
 But if the student would consult the larger general treatises, or 
 follow the progress of research as revealed in such periodicals 
 as the PHILOSOPHICAL MAGAZINE or the ANNALEN DER PHYSIK, 
 he will find himself baffled and mortified, if he has not a good 
 working knowledge of this mathematical method of developing 
 and expressing physical theories. It is true that a good deal of 
 what is thus hidden from the non-mathematical reader he can 
 perfectly well do without. It is also true that one who has a 
 good knowledge of the calculus is likely to find much that is 
 
 16 
 
242 PREPARATION FOR TEACHING 
 
 printed very hard and possibly unprofitable reading. But 
 he who has become familiar with the language of the calculus 
 will always have at least the satisfaction of feeling that he 
 has the key to the gate of knowledge, that he can enter the 
 field that lies before him, however great may be the difficul- 
 ties that would await him there. This sense of freedom, of 
 possibility, is worth much, even though it may be rarely put to 
 the proof. 
 
 In the training of the teacher of physics should be included 
 a respectable amount of chemistry as well as of mathematics, 
 partly because the chemistry is needed in connec- 
 tion with physics, partly because the teacher of 
 physics is likely to be, at first, if not permanently, a teacher of 
 chemistry also. 
 
 One " course " of study being counted as the equivalent of 
 one quarter of the work of one college year, the Master of 
 Summary of Arts, as I have him in mind, well equipped for the 
 Work. school-teaching of physics or mathematics, and 
 
 tolerably fitted for the teaching of chemistry, will have taken, 
 in addition to the pre-college physics of a good school, about 
 five courses in physics, two or more courses in chemistry, for 
 the character of which the reader is referred to Chapter VIII. 
 of the first part of this volume, three or more courses in 
 mathematics, including solid geometry, plane trigonometry, an- 
 alytical geometry, and the elements of calculus with applica- 
 tions to mechanics. This makes ten or more courses of science 
 study, the equivalent of about two and one-half solid years of 
 college work, out of the whole time, at least five years and often 
 more, supposed to pass between admission to college and the 
 attainment of the M.A. degree. 
 
 The physics may well include one course or somewhat more 
 in a general text-book, like one of those named earlier in this 
 M 0re chapter, with accompanying laboratory exercises of 
 
 Specific. an illustrative and not too exacting character, usually 
 quantitative, but not painfully accurate, a course of careful labo- 
 ratory work, with much text-book study, in heat and light, two 
 
PREPARATION FOR TEACHING 243 
 
 such courses in electricity and magnetism, and a half course in 
 thermodynamics. Every one of these courses except the first 
 will naturally require some use of the calculus. 
 
 Somewhere in the curriculum the student should learn to 
 take, and to make use of, the indicator diagram of a steam- 
 engine and the characteristic curves of dynamos. 
 . . ,. i Otto* Work. 
 
 Engineering study in general is, in my opinion, 
 
 more important for the prospective school-teacher of physics 
 than special research in pure science. 
 
 A brief course in mechanical drawing, and another in the use 
 of ordinary wood-working and metal-working tools, should be 
 got in somehow, in the summer if need be, unless the student 
 is already tolerably versed in these arts ; for every teacher of 
 physics should be qualified in some measure to describe and 
 make apparatus. The habit of making rather careful drawings 
 approximately to scale, in the designing of anything to be con- 
 structed, is one which in the end saves time and trouble and 
 expense. A reasonable acquaintance with tools and with the 
 processes of the workshop often enables one to foresee and to 
 avoid, without sacrifice of anything desirable, difficult and ex- 
 pensive manipulations in the plans which at first occur to the 
 designer. How to make things with the least labour, if he 
 must make them, how to get the most for his money, if he 
 has money to spend, are questions which the teacher must 
 ponder well. 
 
 A moderate degree of skill in a few of the simpler operations 
 of glass-blowing should be sought by observation and practice 
 at every reasonable opportunity, and in general the n^t of Ob _ 
 student should give attention not merely to the serration. 
 main tasks which are plainly set before him, but to those 
 sources of extraneous information and experience which, if 
 duly cultivated, will yield a profitable return. The habit of 
 general observation, not of everything under the sun, but of 
 what will bear on one's professional career, cannot be formed 
 too early. Fortunate is he to whom this habit is instinctive ; 
 but he to whom this special talent is not given need not despair. 
 
244 PREPARATION FOR TEACHING 
 
 The resolute and persistent will, this is the potentiality of all 
 talents. 
 
 In addition, the teacher of physics should know something of 
 the history of the science and of the lives of the men who have 
 History of especially developed it. A class is always interested 
 Physics and to hear, for example, a brief account of the long 
 
 contest, beginning in the time of Newton, which 
 ended in the final establishment of the undulatory theory of light. 
 Pupils like to know just what Galvani was doing with frogs' 
 legs when he made his immortal discovery. If they go far 
 enough in the study of physics, they will be entertained by the 
 British-German controversy over the merits of Mayer's work on 
 the mechanical equivalent of heat. It is well also to explode the 
 myth about James Watt and the tea-kettle, replacing it by 
 the sufficiently interesting true account of his development of 
 the steam-engine. 
 
 I have said nothing thus far concerning the study, by the pros- 
 pective teacher, of the art of teaching as such. In common, 
 
 probably, with most college teachers of physics, I 
 Art of hold rather conservative views in regard to such 
 
 study. But it would ill become one who is writing 
 a book on the art of teaching physics to maintain that this art 
 cannot be profitably studied through books or from the oral 
 discourse of those who have practised it long. My state of 
 mind in regard to this matter is perhaps one which may as well 
 be frankly analyzed here and now. In the first place, I have my 
 full share of the prejudice created against "methods' 7 by the 
 superficial, ill-balanced work of the early normal schools. In 
 the second place, I hold that the student who has been well 
 taught, has necessarily had, along with his conscious instruction 
 in the science of physics, a good deal of possibly unconscious 
 instruction in the art of teaching physics. In the third place, 
 I have some apprehension lest the conscious study of this art will 
 be accompanied by an over-conscious attention to the philoso- 
 phy and psychology of the art, with the possible result of set- 
 ting up a more ponderous system of mental machinery than can 
 
PREPARATION FOR TEACHING 245 
 
 be used to advantage in the very practical, common-sense busi- 
 ness of teaching young people. 
 
 The students in any training school or college will perhaps be 
 more exposed to this danger than their teachers will be ; but 
 even the teacher, if his main attention is directed not to any 
 science as such, but to the art of teaching his pupils how to 
 teach their pupils this science, if he habitually looks at his chem- 
 istry or his physics through a double layer of more or less opaque 
 humanity, even the teacher runs the risk of ceasing to be what 
 he ought to be, a chemist or a physicist with an inclination 
 toward pedagogy, and becoming the less robust individual who 
 may be described as a pedagogist with an inclination toward 
 chemistry or physics. The science teachers in teachers' colleges 
 should have the ability, the means, and the opportunity, for doing 
 some original work, work of research, in their sciences as such, 
 without any regard, for the time being, to the pedagogic aspect 
 of their profession, but with every sense and faculty steeped in 
 the atmosphere of pure inquiry and bent to the prosecution of 
 the simple scientific end proposed. 
 
 The art of teaching is now receiving a great deal of intelli- 
 gent attention, and progress is evidently being made. The old 
 normal schools, instead of being abolished as useless, have been 
 improved and are therefore growing in public esteem. Such a 
 school as the very flourishing Teachers College of Columbia 
 University is an experiment, or, rather, an experiment station, 
 which must be watched with interest by intelligent educators 
 everywhere. The opportunity of beginning one's teaching in 
 a moderate way, under the supervision of an experienced 
 teacher and frank critic, before taking the full and permanent 
 responsibility of conducting a class, is an opportunity to be 
 desired. If in divinity schools there is place and use for courses 
 in " Homiletics and Pastoral Care," it is difficult to see why, 
 in the nature of things, there .should not come to be in the for- 
 mal training of the teacher a place and use for courses dealing 
 with the technicalities of his art as such. I observe, however, 
 that, in the catalogue from which I have taken the heading 
 
246 PREPARATION FOR TEACHING 
 
 quoted above, this heading is placed over the very last division, 
 except elocution, of the courses of instruction open to students 
 of divinity. The learning, the science, stands foremost ; then 
 comes the art. Thus should it be in the training of the 
 teacher. 
 
CHAPTER III 
 
 THE TEACHER AS STUDENT, OBSERVER AND WRITER 
 REFERENCES. 
 
 Nichols, E. L. Research Work for Physics Teachers. SCIENCE, Feb. 
 8, 1901. 
 
 IN spite of what I have said in the preceding chapter con- 
 cerning the degree of Doctor of Philosophy, I do not wish 
 to discourage those who feel themselves willing and able to 
 make what I have called a superfluity of preparation for the 
 profession of teaching in schools. To some men the labour 
 of scientific research, with all its inevitable drudgery, with all 
 its large possibilities of negative results, is a joy in itself, a 
 passion not to be quenched by the passage of years or by 
 the lack of visible rewards from without. If a man has this 
 passion, by all means let him cherish it and, so far as he can, 
 gratify it. Let him go on, for example, to the attainment of 
 the doctor's degree, and then, if his life-work proves to be 
 teaching in a school, let him preserve there, so far as he can 
 without neglect of his first duties, his ambition and his habit 
 of scholarship. 
 
 Will such a man find opportunity and means for original re- 
 search while engaged in school-teaching? Perhaps so. The 
 late Professor Rowland once asked a former stu- original 
 dent of his own whether he was doing any such Researcll? 
 work. The reply was, " No, I have n't the time, and I have n't 
 the money ; " whereupon Rowland exclaimed, " Don't need any 
 time, don't need any money, if you have only got the will." 
 But on another occasion, when he was asked what he should 
 do with his students while making his researches, he replied, " I 
 
248 THE TEACHER AS STUDENT 
 
 shall neglect them," which was, in a way, true. It was well for 
 the world that Rowland did neglect his routine work, and he 
 was readily forgiven this shortcoming ; but the ordinary doctor 
 of philosophy must not expect, because he will not be able to 
 deserve, a like indulgence. 
 
 The real obstacle to research by teachers is not so much lack 
 of time and means for laboratory work, as lack of the genius for 
 Professor finding the right thing to do, and lack of time and 
 Nichols's opportunity and will for keeping up with the litera- 
 ture of research. Successful research involves, 
 first, hitting upon some more or less important problem ; 
 second, making reasonably sure that no one else has solved 
 the problem ; third, solving it. In a paper read before 
 the Physics Club of New York, in December, 1900, and pub- 
 lished in SCIENCE for February 8, 1901, Professor Nichols of 
 Cornell has discussed the possibilities of research by teachers 
 in a very interesting and suggestive way. I cannot help think- 
 ing, however, that this paper is likely to be of more use to college 
 teachers than to school-teachers ; for very few men who have 
 not had experience and training in research during their stu- 
 dent days are likely to cope successfully with the difficulties 
 presented even by the apparently simple problems which 
 Professor Nichols mentions as within the reach and power 
 of teachers in schools. 
 
 The advice given by Professor Nichols, that every teacher 
 of physics should habitually read either SCIENCE ABSTRACTS or 
 the BEIBLATTER to the ANNALEN DER PHYSIK, as well as some 
 other standard journal of physics, seems to me excellent in 
 spirit and intention, though possibly a little too sweeping. 
 Much that appears in these periodicals is rather discouragingly 
 beyond the reach of the school-teacher of physics as he now 
 exists, or as he is likely to exist for some years to come. A dry 
 summary of highly technical papers, often contradicting each 
 other, usually given without authoritative criticism or comment, 
 can be inspiring only to him who is in the thick of research, 
 and able to give much of his time to reading and investigation. 
 
THE TEACHER AS STUDENT 249 
 
 Any very important discovery or advance in physics is pretty 
 sure to be noticed before long in more popular publications. 
 NATURE, SCIENCE, and some of the engineering journals will be 
 found more genial and, I believe, more profitable reading than* 
 the ABSTRACTS or the BEIBLATTER by most teachers in schools 
 at present. 
 
 It is of doubtful advantage to any man to undertake a thing 
 which is too hard for him. All of us do best by doing well 
 the things that naturally come to us, from circum- wgrkakin 
 stances or from the promptings of our own natures. to Research. 
 The surest profit of research, the mental and moral exercise 
 and enjoyment of it, may be attained in full measure by him 
 who has no thought of publication, and whose only conscious 
 object is to improve the quality of his teaching. Is there an 
 habitual experiment or an habitual laboratory exercise that 
 goes badly? If so, just there lies the opportunity and the 
 motive for research; and -when this research is successfully 
 ended, not only the teacher's pupils but his fejlow-teachers 
 also should profit by it. Is there spine natural phenomenon, 
 within doors or without, in the sky, the air, the water, the 
 ground, of which the teacher does not have a satisfactory de- 
 scription and theory ; just there is the occasion for first-hand 
 observation and reflection, perhaps for original discovery. The 
 habit of really looking at and thinking about the familiar objects 
 of every-day experience is sure to bring usefulness and may 
 bring fame. Some men have this habit by nature, and may 
 even suffer from a too miscellaneous interest in what goes on 
 about them ; but others must deliberately cultivate the habit, 
 directing it toward such things as are, from a professional stand- 
 point, important for them. 
 
 I shall presently give, at considerable length, examples of the 
 problems, essentially problems of research, which every teacher of 
 elementary pnysics will find in his laboratory work, and of the way 
 in which I have attacked these particular difficulties. I say " at- 
 tacked" advisedly, for I do not claim complete victory, or a fin- 
 ished undertaking. The results reached in this endeavour are not 
 
250 THE TEACHER AS STUDENT 
 
 of very great importance in themselves ; but they will illustrate 
 well enough the short and halting forward steps by which pro- 
 gress in the art of elementary laboratory teaching is made. 
 
 Before giving these illustrations, which will make the next 
 chapter, I wish to enumerate, as examples of the things, outside 
 Physics out of books, which may profitably engage the atten- 
 of Doors. t j on o f tne teacher or his pupils, certain objects 
 and phenomena which have interested me during a recent visit 
 to the seashore. These are : The waves which accompany the 
 progress of a steamer in a straight line through a smooth sea, 
 their shape and succession, the surprising length of time after 
 the steamer has passed before they reach the neighbouring 
 shore, the ripple mark they channel in the sand along the line 
 where each advancing wave meets its retiring predecessor in a 
 swirl ; the bits of mirage, by which, at times, distant objects 
 just above the water-line are shown double, as by a horizontal 
 aerial mirror, and the distinction between such reflection and 
 that produced by the water-surface ; the smooth patches, 
 "slicks," in ruffled water and their probable cause; the wind- 
 ruffled patches in smooth water and the frequent slowness of 
 their progress; the proper angle between boom and keel in 
 sailing, and how much it is affected by friction and leeway ; 
 the floating of sand, in grains and patches, inches across, on 
 the surface of calm water; the functions of the squid's 
 mantle ; the differences of stroke which persons of different 
 bodily shape must use in swimming ; the best position of the 
 body for swimming in rough water ; the presence and circula- 
 tion of fresh water in the sand near the reach of the tides. 
 
 On these and other things which met my eye and held my 
 thought, I probably made no observation or reflection that had 
 not been made a thousand times before, none that would be 
 worth reciting or printing at any length ; but my days were 
 fuller, my enjoyment wider and more rational, my profit greater, 
 than if I had not seen them and thought about them. 
 
 All these things of which I have just been discoursing at- 
 tracted my attention during a vacation. At home I should have 
 
THE TEACHER AS STUDENT 251 
 
 seen few of them and perhaps not have reflected on these few. 
 Change of scene, variety of experience, is for most of us neces- 
 sary, if we would keep our faculties awake. An change and 
 occasional change of text-books, for the mere sake Variety. 
 of refreshment of mind, or, better, the habitual use of a number 
 of text-books, is wise and wholesome. The habit of coming 
 together for professional consultation with other teachers, of 
 visiting their laboratories and classes, is a habit to be resolutely 
 maintained. The man who lives too much within himself, who 
 moves within too narrow limits of experience and thought, soon 
 comes to dread contact with his fellows, to shrink from new 
 ideas as one whose limbs are cramped shrinks from motion. 
 When the teacher finds himself in this condition, he must rouse 
 himself; to yield is for him to become an old man at once, what- 
 ever his age as reckoned by the calendar. 
 
 Of course, he must not give up his professional methods and 
 ideas merely because they are questioned or criticised or de- 
 nounced or ridiculed. He must rather hold himself ready to 
 defend them, so long as he believes them worthy of defence ; 
 but in order to do this he must be willing to hear what is said 
 against them. Few men, I take it, like to be made a target by 
 critics or adversaries ; but those who cannot bear it must be 
 content to remain unseen. 
 
 The practice of writing for publication is to be commended 
 for the teacher, provided there is some professional matter in 
 which he believes himself able to interest and in- writing and 
 struct his fellow-teachers or the public at large. It Speaking. 
 is true that his judgment of what is interesting and instructive 
 may not always be confirmed by that of editors, especially of 
 editors who pay for what they accept ; and it is doubtless true 
 that no form of rejection sufficiently suave to be quite satisfac- 
 tory to the author of the rejected manuscript has yet been 
 found; but, nevertheless, writing is good for the writer. It 
 compels him to think clearly where he may have thought 
 vaguely ; it keeps his attention on the theme discussed and 
 rouses thoughts he never knew before or, knowing, has forgotten. 
 
252 THE TEACHER AS STUDENT 
 
 Even the rejection of his offering by some hard-headed, if not 
 hard-hearted, editor may be salutary, impelling him to cultivate 
 a livelier habit of thought and a better style of expression. Such 
 excellence of language, in speech and writing, as the teacher 
 may readily be capable of, he should habitually maintain ; for a 
 good style is more intelligible, as well as more pleasing, than a 
 bad one. Every English-speaking teacher should be, directly 
 or indirectly, a teacher of English. 
 
CHAPTER IV 
 
 PROBLEMS OF LABORATORY PRACTICE 
 REFERENCES. 
 
 SCHOOL SCIENCE. Chicago. Zeitschrift fur den physikalischen und 
 chemischen Unterricht, Berlin. 
 
 IN this chapter I have brought together accounts of attempts 
 recently made to improve in certain respects the work done in 
 one of my laboratory classes, work similar to that of the physics 
 classes in many secondary schools. I give these accounts as 
 showing the kind of work, original in its way, in which any 
 teacher may employ his energy for the betterment of his art. 
 
 On Water-Proofing Wooden Blocks. 
 
 In elementary laboratory work it is a common practice to put 
 wooden blocks or rods into water, and for such purposes that any 
 considerable amount of soaking would be decidedly objection- 
 able. A simple, easily applied, and thoroughly effectual method 
 of water-proofing is, I fear, still to be discovered. Paint, in 
 a very thick coat, would doubtless protect the blocks for a time ; 
 but painted blocks would be rather unsightly, and, moreover, 
 the paint would come off in the hard usage of elementary labo- 
 ratory work. Similar objections apply to any form of varnish- 
 ing that would really keep out the water. Impregnating the 
 wood with paraffin seems to be, on the whole, the best device. 
 There are various ways and degrees of doing this, and I have 
 been in doubt until recently, as many teachers may still be in 
 doubt, as to the relative efficiency of these various practices. 
 
 From my experiments in water-proofing cherry-wood blocks, 
 I have come to the conclusion that, for ordinary laboratory 
 purposes, the use of an exhaust pump to draw out the air from 
 
254 PROBLEMS OF LABORATORY PRACTICE 
 
 a block submerged in very hot paraffin is not necessary, but 
 that it is well to allow the block to remain buried in the paraf- 
 fin while cooling. A block about 9 cm. 
 long, with the grain, and about 4 cm. by 
 3 cm. across the grain, treated in this 
 way, absorbed about 2.7 gm. of paraffin, 
 increasing in weight from 58.1 gm. to 
 60.8 gm. Later, submerged in water, 
 this block gained in weight about 0.8 
 gm. in 4^ hours and 2.1 gm. in 17^ 
 hours. 
 
 As a result of this study, I have had 
 constructed, for the purpose of water- 
 proofing wooden blocks of a familiar 
 size, about 7.5 cm. square by 3.8 cm. 
 thick, a copper trough 25 cm. long, 9 
 1 3 cm. deep, 
 
 Fig.l 
 
 Fig.2. 
 
 cm. wide, and about 
 slightly rounded at the bottom so as to allow free movement 
 of paraffin beneath the blocks. Across each end of the trough, 
 and extending a little below the bottom, is soldered a metal bar, 
 the ends of which project on 
 either side. These crossbars 
 serve as a support for the trough 
 when it is placed, for cooling, in 
 water. For heating, the trough 
 is supported by resting the ends 
 of the crossbars in slots at the 
 top of brass posts reaching up 
 from a broad wooden base, the 
 height being so adjusted as to 
 adapt it to the use of a Bunsen 
 burner. 
 
 Fig. i shows an end view of 
 
 the trough on its support. Fig. 2 
 
 shows one end of wooden base as seen from above. Fig. 3 
 shows how, by means of a brass strip, ss, properly shaped, the 
 blocks may be prevented from floating in the melted paraffin. 
 
PROBLEMS OF LABORATORY PRACTICE 255 
 
 The following seems to be a good method of procedure. 
 Melt enough paraffin in the trough to have a depth, before the 
 blocks are put in, of about 4 cm., and bring this to a temper- 
 ature of about 1 00 C. Put in six blocks, each having a stout 
 wire twisted around it to separate it from its neighbours and 
 to serve as a handle for lifting it from the trough ; put in the 
 brass strip, ss, Fig. 3 ; heat the bath again to 100 C. ; lift the 
 trough from its support and stand it, or float it, in a large tank 
 of cool water ; after the trough has been in the water half an 
 hour or more, remove it from the tank, lift out the blocks, 
 which will doubtless be covered in part by solid paraffin, and 
 wipe them carefully while the wax is still soft. In order to take 
 out the blocks with ease, it will probably be necessary to apply 
 the flame for a little while to the bottom, sides, and ends of the 
 trough. 
 
 On the Use of the Spring-Balance. 
 
 The spring-balance deserves and, I must admit, needs some 
 words of defence and exposition from its friends. It is so in- 
 expensive, so convenient, so quick in its action, that I make 
 very much use of it, in spite of its exasperating inaccuracy in 
 its native state. This inaccuracy is, of course, due to the 
 cheapness of its construction, the price at which it is sold not 
 warranting the adaptation of the scale of each balance to the 
 idiosyncrasies of its spring, so that the faces are merely stamped 
 in divisions corresponding more or less closely to the behaviour 
 of the average spring ; and, beyond that measure of adjustment, 
 agreement of spring and scale is a matter of luck. 
 
 I have, in the Harvard Descriptive List, written out with care 
 directions for studying inaccuracies of the scale and recording 
 them in a graphical form. But further experience and re- 
 flection have convinced me that the best thing to do with an 
 incorrect scale is to cover it with paper, fastened on with 
 mucilage after the face of the scale has been cleaned and 
 slightly roughened with rather coarse emery, and mark a new 
 and, as nearly as may be, correct scale on this paper. To do 
 
256 PROBLEMS OF LABORATORY PRACTICE 
 
 this successfully, well enough at least to improve greatly the 
 graduation of many balances, is an exercise not too long or too 
 difficult for a rather young class. The following method works 
 well : Cover the scale of the balance, which we will suppose to 
 be one of the very familiar 25o-gm. instruments marked off in 
 lo-gm. divisions, with paper fastened on with mucilage. Cut 
 a thin strip of spring brass to the shape shown in Fig. 4, the 
 scale of which is */ ; bend this strip sharply and carefully along 
 the dotted line dd, and so shape it that, when this bend is 
 fitted to the edge of the balance case, the end ee will clasp the 
 back of the case with some firmness, as in Fig. 5. The part 
 dc should be of such length that c will nearly touch the index of 
 
 d c 
 
 Fig. 4. 
 
 Fig- 5- 
 
 Fig. 6. 
 
 the balance when the two are on the same level, as in Fig. 6. 
 Now suspend the balance in a free vertical position, without 
 load, and slide the spring-brass clasp, which should grip the 
 case firmly enough to stay in position wherever placed, up or 
 down until one edge is in line with the significant part, point 
 or line, of the index, or, rather, make the adjustment in such a 
 way, that, when a fine pencil line is made along one horizontal 
 edge, this mark will be in line with the significant part of the 
 index. After this zero line is drawn, put on a lo-gm. load, 
 make a new adjustment of the slider, draw the corresponding 
 line, etc. A graduation made in this way ought not to be 
 wrong at any mark more than i-gm. Change of performance 
 of the spring, from rust or other causes, may in time invalidate 
 this graduation, but it will always be easy to make a new one. 
 It must be granted that, even after the scale has been cor- 
 
PROBLEMS OF LABORATORY PRACTICE 257 
 
 reeled, the pupil can easily make errors in the use of the spring- 
 balance, and that, in fact, he must look with some care in order 
 not to make errors of a gram or more in his readings. I do 
 not, however, consider this an objection to this form of balance. 
 The habit of intelligent care is one of the most important ob- 
 jects to be attained in the study of physics or in any other study. 
 A boy who is unwilling or unable to read such a spring balance 
 as I have described, on which the lo-gm. divisions are about 
 0.2 cm. long, without commonly making an error exceeding i 
 gram, is not fit to use a beam-balance ; for the latter, though 
 far more sensitive than the spring-balance, is no automaton 
 miraculously contrived to prevent the natural consequences of 
 stupidity and carelessness. In order to yield good results in 
 the hands of some boys, a piece of apparatus must have such 
 cunning that it will not permit itself to be set wrong or read 
 wrong, and such vigour of constitution that it will not mind 
 being knocked off the table occasionally. 
 
 In studying the parallelogram of forces, some teachers use 
 weights suspended by cords passing over pulleys, the latter 
 being attached, but movable, along the edge of a round table. 
 The friction of the pulleys and the need of a table of peculiar 
 form seem to me objections to this device. Spring-balances, 
 correctly graduated, are, I believe, preferable in this experiment. 
 
 On the Use of the Platform-Balance. 
 
 Double-platform balances, costing, with weights, about $7.00, 
 weighing anything up to a kilogram, with an ostensible accuracy 
 of o.i gm. , are very common and extremely useful pieces of 
 laboratory equipment. Unfortunately, they do not always live 
 up to their professions ; and I never feel quite sure of the last 
 tenth of a gram, even if the set of weights accompanying 
 the balance is correct within that limit, which is usually more 
 than doubtful. There are some experiments, which I like 
 to give, in which a change of o.i gm. in the weight of some 
 heavy body is rather important ; and yet, for use in such experi- 
 
258 PROBLEMS OF LABORATORY PRACTICE 
 
 ments, I know nothing which, all things considered, is likely 
 to replace this balance, with all its faults. 
 
 As the absolute weight of the body dealt with, in the experi- 
 ments just mentioned, is usually a matter of small importance, 
 provided its change of weight during an experiment can be 
 correctly found, inaccuracies of the metal weights used are 
 not likely to be troublesome, provided the large weights, in 
 which the perceptible errors are likely to exist, remain in use 
 during the whole operation. The most serious causes of error, 
 and the means for avoiding them, are perhaps sufficiently indi- 
 cated in the following set of rules for the use of the kind of 
 balance now under discussion : 
 
 Directions for the Use of the Double-Platform Balance. 
 
 i. 1 When it is necessary to weigh an object to a fraction of 
 a gram on this balance, a vertical scale should be placed on the 
 table alongside the outer edge of one platform, and the balance 
 should be regarded as in equilibrium only when the edge of 
 the platform is level with some particular mark on this scale. 
 
 2. Before making any weighing, be sure that the balance is 
 in equilibrium, with no load on either platform, and with the 
 sliding weight at zero. This test should be repeated frequently 
 during the use of the balance. 
 
 3. Put the object to be weighed at the middle of the left- 
 hand platform. Put the weights, especially the large ones, as 
 nearly as may be at the middle of the right-hand platform. 
 
 4. Any heavy shock suffered by the balance is likely to put 
 the bearings temporarily out of order, enough to affect the 
 weighings perceptibly. Such a shock is most often given by 
 unloading one platform while the other remains loaded. When 
 
 1 Section i of these directions has reference especially to balances 
 of the old pattern without pointer. Many balances now have pointers, 
 but rather unsatisfactory ones. If the ordinary pointer were doubled 
 in length, and brought to a sharp tip close to the scale, which should 
 be reduced to a single well-defined mark, there would be no need of 
 Direction i. 
 
PROBLEMS OF LABORATORY PRACTICE 259 
 
 the load of either platform is to be removed or much changed, 
 the other platform should first be pushed down as far as it 
 will go. 
 
 5. If the balance has by any accident suffered a disturbing 
 shock, the bearings should be worked back into good condition 
 by pressing firmly down on both platforms and then rocking 
 them up and down several times. 
 
 6. There may be small differences between large weights 
 which are marked alike. Therefore, in any case where a small 
 change in the weight of some heavy object is looked for, as 
 in Exercise 34 (of the list given in Chapter X.), on the Density 
 of the Air, or in Exercise 52, be careful to use the same large 
 weights in all the weighings. 
 
 7. Take great care to let no mercury come into contact with 
 brass weights. Mercury is often carried as a film on the fingers, 
 and is usually to be found in small beads on the table-top. 
 
 8. Always replace the weights in their proper holders when 
 the weighings are finished. 
 
 Measurement of the Expansion of Air. 
 
 I have been from the first much interested in those two 
 exercises of the Harvard Descriptive List which undertake 
 to measure the two coefficients of expansion of air, and 
 have been somewhat disappointed at the comparative neglect 
 of them in the schools. I must confess, however, that they 
 present some difficulties, and that the results obtained from 
 them by my own classes have not been always satisfactory. 
 And yet, I am so fully persuaded of the importance of these 
 exercises, that, instead of giving them up, I have lately revised 
 pretty thoroughly their details, in the hope of making the work 
 easier and the results better. 
 
 The glass tube which is to contain the imprisoned column of 
 dry air should be at the start about 45 cm. long. The diame- 
 ter of its bore should be about 0.15 cm.; for, if it is much 
 smaller than this, the capillary effect on the mercury column 
 which confines the air, which effect will rarely be quite the 
 
260 PROBLEMS OF LABORATORY PRACTICE 
 
 same at both ends of the column, may prove troublesome, and, 
 if it is much larger than this, the mercury column is likely to 
 break, especially in transportation. 
 
 Comparative calibration of different parts of the tube is 
 needed for satisfactory measurement of the expansion of air 
 Calibration under constant pressure. If tubes could readily 
 of Tube. b e found in which the increase of length of the 
 air column, during heating at constant pressure, would occur 
 in a part of the bore differing not more than i per cent in 
 cross-section from the part occupied before expansion, it would 
 hardly be worth while to keep a detailed record of the calibra- 
 tion. But, as this standard of uniformity cannot well be main- 
 tained, a record of the calibration should be kept, and each 
 tube in its finished condition should be accompanied by such a 
 record, which may well be in the form indicated by Fig. 7. 
 
 20.00 9.SQ 9.95 3.60 
 
 Fig. 7- 
 
 This would mean that a certain mercury column was 9.80 cm. 
 long when its middle was at a point indicated by the dot nearest 
 the now sealed end of the tube ; that the same column was 
 9.85 cm. long when its middle was at the point marked by the 
 next dot, and so on. Expansion, during heating at constant 
 pressure, will in this tube take place mainly or wholly in the 
 section between the point marked 9.90 and that marked 10.00. 
 The mean length of the calibrating column in the three right 
 hand sections being 9.85, the variation of bore of the tube will, 
 if neglected, cause an error of about 10 parts in 1000, or 
 i per cent, in the value of the coefficient of expansion calcu- 
 lated from the observations at constant pressure. If the cali- 
 brating is well conducted and recorded, still less uniform tubes 
 than the one here imagined may well be used, proper correction 
 being made for the variation of bore. 
 
 The outer diameter of the tube should be about 0.6 cm. 
 This will insure sufficient strength and will make a good but 
 
PROBLEMS OF LABORATORY PRACTICE 261 
 
 not too tight fit where the tube is pushed through a 0.5-0111. 
 hole in a rubber stopper, as it will be in use after completion. 
 The companion glass tube, which will be connected Diameter of 
 with the one already described and will contain the Tut)e * 
 outer end of the mercury column, will be called the outer 
 tube or the open tube. This outer tube should be at least 50 
 cm. long, but in other dimensions as like as may be to the 
 inner tube which is to contain the imprisoned air. The outer 
 and the inner tubes are to be connected by a piece of antimony 
 rubber tubing about 6 cm. long, 0.3 cm. in diameter of bore, 
 and 0.8 cm. in outside diameter. Into this tube each of the 
 
 glass tubes should extend about i.c cm., leaving 
 
 . . Connections, 
 
 about 3 cm. clear. This arrangement will enable 
 
 us to place the,glass tubes at right angles with each other, as in 
 Fig. 10, without danger of collapsing the rubber connection. 
 The bore of the rubber tube being much larger than the bore of 
 the glass, four times as large, in cross-section, we will suppose, 
 a sort of pocket will exist between the glass tubes, which must 
 be remembered in the operation of filling. 
 
 This operation is one of critical importance, for if it is not 
 properly done, insuring dry air for the expansion, the apparatus 
 is worse than useless. It is, of course, not enough c are in 
 merely to make sure that there is no visible mois- Drying. 
 ture in the tubes. Care must be taken that no invisible layer 
 of water, sufficient to produce any considerable pressure of 
 vapour on evaporation, exists within the closed air space after 
 the filling. It is practically impossible to dry out a small-bore 
 tube after one end is sealed. For sure effects, dry air must be 
 drawn through the tube while it is hot, and this process should 
 continue for some little time, several minutes at least. The 
 heating is readily accomplished by means of a steam jacket 
 (Fig. 8), about 36 cm. long, that is, about 4 cm. shorter than 
 the finished sealed tube is to be. The air is well enough 
 dried by making it bubble gently through eight or ten centi- 
 meters of sulphuric acid among glass beads. 
 
 In preparation for filling, take the selected and calibrated tube 
 
262 PROBLEMS OF LABORATORY PRACTICE 
 
 which is to contain the air and, applying to it, 5 cm. from one 
 end, a slender gas flame (through a burner consisting of a piece 
 Making f glass tubing 2 or 3 cm. long and about 0.05 cm. 
 
 Connections. m diameter of bore), reduce the diameter to about 
 one third of its original size, making this reduction affect as little 
 as may be of the length of the tube. Place the tube in the 
 heating jacket and connect it with its companion glass tube by 
 means of the rubber tube already described, taking care that 
 there be no visible moisture in any of these tubes when they are 
 put together. 1 Connect at the left, Fig. 8, with an aspirator 
 
 JL 
 
 Fig 8. 
 
 pump. Connect the drawn-out end of the air-tube, at the right 
 in Fig. 8, with the drying bottle. Especial care should be taken 
 to have the junctions between rubber and glass tight, other- 
 wise steam, escaping from the heating jacket, may be drawn 
 into the tube by way of these junctions. 
 
 Let steam flow through the jacket, and draw air through the 
 heated glass tube at the rate, let us say, of i cu. cm. per second, 
 Process of to be estimated roughly by means of the bubbles 
 Drying. rising from the acid in the drying bottle. The 
 
 arrangement thus far is indicated by Fig. 8, which shows a 
 
 1 It is well to have a tiny wad of cotton in each end of the main tube 
 while it is being put into the heating jacket ; for this jacket, as well as 
 the stoppers at its ends, through which the glass tube must extend, is 
 likely to be wet, and without precaution water may thence enter the glass 
 tube. 
 
PROBLEMS OF LABORATORY PRACTICE 263 
 
 device for relieving the reduced section of the glass tube from 
 the weight of the connections. The arrow indicates the course 
 of the air coming from the drying bottle. 
 
 Maintain this condition of things ten minutes ; then discon- 
 nect the pump. Apply the small flame once more to the nar- 
 rowed section of the glass tube until this is melted off and 
 neatly sealed. Allow a little time Sealing 
 for the glass to cool after the ap- 
 plication of the flame and then withdraw it 
 from the steam jacket, keeping it all the 
 time connected with its companion tube. Of 
 course the heated tube in cooling draws in 
 some air from the outer tube or the rubber 
 connection, but, as this air has been dried, it 
 will do no harm. The undried air of the room 
 will enter the outer tube only. It is probable 
 that the inner tube would acquire no injurious 
 amount of vapour if the operation of intro- 
 ducing the mercury were deferred for some 
 days or even weeks, though, if this delay 
 were to occur, it would be safer to detach the 
 inner glass tube from the rubber connector 
 and seal its open end with paraffin for the 
 time being. Dry air should, in this case, 
 be drawn through the connector and the 
 outer tube before reconnecting for further 
 operations. 
 
 The business of putting in the mercury is 
 facilitated by the use of a mercury bottle, or 
 reservoir, having a side opening introduction 
 near its bottom, as in Figs. 10 of Mercury, 
 and ii. The tube to be filled, being con- 
 nected with this opening, will receive the 
 mercury horizontally, under a pressure which 
 need differ but little from that of the atmos- 
 phere, a condition of things which make it Flg * 9- 
 
264 PROBLEMS OF LABORATORY PRACTICE 
 
 easy to control with considerable nicety the amount of air to 
 be left in the tube. This is an important consideration ; for, 
 if too little air remains, small errors of volume become im- 
 portant ; and, if too much air remains, expansion at constant 
 pressure may reach beyond the limit of the inner tube. 
 
 Connect, then, the tube, the mercury bottle, a pressure- 
 gauge and the aspirator air-pump, according to the indications 
 Adjustment ^ ^&' 9> wmcn represents the bottle lying on its 
 of Air- side and does not undertake to show the method 
 
 by which it is fastened to its support. Before 
 the pump is set in operation, a rough calculation should be 
 
 Fig. 10. 
 
 made of the degree of exhaustion required. Let us suppose 
 that the closed tube is 40 cm. long, the rubber connection 
 equivalent in capacity to 1 2 cm. of the glass, the outer tube, 
 of same bore as the sealed tube, 50 cm. long, making a total of 
 102 cm. We wish to have the imprisoned dry air column, at 
 atmospheric pressure and ordinary temperature, about 26 cm. 
 long. Accordingly, before admitting mercury to the outer tube, 
 we should reduce the air pressure within the tube to 26 / 102 of 
 the barometic pressure, about 19 cm. It is well, however, to 
 make a first trial with a somewhat greater pressure ; for it is 
 better to take out too little air at first than too much. When, 
 therefore, the gauge indicates about 21 cm. pressure, close the 
 pinch-cock c, disconnect with the pump beyond <:, tip the bottle 
 
PROBLEMS OF LABORATORY PRACTICE 265 
 
 up into the position shown by Fig. 10, thus bring the mercury 
 over the end of the tube, lift the sealed tube to a vertical posi- 
 tion, as in the figure, so that the mercury entering will leave no 
 air bubbles in the rubber connector, and then open the pinch- 
 cock, letting the air in rather slowly. When equilibrium is 
 reached, lay the sealed tube horizontal, as in Fig. n, and 
 
 Fig. ii. 
 
 measure the length of the imprisoned air-column. If this is more 
 than 27 cm. long, it will be well to take out a little more of the 
 air, for which operation the position of Fig. 9 should be re- 
 sumed. If the length of the air-column proves to be between 
 24 cm. and 27 cm. long, it is well enough, and the tube should 
 be disconnected from the bottle, the apparatus being, for this 
 operation, laid on its side, as in Fig. 12, in order to avoid 
 
 Fig. 12. 
 
 spilling mercury. A part of the mercury in the outer tube 
 should now be allowed to run out, so that the column finally 
 left in it, when the whole is laid horizontal, shall be not far 
 from 35 cm. long. 1 
 
 1 I have lately tested 23 tubes prepared, either by myself or under my 
 supervision, in general accordance with the directions here given. Two 
 of them were bad, giving more than .004 for a, the coefficient of pressure 
 increase. This probably indicated incomplete drying, due, perhaps, to 
 
266 PROBLEMS OF LABORATORY PRACTICE 
 
 If manufacturers would properly select, calibrate, clean, dry 
 out and seal the tubes, and close one end temporarily with 
 Calibration, paraffin (see p. 263), it would be an easy matter 
 etc., by Man- for teachers to fill them. This division of labour 
 would avoid the danger of breaking, to which the 
 mercury column is subject during transportation. 
 
 some carelessness in following directions. The others gave for a, 
 values ranging from .00356 to .00379, the mean being .00366. Most of 
 the variation was probably due to inequality of capillary effects at the 
 hot and cold ends, respectively, of the mercury column. Each end of 
 this column should be jarred smartly just before readings are made. 
 
CHAPTER V 
 
 SCHOOL TEXT-BOOKS OF PHYSICS 
 
 REFERENCES. 
 
 This list is made up of general text-books intended for school use, 
 most of which include or have reference to directions for a course of 
 laboratory work to be done by the pupils. Laboratory manuals, as dis- 
 tinguished from text-books, special treatises on parts of physics, and 
 general text-books suitable for the use of teachers rather than pupils, will 
 be named later in connection with Chapters VIII. and X. 
 
 Avery, E. M. Elementary Physics. New York, Butler, Sheldon, & 
 Co. School Physics. Same author and publisher. 
 
 Carhart and Chute. High School Physics. Boston, Allyn & Bacon. 
 1902. Pp. 433. 
 
 Cooley, L. B. C. Student's Manual of Physics, New York, Ameri- 
 can Book Co. 
 
 Crew, Henry. Elements of Physics. London and New York, Mac 
 millan. 1900. Pp. 353. 
 
 Gage, A. P. Boston, Ginn & Co. 
 
 Elements of Physics. 1898. Pp. 381. 
 
 Introduction to Physical Science. 1896. Pp. 374. 
 
 Principles of Physics. 1895. Pp- ^34- 
 
 Gilley, F. M. Principles of Physics. Boston, Allyn & Bacon. 1901. 
 Pp. 552. 
 
 Hall, E. H. and Bergen, J. Y. Text-book of Physics. New York, 
 Henry Holt & Co. 1897. Pp. 596. 
 
 Henderson, C. H. and Woodhull, J. F. Elements of Physics. New 
 York, D. Appleton & Co. 1900. Pp. 388. 
 
 Hoadley, G. A. Brief Course in General Physics. New York, 
 American Book Co. 1900. Pp. 463. 
 
 Nichols, E. L. The Outlines of Physics. London and New York, 
 Macmillan. 1897. Pp. 452. 
 
 Rowland, H. A. and Ames, J. 8. Elements of Physics. New York, 
 American Book Co. 1900. Pp. 252. 
 
 Stone, W. A. Experimental Physics. Boston, Ginn & Co. 1897. 
 Pp. 378. 
 
 Thwing f C. B. An Elementary Physics. Boston, Sanborn & Co. 
 1900. Pp. 371. 
 
268 SCHOOL TEXT-BOOKS OF PHYSICS 
 
 Wentworth, GK A. and Hill, G. A. A Text-book of Physics. Boston, 
 Ginn & Co. 1898. Pp. 440. 
 
 Wright, M. B. Elementary Physics for the Use of Schools and Col- 
 leges. London and New York, Longmans, Green & Co. Pp. 256. 
 
 WE have now considered the natural qualifications of a 
 teacher of physics, his formal professional education and some 
 of the means and habits by which he can keep himself a student 
 and a thinker during the routine practice of his profession. It 
 is now time for us to consider what should be his general 
 method or theory of teaching. 
 
 If I had undertaken to write on this subject twenty years ago, 
 it is doubtful whether I should have said anything about labora- / 
 tory work for the pupils in general of secondary schools. Noi 
 
 such work was provided for by the text-books in 
 Retrospect. 
 
 common use at that time ; and the school-teachers 
 
 of physics, who, as a rule, had never enjoyed laboratory oppor- 
 tunities for the study of the science, and who often were mere 
 conscripts in the service of physics teaching, were not much in 
 the habit of extending their activity beyond the reach and direc- 
 tions of the book in hand. 
 
 Fifteen years ago I should have had to consider the ques- \ 
 tion, strictly a question at that time, whether class laboratory 
 work in the school teaching of physics is practicable or de- 
 sirable. To-day the question is, What laboratory work shall ' 
 be done, how much, and in what spirit? Practically, all the 
 American physics text-books written for use in secondary schools . 
 nowadays take class laboratory work for granted, although they 
 differ among themselves in the amount and character, or motive, 
 of the exercises which they recommend. 
 
 The main purpose of the text-books twenty years ago was to 
 give information. Training of the senses and of the powers of 
 General Infer- observation and reflection was hardly considered in 
 mation. Type their construction. They had little more care than 
 dictionaries have for the intellectual processes of 
 their readers. In their one function they probably were, when 
 faithfully studied, fairly successful. For example, Arnott's Ele- 
 
SCHOOL TEXT-BOOKS OF PHYSICS 269 
 
 ments of Physics, 1877, recommended to schools by Harvard 
 University in 1881, contained a vast number of interesting state- 
 ments, most of which would still be accepted as true. It had 
 8 73 pages, and, though it was without an index, its table of con- 
 tents covered 13 pages. It dealt with an enormous variety of 
 particulars. But it did not, I believe, give one problem of any 
 kind for solution by the reader. In fact, I doubt whether there 
 was in the whole book a single interrogation, except those of a 
 rhetorical character. The object and hope of the book seemed 
 to be, so fully to anticipate all needs and questions of the reader 
 that he would never have to do any thinking on matters of 
 physics. 
 
 Of course, this book was the extreme of its type, and for that 
 reason I have described it, my object being not so much to show 
 how great the change has been in twenty years, as to make plain 
 what manner of book results from the complete neglect of the 
 training function. In spite of the fact that many a middle- 
 aged man remembers such books with a kind of fondness, and 
 loyally declares his indebtedness to them, a general recognition 
 of their superficial and unsatisfactory character has gradually 
 retired them from use. Books appealing more to the reason of 
 the pupil, treating him as a growing thing, to be fed, developed, 
 and trained, rather than as a receptacle to be filled, have taken 
 their place. 
 
 It is not in physics alone, or in natural science alone, that a 
 change like this has occurred. A general movement of the 
 same kind was characteristic of the latter part of the 
 nineteenth century in all fields of educational ac- change of 
 
 tivitv in America. One of the first text-books of View and 
 
 Method. 
 physics, if not the very first, to show this movement 
 
 was the Elements of Physics, written by Mr. A. P. Gage of the 
 Boston English High School, which appeared in 1882. This 
 book carried on its cover the exhortation, " Read Nature in the 
 Language of Experiment," and it described many experiments 
 to be performed by the pupils. The Author's Preface began 
 thus: "In his report for the year 1881, Mr. E. P. Seaver, 
 
270 SCHOOL TEXT-BOOKS OF PHYSICS 
 
 Superintendent of the Public Schools of Boston, says : l It is 
 a cardinal principle in modern pedagogy that the mind gains a 
 real and adequate knowledge of things only in the presence of 
 the things themselves. Hence, the first step in all good teach- 
 ing is an appeal to the observing powers/ " etc. That is, labo- 
 ratory work, the laboratory method of study for pupils of the high 
 school age, was in the air, so much so that its most enthusiastic 
 advocates did not trouble themselves to argue for the desirability, 
 but only for practicability, of such a feature in the school course. 
 
 Gage's book soon came into wide use, and it must have ex- 
 erted a great influence on the methods of instruction in physics 
 in the United States. Meanwhile there were other much-used 
 text-books, good in their way, which I do not mention here by 
 name, because they were not particularly influential in pushing 
 forward that revolution of practice the course of which I am 
 roughly tracing. 
 
 An act of importance in this history was the publication, in 
 1886, of the following statement, as a definition of one of the 
 alternative requirements in physical science for ad- 
 Action on mission to Harvard College : " A course of experi- 
 
 Physics for m ents in the subjects of mechanics, sound, light, 
 Admission. 
 
 heat, and electricity, not less than forty in number, 
 
 actually performed at school by the pupil. These experiments 
 may be selected from A. M. Worthington's Physical Laboratory 
 Practice (Rivingstons, London, 1886), or from the New 
 Physics, by John Trowbridge (Appleton & Co., New York), 
 or from any similar laboratory manual." This was supplemented 
 by the further statements, " In the second of the alternatives in 
 elementary physics, . . . the candidate will be required to pass 
 both a written and a laboratory examination. The written ex- 
 amination will be directed to testing the candidate's knowledge 
 of experiments and experimenting, as well as his knowledge of 
 the principles and results" of the science. "The laboratory 
 examination will be directed to testing his skill in experimenting. 
 At the hour of the written examination the candidate will be 
 required to hand in the original note-book in which he recorded 
 
SCHOOL TEXT-BOOKS OF PHYSICS 2JI 
 
 the steps and results of the experiments which he performed at 
 school," etc. " Most pupils will need lectures or other oral ex- 
 planations in addition to the descriptions given in the laboratory 
 manuals. When it is impossible to provide lectures, an addi- 
 tional text-book made from a different standpoint will be found 
 of advantage." 
 
 From Arnott's Physics (Harvard Requirements, 1881) to this 
 statement is a very wide swing of the educational pendulum, 
 too wide, indeed. Chemists were more influential change Too 
 than physicists in framing the new science require- Great - 
 ments, and they made the mistake of treating the physics just as 
 they treated the chemistry. The emphasis was all put on " ex- 
 periments and experimenting," the other work of the proposed 
 requirement being mentioned later and almost incidentally. 
 The written examination was to be directed in part to experi- 
 ments and experimenting, while the laboratory examination must 
 be devoted exclusively to experimenting. Undoubtedly this was 
 too great a reaction from the methods of the preceding decade. 
 
 The latitude of choice, in laboratory work, permitted by the 
 letter of the new requirement, forty experiments chosen at will 
 
 from either of two very unlike manuals, " or from 
 
 , Influence of 
 
 any similar laboratory manual, made it neces- Harvard 
 sary for the College to get out a Descriptive '^e^riptive, 
 List of acceptable experiments, that is, a pam- 
 phlet giving detailed directions for the performance of the pre- 
 scribed number of laboratory exercises. This List soon came 
 into very common use within the especial sphere of Harvard 
 influence, and presently a number of text-books appeared-which 
 were prompted, directly or indirectly, by the course of labora- 
 tory work laid down in this pamphlet. These books, though 
 differing considerably among themselves, constituted a strongly 
 marked type, almost the antipodes of the Arnott's Elements, 
 which had not long preceded them. 
 
 But some years of use brought to general recognition the 
 already noted defect of the Harvard requirement, and of the 
 text-books corresponding to it, the over-emphasis on exacting 
 
2/2 SCHOOL TEXT-BOOKS OF PHYSICS 
 
 laboratory work, and the consequent lack of opportunity for 
 sufficiently varied instruction. Accordingly, in 1897, the Har- 
 vard Catalogue gave a new statement of the re- 
 A Revision. 
 
 quirement in Elementary Physics, from which state- 
 ment the following extracts are taken : " Elementary Physics, 
 A course of study dealing with the leading elementary 
 facts and principles of physics, with quantitative laboratory 
 work by the pupil. 
 
 " The instruction given in this course should include qualita- 
 tive lecture-room experiments, and should direct especial atten- 
 tion to the illustrations and applications of physical laws to be 
 found in every-day life." 
 
 "The pupil's laboratory work should give practice in the 
 observation and explanation of physical phenomena, some fa- 
 miliarity with methods of measurement, and some training of 
 the hand and the eye in the direction of precision and skill. It 
 should also be regarded as a means of fixing in the mind of the 
 pupil a considerable variety of facts and principles." 
 
 The Descriptive List was re-written to fit the new require- 
 ment. But such text-books as have been written with especial 
 reference to this List, even in its revised form, continue to be 
 a rather marked type, distinguished by their great attention to 
 laboratory work, by their detailed description of such work, and 
 by the intimate relation which they maintain between it and 
 work of other kinds. 
 
 In most parts of the country the change to laboratory methods 
 of instruction was less rapid and less sweeping than in those 
 
 places where the influence of Harvard was pre- 
 Otner Inliu- f l 
 
 ences. Ann dominant ; but a movement of the same general 
 character has been widespread, many teachers in 
 many places helping it on, each in his own way. Ann Arbor, 
 through the books written by men connected with her educa- 
 tional institutions, early became and has remained a centre of 
 great influence. 
 
 It is quite probable, however, that, even to the present time, 
 the most successful text-books, from the point of view of numbers 
 
SCHOOL TEXT-BOOKS OF PHYSICS 273 
 
 sold, have been those making little of laboratory work, follow- 
 ing, rather than leading, the change of opinion and practice. 
 Books still appear in which the treatment of labo- conservative 
 ratory work seems rather perfunctory. It must be ^ wika ' 
 said in favour of such books that for cyclopaedic purposes or any 
 hasty use they are more convenient than those in which the 
 laboratory work is more prominent and more closely amalga- 
 mated with the other parts. 
 
 The ideal text-book, which is to satisfy all kinds of teachers 
 and all kinds of schools and sweep all competitors from the 
 field, has, apparently, not yet appeared, in spite of NoAiiSuffi- 
 the many efforts which are constantly being made cientBook. 
 to produce it. There seems to be, for the young teacher, no 
 escape, at present, from the task of studying the conditions of 
 his own school, studying the characteristics of a number of 
 text-books, and then making his choice according to his own 
 best judgment, choosing more than one book if this is practi- 
 cable. In a few years he will be writing a book of his own, 
 which may prove to be the book. 
 
 In the next chapter I shall discuss and illustrate various 
 theories, or views, of laboratory work which appear to have 
 guided the authors of current school text-books of physics. 
 
 18 
 
CHAPTER VI 
 
 DISCOVERY, VERIFICATION, OR INQUIRY? 
 
 REFERENCES. 
 
 Armstrong, W. E. The Heuristic 1 Method of Teaching. Vol. 2 of 
 Special Reports on Educational Subjects. Department of Education of 
 the English Government. Pp. 389-413. 
 
 Cajori. The Pedagogic Value of the History of Physics. SCHOOL 
 REVIEW. May, 1899. Pp. 278-285. 
 
 Fouillee, A. Education From a National Standpoint. London, 
 E.Arnold. New York, D. Appleton & Co. 1892. Pp.332. Chap. II. 
 MacGregor, J. Q. Knowledge-Making. NATURE. Dec. 14, 1899. 
 
 The Prefaces of all American school-books of physics published during 
 the last ten years. 
 
 YEARS ago, when I was a novice in the laying out x)f a course 
 of physics for schools, an eminent professor declared to me 
 " ind ctive " w ^ m uch impressiveness, " There are two ways of 
 and"Deduc- teaching science, the inductive method and the 
 deductive method. The inductive method is the 
 only one that has any business in the schools." Another, still 
 more eminent, authority, when in his presence I happened to 
 use the phrase, " the verification of Boyle's law," exclaimed with 
 emphasis, "That is the very attitude we want to avoid, the 
 attitude of verification." 
 
 In the light of all my observation and experience, I am now 
 of the opinion that the first maxim was a very bad one, and the 
 second a very good one. The first is a harmful exaggeration 
 of the truth of the second. 
 
 It is certainly unwise to take the position that the pupil must 
 be brought to the acceptance of every truth by the roundabout 
 
 1 See also the last chapter of this book. 
 
DISCOVERY, VERIFICATION, OR INQUIRY 2?$ 
 
 % 
 
 method of proceeding from axioms along a continuous chain of 
 demonstration, which he must put together link by link. It is 
 well to follow this course in geometry ; it is well to follow it 
 often in physics, partly for the mental training it gives, and partly 
 for the light it throws on the methods by which others have 
 sought out the truths of the science ; but it is absurd to say 
 that the young pupil should be permitted to take nothing at 
 second-hand. Youth is too short, and life is too short, for such 
 a doctrine. 
 
 It is probable, indeed, that no teacher and no writer of text- 
 books would profess to hold this doctrine without limitations. 
 But, nevertheless, the "inductive method," or the A j nigesof 
 method of discovery, is often overworked, with the Inductive 
 result that it must break down or be continued as 
 a mere pretence, most harmful to the intellectual morals of 
 all who are parties to it. 
 
 For example, it is well, of course, to encourage and require 
 the pupil to put down at the end of an experiment what he has 
 got out of it ; but it has often seemed to me that the printed 
 order to " infer," which is given at the end of each exercise in 
 some of the ruled and formulated note-books now so much 
 used, is often too large for the occasion and leads the pupil to 
 put down some unqualified law, not justified by the evidence 
 which he presents, or to venture some platitudinous remark 
 where the only real inference is a numerical result. 
 
 If my memory is not playing me false, I once saw directions 
 for an experiment in which the pupil was to watch intently for 
 some time a bit of wood lying on a table, and then, after re- 
 flection, to write down the inference, Matter cannot set itself 
 in motion. This experiment was very consistently followed by 
 another, in which the pupil, after poking the object and duly 
 reflecting, was expected to write down the inference, Matter 
 can be set in motion by force. I remember another book of 
 experiments, to be used at home by young boys, which began 
 by the dropping of a stone into a vessel filled with water, and 
 developed the subject and the pupils so rapidly as to ask 
 
276 DISCOVERY, VERIFICATION, OR INQUIRY 
 
 
 
 the latter, on the second page, whether, in their opinion, 
 according to Experiment 4, sunlight is matter. 
 
 Such is the method of discovery at its worst. It would be 
 unfortunate for young pupils to get the notion that science 
 has been developed by such methods of observation and in- 
 ference as those just indicated. 
 
 But what of this method at its best ? Doubtless at its best it 
 works very well ; but what are the conditions necessary for this 
 The Method success? A very competent teacher, who knows 
 at its Best. t j ie g r0 und thoroughly, and will 'not delude him- 
 self or his pupils with exaggerated notions of their independ- 
 ence and originality in science, and a very small class. The 
 method, sometimes advocated, of teaching children to swim by 
 throwing them into deep water, will surely be fatal to a very 
 large proportion of the unhappy youngsters, unless there is 
 some experienced person with every group of three or four. 
 For a single pupil in the art of swimming a judicious teacher 
 is better than a life-preserver ; but, if the teacher must have 
 fifteen or twenty beginners in charge at once, in the name of 
 humanity let him give them something to float with, or keep 
 them very near the shore. Usually, I am sure, the teacher who 
 thinks to let his pupils " find out everything for themselves " 
 will find out for himself that he has somehow got the hardest 
 part of the undertaking. For visible progress must be made, 
 tangible results must be reached ; the teacher must somehow 
 bring things to pass, in spite of the vast capacity for going 
 wrong which marks the efforts of the ordinary individual, as 
 it has marked the efforts of the human race, to " find things 
 out." 
 
 Young people are not averse to games of hunting ; but, if the 
 hunting lasts very long without result, most of the participants 
 Art of Dis- w iM fell out > an l tne g am e, m school or out, will flag. 
 
 covering Gen- Most general laws or relations in physics are too 
 era! Laws 
 
 cannot t>e difficult for the pupil to seek out. Even when all 
 
 Taught. t j ie necessary ( } ata are at hand, the unprompted 
 
 recognition, the genuine discovery, of the resultant law is either 
 
DISCOVERY, VERIFICATION, OR INQUIRY 277 
 
 an accident or an inspiration akin to accident The art of such 
 discovery cannot be taught. But physics is peculiar among the 
 natural sciences in presenting in its quantitative aspect a large 
 number of perfectly definite, comparatively simple, problems, 
 not beyond the understanding or physical capacity of young 
 pupils. With such problems the method of discovery can be 
 followed sincerely and profitably. 
 
 Let us now consider the method of verification. It is hard 
 to imagine any disposition of mind less scientific than that of 
 one who undertakes an experiment knowing the Method of 
 result to be expected from it and prepared to look Verification. 
 so long, and only so long, as may be necessary to attain this 
 result. Better by far to take a statement on faith than to culti- 
 vate the habit of hunting for evidence in its favour and shutting 
 one's eyes to inconvenient evidence against it. A trait that has 
 characterized the great masters of science has been the power 
 and habit of sternly searching the evidence for, as well as the 
 evidence against, their own propositions. 
 
 The suggestion that pupils whose minds are prejudiced in 
 favour of a certain belief will pervert the evidence of their own 
 senses is sometimes ridiculed or resented ; but, unfortunately, 
 I have seen too many instances of such perversion p re : udice 
 
 to doubt its prevalence. It is sometimes conscious, Perverts 
 ^ , ... Evidence, 
 
 sometimes unconscious. Even when conscious, it 
 
 is frequently quite open and without sense of wrong-doing. 
 " Why should I put down an observation which I know can't be 
 right?" the boy will ask in perfect innocence. 
 
 Of course, there are cases in which the conditions of a par- 
 ticular observation are such as to make it peculiarly uncer- 
 tain, much more uncertain than the other observations which 
 would naturally be grouped with it, and in cases like this the 
 observation in question should be rejected, even if it happens 
 to agree with our preconceived notion of what it should be. 
 But when all the observations of the same sort have been made 
 under equally good conditions, so far as these conditions are 
 known, we must not reject some of them because they do not 
 
2/3 DISCOVERY, VERIFICATION, OR INQUIRY 
 
 agree with the others, or because they do not agree with our 
 notions of what they ought to be. Yet I have again and again 
 found the tendency to do just this thing, and not always among 
 pupils only. 
 
 There is very little to choose between the method of verifica- 
 tion at its worst and the pseudo method of discovery. The 
 former says to the pupil, The fact is so and so ; make observa- 
 tions accordingly. The latter says, Make observations; from 
 these discover the fact, which is so and so. We need something 
 better than either of these methods to justify the expense and 
 work of laboratory courses. 
 
 I would keep the pupil just enough in the dark as to the 
 probable outcome of his experiment, just enough in the attitude 
 of discovery, to leave him unprejudiced in his observations, 
 and then I would insist that his inferences, so far as they pro- 
 Method of f ess to be derived from his own seeing, must agree 
 Inquiry. with ^} ie re cord, previously made and unalterable, 1 
 of these observations. The work may relate to some single 
 phenomenon, fact, or constant, or to some general law ; but in 
 any case the experimenter should hold himself in the attitude 
 of genuine inquiry. 
 
 This attitude is not necessarily inconsistent with fore-knowl- 
 edge of what the result sought should be according to the 
 Spirit of the testimony of books. Much depends on the spirit 
 Teaching. o f the teaching. If this is such as to show that no 
 forcing or perversion of observations, no pretence in the reason- 
 ing from these observations, will be tolerated, if known, the 
 pupils are likely to be powerfully affected by it. But if the text- 
 book used is one that emphatically states laws or quantities, and 
 then instructs the pupil to " verify " these laws or quantities in 
 the laboratory exercises, it will require strong counter-instruc- 
 tion from the teacher to make these exercises proceed in the 
 
 1 Sometimes an inspection of the observations will disclose a perfectly 
 obvious blunder, such as a mistake of ten degrees in reading a thermom- 
 eter. Of course in such cases the record should be amended, with a 
 note describing the change. 
 
DISCOVERY, VERIFICATION, OR INQUIRY 2J$ 
 
 right spirit. It is better to keep young observers out of tempta- 
 tion until they are accustomed to depend on themselves. 
 
 Consider, for example, the law of Boyle regarding gases. 
 This law is very important, and the manipulation of the appara- ' 
 
 tus illustrating it is excellent practice for the pupil. 
 
 . . a . ,, . . . ... Illustrations. 
 
 But the law is numerically so very simple that, if it 
 
 were clearly in the minds of the class before the experiment, 
 and especially if the order to " verify " the law had been issued, 
 some in any large class would be pretty sure to feel their way 
 along, making calculations in advance of records, leaving out 
 undesired millimeters, and attain a result in beautiful accord 
 with the idea which inspired them, but probably not quite in 
 accord with the evidence of the apparatus and their own unper- 
 verted senses. On the other hand, the parallelogram of forces 
 is a law so complicated that it is difficult for the pupil, when he 
 is making his observations on the magnitude and directions of 
 the three balanced forces, to see whether these observations 
 will or will not lead to a perfect parallelogram, and there is no \ 
 harm in letting him know, in advance, just what the law is, pro- 
 vided there is some adequate control and check on the use of 
 these observations. 1 The object of the experiment in this case 
 is to make the pupil realize the meaning of the law, while giving 
 him an opportunity to exercise, and by the final result to test, 
 his skill. 
 
 The teacher and the pupils should know that various so- 
 called laws are not strictly true and that even elementary labo- 
 ratory work may go far enough to show their falli- Imccnra of 
 bility. For example, according to my observation Some 
 of wooden blocks sliding on a surface of paper, ' aws ' 
 friction is not independent of velocity, but is a little greater at 
 high speed than at low, a conclusion contrary to what I should 
 
 1 My practice is to have the pupil make his observations, that is, draw 
 his lines and record his readings, on a sheet of paper placed beneath the 
 strings through which the forces are applied, and then, with a pin, prick 
 through the significant parts of his diagram into a sheet of paper beneath, 
 which sheet remains in the laboratory as a copy of the record. 
 
280 DISCOVERY, VERIFICATION, OR INQUIRY 
 
 have expected. The difference is so slight, however, that a 
 boy who has been told, as boys are sometimes told in advance 
 of experiment, that there is no such difference, is pretty sure 
 not to find it, and that very promptly. A good practice in 
 such a case is to tell the class that the difference, or depar- 
 ture from the so-called law, if there is any, is slight, and that, 
 after each pupil has tried the experiment and recorded his 
 unbiased judgment, the opinion of the majority will be taken 
 and announced. The fact of the inequality noted in such a 
 case as this may not be important, but the power and habit of 
 seeing what there is to see, and not merely what one is told to 
 see, is important. 
 
 Another instance in which class observation brings out an 
 interesting fact which the experiment was hardly expected 
 to reveal, is found in the exercise on the position of the 
 image formed by a plane mirror. In writing the directions 
 for such an exercise I had made no mention of the need 
 of making some allowance for the refraction by the glass, 
 which virtually brings the reflecting back surface of the mirror 
 a little forward from the straight line over which it is care- 
 fully placed. Examining the work of pupils, however, I 
 have found that this refraction does produce a plainly per- 
 ceptible effect in many cases. If nearly perpendicular in- 
 cidence and reflection were used, this virtual moving forward 
 would be equal, nearly, to one-third the thickness of the 
 glass; but, as the incidence used is generally very oblique, 
 the virtual reflecting surface, as found by the point of crossing 
 of the lines of incidence and reflection, may be nearer to 
 the front surface than to the back surface of the mirror. It 
 would be unfortunate to blink out of sight a fact like this, even 
 though its complete discussion may have to be postponed for 
 a time. 
 
 I have already alluded to cases in which the laws to be illus- 
 trated or revealed by the experiment are of such a nature that 
 the work of no one pupil is sufficient for the general purpose, 
 and combination or comparison of results becomes necessary 
 
DISCOVERY, VERIFICATION, OR INQUIRY 281 
 
 One of the best illustrations of this class of exercises is fur- 
 nished by experiments on the deflection of rods of various 
 dimensions. My habit in dealing with this matter Pooling of 
 is the following : Each member of the class has at Observations. 
 his command two white pine rods, as nearly alike in grain as may 
 well be, each a little more than a meter long, one being i cm. 
 square in cross-section, the other 2 crn. by i cm. Each rod is 
 studied under various loads, and for each rod and each condi- 
 tion of trial the mean deflection per i-gm. load is found and 
 reported by the student to whom that particular mustration . 
 
 rod is assigned. The results are then grouped Laws of 
 
 Bending, 
 under headings as follows : 
 
 ist Case, rod no. i (i cm. square), supports 100 cm. 
 apart. 
 
 zd Case, rod no. i, supports 50 cm. apart. 
 
 $d Case, rod no. 2 (2 cm. by i cm.) on broad side, supports 
 100 cm. apart. 
 
 tfh Case, rod no. 2 on edge, supports 100 cm. apart. 
 
 The results found for any one case by different members of 
 the class will differ greatly, partly because the various rods differ 
 somewhat in quality and, very slightly, in dimensions, partly 
 because the work of observation is not first-rate, partly because 
 of numerical errors in the computations. Some reports are so 
 wild, from evident misapprehension of the problem, or from 
 gross numerical errors, like misplacement of the decimal point, 
 that they must be rejected ; but it will be seen from the numbers 
 given below that a very liberal standard of admissibility is 
 applied, and that the range of numerical values grouped together 
 is large. Nevertheless, and this is a very instructive lesson to 
 students, general results of considerable accuracy can be worked 
 out from a great mass of individually inaccurate data, provided 
 the inaccuracies are of the accidental sort, so that errors in one 
 direction may, in the general average, be eliminated, or offset, 
 by errors in the opposite direction. 
 
282 DISCOVERY, VERIFICATION, OR INQUIRY 
 
 DEFLECTIONS PER ONE GRAM OF LOAD. 
 
 ist Case. 
 
 2 d Case. 
 
 0.000915 cm. 
 
 800 
 
 O.OOOII5 cm. 
 
 1090 
 
 140 
 
 1090 
 
 140 
 
 957 
 
 129 
 
 1050 
 
 I 3 6 
 
 1010 
 
 I ? c 
 
 884 
 
 103 
 
 895 
 
 120 
 
 920 
 
 1 2O 
 
 951 
 
 124 
 
 914 
 
 IO9 
 
 I22O 
 
 r 35 
 
 870 
 
 1 20 
 
 IO5O 
 
 US 
 
 II5O 
 
 1 60 
 
 950 
 
 147 
 
 II7O 
 
 140 
 
 II4O 
 
 153 
 
 1330 
 
 130 
 
 3d Case. 
 
 4th Case. 
 
 0.000620 cm. 
 
 0.000135 cm. 
 
 434 
 
 109 
 
 725 
 
 I2 3 
 
 700 
 
 I2 3 
 
 587 
 
 130 
 
 418 
 
 III 
 
 465 
 
 125 
 
 47 
 
 116 
 
 463 
 
 120 
 
 445 
 
 120 
 
 597 
 
 143 
 
 502 
 
 I2 9 
 
 505 
 
 1 2O 
 
 520 
 
 I4O 
 
 450 
 
 120 
 
 420 
 
 IO 5 
 
 596 
 
 132 
 
 435 
 
 1 08 
 
 463 
 
 123 
 
 426 
 
 1 1 1 
 
 Mean 0.001018 cm. 0.000130 cm. 0.000512 cm. 0.000122 cm. 
 
 In comparing case i with case 2 we get the effect of doub- 
 ling the length, other things being equal. We see at once that 
 Search for deflection increases with increase of length ; but is 
 the Laws. deflection proportional to length ? Is the rule 
 D oc L ? Evidently not ; the deflection increases in far greater 
 proportion than the length. 
 
 Is the rule D oc L 2 ? This would require the deflection of 
 the ist case to be only four times that of the 2d case, and it 
 is more than that. 
 
 Is the rule D oc L 8 ? This would require the first deflection 
 to be 8 times the second. In fact, it is 7.8 times the 2d. This 
 is very fair agreement, and shows that the formula last written 
 comes pretty near, at least, expressing the experimental facts 
 of the case. That is all we can claim for the testimony, 
 that it points to the law D oc L 3 , which more careful and 
 extensive experiments by others have shown to be very nearly 
 correct. 
 
 A comparison of cases i and 3 shows the effect of doubling 
 
DISCOVERY, VERIFICATION, OR INQUIRY 283 
 
 the width, other things remaining unchanged. The ratio of 
 deflection i to deflection 3 is 1.99, indicating the otherwise 
 known law D oc i / W. 
 
 Comparison of cases i and 4 shows the effect of doubling 
 the thickness, other things remaining unchanged. The ratio 
 of deflection i to deflection 4 is 8.34, which is in tolerable 
 accord with the accepted law D oc i / T 3 . 
 
 Grouping these various proportions into one general formula, 
 and introducing also the already known rule D oc P, where P 
 is the load, we get 
 
 P X L 3 
 
 This derivation of formulas I do not expect the students 
 to carry through by themselves ; for, as a rule, no one student 
 has from his own observations sufficiently reliable data to make 
 the whole discussion satisfactory, and, moreover, the ordinary 
 student could not reasonably be expected to conduct such a 
 discussion without assistance. I put the tabulated individual 
 results on the blackboard, and go through, in a lecture, the 
 course of reasoning indicated by what has just been given. 
 The numbers shown above were reported by twenty members 
 of a class in the year 1900-1901, and were used by me in class 
 substantially as I have used them here. 
 
 The comparison of masses by the acceleration test is another 
 case in which, owing to experimental difficulties, a general 
 aggregation of results is desirable. In this exercise 
 
 two cars, one loaded with iron, the other with lead, lustration of 
 are set in motion by the equal pulls of like tubes of 
 india-rubber, equally stretched, along inclines so adjusted as to 
 neutralize friction. When apparent equality of acceleration 
 has been attained, by varying one or the other load, the cars, 
 each with its contents, are separately weighed. Students work 
 in groups, usually of three, in this undertaking, and record, as 
 their results, the weighings. In 1900-1901 twenty such groups 
 reported the following numbers : 
 
284 DISCOVERY, VERIFICATION, OR INQUIRY 
 
 ist Case. 
 
 2d Case. 
 
 3d Case. 
 
 With Iron. 
 
 With Lead. 
 
 With Iron. 
 
 With Lead. 
 
 With Iron. 
 
 With Lead. 
 
 1460 
 
 1410 
 
 1240 
 
 1255 
 
 IOIO 
 
 1050 
 
 1500 
 
 1490 
 
 1270 
 
 1290 
 
 1040 
 
 1090 
 
 1500 
 
 !590 
 
 1370 
 
 1330 
 
 1160 
 
 1170 
 
 1490 
 
 1450 
 
 1260 
 
 1240 
 
 IO4O 
 
 1030 
 
 1480 
 
 1490 
 
 1260 
 
 1240 
 
 1020 
 
 IOIO 
 
 1540 
 
 1500 
 
 1310 
 
 1240 
 
 1080 
 
 1 100 
 
 1550 
 
 1450 
 
 I 3 20 
 
 1290 
 
 1090 
 
 1090 
 
 1490 
 
 1520 
 
 1 2DO 
 
 1300 
 
 IO4O 
 
 1090 
 
 1460 
 
 1480 
 
 1256 
 
 1270 
 
 IO4O 
 
 1040 
 
 1460 
 
 143 
 
 1240 
 
 1220 
 
 IOIO 
 
 IOIO 
 
 1490 
 
 143 
 
 1270 
 
 1242 
 
 1040 
 
 IO2O 
 
 1530 
 
 1500 
 
 1330 
 
 1340 
 
 1072 
 
 1094 
 
 !54Q 
 1460 
 
 1520 
 1500 
 
 '350 
 1260 
 
 I32O 
 1280 
 
 1080 
 
 1050 
 
 1080 
 
 1030 
 
 !53Q 
 
 1560 
 
 1330 
 
 1340 
 
 1072 
 
 1094 
 
 1500 
 
 1480 
 
 1270 
 
 I3OO 
 
 1030 
 
 1040 
 
 1460 
 
 1490 
 
 J 43 
 1460 
 
 1240 
 1260 
 
 I2IO 
 1280 
 
 IOIO 
 
 1030 
 
 IOIO 
 
 1082 
 
 1480 
 
 1500 
 
 1250 
 
 I24O 
 
 1020 
 
 IO2O 
 
 1498 
 
 1480 
 
 1272 
 
 1292 
 
 1046 
 
 1063 
 
 Mean 1495 S m - 
 
 1483 gm. 
 
 I28ogm 
 
 . 1276 gm. 
 
 1044 gm. 1061 gm. 
 
 Ratio i 
 
 .008 
 
 1.003 
 
 
 0.984 
 
 The mean ratio of " with iron " to " with lead," as found from 
 these numbers, is 0.9997. Of course, there is something of luck 
 in the very close approach of this final ratio to i. 
 
 Similar luck is not evident in the figures given in the next 
 table, which shows the results obtained by ten different groups 
 of students, usually four in a group, from exercises 
 Illustration: 37 an ^ 3$ of the Harvard Descriptive List of Ele- 
 mentary Exercises in Physics. These experiments 
 deal with action and reaction, and undertake to 
 compare, in terms of an arbitrary unit, the total momentum of two 
 balls before collision with their total momentum after collision. 
 
 In case i, the smaller ball strikes the larger at rest; in case 
 2, the larger ball strikes the smaller at rest; in case 3, the two 
 balls meet, each being in motion ; in case 4, the smaller ball, 
 encircled by a belt of putty to make the collision inelastic, is 
 struck, at rest, by the larger ball. 
 
 The momentum of each ball before collision is estimated 
 from its mass and the horizontal distance it has swung, as a 
 
DISCOVERY, VERIFICATION, OR INQUIRY 285 
 
 pendulum, to the collision, which occurs when each ball is in 
 its position of rest. The momentum of each ball after collision 
 is estimated from its mass and the distance it swings after 
 collision. As friction of the air does produce a perceptible 
 effect, even in a single swing, this method of estimation gives 
 a slightly too great numerical value for the momentum of each 
 ball before collision, and a slightly too small value for the 
 momentum of each after collision. This defect plainly shows 
 in the results here put down, which were reported by a class 
 under my instruction in 1900-1901. 
 
 ist Case. 
 
 zd Case. 
 
 3d Case. 
 
 4th Case. 
 
 Momentum. 
 
 Momentum. 
 
 Momentum. 
 
 Momentum. 
 
 Before. 
 
 After. 
 
 Before. 
 
 After. 
 
 Before. 
 
 After. 
 
 Before. 
 
 After. 
 
 1485 
 
 H97 
 
 2799 
 
 3005 
 
 20 5 8 
 
 22O7 
 
 5598 
 
 5378 
 
 1 554 
 
 1558 
 
 2725 
 
 2853 
 
 1948 
 
 1762 
 
 5450 
 
 5069 
 
 1516 
 
 1282 
 
 2447 
 
 2727 
 
 1989 
 
 2015 
 
 5495 
 
 5455 
 
 T 53 
 
 1518 
 
 1826 
 
 1440 
 
 1074 
 
 1180 
 
 3652 
 
 3837 
 
 1569 
 
 1598 
 
 2689 
 
 2637 
 
 1904 
 
 2054 
 
 5378 
 
 5534 
 
 
 1458 
 
 2745 
 
 2626 
 
 1988 
 
 1729 
 
 5490 
 
 594 
 
 1500 
 
 1683 
 
 1800 
 
 1895 
 
 1061 
 
 1129 
 
 3621 
 
 3627 
 
 1449 
 
 1448 
 
 2717 
 
 2512 
 
 1993 
 
 1992 
 
 5435 
 
 5238 
 
 1554 
 
 1558 
 
 2725 
 
 2852 
 
 1948 
 
 1762 
 
 5449 
 
 5069 
 
 1475 
 
 1250 
 
 1921 
 
 1883 
 
 I 201 
 
 III2 
 
 3817 
 
 3706 
 
 Mean 1512 
 
 1485 
 
 2439 
 
 2 343 
 
 I7l6 
 
 1694 
 
 4939 
 
 4803 
 
 Ratio ' i 
 
 .Oil 
 
 1.041 
 
 I.C 
 
 '13 
 
 i 
 
 .028 
 
 The mean ratio is 1.023. The air friction, already mentioned, 
 would go far toward explaining the departure of this ratio from 
 unity. 
 
 A very troublesome exercise, from the point of view of accu- 
 racy of results, is that in which an attempt is made to find the 
 density of air at atmospheric pressure by noting the Density of 
 loss of weight of a large bottle of known capacity Air 
 from which a measured fraction of the air is pumped Experi 
 out, the weighing being done on the familiar platform balance 
 mentioned in Chapter IV. Some teachers maintain that it is 
 not worth while to try to do this experiment, unless a more 
 accurate balance than this one is used ; and I must admit 
 that my students, usually working in pairs in this exercise, get 
 some very wild results from their observations. 
 
286 DISCOVERY, VERIFICATION, OR INQUIRY 
 
 The time allowed for the actual performance of the exercise 
 is about an hour and a half, and in this time each pair of 
 students is expected to go through the experiment three 
 times. Very careful instructions are given as to the use of the 
 balance. 
 
 The following results are obtained from data reported by 
 members of a class working under my supervision in the fall of 
 1901. I have taken twenty consecutive reports from the record- 
 book, passing over only such as were incomplete or were dupli- 
 cates of others taken. The calculations of results I have made 
 myself, as my main object at this moment is to show how good 
 or how bad data students get with the apparatus at their com- 
 mand in this exercise. The capacity of the bottle used was 
 about 190001. cm. in all cases. The barometric pressure was 
 about 76.7. In most cases the pumps took out about 90 per 
 cent of the air. It appears that in most cases the pressure- 
 gauge was read with tolerable accuracy, though there is one 
 case of apparently large error in this operation, so that most 
 of the inaccuracy of the results is to be charged to incorrect 
 weighing. The results are as follows : 
 
 Density of air in the neighbourhood of 20 C. under a pres- 
 sure of about 76.7 cm. of mercury: 
 
 .00125 
 
 [.00047] 
 
 .00129 
 
 .00119 
 
 .00123 
 
 .00117 
 
 [.00059] 
 
 [.00456] 
 
 .00115 
 
 .00102 
 
 .OOI2O 
 
 .00083 
 
 .00140 
 
 [.00174] 
 
 .00084 
 
 .00104 
 
 .00130 
 
 .00115 
 
 .00110 
 
 .00133 
 
 I have bracketed four of these quantities, because I think the 
 badness of these four is not' properly chargeable to the poor 
 performance of the balance. The [.00174] is obtained from 
 data which appear to be affected by a very large pressure-gauge 
 error. The values [.00047] an( ^ [ 000 59] are fr m d ata in 
 which an error of i gm. or more is apparently made in the 
 weighing, and the value [.00456] involves an error of about 
 
DISCOVERY, VERIFICATION, OR INQUIRY 287 
 
 5 gms. Errors of such magnitudes cannot fairly be laid to the 
 balance. They are blunders, such as might be made with a 
 much better balance. The variation among the remaining 
 values is large, but not, in my opinion, so large as to destroy 
 the value of the exercise, which is an instructive one. The 
 bracketed results being omitted, the mean of the values here 
 given is .00116-, which is about 5% low. 
 
 I have intimated that the numbers given in the preceding 
 tables are culled, to some extent, from the reports handed in by 
 students, many reports being so defective as to show p up ii s 
 that the makers have failed to understand the ex- Blunders. 
 periment or have blundered seriously in their calculations. 
 The practice, which I commonly follow, of leaving the class 
 quite uninstructed as to the magnitude of the numerical result 
 to be expected in any case, has this disadvantage, if disadvan- 
 tage it be, that the student frequently does not know, before he 
 hands in his result, whether it is right or absurdly wrong. This 
 leaves the boy free to make all the mathematical errors of which 
 he is capable ; and the number and variety of these which he 
 can put into a simple calculation, especially if it involves a 
 trifle of algebra, is the despair of the teacher, I cannot say 
 the wonder of the teacher, for the phenomenon, remarkable as 
 it is, soon fails to excite surprise. 
 
 I have sometimes supposed myself to be afflicted in a peculiar 
 degree by this kind of shortcoming on the part of my students, 
 who, in that one of my classes which has to do with such work 
 as we have been discussing, are for the most part youths who 
 have entered college with a " condition " in physics ; that is, 
 they are a picked class, selected by this criterion, that they 
 have been unable or unwilling to learn physics in school. But 
 I find upon inquiry that other teachers, not only in this country 
 but in England also, report a similar weakness in their pupils. 
 Mathematical feebleness and fallibility are the birthright of no 
 small part of every class beginning physics. The only question 
 is, what to do about it. 
 
 My own practice, which I do not recommend for schools, is 
 
288 DISCOVERY, VERIFICATION, OR INQUIRY 
 
 to put my students on their own responsibility, and require 
 them to stand or fall by the first report they make on an exer- 
 Repetition of c ^ se< ^ a student wishes to repeat an exercise, or 
 Exercises. repeat a calculation, after finding that his first re- 
 port is unsatisfactory, he is usually permitted to do so, but 
 with the understanding that a good second report is not to 
 be taken at the same value as a good first report ; and repeti- 
 tions under these conditions are rather infrequent. Thus the 
 full measure of his shortcomings is often not realized by a 
 heedless student until the half yearly day of reckoning comes, 
 and then he is likely to be woefully surprised at the fix in 
 which he finds himself. If I were teaching in a school with 
 pupils some years younger, I should no doubt make a prac- 
 tice of requiring them to repeat, and improve on, work badly 
 done. 
 
CHAPTER VII 
 
 THE TECHNIQUE OF LABORATORY MANAGEMENT 
 REFERENCES. 
 
 Eastern Association of Physics Teachers. Report on Methods of In- 
 struction in Physics in Secondary Schools. 1900. 
 
 Strong, E. A. Physics in The High Schools of Michigan. SCHOOL 
 REVIEW. April, 1899. Pp. 242-245. 
 
 Threlfall, R. On Laboratory Arts. London and New York, Mac- 
 millan. 1898. Pp. 338. 
 
 IN the preceding chapter we have discussed the spirit and 
 object of laboratory work. We have now to consider what may 
 be called the technique of laboratory management. 
 
 One of the most important questions to be considered under 
 the heading of this chapter is whether a class should be taken 
 through its laboratory work with an even front, all Report on 
 the members of any laboratory section doing the Methods, 
 same experiment at the same time, or whether a more open and 
 irregular formation of the forces engaged should prevail. On 
 this question the Report on Methods of Instruction, by a Com- 
 mittee of the Eastern Association l of Physics Teachers, issued 
 in 1900, has something to say. 
 
 1 The geographical range of inquiry on which this report is based 
 was much wider than the title of the association would indicate, as the 
 following quotation from the report will show: 
 
 " Responses to this circular were received from one hundred and 
 seventy-nine (179) teachers of physics, representing geographically twenty- 
 five (25) States and territories, besides the District of Columbia." 
 
 Although I shall have occasion to criticise the report in one or two 
 particulars, I regard it as a valuable document, most of its recommenda- 
 tions being, in my opinion, excellent. The very fact of such an inquiry 
 and discussion as this report represents is a most encouraging indication 
 of the zeal and intelligence now common among teachers of physics. A 
 somewhat similar enterprise was conducted some years ago by an asso- 
 ciation of Colorado teachers. 
 
290 LAB OR A TOR Y MANA CEMENT 
 
 Among the propositions set forth by the committee in its 
 introductory circular, sent out for comment and discussion, was 
 the following : " (e) With large divisions, it is economy of time 
 and energy for all the pupils to be at work simultaneously upon 
 the same problem [laboratory exercise] whenever the character 
 of the work will permit.' 7 
 
 After the replies had been received, the committee reported 
 as follows : " Simultaneous work upon the same problem by all 
 
 pupils in the laboratory is not to be recommended 
 Even Front? r r _ __ 7 . 
 
 as a rule. When, however, the laboratory divisions 
 
 are much too large for the teaching force engaged, this seems 
 to be the only practicable plan, although its educational value 
 is questionable, and the great expense caused by the necessary 
 duplication of apparatus would prevent its adoption in many 
 schools, and preclude its application to problems with which 
 costly apparatus must be employed.' 7 
 
 The reasons for this change of position on the part of the 
 committee, so far as they are expressly set forth in the report, 
 are contained in the following passage: "The proposition" 
 (e) " was assented to with much hesitancy by many, although 
 there were some who seemed to think that such an arrange- 
 ment would work well ; in fact, those who have large 
 divisions generally state that this is their usual manner of work- 
 ing. We note a few of the remarks upon this question : ' I 
 think better results may be obtained with the whole class working 
 on the same problem.' 'The character of the work and the 
 difference existing among pupils will never permit its efficient 
 application.' 'Lack of apparatus would forbid in most high 
 schools.' ' This method is a very poor method and should be 
 adopted only as a last resort.' ' Works toward mechanical results 
 in California? ' Too much like " nickeHn-the-slot " work ! ' " 
 
 This statement of reasons seems to me far from conclusive, 
 and I cannot help thinking that the committee was hasty in ad- 
 mitting, as it seems to do, that the simultaneous method is only 
 a last resort for teachers overborne by too large sections. 
 
 Why is the "educational value" of the method "question- 
 
LABORATORY MANAGEMENT 291 
 
 able " ? The essence of the method is, the same sequence of 
 exercises for all pupils and opportunity for convenient, econom- 
 ical and timely discussion of these exercises by Wastefulness 
 the teacher and the class. Do considerations of of Irregular 
 "educational value" require a sequence espe- 
 cially adapted to each pupil? Do they require that the 
 explanations and discussions which should accompany every 
 exercise shall be repeated between the teacher and each single 
 pupil of a squad of fifteen, the limit recommended by the com- 
 mittee for the size of a laboratory division? What is more 
 wasteful of the teacher's time, more cruelly exhausting of his 
 nervous energy, than the constant and needless repetition of 
 oral instructions and explanations? 
 
 The only way, so far as I can see, to avoid such a painful 
 labour where the irregular order of progress prevails, is so to 
 arrange the apparatus that the printed or written directions will 
 be sufficient to guide the pupil in its use, without oral instruc- 
 tion. But this will have a tendency to work the exercises into 
 such forms that the pupil cannot go astray therein, the true 
 " nickel-in-the-slot " method. 
 
 " Lack of apparatus would forbid [the use of the simultaneous 
 method] in most high schools," is one comment. But is this 
 true? In small high schools the reduplication of Reduplication 
 apparatus required by this method is moderate, and of Apparatus, 
 as for the large high schools, according to the committee, 
 " those who have large divisions generally state that this is thejr 
 usual manner of working." That is, the thing declared imprac- 
 ticable is done and done habitually. The outlay of money 
 needed to provide a squad of fifteen with the apparatus for 
 elementary laboratory work in the simultaneous method is not 
 formidable. Any school board which hesitates to make it, and 
 yet throws the burden of laboratory instruction upon the teacher, 
 should read again the "Song of the Shirt." 
 
 It is true that a rigid following of the method in question 
 would 'prevent any one pupil from doing more laboratory work 
 than any other. This might or might not be unfortunate ; but 
 
292 LABORATORY MANAGEMENT 
 
 it is not necessary to be absolutely strict in the practice of 
 this method. It is comparatively easy to devise supplementary 
 Elasticity of exercises for the more rapid workers, to be intro- 
 Method. duced as occasion requires. For example, if one 
 
 boy measures the expansion of brass only, another may measure 
 also the expansion of iron. 
 
 Moreover, it is very good practice for even the best pupil to 
 repeat an experiment, going over it as many times as the 
 length of the laboratory period will permit, watching for varia- 
 tions and studying for improvements in his own work. Finally, 
 there are always numerical problems which may well occupy 
 the attention of the exceptionally rapid worker. 
 
 It must be remembered that the method of irregular progress 
 does not necessarily imply that one pupil will, in the end, have 
 had more opportunity and done more work than his less effi- 
 cient classmate. Adaptation of work to individual capacity is 
 a problem in itself. It can be worked out best, other tilings 
 being equal, by the teacher who has made the best disposition 
 of his other work, and has thereby conserved his own energy 
 and that of his pupils. 
 
 We may next consider what is the proper size of a laboratory 
 
 division. The Committee Report from which I have been 
 
 quoting in this chapter declares that " the number 
 
 51Z6 01 
 
 Laboratory of pupils in a laboratory division should be about 
 ten or twelve, and should not exceed fifteen for one 
 teacher." This recommendation accords well with the opinion 
 which I have long held and frequently expressed. In a large 
 college class, made up to a very considerable extent of young 
 men who have been over the same course of work once before, I 
 have sections of twenty-five or thirty, in charge of a single assist- 
 ant, but I am not entirely satisfied with this arrangement. 
 
 A certain amount of direct personal oversight and criticism, 
 while the exercise is in progress, is needed by most young 
 pupils. As a rule, the teacher should be able to look at the 
 work of every member of the division during every laboratory 
 period. 
 
LABORATORY MANAGEMENT 293 
 
 Should the pupils work singly, though simulta- individual or 
 neously, or in groups, each group having one set Group Work? 
 of apparatus? 
 
 There are some familiar and important experiments which 
 cannot well be done by a single pupil; there are undeniable 
 advantages in serious and honest consultation between members 
 of the class, in the presence of the apparatus. But, on the 
 whole, I believe that co-operation works badly. There is divi- 
 sion of responsibility. One or two members of a group will 
 dominate it. If they happen to be interested and energetic, 
 they will do more than their fair share of the work, leaving the 
 others as spectators ; if they are indifferent and lazy, they will 
 impose on the others careless and inaccurate methods. Group 
 work is, according to my experience, and I am compelled to 
 use it to some extent in one of my classes, worrying to the 
 instructor and rather unsatisfactory to the students. 
 
 I must admit, however, that working in groups of two is the 
 common practice in one of the most successful and satisfactory 
 school laboratories with which I am acquainted. A great deal 
 depends on the spirit which the teacher is able to inspire in 
 his class. 
 
 The period for a laboratory exercise should, by general agree- 
 ment, be twice the length of the ordinary school period, as a 
 rule. There are, however, many experiments such 
 as beginners naturally take, those having to do with Laboratory 
 specific gravity, for example, which can well be Exercise - 
 done in a single school period, if the work is well planned. It 
 is my opinion that, if the whole laboratory course is extended 
 through two years, as it is in many schools, the work of the first 
 year may well be done in single school periods, the more diffi- 
 cult and longer experiments being taken in the second year. 
 
 It was with this possibility in view that the set of experiments 
 given in the Harvard Descriptive List was divided into a First 
 Part and a Second Part. It would be a pity to let the real or 
 supposed impossibility of arranging for double periods prevent 
 the beginning of laboratory work. But for such experiments, 
 
294 LABORATORY MANAGEMENT 
 
 or exercises, as most of those given in the Second Part of the 
 list just mentioned double periods are needed. 
 
 According to the report which has been referred to so often 
 in this chapter, " Both teacher and pupil should be prepared 
 The Teacher's beforehand for the work to be done in the labo- 
 Preparation. ra tory. The kind and extent of this preparation 
 should depend upon the character of the exercise, the manner 
 in which it is to be approached, its relation to other work, 
 etc." This merely needs amplification and illustration. The 
 preparation demanded of the teacher is physical as well as mental. 
 He must know the theory of the experiment and must have 
 such knowledge of its actual operation as can be acquired in 
 no other way than by going through it with such apparatus as 
 the pupil is to use. Unless he has done the experiment many 
 times in this way, he should have done it recently. He should 
 make sure that all the apparatus which will be needed by the 
 class is in good condition and in the right place, not only the 
 large things, but also the little things, not only bottles and spring 
 balances, but also thread for suspending the bottles on the 
 balances. Not only Bunsen burners, and boilers, etc., but large 
 stoppers for the tops of the boilers and perhaps small stoppers 
 to close holes in the large stoppers. 
 
 Unless these small necessaries are thought of in advance and 
 provided, the work of the class is presently suspended, while 
 the instructor trots excitedly about the laboratory, ransacking 
 closets and drawers in a possibly vain attempt to supply the 
 needed article. This wastes time and demoralizes the class. 
 
 Almost equally bad is the habit of shouting tardy explanations 
 and instructions to the section after it has begun work. If the 
 teacher cannot practice foresight, he must not expect his pupils 
 to exercise care. 
 
 When a printed manual, giving detailed directions for labo- 
 ratory work, is used, it is hardly necessary or advisable for the 
 Use of a teacher to go completely through the experiments 
 
 Manual. j^y wa y o f ex ample in the presence of the class, 
 
 nor should he get into the habit of repeating to the class the 
 
LABORATORY MANAGEMENT 295 
 
 directions of the manual ; for such a practice lessens the pupil's 
 feeling of obligation to read the directions carefully and robs 
 him of the discipline which he should get by interpreting these 
 directions for himself. The habit of waiting or asking to be told 
 things that are in plain print before him, is one of the besetting 
 vices of the American youth when he comes to college. 
 
 I have discussed elsewhere (Chapter IV.), at considerable 
 length, the question whether the pupil should be told in ad- 
 
 vance iust what he is expected to find in his ex- 
 
 The Prepa- 
 periments, the exact law, if he is looking for a law, ration of the 
 
 the exact value of the numerical constant, if he is 
 looking for such a constant. In my opinion he should not, 
 as a rule, be so informed. But he should know enough about 
 the proposed pvpprrmprii- tg^enabjE. .Jugi! to get about it 
 promptly, when the arjrmratus is placed at his disposal, and to 
 go through it with a good notion" of what he is driving at. 
 Accordingly, it is well for the teacher to exhibit the apparatus 
 to the class iir^v!ncT*oft:he laboratory work, with veriTbrief 
 remarks concerning its use, it it amTTtTe^printed directions are 
 satisfactory, with more extended comments and directions, if 
 the apparatus or the manual is defective. After such an expo- 
 sition the pupil can read the directions more intelligently than 
 if he had not seen the apparatus, and he should be expected 
 to read them through before beginning the laboratory work. 
 
 During the actual progress of the exercise the 
 teacher should maintain a vigilant oversight and be {JjJ^f 1 * 
 unsparing of helpful criticism, but he should not Meddling. 
 meddle and he should not demand impossibilities. 
 
 Boys working singly, with well-devised apparatus and well- 
 considered methods, will almost always show an excellent spirit 
 in their laboratory manipulations and not infrequently a com- 
 mendable degree of ingenuity. Their zeal, however, does not 
 always inspire them to put away their apparatus when they have 
 done with it. For example, failure to replace their weights in 
 proper holders after use of a balance is one of the minor evils 
 with which a teacher has to deal. The pupil should find his 
 
296 LABORATORY MANAGEMENT 
 
 apparatus in good condition and should leave it in good 
 condition. 
 
 As to the proper character of the pupil's record of his work, 
 Form of * can nar cUy give better advice than by making one 
 
 Record. more quotation from the report now so familiar to 
 
 readers of this chapter : " The pupil should keep a laboratory 
 note-book which should contain a concise statement of : 
 
 (a) Problem to be solved. 
 
 (b) Method of work. 
 
 (c) Apparatus and material used ; and, in many cases, a 
 rough sketch of the arrangement of the apparatus. 
 
 (d) Necessary formulas and computations. 
 
 (e) Observed results, together with such inferences as the 
 pupil may reasonably be expected to make." 
 
 Nothing is here expressly said concerning the observations, 
 which are, presumably, to be recorded in connection with the 
 " Method of work." It will probably be necessary for the 
 teacher at the beginning of the course to prescribe pretty fully 
 the form of observation record ; but the pupils should become 
 accustomed, as the work goes on, to plan their own arrange- 
 ment of the facts to be put down. The effort should be to write 
 what is essential, and only what is essential, and all in such a form 
 as to be easily intelligible to the reader. The pupil should try 
 to make such a record as would be most useful to himself years 
 afterward, if he should have the task of taking a class through 
 the same experiments. This may seem to be asking a good 
 deal of young pupils, and of course they will fall short of per- 
 fection ; but the thing to be impressed on them is that a record 
 should tell a plain tale to people who are not present when the 
 record is made, or who, through lapse of time, have forgotten 
 much of what the record sets forth. 
 
 Of course, if a laboratory manual giving detailed directions 
 for the work is used, it is not necessary or profitable to copy 
 all of these directions into a note-book. An abstract of the 
 method should be given in the pupil's own language or indi- 
 cated by the recorded observations. 
 
LABORATORY MANAGEMENT 
 
 297 
 
 Practice of the graphical method of record, by means of the 
 simplest possible drawings, is of very great service ; for it re- 
 quires the pupil really to study his apparatus, and yet, by 
 saving many words, may save his time as well as that of the 
 reader. 
 
 The following example may illustrate some of the 
 precepts which have now been given : 
 
 Illustration. 
 
 Exercise Feb , , 
 
 STUDY OF THE ZERO-POINT ERROR AND THE 
 BOILING-POINT ERROR OF A CENTI- 
 GRADE THERMOMETER. 
 
 The general method used was the one given in , 
 
 but the boiler used was different from the one shown in the book, 
 
 having a top that screwed on and 
 ing the height of water in the body 
 of the boiler. See Fig. 13. 
 
 The thermometer tested was 
 
 No It had a paper scale 
 
 and was graduated in degrees, the 
 scale extending from 10 below o 
 to 110 above. 
 
 Reading in ice and water (or 
 snow) before heating +0.2. 
 
 Reading in steam, as in Fig. 
 
 13. = 99-7- 
 
 Reading of barometer = 76.5 cm. 
 
 Reading of thermometer in 
 steam as in Fig. 13, but with steam 
 outlet nearly closed, and mercury 
 gauge as in Fig. 14, = 101.1. 
 
 (Real difference of level of the 
 mercury columns about 4.2 cm. ; 
 allowance of o.i cm. made for pres- 
 sure of water, about 1.5 cm., in left- 
 hand side of the gauge.) 
 
 Reading in steam, with steam 
 escape wide open, but with o 
 mark just above top of stopper 
 
 -93.7 . 
 
 Reading in ice and water after 
 heating = 0.1. 
 
 a water-gauge at the side for show 
 
 Fig.13. 
 
298 LABORATORY MANAGEMENT 
 
 Conclusions : The thermometer read about 0.2 too high in ice and 
 water at first, and about 0.1 too low at the last. The reason for this 
 change I do not know, but it appears to have been caused 
 by the heating. 
 
 The thermometer, with bulb and stem in steam, read 
 99.7 when the barometer read 76.5 cm., 0.5 cm. above 
 
 1 standard. According to my observations, a rise of pres- 
 cnl sure equal to 4.1 cm. of mercury caused a rise of 1.4 de- 
 grees in the boiling temperature. This is (1.4-^-4.1) 
 degrees = 0.34 degree, for i cm. According to this, if 
 t* 16 barometer had read 76 cm., instead of 76.5, the ther- 
 mometer would have read about (0.34 X 0.5) degrees, 
 = 0.17 degree, lower than it did ; that is, 99.7 o. 17 = 99.5, nearly. 
 
 Drawing the stem, from 100 to o, out of the steam, while the bulb 
 remained in the steam, lowered the reading about i. 
 
 The next recommendation of the Eastern Association runs 
 as follows : " The laboratory note-book should be written up in 
 
 Time for tne ^ a ^ orator y at tne tmie tne wol "k is done. The 
 Record and writing should be in ink so that the original entry 
 Calculations. cannot ^ Q erased." It is doubtful whether, under 
 the conditions imposed by this rule, the average pupil could 
 be expected to complete such a record and discussion as that 
 just given, unless the time allowed for the whole exercise were 
 more than two consecutive school periods. Could not a part 
 of the work, the writing out of conclusions, be done later and 
 elsewhere? If not, I should fear that the observations would 
 be hurried and unsatisfactory. 
 
 It is, of course, desirable to discuss the observations and de- 
 rive the conclusions as promptly as may be. Promptness saves 
 time and contributes toward good results. But independent 
 thinking, even on so simple a problem as calculating what the 
 thermometer reading would be if the barometer reading were 
 changed a certain amount, the calculation to be on the basis 
 of the pupil's own observation of the effect of increased pres- 
 sure, keeps the ordinary boy thinking for a considerable time, 
 unless he gets very effective help from the teacher or some one 
 else. 
 
 It is, perhaps, the "some one else," the possibly injudicious 
 guide and collaborator, that the Eastern Teachers undertake to 
 
LABORATORY MANAGEMENT 299 
 
 avoid in their prescription that the record and discussion shall 
 be finished at once and in the laboratory. I must admit that 
 there is danger of a great evil from this side, and I do not see 
 how to avoid it altogether without following the strict and diffi- 
 cult rule which they lay down. This danger, however, is not 
 peculiar to physics. It besets all work not done under the eye 
 of the teacher. 
 
 It is true that, in the case of boys applying for admission to 
 college, the college may require the teacher's certificate that 
 the note-book is the candidate's own record of his oversight of 
 own laboratory work, but it is evidently unfair to Note - Book - 
 ask that the teacher shall have seen every word of it written, or 
 shall have made sure that every mental operation represented 
 in it is original with the pupil. That the actual laboratory work 
 and handwriting are the pupil's own, the teacher can reasonably 
 be expected to know and to declare ; and this declaration 
 assures the college examiners that the candidate has at least 
 gone through the motions of using apparatus and keeping 
 a record. This fact raises a sufficient presumption in his 
 favour to justify the examiners in admitting him to their 
 tests. The mere clerical practice of keeping an orderly note- 
 book is valuable and something to be counted in the candi- 
 date's favour. 
 
 If teachers find it readily practicable to live up to the rule 
 given by the Eastern Association, well and good. But I fear 
 that many conscientious teachers have expended in the over- 
 sight of the record an amount of care, and even of anxiety, 
 quite incommensurate with the attention given to it by the 
 college examiners, and quite unnecessary for the proper func- 
 tion of the note-book. 
 
 The practice of making the record in ink from the start, and 
 in such form that it will not have to be rewritten, is an excel- 
 lent one. A copied, or rewritten, record is sure to First Record 
 look better than the original, but it is not the main Should stand, 
 object or virtue of a record to look well. Note-books should 
 not be confounded with copy-books for the practice of penman- 
 
300 LABORATORY MANAGEMENT 
 
 ship. Moreover, the original notes, if made on loose sheets as 
 they frequently are when copying is intended, are very likely to 
 be misplaced and lost. Taking the notes in one book, and then 
 copying them off in fair form into another book, both books 
 being preserved, is a practice which avoids this difficulty ; but it 
 involves labour which is, in my opinion, unnecessary, and, on 
 the whole, unprofitable. 
 
 The habit, which some teachers follow, of encouraging their 
 pupils to make a hasty first trial of an experiment, the record of 
 Tentative which trial is not preserved unless it happens to be 
 Work. satisfactory, seems to me rather objectionable, as it 
 
 may appear to warrant the practice of culling observations and 
 leaving out those which do not accord well with others. 
 
 In a college class, made up largely of students who have 
 failed in physics at the admission examination, I am much less 
 "Data regardful of the note-book than I should be in a 
 
 SUps." school with younger pupils. My practice is to re- 
 
 quire the student to write out and hand in, before he leaves the 
 laboratory, a brief record of his numerical observations in the 
 experiment which he has just performed. These notes he 
 makes on a slip of paper, usually about 3.5 X 4-5 inches, 
 called a data slip, which is soon pasted into a large scrap- 
 book under the student's name, four pages of the book being 
 devoted to his record for the whole course. A similar set of 
 notes, with such amplifications as may be required, usually 
 very few or none, is made by the student in his note-book. 
 
 The laboratory exercise for each student in this course comes 
 once a week, and one week after he performs any experiment 
 
 he is required to hand in the worked-out result or 
 "Result Slips." . . . . . . .. ... 
 
 conclusion from this experiment on a result slip, 
 
 which is presently pasted by one edge into the scrap-book, just 
 over the corresponding data slip, to which it is like in form and 
 size. The result must be such as the data, which the student 
 has had no opportunity to alter while working out his result, 
 will yield. 
 
 By this device, I have at any time during the year a bird's-eye 
 
LABORATORY MANAGEMENT 301 
 
 view of what each student in the course has done in the way of 
 laboratory work. 
 
 The note-book is examined only twice during the year, and, 
 as it is, in considerable part, a duplicate of the scrap-book record, 
 not very much importance is attached to it. I feel, however, 
 that it would be an injury to the students to dispense altogether 
 with the note-book, the keeping of which helps to keep the 
 lessons of the course in their minds. It will be seen that the 
 practice just described involves some copying, but, as the 
 records are usually brief, this is no great hardship. 
 
 As the method of individual laboratory work makes each 
 student's data differ in some particulars from the data of others, 
 the danger of illicit practices in the working out of results is less 
 than one might at first suppose. 
 
 It is my frequent practice to comment briefly, at the first 
 convenient opportunity, on the character of the results yielded 
 by any given exercise, illustrating my remarks, which 
 are addressed to the class as a whole, by examples Laboratory 
 from good or bad reports, and exhibiting such or ' 
 tables as are shown in the preceding chapter of this book. 
 True, it is not best to say much to a class in regard to the 
 mental or moral discipline gained from any study. Young 
 people are proverbially averse to sermonizing, and like to feel 
 an immediate motive for what they do. Yet one of the most 
 important objects of laboratory work, properly conducted, is to 
 show the pupil side by side the poor results of poor work, physi- 
 cal or mental, and the good results of good work. There is a 
 convincing tangibility about the results of definite laboratory 
 problems, which is bound to make an impression. 
 
 Moreover, the fact that a large number of moderately good 
 results contribute to give at last a very good one, positive and 
 negative casual errors eliminating each other in the long run, 
 though certain constant errors remain to be investigated and 
 discussed, this is a truth better taught in the concrete than in 
 the abstract, and certain laboratory exercises are peculiarly well 
 adapted to teach the lesson. 
 
302 LABOR A TOR Y MAN A GEMENT 
 
 In some exercises, which relate to the properties of individual 
 objects, the specific gravity of wooden blocks, for example, or 
 Teacher's ^ ie * ca ^ ^ en tn f lenses, the different members of 
 Record of a class, each having his particular object to work 
 with, may correctly get different results. In such 
 cases, the teacher should mark each of the objects studied and 
 make such a record of its properties that he can readily tell 
 whether any pupil, studying a given object, has or has not done 
 his work well. Some little business ability is needed to make 
 and keep such a record with sufficient accuracy and without an 
 unreasonable amount of labour and worry. But, if it is well 
 planned and vigorously kept up, it will amply repay what it 
 costs. 
 
 The obvious fact is that the pupil has a right to know, and 
 that not so very long after the exercise is finished, whether he 
 has or has not done well in any particular task. Without such 
 an assurance he may be unduly discouraged or unduly confi- 
 dent. This being the case, there is no more distressing job for 
 the teacher than that of trying, without an adequate knowledge 
 of the facts, to pass judgment on work done. 
 
 It is plain enough that the business of teaching physics by 
 the laboratory method imposes on some one a large amount of 
 Economy of P ure ty mechanical labour in the preparation and 
 Teacher's care of apparatus, to say nothing of its manufacture. 
 It is the duty of the teacher, who needs, of course, 
 to be continually in a state of mental activity and alertness, to 
 save himself all unnecessary physical labour, unless he happens 
 to be so constituted as to enjoy it. 
 
 As a rule, the teacher should not be expected to make appa- 
 ratus which he can find ready made to his liking ; for he is, pre- 
 Relief from sumably, the mental superior and the mechanical 
 Manual Labour, inferior of the workman employed by the manufac- 
 turer. Even in the handling of the apparatus after it is in the 
 laboratory, there is much purely physical routine labour which a 
 person who can hardly read and write, who is at any rate less 
 highly trained and paid than the teacher, can do quite well 
 
LA BORA TOR Y MA NA CEMENT 303 
 
 enough. Such is the work of setting out, putting away, and 
 cleaning apparatus, and doing errands and odd jobs of various 
 sorts. The most satisfactory person for this kind of service is 
 one who is entirely satisfied with it, takes pride in it, asks 
 nothing better than to do it, for reasonable pay, all his life. I 
 have known a number of such men, all Irish as it has happened, 
 and could ask for no better service than they have habitually 
 given, after, of course, some painstaking initial training. 
 
 But I am aware that such assistants are not usually to be had 
 by school-teachers of physics. \ Such teachers, within my ac- 
 quaintance, make excellent use of pupil assistants, or of 'pren- 
 tice teachers who are willing to work for little pay for a year or 
 two in the hope of acquiring valuable methods and experience. 
 Sometimes these assistants are young women. 
 
 The importance of having some orderly and natural arrange- 
 ment of apparatus for the moment not in use, instead of a mere 
 haphazard distribution which only one person can Arrangement 
 remember and which no one can explain, is too of Apparatus 
 obvious to need discussion. There is much in favour of arranging 
 apparatus, as nearly as may be, in the order of its use during the 
 year. This facilitates not only the parading and retirement of 
 apparatus for use, but also its survey with regard to future needs. 
 The assistant should be taught to look weeks, or even months, 
 ahead and give early notice of any lack, in order that the worry 
 and expense of hasty provision at the last may be avoided. 
 
 Detailed suggestions for the arrangement and equipment of a 
 laboratory will be given in Chapter XII. 
 
CHAPTER VIII 
 
 LECTURES AND RECITATIONS 
 
 REFERENCES. 
 
 Day, R. E. Numerical Examples in Heat. London and New York, 
 Longmans, Green & Co. 1889. Pp. 176. Gives the answers. 
 
 Dolbear, A. E. The Art of Projection. Boston, Lee & Shepard. 
 1892. Pp. 178. 
 
 Jones, D. E. Examples in Physics. London and New York, Mac- 
 millan. 1900. Pp. 348. 
 
 Matthews, C. P. and Shearer, J. Problems and Questions in Physics. 
 London and New York, Macmillan. 1897. Pp. 247. 
 
 Pierce, E. D. Problems in Elementary Physics. New York, Henry 
 Holt & Co. 1896. Pp. 194. 
 
 Snyder, W. H. and Palmer, I. O. One Thousand Problems in Phy- 
 sics. Boston, Ginn & Co. 1900. Pp. 142. Gives copies of Harvard 
 admission papers in physics. 
 
 "Wright, L. Optical Projection. London and New York, Longmans, 
 Green & Co. 1901. Pp. 438. 
 
 THERE is no aspect of laboratory work more striking than 
 the poor results which it, when standing alone, yields in written 
 examinations containing problems and illustrations not explicitly 
 occurring in the laboratory. 
 
 The pupil who is dull or lazy at mathematics is very apt to feel 
 that the mere mechanical performance of the experiments set 
 Laborat before him should, by any reasonable measure and 
 
 Work not appreciation of human effort, be enough to save 
 him. He " has been there every time," has even 
 perhaps, " handed in all of the results," right or wrong. Is it 
 not, then, cruel injustice to find him wanting at the last, 
 merely because he " could n't remember all those formulas and 
 things," relating to specific gravity, fluid pressure, levers, the 
 parallelogram of forces, etc. The fact is, that most boys are 
 
LECTURES AND RECITATIONS 305 
 
 more inclined to work hard with their hands than with their 
 Heads, more willing to handle apparatus than to draw any 
 mental results from their activity. Even older persons have 
 been known to lack the resolution and the intelligence to 
 read all the lessons their own experience has written. Old 
 or young, those who do not need urging and guidance are 
 exceptional. 
 
 The laboratory method is a good method, so far as it goes. 
 For most pupils it is essential to a firm understanding, a clear 
 vision, a just perspective. Experience of the senses is the 
 solid ground from which the highest flights of speculation and 
 theory in science begin, and to which they must return, with 
 or without safety to the voyager. But learning by experience 
 is a plodding method, and the student who aspires to any great 
 height or breadth of intellectual reach must not confine him- 
 self to it. 
 
 There are several more or less distinct functions which lec- 
 tures and recitations, in connection with laboratory work, can 
 perform ; the introductory explanation of the labo- j^^^ of 
 ratory exercises, the derivation and discussion of Lectures and 
 immediate results from these exercises, the applica- Recitations - 
 tion of these results to problems not given for solution by trial 
 in the laboratory, the introduction of facts and principles not 
 touched by the laboratory work, the discussion of physical 
 phenomena in general. For each of these several purposes 
 the methods of continuous discourse by the teacher, of inter- 
 change of question and answer between teacher and pupils, 
 of lecture-table experimentation, will naturally be used in 
 turn. 
 
 It is quite impossible to assign to each of these methods its 
 exact relative value, or to state the proportions in which it 
 should be mixed with the others. The teacher perhaps feels 
 surest that he is interesting his class when he is showing 
 experiments, surest that he is getting it ready for an examina- 
 tion when he is conducting or enduring a sort of cross-exam- 
 ination, or "quiz," surest that he is giving a comprehensive 
 
306 LECTURES AND RECITATIONS 
 
 view of the field before him, or, rather, setting forth such a 
 view for those to take who can, when he is speaking at length 
 and without interruption. 
 
 Interest is almost as essential to the boy in the classroom as 
 to the horse at the watering-trough, and therefore experiments, 
 or at least some form of stimulus other than that yielded by 
 the pupil's bare sense of duty, must be supplied, when the 
 exercise would otherwise be one of unbroken discourse by the 
 teacher. Which of us does not feel a little wearied at the 
 end of an hour's talk by the most esteemed philosopher? 
 Young pupils must not be expected to maintain a continuous 
 mental flight for more than a few minutes at a time. But this 
 warning is probably unnecessary. Few teachers in schools 
 have time to construct set lectures which they would be will- 
 ing to deliver to their pupils. 
 
 On the other hand, the preparation of experiments which 
 can be depended upon to come off at the right time, and with 
 the right effect, is a serious undertaking, if it is to be a frequent 
 one. The tendency is, therefore, I suspect, for the teacher 
 to use very largely, and sometimes to abuse, the recitation 
 or " quiz " method of keeping his class occupied. I use this 
 last phrase advisedly ; for the necessity, imposed by the school 
 programme, of keeping a class for the whole of a certain time 
 in a recitation-room, because it would disturb other classes to 
 dismiss this one before the stroke of the bell, must often lead 
 to expedients, more or less conscious, for killing time. 
 
 For this purpose there is no device more convenient or more 
 serviceable than to ask questions, especially questions which 
 Abuse of the tne pupils cannot answer with readiness, sometimes 
 "Quiz." questions which are purposely obscure, and so 
 
 keep up a kind of game of mystification till the hour is over. 
 As an example, let the following serve, a by no means wholly 
 imaginary conversation between an excellent but overworked 
 teacher of science, of all the sciences, and his class in physiology, 
 the subject being the nervous system, and the especial topic, 
 the sensations of a person who has lost a limb : 
 
LECTURES AND RECITATIONS 307 
 
 Teacher. " Now I have heard that sometimes a man whose 
 leg has been cut off will complain of feeling a pain in the toes 
 of the foot that he has lost ; he will perhaps feel as if his toes 
 were cramped, and he will ask some one to go and get the leg 
 and do what? " No answer from the class. 
 
 Teacher. " Come now, children, come, speak up do what ? 
 What do you suppose he wants them to do with the leg? " 
 
 Pupil. " Bury it." 
 
 Teacher. " No, it 's buried already, we will suppose." 
 
 Another pupil. " Burn it." 
 
 Teacher. " Oh, no ! Come, come, children, what does he 
 want them to do with the leg?" 
 
 Class is silent. 
 
 Teacher, as the bell rings, " Straighten out the toes" 
 
 The teacher of physics is fortunate above the teachers of 
 most other subjects in having always the legitimate and most 
 salutary resource of numerical problems, to be Numerical 
 worked out on the spot, and to be discussed proWems - 
 immediately, in the presence of all the class, as soon as they 
 have been done, rightly or wrongly, by a considerable number. 
 Of course this kind of exercise can be overdone, and can be 
 mismanaged otherwise. It is usually necessary to repress one 
 or two bright pupils, who will do the work more quickly than 
 others, and whose superiority in this particular, if not judi- 
 ciously ignored, will discourage and bring to a standstill the rest 
 of the class. Moreover, the problems to be given should be 
 selected with care. They should be representative, putting 
 into application some important fact or principle, theoretically 
 rather simple and numerically brief. Fortunately, there are 
 good printed collections of problems suitable for the use of 
 beginners in physics, books for which we cannot too gratefully 
 thank the painstaking and public-spirited makers. 
 
 As to the need of careful preparation for lectures and for 
 lecture-table experiments, there is little call for ex- preparation 
 hortation. Nearly every one has felt or has seen for Lectures, 
 the melancholy results of the lack of such preparation. But 
 
308 LECTURES AND RECITATIONS 
 
 something of possible use may be said in regard to the way in 
 which the teacher can best expend his effort. 
 
 In the first place he should consider whether the thing which 
 he proposes is important, and in the next place whether it will 
 produce on the pupil an effect which will justify the labour 
 necessary to prepare and present it. 
 
 The teacher sometimes undertakes an experiment without 
 fully realizing its difficulties or the imperfection of the apparatus 
 furnished for its performance, and, having ill success in his first 
 trials, becomes roused to an obstinate effort to make that par- 
 ticular thing work. Such an experience may do no especial 
 harm, may even be, in a way, profitable, if it occurs in a period 
 of leisure when there is time to make experiments, and time to 
 make mistakes ; but if it comes shortly before the lecture-hour, 
 it may be disastrous ; for men of a certain temperament, when 
 once involved in struggle with difficulties, can think of nothing 
 else for the time being, and if they do come tardily to the 
 conclusion to leave the struggle for a more convenient season, 
 they do so with a sense of defeat that unnerves them for the 
 prompt and confident doing of things that are commonly quite 
 within their powers. Those who have this peculiar form of 
 obstinacy, which may be a source of strength under some 
 conditions, must on unimportant occasions beware of the under- 
 tow of their own disposition and keep well above it. 
 
 In the way of lecture-table experiments it is not necessarily 
 the laborious achievement that counts. The little, simple, 
 What Expert- eas ^Y performed, easily seen, but striking, exhibi- 
 mentsare tions of phenomena and illustrations of principle, 
 happily introduced and well executed, are the most 
 profitable things to show, such, for example, as curious hydro- 
 static effects, various aspects of surface tension, experiments with 
 static electricity, etc. 
 
 There are, of course, many desirable experiments which re- 
 quire considerable care at every annual repetition. For exam- 
 ple, although I have written out and printed careful directions 
 for the preparation and use of apparatus for the sudden 
 
LECTURES AND RECITATIONS 309 
 
 freezing of water, I could not now undertake to make this 
 preparation in half an hour with confidence of success. The 
 method is to boil distilled water for several minutes in a test- 
 tube, then pour oil on its surface, etc. But there is apparently 
 a difference in the adaptability of test-tubes for this use. In 
 some of them the condition of bumpy boiling does not occur, 
 even after ebullition has been maintained for several minutes, 
 and I never feel much hope that sudden freezing will occur 
 where "bumping" has not occurred. For safety, I make 
 ready a number of tubes, three or four, set them all to 
 cool in ice-water, and finally, in the presence of the class, try 
 one after another in the freezing mixture till one has proved a 
 success or till all have proved failures. Similarly, in making 
 preparation for the freezing of water during its own boiling, 
 over sulphuric acid and under the bell-jar of an air-pump, 
 much care is necessary. The pump must be in such con- 
 dition that it will lower the mercury gauge nearly to 0.45 cm., 
 and a pump which is subject to much and varied uses is not 
 always in this state of effectiveness. 
 
 Whenever a teacher finds that an experiment works well, 
 subjectively and objectively, in itself and on the class, he should 
 leave the apparatus for this experiment in the most LookFor- 
 secure and convenient condition for use the next ward a Year, 
 year, and should make, if possible, such brief notes in regard to 
 its use as will make all further tentative experimentation with it 
 unnecessary. 
 
 As a rule, all experiments, whether simple or otherwise, 
 should be tried anew before each exhibition of them ; there are 
 
 so many ways in which they can go wrong. Annual 
 
 ... ... Practice. 
 
 practice m the art of picking up bits of paper by 
 
 means of an electrified rod of gutta-percha might seem unnec- 
 essary care; but I consider it worth while. Sometimes the 
 paper does not come up. 
 
 Even when an experiment is perfectly successful for the 
 near-by observer, it is necessary to consider whether it will be 
 apparent to a whole class in a large room. For example, the 
 
310 LECTURES AND RECITATIONS 
 
 indications of a gold-leaf electroscope are very likely to be in- 
 visible at a comparatively short distance, because of the light of 
 windows reflected from the surface of the glass. Shading the 
 windows, lighting the electrometer by means of a lamp screened 
 from the spectators, and using white paper behind the instru- 
 ment, makes a great improvement. 
 
 For lecture-table experiments with electric currents a galvan- 
 ometer with vertical index, attached to a needle free to move 
 in a vertical plane, is extremely useful. Fortunately, 
 Gaivano- such instruments are now common in the apparatus 
 market. 
 
 For the exhibition of weaker currents, requiring the use of 
 an astatic galvanometer with a mirror, I have found the device 
 illustrated by the following figures very satisfactory. In Fig. 15 
 (p. 311), / is a powerful spiral incandescent lamp (or a Wels- 
 bach burner), within an opaque vertical cylinder, E, pierced by 
 a small orifice, o, through which light goes to the plane galvan- 
 ometer mirror, m, through the converging lens, c. After reflection 
 from m, the light passes through the plane glass, g, to a second 
 plane mirror,/, which is held by an adjusting screw, a, Fig. 16, 
 passing through the fixed incline, /, at such an angle as to send 
 the light to the scale, s, which is placed some feet above the 
 galvanometer and is inclined about 45 from the vertical. The 
 various distances are such that an image of o is formed on this 
 screen, and this image can easily be seen by a large class in a 
 room but little darkened. The envelope E, in which the lamp 
 is placed, should be open at top and bottom, to escape over- 
 heating, but above the top there should be a non-reflecting 
 metal screen to absorb the light which, if not arrested, would 
 reach the scale on which the image of o is shown. 
 
 The especial merit of this arrangement of lamp, lens, mirrors, 
 etc., is that it places the scale directly before the spectators, 
 while leaving the space in front of the galvanometer clear for 
 the operations of the lecturer. 
 
 The use of the projecting lantern is now so common, and is 
 so fully described by the publications of the manufacturers, that 
 
LECTURES AND RECITATIONS 
 
 I shall not dwell upon it. " Slides " sufficiently good for cer- 
 tain purposes, tlie exhibition of rough diagrams, for example, 
 can be made without the use of photography by projecting 
 merely scratching the needful lines through the film 
 
 Fig.J6. 
 
 of an ordinary photographic plate. For extended use of the 
 lantern the usual arrangement of putting it in the rear of the 
 lecture-room, the screen hanging behind the lecture-table, is 
 probably the best ; but when its use is a mere incident in a 
 
312 LECTURES AND RECITATIONS 
 
 lecture, it is more convenient for the lecturer, who will probably 
 manage the lantern himself, to have it on the lecture-table, the 
 screen being at one side of the room. 
 
 An interesting and useful device, not new but perhaps un- 
 familiar to most people, has for its object the projection of the 
 image of any flat object of suitable size in its natural colours. 
 For example, a picture on the page of a book is illuminated 
 obliquely by means of the condensing lens of the lantern, and 
 the projecting lens of the lantern, detached from its usual posi- 
 tion, is used to throw the image of the picture on the screen. 
 Partitions should be used to prevent the escape of too much of 
 the light laterally. 
 
 Opaque roll window-shades, intended for thoroughly darken- 
 ing a room, are troublesome unless carefully made, with the 
 Window- edges projecting a considerable distance, two inches 
 Shades. i e t us saVj ]f th e windows are large, into the win- 
 
 dow casing on each side. Without this precaution, the shades 
 are likely to bulge inward during a high wind and draw their 
 edges from cover. Such shades should be made to pull down, 
 like ordinary shades, not up, lest the wear and tear on the work- 
 ing cords be too great. If the room is to be darkened but infre- 
 quently, light, portable, wooden frames covered with oil-cloth, 
 held in place within or against the window casings by any simple 
 fastening, serve well enough. 
 
 As a rule, qualitative experiments are given to better advan- 
 tage in the lecture-room, as quantitative experiments are given 
 Qualitative to better advantage in the laboratory ; for the for- 
 Experiments. mer nave generally a spectacular aspect, often suffi- 
 ciently revealed in a glance at the critical moment, and as easily 
 shown to many spectators as to one, while the latter are more 
 frequently painstaking, prolonged, and comparatively unevent- 
 ful, requiring also close observation at short range, which can- 
 not be given by the whole class at once. 
 
 I used to give as a laboratory exercise a study of the phe- 
 nomena occurring in the heating and boiling of water, and had 
 contrived for this purpose a small-scale piece of apparatus, which 
 
LECTURES AND RECITATIC 
 
 313 
 
 could easily be furnished to each member of a laboratory sec- 
 tion. But after some years of trial I came to the conclusion 
 that I had better point out the significant features of the pro- 
 cess to a whole class at once than to each member of the class 
 in turn. Accordingly, I now show the experiment, on a com- 
 paratively large scale, in the lecture-room. 
 
 Similarly, I used to have each student or each pair of students 
 go through certain experiments with a pressure-gauge in water, 
 to illustrate or discover the facts that pressure increases with 
 depth, is independent of direction, etc. Now I do not insist 
 upon this, but show these experiments to groups of students or 
 to a whole class at once. A little contrivance adapts them to 
 the projecting lantern, the index of the gauge being shown on 
 the screen, while the vessel containing the water is in direct 
 view of the spectators. This requires the gauge to be fixed at 
 a certain height and the water in which it is submerged to be 
 moved up and down. 
 
 It is well, after showing important 1 experiments like this to a 
 class, to leave the apparatus at the disposal of students, who, in 
 the laboratory, may wish to examine it at short range or to use 
 it for themselves. 
 
 1 I think that I should in some place, here 
 as well as elsewhere, object to that device, still 
 to be seen even in new books, which undertakes 
 to prove the equality of vertical and horizontal 
 pressure at a given depth in water by showing 
 that the water produces the same effect on a 
 vertical mercury column when admitted to the 
 top of it through a horizontal tube, as when ad- 
 mitted through a vertical tube. See a and b of 
 Fig. 17. This experiment shows that the verti- 
 cal pressure at a in the one tube is equal to 
 the vertical pressure at 6, on the same level, 
 in the other tube ; but to say that the vertical 
 pressure at b must be the same as the horizon- 
 tal pressure at the open end of the horizontal 
 part of the tube, is to beg the whole question 
 at issue. 
 
 j 
 
 r 
 
 Fig,17. 
 
314 LECTURES AND RECITATIONS 
 
 It is obvious that certain matters must be treated by lecture 
 and recitation methods, if at all, for the reason that they cannot 
 Applications be brought into the laboratory and put at the dis- 
 of Physics. posal of individual pupils. Such are large-scale sys- 
 tems of heating, ventilation, drainage, lighting, transmission of 
 power, etc. These should be presented by the aid of diagrams 
 and verbal explanations, to be followed, if this is practicable 
 under good conditions, by visits to the apparatus itself in 
 position and operation. 
 
 It is a question how much instruction on such topics should 
 be undertaken, and this question must be answered with some 
 reference to the local conditions and the general character of 
 the school. It is reasonable that all boys, at least, should 
 acquire a good general understanding of ordinary domestic 
 scientific appliances, and, in their simpler forms, of the steam- 
 engine, telegraph, telephone, dynamo, and motor; but it is 
 easily possible to go too far into details. I can give no better 
 criterion for deciding what things to take and what things to 
 leave untouched, than that which is furnished by the interest and 
 probable future needs, viewed broadly, of the ordinary pupil. 
 (See Chapter X.) 
 
 The immediate aim, though not the sole object, of instruc- 
 tion in physics should be to give the power and the habit of 
 using physical knowledge. It should, therefore, on the side 
 of illustrations and applications, be suggestive and directive 
 rather than exhaustive. The pupil should be encouraged to 
 see and think about physical phenomena and physical devices 
 which are outside the classroom ; but the teacher should not 
 be expected to bring all such things to his attention and make 
 him understand them. 
 
 In the way of practical applications of theory, as well as of 
 theory itself, most general text-books of physics contain more, 
 and should contain more, than the ordinary class can be ex- 
 pected to master while in school. The teacher should not be 
 afraid to use his own best judgment, and omit what he feels to 
 be impracticable or comparatively useless. I never find a 
 
LECTURES AND RECITATIONS 315 
 
 general text-book of which I can require a class to take every 
 page. The fact is, of course, that the author has in mind a 
 greater variety of readers than is found in any one class, and it 
 is generally easier for the teacher to skip an unnecessary page 
 than to supply a missing one. 
 
 Although in this chapter I have expressly taken it for granted 
 that the teacher will see the need of thorough preparation for 
 what he is to say and what he is to do in the lecture- care for 
 room, it may be worth while to remark that such Form - 
 preparation will include not merely the parts which are to make 
 up the teacher's performance, but the performance as a whole. 
 The teacher must consider not only what to say and what to 
 do, but when, in what order, each thing is to come. He must 
 think, too, not only of logical sequence, but also of the state of 
 mind and body of his class, following no single line of thought 
 too long, presenting no especially difficult matter when the 
 class is tired. 
 
 Physics is, at the best, hard for most minds, young or older ; 
 and if the teacher is blessed with the gift, or can by pains acquire 
 the power, of presenting his subject in an attractive way, of 
 making his teaching artistic in form as well as sound in sub- 
 stance, he will win not only the respect of his pupils but, what 
 is perhaps to both sides more stimulating, their admiration. 
 
CHAPTER IX 
 
 PHYSICS IN PRIMARY AND GRAMMAR SCHOOLS 
 
 REFERENCES. 
 
 Bailey, J. H. Inductive Physical Science. Boston, D. C. Heath & 
 Co. 1896. Pp. 105. Qualitative work. 
 
 Cooley, L. R. C. Easy Experiments in Physical Science. New York, 
 American Book Co. Pp. 85. Qualitative work. 
 
 Gifford, J. B. Elementary Lessons in Physics. Boston, Thompson, 
 Brown & Co. 1894. Pp. 161. Largely qualitative. 
 
 Gregory, R. A. and Simmons, A. T. Elementary Physics and Chem- 
 istry, First Stage. 1899. ^P- I 5- Elementary Physics and Chemistry, 
 Second Stage. 1900. Pp. 140. London and New York, Macmillan. 
 
 Harrington, C. L. Physics for Grammar Schools. American Book 
 Co. 1897. Pp. 123. Largely qualitative. 
 
 Jackman, W. S. Nature Study for Grammar Grades. New York, 
 Macmillan. 1898. Pp. 407. A book of suggested experiments (for 
 teacher or pupil) and questions. 
 
 Loewy, B. A Graduated Course of Natural Science. Parts I. and 
 II. London and New York, Macmillan & Co. 
 
 I AM quite in sympathy with the not uncommon practice of 
 giving a little, a very little, physics of a descriptive and illus- 
 " Nature trative kind to young children as a part of what is 
 study." often called " nature study." But as I have never 
 
 taught physics to such children in any systematic way, and am 
 not even widely read in the literature of " object lessons," it be- 
 comes me to speak with caution in regard to such teaching. I 
 shall venture the suggestion, however, that some of the books in 
 which these lessons are set forth make too little appeal to the 
 experience and the imagination of the pupils. 
 
 For example, from an English book which has much to be 
 commended of instruction in regard to common things, I take 
 the following passages, which certainly explain themselves : 
 
PRIMARY AND GRAMMAR SCHOOLS 317 
 
 " Have this stone, this block of wood, and this piece of iron 
 any shape of their own ? Yes. they have, and we cannot alter 
 the shape of either of them. Let one of the boys take the 
 block of wood in his hand, and another the piece of iron, and 
 try to squeeze them into any other shape. He cannot alter 
 the shape of either the wood or the iron with all his pressing." 
 
 " Let another boy try with the stone." 
 
 " Now put the stone, or the wood, or the iron into a basin, a 
 tumbler, or some such vessel, and let the class see for themselves 
 that these substances do not take the shape of the vessel in 
 which they are placed." 
 
 I find it difficult to believe that children old enough to go to 
 school would need to make or to see any of the experiments 
 here described, in order to reach the desired con- f 
 
 Cflild s 
 
 elusion ; and it is bad practice to ignore the vast Experimental 
 
 , , , . , . ., i Knowledge. 
 
 amount of knowledge which comes to every child 
 
 by mere virtue of his living and having his five senses, 
 knowledge which becomes a part of him, is blended with his 
 natal instincts, long before he can read and write. 
 
 No small part of the difficulty which young pupils often meet 
 in the study of physics is difficulty with words, due, often, 
 to lack of simplicity or lack of precision in the Ian- ^ . 
 guage of the book or the teacher. For example, with 
 what pupil is ever confused as to the fact of " im- 
 penetrability," and what pupil is not confused by the word? I 
 was once asked by a grammar-school teacher what I thought of 
 a certain text-book of physics which he was using. I replied 
 that it seemed to me to dwell too much on words and defini- 
 tions. But the teacher said that it was necessary to make a good 
 deal of effort to get down to the comprehension of his pupils. 
 For example, he had lately spent many minutes in trying to get 
 his class to understand the book definition of uniform velocity, 
 which ran somewhat as follows : Uniform velocity is such a rate 
 of motion that equal distances are traversed in equal successive 
 intervals of time. I then suggested that the idea of uniform 
 velocity could be given with perfect clearness in a very short 
 
318 PRIMARY AND GRAMMAR SCHOOLS 
 
 time by means of an illustration, and that the analysis and mas- 
 tery of such a definition as he had been using, though it might 
 be highly profitable to the pupils as an exercise in language, 
 was not the study of physics. This the teacher admitted, but 
 he held that such language lessons are a legitimate use of the 
 time assigned to physics in a grammar school. 
 
 This teacher's view may be right, but let us, at least, locate 
 the difficulty properly, and not condemn the study of physics 
 as too hard for grammar schools, merely because many of its 
 simpler truths are often, unnecessarily, expressed too abstrusely. 
 Why could we not say, Uniform velocity is velocity that is 
 unchanging, neither growing greater nor growing less 1 
 
 The habit of overlaboured expression, on which I have been 
 commenting, is often the result of a commendable desire to 
 LackofPre- escape a still worse fault, the habit of indefinite- 
 cision. ness, lack of precision of speech and meaning. I 
 
 have known a class to spend nearly an hour on an elementary 
 exercise, leading up to the hydrostatic press, without any 
 general understanding as to whether the word size, as used 
 with regard to the tubes employed in the experiment, meant 
 diameter or area of cross-section. 
 
 An interesting and important question is, whether the study 
 of physics by young pupils should be mainly qualitative or 
 Qualitative or mainly quantitative, that is, whether it should be 
 Quantitative? devoted mainly to the development and illustra- 
 tion of important phenomena, or mainly to the study of 
 numerical laws relating to such phenomena. In my opinion, 
 the little physics taught in primary schools or in the lower 
 grades of grammar schools, should be mostly or wholly of 
 the lecture-table sort, and qualitative. But as soon as the 
 formal study is begun, with laboratory work by the pupils, I 
 am clear that the work should be, I had almost said must 
 be, chiefly quantitative. It is so difficult to design a course 
 of laboratory experiments which will lead the pupil to dis- 
 cover or observe, in any general way, phenomena not pre- 
 viously known to him, so difficult, therefore, to prevent 
 
PRIMARY AND GRAMMAR SCHOOLS 319 
 
 qualitative laboratory work from becoming a farce and a bore, 
 in which the wearied teacher points out to each pupil the 
 thing which the latter is supposed to discover, that I have 
 long considered the undertaking unprofitable. Of course it 
 is easy to write out a long list of questions, most excellent 
 if the pupil could find the answers to them, leaving it for the 
 teacher to make the apparatus and devise all details ; but how 
 much is really accomplished by such imposing suggestions ? 
 
 It is true that writers of great ingenuity have undertaken to 
 lay out practical courses of qualitative work, and that some 
 teachers of great zeal are following more or less closely the 
 courses which they have described ; but I get from their work, 
 so far as I am familiar with it, at times the impression of 
 tremendous "inductive" feats, surpassing the intuitions of 
 Newton, and at others the impression of an effort rather to 
 occupy the pupil as long as possible with certain simple pieces 
 of apparatus than to teach him as much as possible in a given 
 time. The latter practice reminds one of a box of puzzle 
 blocks with a chart of the figures which, with sufficient ingenu- 
 ity and time, can be constructed from them. Puzzle blocks 
 are very good indeed in their way, and I am far from asserting 
 that the kind of laboratory work which I have compared to 
 their use is profitless. It does, no doubt, give some manipu- 
 lative skill, and it gives some practice in keeping a record of 
 observations, but, as a means of getting forward with the study 
 of physics, I believe that it can be greatly improved upon. 
 
 The practice of dwelling unnecessarily long on things familiar 
 and essentially simple, of discussing them at great length and 
 laboriously writing out observations upon them, is Too Slow 
 a vicious one ; for it inculcates a habit of potter- ^ogress. 
 ing, and is quite as likely to result in confusion of ideas as in 
 lucidity. The fact that a pupil cannot give a clear account of 
 some particular fact or law is no sure proof that he has not 
 spent too much time on it. It is possible to gaze at one's 
 own name until it looks unfamiliar and weird. 
 
 Movement, a certain sense of progress, is essential to the 
 
320 PRIMARY AND GRAMMAR SCHOOLS 
 
 best working of the pupil's mind, which, like a bicycle, simply 
 lies down if it is kept too long in one spot. It is better to 
 maintain this progress, even with the certainty that some things 
 will be passed by unseen, and that many of the things seen 
 will be forgotten, than to lose headway and the alertness which 
 goes with it. Many repetitions are necessary for the mastery 
 of certain truths ; but these repetitions should not all come at 
 one stretch. An occasional brief return to the difficult point, 
 when the mind is fresh, is better in many cases than the 
 attempt to level every obstacle and clear up every doubt at 
 the first progress. 
 
 Quantitative Laboratory Work in Grammar Schools. 
 
 For eight or nine years now the grammar schools of Cam- 
 bridge, Massachusetts, have maintained a course of quantita- 
 Exercises ^ ve laboratory work for pupils of the ninth grade, 
 Taken. averaging perhaps fourteen years of age. The titles 
 
 of the exercises in this course are, for the most part, such as 
 are to be found in the First Part of the Harvard Descriptive 
 List or the corresponding list of the National Educational 
 Association (see Chapter X.) ; and the method of perform- 
 ance of these exercises follows pretty closely the directions 
 given in the Descriptive List. The pupils, however, do not 
 have these or any printed directions before them in doing 
 their work, nor have they, in fact, any text-book of physics. 
 
 Apparently the teachers prefer not to have a book in the 
 hands of the pupils. The time allowed for the whole course 
 
 is only two school periods, of 40 minutes each, a 
 Wo Text-book. . * j t_ 
 
 week for one school year, and physics is treated 
 
 as one of the minor studies of the grammar school course. 
 Under these conditions the teachers apparently feel that it is 
 hardly worth while to take up a text-book, some parts of which 
 might be too difficult or too laborious for their pupils. I 
 think, too, that they find a certain legitimate satisfaction in 
 lecturing to their classes in this study, which is more objective 
 than most others with which they have to do. 
 
PRIMARY AND GRAMMAR SCHOOLS 321 
 
 It must be admitted that when these Cambridge pupils, 
 after dropping the study of physics entirely for two years, re- 
 sume it in the third year of the high school course, permanence 
 there is generally not very much immediately of Results? 
 visible in their minds. as the result of their previous work in 
 this subject. But in what study will the direct product of two 
 school periods per week for one grammar school year show 
 to great advantage two years later? Arithmetic, geography, 
 history? In no study that can be named, unless circumstances 
 are such as to keep the lessons of that study frequently in 
 practice. 
 
 Many of the things learned by a boy in such a course of 
 physics as that indicated above, will go into frequent practice in 
 his e very-day life. He will, therefore, probably remember his 
 physics as well as he remembers anything on which so little time 
 has been spent. It will be best, if not necessary, to go all over 
 the same ground again in the high school ; but that is no proof 
 whatever that the first study has not been profitable. Such 
 preliminary study is like the coat of oil which is laid on wood 
 to prepare it for varnishing. The oil dries in and disappears, 
 but the varnish, the show coat, sticks because the oil has gone 
 before it. 
 
 But the question remains, whether such work had better be 
 done by a grammar school class. There is a chance for mis- 
 understanding here. The question is not, whether the same 
 list of experiments done later will teach more, for it must be 
 granted that almost any study pursued at the grammar school 
 age would yield larger results with an equal expenditure of time 
 two or three years later. The question is, whether this course, 
 or some such course, of physics is more profitable to the class 
 as a whole than anything which could, or would, take its place. 
 
 I am, possibly, too much influenced by the circumstances of 
 the case to give this question a judicial answer. If all the 
 pupils were to go forward into a higher school, I should perhaps 
 answer it in the negative ; but a comparatively small propor- 
 tion of them do this. Is it wise, is it fair, to let the great 
 
322 PRIMARY AND GRAMMAR SCHOOLS 
 
 majority of public-school children close their school life without 
 any formal study of natural science ? Are school authorities 
 sufficiently sure, for example, of the superior profitableness of 
 the back part of the arithmetic, partial payments, etc., to war- 
 rant them in preserving all its commercial features to the exclu- 
 sion of natural science ? 
 
 The following paragraphs are written by Mr. Frederick S. 
 Cutter, the master of the Peabody Grammar School of 
 Cambridge : 
 
 " The time allotted to the subject [of physics] is one hour and 
 twenty minutes a week throughout the school year, of which 
 thirty minutes is for laboratory work and fifty minutes for dis- 
 cussion and lecture-table instruction in the classroom. The 
 class is divided [for laboratory work] into sections of sixteen 
 (or less) pupils each." 
 
 " Time for the introduction of physics, and also geometry, 
 was obtained in the revision of the course of study by complet- 
 Commentsby ing the sub J ect of geography in the eighth grade 
 School- and by modifying the requirements in arithmetic. 
 
 The one hour and twenty minutes a week devoted 
 to physics is supplemented by a part of the time assigned to 
 language work, when written compositions are prepared by the 
 pupils in which accounts of their experiments are given from 
 the notes taken in the laboratory. These compositions are 
 usually illustrated, for children as a rule like to write about 
 what they have performed, and take pleasure in the adornment 
 of their papers. Thus the subjects of physics, language, and 
 drawing are most profitably correlated. 
 
 "Before the introduction of laboratory physics there were 
 some who feared that a serious difficulty would be the time and 
 labour required of the teacher in preparation for an experiment 
 to be performed by sixteen children, and afterwards in putting 
 the things away. But in practice it is found that the teacher 
 can be largely relieved by several of the most trustworthy pupils, 
 who are always glad to offer their services as assistants. To 
 one can be given entire charge of the sixteen large glass jars, 
 
PRIMARY AND GRAMMAR SCHOOLS 323 
 
 the filling, the emptying, and the putting away in proper condi- 
 tion ; to another can be given the care of the sixteen overflow 
 cans ; to another the care of the spring-balances, etc. The 
 children selected will profit by the responsibility they assume, 
 and will take increased interest in the work, their influence 
 being favourably felt throughout the class. If the teacher 
 announces in the morning session what will be needed for the 
 experiment in the afternoon, the pupils can get everything in 
 readiness during the noon intermission." 
 
CHAPTER X 
 
 PHYSICS IN VARIOUS KINDS OF SECONDARY SCHOOLS 
 
 REFERENCES. 
 
 Laboratory Manuals : 
 
 Manuals included in text-books and not published separately are not 
 here named. 
 
 Adams, C. F. Physical Laboratory Manual for Secondary Schools. 
 Chicago & New York, Werner School Book Co. 1896. Pp. 183. 
 
 Allen, C. R. Laboratory Exercises in Elementary Physics. New 
 York, Henry Holt & Co. 1892. Pp. 277. 
 
 Ames, J. S. and Bliss, W. J. A. Manual of Experiments in Physics. 
 American Book Co. 1898. Pp. 544. 
 
 Ayres, F. H. Laboratory Exercises in Elementary Physics. London, 
 E. Arnold. New York, D. Appleton & Co. 1901. Pp. 193. To accom- 
 pany Henderson and Woodhull's Elements of Physics. 
 
 Chute, H. N. Physical Laboratory Manual. London, Isbister & Co. 
 Boston, D. C. Heath & Co. 1894. Pp. 218. 
 
 Crew, H. and Tatnall. Laboratory Manual of Physics. London and 
 New York, Macmillan. 1902. Pp. 234. 
 
 Gage, A. P. Physical Experiments. Boston, Ginn & Co. 1897. 
 
 Pp. 195- 
 
 Gage, A. P. Physical Laboratory Manual and Note-book. 1890. 
 Pp. 244. Boston, Ginn & Co. 
 
 Glazebrook, R. T. and Shaw, "W. N. Practical Physics. London and 
 New York, Longmans, Green & Co. New Edition, 1901. Pp. 659. Too 
 difficult for school use. 
 
 Henderson, John. Elementary Physics. London and New York, 
 Longmans, Green & Co. 1895. Pp. 132. For colleges rather than 
 schools. 
 
 Henderson, C. H. and Woodhull, J. F. Physical Experiments. New 
 York, Appleton & Co. 1900. Pp. 112. To accompany the Authors' 
 Elements of Physics and sometimes bound with the Elements. 
 
 Hopkins, W. J. Preparatory Physics. Longmans, Green & Co. 1894. 
 Pp. 147. 
 
 Hortvet, J. A Manual of Elementary Practical Physics for High 
 Schools. Minneapolis, H. W. Wilson. 
 
 Kelsey, W. R. Physical Determinations. London, Arnold. New 
 York, Longmans, Green & Co. 1901. Pp. 328. 
 
VARIOUS KINDS OF SECONDARY SCHOOLS 325 
 
 Nichols, Smith and Turton. Manual of Experimental Physics. Bos- 
 ton, Ginn & Co. 1899. Pp. 324. 
 
 Rintoul, D. An Introduction to Practical Physics. London and New 
 York, Macmillan. 1898. Pp. 166. Mensuration, Mechanics, and Heat. 
 Schuster, A. and Lees, C. H. Intermediate Course in Practical Phy- 
 sics. London and New York, Macmillan & Co. 1896. Pp. 248. De- 
 scribes a course given in Owens College. 
 
 Stewart, B. and Gee, W. W. H. Elementary Practical Physics. 
 Vol. I. General Processes. 1893. P P- 2 95- Vol< JI - Electricity and 
 Magnetism. 1896. Pp. 503. Vol. III. Practical Acoustics (by C. L. 
 Barnes). 1897. Pp. 214. London and New York, Macmillan & Co. 
 Rather beyond school class use. 
 
 Stratton. Outline of a Course in General Physics for Secondary 
 Schools. SCHOOL REVIEW. January, 1898. 7 pages. 
 
 Watson, Wm. Elementary Practical Physics. A Laboratory Manual 
 for Beginners. London and New York, Longmans, Green & Co. 1896. 
 Pp. 238. 
 
 Woodhull, J. F. First Course in Science. Vol. I. Book of Experi- 
 ments. Henry Holt & Co. 1893. Pp. 79. Light only. Vol. II. is a 
 text-book to accompany the manual. Pp. 133. 
 
 Worthington, A. M. Physical Laboratory Practice. London, Long- 
 mans, Green & Co. 
 
 General Text-books, Mainly for Teachers' Use : 
 
 Anthony, W. A. and Bracket, C. F. Elementary Text-book of Phy- 
 sics. Revised by Magie. New York, John Wiley & Sons. 1897. 
 Pp. 512. 
 
 Barker, G. F. Physics. Advanced Course. London, Macmillan & 
 Co. New York, Henry Holt & Co. 1892. Pp. 902. 
 
 Daguin, P. A. Traite Elementaire de Physique. Paris. 3 vols. 
 Contains much descriptive and historical matter. 
 
 Daniell, A. A Text-book of Physics. London and New York, Mac- 
 millan & Co. 1895. P P- 7 82 - 
 
 Deschanel, A. P. Natural Philosophy. Translated and revised by 
 Everett. London, Blackie & Son. New York, D. Appleton & Co. 
 4 vols. The 3d vol., Electricity and Magnetism, issued in 1901. 
 
 Ganot's Physics. Translated and edited by E. Atkinson. London, 
 Longmans, Green & Co. New York. Wm. Wood & Co. Pp. 1115. 
 
 Ganot's Popular Natural Philosophy. Translated and edited by E. 
 Atkinson. Longmans, Green Co. 1900. Pp. 752. 
 
 Hastings, C. S. and Beach, F. E. Text-book of General Physics. 
 Boston, Ginn & Co. Pp. 768. 
 
 Lehfeldt, R. A. A Text-book of Physics, with Sections on the Appli- 
 cations of Physics to Physiology and Medicine. London, Arnold. New 
 York, Longmans, Green & Co. 1902. Pp. 312. 
 
 Nichols, E. L. and Franklin, W. S. Elements of Physics. Vol. I. 
 Mechanics and Heat. 1898. Pp. 219. Vol.11. Electricity and Magnet- 
 
326 VARIOUS KINDS OF SECONDARY SCHOOLS 
 
 ism. 1896. Pp. 272. Vol. III. Light and Sound. 1899. Pp. 201. 
 London and New York, Macmillan. 
 
 Watson, Wm. A. Text-book of Physics. London and New York, 
 Longmans, Green & Co. 1899. Pp. 896. 
 
 Special Treatises, Mainly for Teachers' 1 Use : 
 
 Abney, W. D. W. Treatise on Photography (Text-books of Science). 
 London and New York, Longmans, Green & Co. 1901. Pp. 425. 
 
 Anderson, J. Strength of Materials and Structures (Text-books of 
 Science). London and New York. Longmans, Green & Co. 1892. 
 Pp. 307. 
 
 Benjamin, P. A History of Electricity. New York, John Wiley & 
 Sons. Pp. 611. 
 
 Carpenter, R. C. Heating and Ventilation of Buildings. New York, 
 John Wiley & Sons. 
 
 Goodeve, T. M. Text-book on The Steam Engine and on Gas Engines. 
 London, C. Lockwood & Sons. New York, D. Van Nostrand Co. 
 
 Halliday, G. Steam Boilers. London, Edward Arnold. New York, 
 Longmans, Green & Co. 1897. Pp. 392. 
 
 Hardin, W. L. Liquefaction of Gases. London and New York, 
 Macmillan. 1899. Pp. 250. 
 
 Harrington, M. W. About the Weather. (Home Reading Books.) 
 New York, D. Appleton & Co. 1901. Pp. 246. 
 
 Hawkins, C. C. and Wallis, F. The Dynamo. London, Whittaker 
 & Co. New York, Macmillan & Co. 1896. Pp. 526. 
 
 Holmes, G. C. V. The Steam Engine. (Text-books of Science.) 
 London and New York, Longmans, Green & Co. 1897, Pp. 528. 
 
 Holden, E. S. Stories of the Great Astronomers. 1901. Pp. 255. 
 The Family of the Sun. 1899. Pp. 252. (Home Reading Books.) 
 New York, D. Appleton & Co. 
 
 Hopkins, W. J. Telephone Lines and Their Properties. 1886. 
 Pp. 272. The Telephone. 1898. Pp. 83. New York and London, 
 Longmans, Green & Co. 
 
 Jackson, D. C. and J. P. Alternating Current and Alternating Cur- 
 rent Machinery. London and New York, Macmillan. 1902. Pp. 482. 
 "For Artisans, Apprentices, and Home Readers." 
 
 Jones, H. C. Theory of Electrolytic Dissociation. London and New 
 York, Macmillan. 1900. Pp. 289. 
 
 Le Blanc, M. Electrochemistry. London and New York, Macmillan. 
 1896. Pp. 284. 
 
 Maxwell, J. C. Theory of Heat. With corrections and additions by 
 Lord Rayleigh. London and New York, Longmans, Green & Co. 
 Pp. 348. 
 
 Preeca, W. H. and Sivewright, J. Telegraphy. London and New 
 York, Longmans, Green & Co. 1897. Pp. 417. 
 
 Preston, T. The Theory of Heat. 1894. Pp. 719. The Theory of 
 Light. 1901. Pp. 586. London and New York, Macmillan. 
 
VARIOUS KINDS OF SECONDARY SCHOOLS 327 
 
 Shelley, C. P. B. Work-Shop Appliances. London and New York, 
 Longmans, Green & Co. 1897. Pp. 377. 
 
 Shenstone, W. A. The Methods of Glass-Blowing. London and New 
 York, Longmans, Green & Co. New ed., 1902. Pp. 86. 
 
 Slingo, W. and Brooker, A. Electrical Engineering for Electric 
 Light Artisans and Students. London and New York, Longmans, Green 
 & Co. 1898. Pp. 780. 
 
 Stretton, C. E. The Locomotive and Its Development. London, C. 
 Lockwood & Sons. 
 
 Thompson, S. P. Elementary Lessons in Electricity and Magnetism. 
 1894. Pp. 638. Light Visible and Invisible. 1897. Pp. 294. London 
 and New York, Macmillan. 
 
 Treadwell, A. The Storage Battery. London, Whittaker & Co. 
 New York, Macmillan & Co. 1898. Pp. 257. 
 
 Whetharn, W. C. D. Solution and Electrolysis. Cambridge, Uni- 
 versity Press. New York, Macmillan. 1895. ^P' 2 9^- 
 
 Wilson, E. Electrical Traction. London, Edward Arnold. New 
 York, Longmans, Green & Co. 1897. Pp. 253. 
 
 "Wright, M. R. Sound, Light, and Heat. Pp. 272. Heat. Pp. 346. 
 London and New York, Longmans, Green & Co. 
 
 Yorke, J. P. Magnetism and Electricity. London, Edward Arnold. 
 New York, Longmans, Green & Co. 1899 Pp. 264. 
 
 ON the subject of this chapter we have something approach- 
 ing the authority of official utterance in the various publications 
 made by the National Educational Association during the past 
 ten or twelve years. 
 
 College Entrance Physics of the National Educational Association. 
 
 The general definition or description of the type of physics 
 course, preparatory for college, which is approved by the 
 National Educational Association, is shown by the 
 following extract from the report of its committee Recommen- 
 on College Entrance Requirements, which report 
 was published in 1899 by the authority of the association. 
 
 "Your committee suggests that an effective working basis 
 for a secondary school course in physics would be attained by 
 planning such a course substantially in accordance with the 
 following propositions : 
 
 " i. That in public high schools and schools preparatory for 
 college physics be taught in a course occupying not less than 
 
328 VARIOUS KINDS OF SECONDARY SCHOOLS 
 
 one year of daily exercises, more than this amount of time to 
 be taken for the work if it is begun earlier than the next to the 
 last year of the school course. 
 
 "2. That this course of physics include a large amount of 
 laboratory work, mainly quantitative, done by the pupils under 
 the careful direction of a competent instructor and recorded by 
 the pupil in a note-book. 
 
 "3. That such laboratory work, including the keeping of a 
 note-book and the working out of results from laboratory obser- 
 vations, occupy approximately one-half of the whole time given 
 to physics by the pupil. 
 
 "4. That the course also include instruction by text-book 
 and lecture, with qualitative experiments by the instructor, 
 elucidating and enforcing the laboratory work, or dealing with 
 matters not touched upon in that work, to the end that the 
 pupil may gain not merely empirical knowledge,, but, so far as 
 this may be practicable, a comprehensive and connected view 
 of the most important facts and laws in elementary physics. 
 
 "5. That college-admission requirements be so framed that a 
 pupil who has successfully followed out such a course of physics 
 as that here described may offer it toward satisfying such re- 
 quirements." l 
 
 The report from which the preceding extract is taken was 
 approved in the year following its publication, in the following 
 Histor of resolution : " Resolved, That the Departments of 
 theW.E.A. Secondary and Higher Education of the National 
 Educational Association commend the report of 
 the special Committee on College-Entrance Requirements as 
 offering a basis for the practical solution of the problems of 
 college admission, and recommend the report to the colleges 
 of the country." 
 
 The report under discussion consisted of two parts, a shorter 
 part, for which the committee itself took the responsibility, and 
 
 1 These five propositions are substantially a repetition of recommenda- 
 tions made to the General Committee by the Committee on Physics, 
 the membership of which is given later. 
 
VARIOUS KINDS OF SECONDARY SCHOOLS 329 
 
 from which the extract above given is taken, and a longer part 
 containing many details offered in the reports of various sub- 
 committees. In this supplementary part of the report the 
 matter relating to physics, quoted in full below, is little more 
 than the Table of Contents of the Harvard Descriptive List 
 (see Chapter V.) and two paragraphs taken, almost without 
 change, from the Introduction to that list. As this fact is 
 capable of misinterpretation by those not fully acquainted 
 with the circumstances, I shall give some account of the 
 matter here. 
 
 As chairman of the committee mentioned in the quotation 
 following, I had reported to Dr. Nightingale, the chairman of 
 the general Committee on College Entrance Requirements, 
 that, inasmuch as the Physics Committee was made up largely 
 of gentlemen who had written text-books very different text- 
 books for schools, or were in the way of writing such books, 
 I could not undertake to get from them any general agreement 
 as to the details of what a course in schools should be. But, 
 as Dr. Nightingale insisted on some kind of a report on this 
 subject, I at last sent him what is practically a description of 
 the Harvard requirement in laboratory work, as my individual 
 report, at the same time notifying the other members of the 
 committee of what I had done, and requesting each of them to 
 take corresponding individual action, if he felt moved to do so. 
 The quotations which follow show the result. 
 
 " The Committee on Physics of the Science Department of 
 the National Educational Association did not submit a regular 
 report signed by the members of the committee. 
 These were: Professor E. H. Hall, Harvard Uni- 
 
 versity, chairman ; Professor H. S. Carhart, Uni- Ph y slcs 
 
 Cemmittee. 
 versity of Michigan, Ann Arbor ; R. B. Fulton, 
 
 Chancellor, University of Mississippi ; C. L. Harrington, Sachs' 
 Collegiate Institute, New York, N. Y. ; Julius Hortvet, East 
 Side High School, Minneapolis, Minn. ; C. J. Ling, Manual 
 Training School, Denver, Colo. ; Professor E. L. Nichols, 
 Cornell University, Ithaca, N. Y. ; E. D. Pierce, Hotchkiss 
 
330 VARIOUS KINDS OF SECONDARY SCHOOLS 
 
 School, Lakeville, Conn. ; Professor Fernando Sanford, Leland 
 Stanford, Jr., University, Cal. ; Professor B. F. Thomas, Ohio 
 State University, Columbus; Edward R. Robbins, Lawrence- 
 ville School, Lawrenceville, N. J. 
 
 "The basis of a report, suggested by Professor Hall, and 
 consisting of a list of laboratory experiments, is given below. 
 Comments by the members of the committee, in case they dis- 
 sented from any part of this, were to be sent at once to the 
 chairman of the Committee on College-Entrance Requirements. 
 It may be assumed that the list met with the approval of those 
 who did not so indicate dissent. Such comments as have been 
 received are given after Professor Hall's statement. 
 
 " Outline of Laboratory Work in Physics for Secondary Schools. 
 
 " At least thirty-five exercises, selected from a list of sixty or 
 
 more, not very different from the list given below. In this list 
 
 the divisions are mechanics (including hydrostatics), 
 
 List of light, heat, sound, and electricity (with magnetism). 
 
 At least ten of the exercises selected should be in 
 
 mechanics. The exercises in sound may be omitted altogether ; 
 
 but each of the three remaining divisions should be represented 
 
 by at least three exercises. 
 
 " The division of the list into a first part and a second part 
 is intended to facilitate and encourage beginning the study of 
 physics very early in the school course. Most of the exercises 
 in the first part have proved to be within the power of boys of 
 fourteen or fifteen years, although older pupils can do them 
 more readily, as they can do all other work except tasks of 
 pure memory. The cost of apparatus for the exercises of the 
 first part is very small. 
 
 " First Part. 
 PRELIMINARY EXERCISES. 
 
 [Recommended, but not to be counted.] 
 
 A. Measurement of a straight line. 
 
 B. Lines of the right triangle and the circle. 
 
VARIOUS KINDS OF SECONDARY SCHOOLS 33 I 
 
 C. Area of an oblique parallelogram. 
 
 D. Volume of a rectangular body by displacement of water. 
 
 MECHANICS AND HYDROSTATICS. 
 
 1. Weight of unit volume of substance. 
 
 2. Lifting effect of water upon a body entirely immersed in it. 
 
 3. Specific gravity of a solid body that will sink in water. 
 
 4. Specific gravity of a block of wood by use of a sinker. 
 
 5. Weight of water displaced by a floating body. 
 
 6. Specific gravity by flotation method. 
 
 7. Specific gravity of a liquid : two methods. 
 
 8. The straight lever : first class. 
 
 9. Centre of gravity and weight of a lever. 
 10. Levers of the second and third classes. 
 IT. Force exerted at the fulcrum of a lever. 
 
 1 2. Errors of a spring balance. 
 
 13. Parallelogram of forces. 
 
 14. Friction between solid bodies (on a level). 
 
 15. Coefficient of friction (by sliding on incline). 
 
 LIGHT. 
 
 1 6. Use of Rumford photometer. 
 
 1 7. Images in a plane mirror. 
 
 18. Images formed by a convex cylindrical mirror. 
 
 19. Images formed by a concave cylindrical mirror. 
 
 20. Index of refraction of glass. 
 
 21. Index of refraction of water. 
 
 22. Focal length of a converging lens. 
 
 23. Conjugate foci of a lens. 
 
 24. Shape and size of a real image formed by a lens. 
 
 25. Virtual image formed by a lens. 
 
 Second Part. 
 
 MECHANICS. 
 
 26. Breaking strength of a wire. 
 
 27. Comparison of wires in breaking tests. 
 
33 2 VARIOUS KINDS OF SECONDARY SCHOOLS 
 
 28. Elasticity : stretching. 
 
 29. Elasticity : bending ; effects of varying loads. 
 
 30. Elasticity: bending; effects of varying dimensions. 
 
 31. Elasticity: twisting. 
 
 32. Specific gravity of a liquid by balancing columns. 
 
 33. Compressibility of air : Boyle's law. 
 
 34. Density of air. 
 
 35. Four forces at right angles in one plane. 
 30. Comparison of masses by acceleration test. 
 
 37. Action and reaction: elastic collision. 
 
 38. Elastic collision continued : inelastic collision. 
 
 HEAT. 
 
 39. Testing a mercury thermometer. 
 
 40. Linear expansion of a solid. 
 
 41. Increase of pressure of a gas heated at constant 
 
 volume. 
 
 42. Increase of volume of a gas heated at constant pressure. 
 
 43. Specific heat of a solid. 
 
 44. Latent heat of melting. 
 
 45. Determination of the dew-point. 
 
 46. Latent heat of vaporization. 
 
 SOUND. 
 
 47. Velocity of sound in open air. 
 
 48. Wave-length of sound. 
 
 49. Number of vibrations of a tuning fork. 
 
 ELECTRICITY AND MAGNETISM. 
 
 50. Lines of force near a bar magnet. 
 
 51. Study of a single-fluid galvanic cell. 
 
 52. Study of a two-fluid galvanic cell. 
 
 53. Lines offeree about a galvanoscope. 
 
 54. Resistance of wires by substitution : various lengths. 
 
VARIOUS KINDS OF SECONDARY SCHOOLS 333 
 
 55. Resistance of wires by substitution : cross-section and 
 
 multiple arc. 
 
 56. Resistance by Wheatstone's bridge : specific resistance 
 
 of copper. 
 
 57. Temperature coefficient of resistance in copper. 
 
 58. Battery resistance. 
 
 59. Putting together the parts of a telegraph key and sounder. 
 
 60. Putting together the parts of a small motor. 
 
 6 1. Putting together the parts of a small dynamo. 
 
 " Professor Carhart suggests forty experiments similar to these. 
 Twenty-four of these coincide exactly in title with items in the 
 above list. The following fourteen are new, but many of them 
 are probably implied in the list of sixty-one : 
 
 The Jolly balance. 
 
 Laws of the pendulum. 
 
 Pressure. 
 
 Curve of magnetization. 
 
 Action of current on needle. 
 
 Fall of potential in conductor. 
 
 E. M. F. of cell. 
 
 The tangent galvanometer. 
 
 Velocity of sound in solids (Kundt). 
 
 La\v of length for strings (sound). 
 
 Law of diameter for strings (sound). 
 
 Law of tension for strings (sound). 
 
 Law of reflection (light). 
 
 Measurement of angle of prism (light)." 1 
 
 The next following quotation is an extract from the Defini- 
 tion of Requirements issued by the College En- . ti 
 trance Examination Board of the Middle States Middle states 
 and Maryland, February i, 1901. 
 
 1 In the NEW ENGLAND JOURNAL OF EDUCATION for December 26, 
 1901, and January 2 and 9, 1902, Mr. Stratton D. Brooks, High School 
 Visitor for the University of Illinois, has, under the title, " Suggested 
 List of Experiments in Physics," worked over this N. E. A. list and 
 given corresponding references to several well-known text-books. 
 
334 VARIOUS KINDS OF SECONDARY SCHOOLS 
 
 " 8 Physics. 
 
 " The requirement in physics is based on the report of the 
 Committee on Physics of the Science Department of the Na- 
 tional Educational Association. 
 
 " It is recommended that the candidate's preparation in 
 physics should include : 
 
 "a. Individual laboratory work, comprising at least thirty- 
 five exercises selected from a list of sixty or more, not very 
 different from the list given below. 
 
 " b. Instruction by lecture-table demonstrations, to be used 
 mainly as a basis for questioning upon the general principles 
 involved in the pupil's laboratory investigations. 
 
 " c. The study of at least one standard text-book, supple- 
 mented by the use of many and varied numerical problems, 
 1 to the end that the pupil may gain a comprehensive and 
 connected view of the most important facts and laws in ele- 
 mentary physics. 7 " 
 
 The list of titles of experiments which follows this passage in 
 the original context is precisely the same as that numbered from 
 i to 6 1 in the Report of the National Education Association 
 and in the Harvard Descriptive List. 
 
 It appears, then, that we have, in the course of work outlined 
 by the preceding quotations, a type of college entrance require- 
 
 ment in physics which is tolerably well defined and 
 of Such a widely approved. Whether this type is established 
 
 and maintained as generally as it is approved, may 
 be an open question. In that part of the country which comes 
 under my personal observation, it is very generally established. 
 But in this same region the boys who go through a high school 
 course, without having preparation for college in view, do not, 
 as a rule, take just this course of physics. They take one which 
 is more " practical " or more " general " or more " popular," 
 almost always, I believe, a course that involves less close atten- 
 tion and hard thinking. This fact naturally raises a number of 
 
VARIOUS KINDS OF SECONDARY SCHOOLS 335 
 
 questions. Is the college requirement, as interpreted and 
 maintained by Harvard, for example, more severe than it should 
 be? Are its applications to every-day life too remote? Does 
 it require too much use of mathematics? Does it have too 
 large a proportion of painstaking laboratory work, and too little 
 in the way of lecture-room exhibitions ? In particular, should 
 the course make great use of the projecting lantern, with a large 
 collection of interesting "slides," illustrating scientific objects 
 of general or local importance ? Do the teachers who devise 
 the courses of physics study followed in " English high schools," 
 and other schools of the same general character, virtually express 
 an unfavourable judgment of the college requirement physics 
 for boys who are not to go to college? 
 
 It is possible that some of these questions would be and 
 should be generally answered in the affirmative, but this is not 
 
 the inevitable conclusion. There is still the possi- T 
 
 Essential 
 
 bility that those who have advocated l the same Difference in 
 work for boys who are to go to college as for boys 
 who are not to go to college have overlooked one very impor- 
 tant fact, namely, that the two sets of boys may not be just alike 
 in their mental traits and attainments. As a rule, so far as my 
 observation and inquiry have gone, they are notably different, 
 the boys who naturally go to an " English high school " being 
 less scholarly and more narrowly utilitarian in their views than 
 their contemporaries and associates who naturally go to a 
 " Latin school." 
 
 Moreover, I can see little prospect of the disappearance or 
 even the diminution of this unlikeness. The now well estab- 
 lished practice of teaching, in the English high schools, such 
 arts as book-keeping, short-hand, and typewriting, inevitably 
 draws into these schools a numerous class of boys and girls who 
 by birth and home influence have received little of scholarly 
 capacity or impulse. Yet their parents demand, and with good 
 show of reason, that if public money is spent to advance the few 
 
 1 See the Report of the Committee of Ten, which is very emphatic on 
 this point. 
 
336 VARIOUS KINDS OF SECONDARY SCHOOLS 
 
 to the doors of college, with the comparatively profitable learned 
 professions in view beyond, public money shall be spent to 
 advance the many toward the practice of their useful and 
 honourable, if less distinguished, vocations. The ordinary city 
 high school will therefore continue to have a general class of 
 pupils who are not capable of going side by side with the pupils 
 of the Latin schools, a class who have left the grammar schools 
 comparatively old, and will leave the high school at a lower in- 
 tellectual level than their Latin school contemporaries, unless 
 the course of the former school is made longer than that of 
 the latter, which is not likely to be the case. 
 
 Furthermore, even if the natural difference in kind of pupils 
 did not exist, the fact that the pupils in one school are pre- 
 Stimulusof P arm g to meet "requirements set by an authority 
 College Re- outside the school, while the pupils in the other 
 school are without this stimulus, will probably 
 always keep the general standard of the work higher in the 
 former school than in the latter. It is very doubtful whether 
 local authority, or even the authority of any state board of 
 education, unsupported by the strongly asserted requirements 
 of colleges, can ever be depended on to keep the general 
 standard of graduation from the high school up to the proper 
 level of admission to college. A school which sends but few 
 boys to college will prepare but few boys for college. 
 
 What, then, should such a school undertake to do in physics ? 
 Should it follow the college preparatory course as far as it can, 
 What Hi h ta ^ m g na ^ o r two-thirds of it, for example; or 
 Schools should it maintain a course designed with especial 
 
 reference to the character and aims of its own 
 pupils ? I cannot doubt that the latter alternative will prevail, 
 and ought to prevail, though it should be the constant effort of 
 all school authorities to broaden and elevate, so far as this may 
 be practicable, the ideas of their pupils as to what is attainable 
 and what is worth while. 
 
 Without directly following the college requirement course in 
 physics, the high school course has been profoundly influenced 
 
VARIOUS KINDS OF SECONDARY SCHOOLS 337 
 
 by it, and will doubtless continue to be so. On the other 
 hand, it behooves those of us who have most to do with the 
 college requirement, to keep watch of the development of 
 physics in the high schools, with the hope of finding therein 
 examples which we may profitably follow. 
 
 For the high school course in physics, as distinguished from 
 the college requirement course, there is not, so far as I am 
 aware, any general description arrived at by formal ph sicsin 
 consensus of opinion. The following extract from Brookiine 
 the official description of the physics work in the 
 high school of Brookiine, Massachusetts, gives account of a 
 course developed by Mr. John C. Packard, the teacher of 
 physics in that school, which is in marked and interesting 
 contrast with the college requirement course : 
 
 " There are two courses in physics. 
 
 " i. The so-called Popular Course, the fundamental aim of 
 which is : 
 
 " (a) To develop in the pupil the habit of steady, persistent, 
 logical thinking ; 
 
 " (b) To render him fairly intelligent in reference to his own 
 scientific environment ; 
 
 " (c) To beget a sense of power in his own ability to appre- 
 ciate scientific truth and to draw legitimate conclusions from 
 simple data ; 
 
 " (d) To teach him to apply the elements of Algebra and 
 Geometry to the problems of daily life, and finally 
 
 " (e) To arouse within him a deep sense of appreciation of 
 all that modern science has done and is still doing for the com- 
 fort and convenience of the race. 
 
 "With these ends in view the head of the department in 
 common with many others has discovered that but very little 
 reliance can be placed upon the ordinary text-book, since so 
 few opportunities are given in the average manual for any 
 original independent thinking and since in general such books 
 contain so little of anything like a practical application of the 
 principles of physics to the phenomena of daily life. He has felt 
 
338 VARIOUS KINDS OF SECONDARY SCHOOLS 
 
 obliged therefore to substitute for such text-books, as others 
 have, a special manual, as yet in manuscript form, in which the 
 student is told as little as possible directly, but is given, practi- 
 cally, a series of original exercises in Mechanics, Optics, and 
 Electricity which he is to work out by the aid of a set of simple 
 apparatus, his mathematical instincts, and his own brain, and 
 apply in a continuous sequence suggested by an abundance of 
 questions, problems and references to the affairs of daily life. 
 
 "The aim is to be thoroughly practical. In Hydraulics, for 
 instance, more attention is paid to the water-meter, the simple 
 motor, and the turbine than to the lifting pump, the ram and 
 the breast-wheel, as the average man is more likely to see and 
 use the former than the latter series. In Optics again, the 
 camera, the opera glass, and the spyglass are dealt with more 
 fully than the telescope and the compound microscope for the 
 same reason. 
 
 " Continual reference is made to the current literature of the 
 day and to the science of Boston and vicinity. 
 
 " It is intended that a series of illustrated lectures shall 
 accompany the course giving a brief summary of the history 
 of Physics and a glimpse of the wonderful scientific achieve- 
 ments of our own age. 
 
 " The work is distributed somewhat as follows : 
 
 " September, October, November, Mechanics, including 
 Hydrostatics and Pneumatics. 
 
 11 December, January, February, Optics. 
 
 " March, April, May, Electricity. 
 
 " June, Review. 
 
 " Toward the close of the school year special topics are 
 suggested for more exhaustive treatment than is possible in 
 the regular classroom work. Each pupil is expected to choose 
 one or more of such topics and to present an illustrated paper 
 upon the subject selected, at the end of the year. 
 
 "Among the topics recently suggested may be mentioned 
 the following : 
 
 i. Mechanics of the Clock. 
 
VARIOUS KINDS OF SECONDARY SCHOOLS 339 
 
 2. Mechanics of the Bicycle. 
 
 3. Mechanics of the Sewing Machine. 
 
 4. Hughes' Induction Balance. 
 
 5. The Microphone. 
 
 6. Consumption of Gas, Water and Electricity in the 
 Household. 
 
 7. Testing a Water-Meter. 
 
 8. The Fire-alarm System of Brookline. 
 
 9. School-room Ventilation. 
 
 10. The Long-Distance Telephone. 
 
 1 1 . The Transformer. 
 
 12. The Gas-Engine. 
 
 13. The Horse Power of an Electric Motor. 
 
 " This entire course, extending over one year's time, is re- 
 quired of the sub-classical, the scientific and the manual train- 
 ing pupils and at least one-half the course, i. e., the first five 
 months, of the classical. 
 
 " The time is equally divided between laboratory and lecture- 
 room work, each requiring two periods per week beside the 
 usual preparation for a full study. 
 
 " Complete notes are kept by the pupils, of both the labora- 
 tory and the lecture work. These notes are inspected from 
 time to time by the instructor," etc. 
 
 I am far from asserting that the course outlined by Mr. Pack- 
 ard is not better for the average high school pupil, boy or girl, 
 
 than the college preparatory course, which also is 
 
 * Problem to be 
 
 given in the same school. Mr. Packard and others Solved by 
 
 who, like him, have worked out the problem of gen- Ex P enence - 
 eral high school physics approximately to their own satisfaction 
 on somewhat new lines, will do a service to the public by put- 
 ting the results of their experimentation into the form of text- 
 books or manuals available for all teachers. These books may 
 or may not prove to be generally acceptable and usable ; but 
 in any case they will be an important contribution to that vigor- 
 ous trying-out process through which all methods of science 
 teaching are now going in the schools of this country. 
 
340 VARIOUS KINDS OF SECONDARY SCHOOLS ' 
 
 The word of caution which I would give to those who aim 
 especially to make their teaching "practical" is, that they 
 should beware of encouraging the idea, which many of their 
 pupils are only too much inclined to hold, that the object of 
 schooling is to give a certain final and sufficient store of knowl- 
 edge and not, rather, so to fit the pupil that he may, after his 
 school days are over, go on increasing in knowledge, finding 
 constantly new uses for that stock of elementary fundamental 
 ideas which a well devised school course should inculcate. To 
 this suggestion the teacher will perhaps reply that the average 
 high school pupil has not sufficient initiative and imagination to 
 find for himself the use of abstract ideas, and that the attempt to 
 implant such ideas in a mind essentially concrete is labour and 
 opportunity lost. I have no confident answer to make to such 
 an assertion. The problem here is to find the right proportion 
 of those constituents which all admit to be necessary. There 
 is no hard and fast rule to be laid down. 
 
CHAPTER XI 
 
 ON THE PRESENTATION OF DYNAMICS 
 
 REFERENCES. 
 
 Magnus, P. Lessons in Elementary Mechanics. London and New 
 York, Longmans, Green & Co. 1892. Pp. 377. 
 
 Maxwell, J. C. Theory of Heat. London and New York, Long- 
 mans, Green & Co. Chapter IV. 
 
 I HAVE not undertaken to give in this book a pedagogic treat- 
 ment of the various parts of elementary physics ; but there is 
 one part, namely, dynamics, so fundamental yet so often 
 neglected or badly taught, that I propose to give it especial 
 attention here. 
 
 It must be admitted once for all that the elementary ideas in- 
 volved in questions of acceleration are difficult for the ordinary 
 mind to grasp. The formulas, at least for cases of Difficultyand 
 uniform acceleration, are very simple, but the Importance of 
 primary conceptions underlying these formulas, 
 the definite notions of force, momentum, and kinetic energy, 
 the ordinary student rarely masters and retains. Should we, 
 therefore, give up the attempt to teach this part of physics in 
 school courses, or the early courses in college, and content our- 
 selves with giving, in mechanics, the statical aspect only? 
 
 I fear that many teachers will answer this question in the 
 affirmative, but I am not yet ready to do so. We cannot afford 
 to avoid everything that is difficult for the average boy, or practi- 
 cally impossible for the dull boy. We must conduct our classes 
 with some regard to the most vigorous minds among our pupils ; 
 and such minds will find, in the broadening of their vision 
 through the study of dynamics, perhaps the most profitable part 
 
342 ON THE PRESENTATION OF DYNAMICS 
 
 of all their training in physics. How can we be content to let 
 a boy of eighteen years or older leave our classrooms without 
 having had an opportunity to learn the meaning of the term 
 energy, as strictly used, a conception without which all en- 
 deavour to understand and use the law of conservation of energy, 
 the grandest, yet one of the simplest, of the generalizations of 
 physical science, is feeble, if not futile ? 
 
 But may not a man be useful and happy who does not under- 
 stand the conservation of energy? Yes, if he knows that he 
 does not understand it, and does not profess to understand it. 
 But this law is peculiarly one which many people talk about, and 
 fancy themselves to understand, while their whole notion of it is 
 so vague that it is quite as likely to lead them wrong as right 
 when they would make any application of it. The law lies all 
 about us, and nearly every one has some not altogether false 
 idea of its meaning, some fairly good illustration of it at com- 
 mand ; but understand it he certainly does not, if he has not 
 mastered the meaning of certain little words, and certain short 
 formulas, the full significance of which is not made plain by the 
 experience and conversation of every-day life. Great thinkers 
 groped long for the full meaning of the law, discoursing mean- 
 while of the " conservation of force," and using " force " some- 
 times in its proper sense, sometimes in the sense of " energy," 
 feeling their own confusion of ideas, but unable to see just where 
 their trouble lay. 
 
 I began this chapter by admitting the difficult nature of the 
 ideas used in dynamics. I believe, however, that the effort of 
 Difficulty In- masterui g these ideas will be less for the next gen- 
 creased t>y eration than for the present, not through any con- 
 TeacMni:. s jd era bi e growth in the power of the human brain 
 within a few decades, but because good methods of instruction, 
 if we can establish and maintain them, will gradually produce 
 teachers thoroughly competent to guide their pupils through the 
 initial difficulties of dynamics. That all teachers of physics are 
 not yet in this condition, a very brief tour of visits to classrooms 
 will show. 
 
ON THE PRESENTATION OF DYNAMICS 343 
 
 Not long ago, in a flourishing city school, I heard part of a 
 recitation on the meaning and application of the law of acceler- 
 ation, f= , where v is the velocity imparted instances. 
 
 in t seconds by the force f to the mass ni. The teacher re- 
 marked to me when I entered the room that he found it hard 
 to get his pupils to understand the dyne. I expressed sym- 
 pathy j but, in the discussion with pupils which presently fol- 
 lowed, the teacher repeatedly gave his approval to the following 
 statement : A dyne is the force which will move one gram one 
 centimeter in one second. 
 
 In another school, an excellent school, I heard a teacher, 
 after giving his pupils to understand that sliding friction is some- 
 what less with high velocity than with low velocity, a very doubt- 
 ful proposition in itself, explain this alleged fact by declaring 
 that the momentum of the moving body helps to carry it over 
 the frictional obstacles. The experiments under discussion were 
 such as involved uniform velocity of the sliding body. 
 
 In still another excellent school I heard a teacher discuss the 
 pressure in a siphon, in operation, as if the question were one of 
 simple hydrostatics, assuming the pressure at a given level, in 
 the stream within the siphon, to be just as great as the pressure 
 in the still water at the same level outside the siphon, thus 
 neglecting altogether the difference of pressure used in giving 
 momentum to the water entering the tube. 1 
 
 The law that action is equal to reaction and opposite in 
 direction, is so very simple in form and so easily remembered 
 verbally, that probably most people who have ever heard it 
 
 1 The case of pressure in the siphon, during flow, seems rather too 
 difficult for profitable discussion, in detail, with a school class or a young 
 class in college. I think it better to keep to the static aspect, consider 
 the siphon filled, with its lower end closed for the moment, and merely 
 show that the pressure within the siphon at this end at this moment is 
 greater than the atmospheric pressure, so that water must flow out as 
 soon as the tube is opened. Yet some clear elementary conception of 
 the dynamics of the flowing water is needed, in order to enable the 
 teacher of young pupils to see why he had better leave that matter un- 
 touched by his class. 
 
344 ON THE PRESENTATION OF DYNAMICS 
 
 think they understand it. Yet there is plenty of evidence that 
 teachers sometimes fail to realize and apply it, even in simple 
 cases of collision of bodies. There is a certain experiment or 
 set of experiments, to the devising of which I have given a 
 great deal of care and thought, intended to illustrate the fact 
 that the algebraic sum of the momenta of two bodies is the 
 same after their collision as before, and that this rule holds 
 true as well for ivory balls with putty interposed as for ivory 
 balls in naked shock. Yet once a teacher of considerable ex- 
 perience, who now holds and deserves an important position 
 in the school system of a large city, complained to me that tins 
 set of experiments was a comparative failure, because, according 
 to his observations, it seemed to indicate that inelastic bodies 
 preserved their total momentum as well as elastic bodies. I 
 explained the situation to him in a word ; he thanked me heart- 
 ily, and has, I feel sure, ever since found that particular experi- 
 ment easier to deal with and more profitable to discuss than it 
 used to be. 
 
 I found, too, that another teacher, a well-known man, observ- 
 ing that the total momentum after collision was usually, by the 
 somewhat defective method of estimation prescribed in the 
 experiment referred to, made to appear slightly less than the 
 total momentum before collision, was in the habit of teaching 
 his pupils that the difference found was due to the loss of 
 momentum (or energy ?) in the production of heat at the colli- 
 sion. Of course, a teacher in such confusion of mind, as to 
 the relations of momentum and energy, would make a muddle 
 in the minds of his pupils. 
 
 x Lest these instances of faulty teaching should be considered 
 \ invidious, let me say that I have long since come to the con- 
 I elusion that it is unfair and unsafe to condemn any teacher for 
 I any single mistake, however glaring. 
 
 It is plain that a considerable part of our trouble with ele- 
 mentary dynamical notions comes from our unfortunate, but at 
 present unavoidable, multiplicity of force-units. We have, at the 
 
ON THE PRESENTATION OF DYNAMICS 345 
 
 least, the pound and the gram as gravitation units of force, the 
 same names being used also for units of mass, and the poundal 
 and the dyne as absolute, or acceleration, units of Multiplicity 
 force. Some generations hence the pound and the of Force- 
 poundal may have disappeared from common use, m Sf 
 the decimal system of weights and measures being then fully 
 established ; but it is doubtful whether the change will be 
 rapid, and in any case we of the present day must face the 
 difficulties of the transition state. Perfectly clear fundamental 
 ideas on the part of the teacher are essential to success in this 
 field of operations. 
 
 Moreover, the teacher should have a well thought out plan 
 of campaign, though he should be able and willing to change 
 this plan as occasion seems to require. It is a Need of 
 great mistake to insist that the pupil must get his Simplicity. 
 ideas in the same order in which a master of the subject may 
 choose to arrange his own matured conceptions. Such a 
 master is apt to be too subtle and guarded in his preliminary 
 statements, to look so far ahead as to raise difficulties which 
 have not yet occurred to the pupil, difficulties the too early 
 consideration of which confuses and discourages the beginner. 
 It is well to begin with simple and rather dogmatic statements, 
 to be supported by experiment and argument and illustration 
 as these are consciously or unconsciously demanded by the 
 class. Simple problems, too, should be given in abundance, in 
 order that the pupil may acquire that firm grasp of ideas which 
 comes only by use. 
 
 To give a pedagogical syllabus of elementary ideas and rela- 
 tions in dynamics would be foreign to the purpose of this book ; 
 but the tabulation of a few -important equations for Tabulation 
 each of several systems of units may serve a useful of Equations. 
 purpose, by showing similarities and differences, and even by 
 exhibiting the complexity of the present situation in every-day 
 dynamics. In the equations which are given below, acceleration, 
 whenever mentioned, is assumed to be uniform acceleration, 
 and force, whenever mentioned, is assumed to be uniform force. 
 
34^ ON THE PRESENTATION OF DYNAMICS 
 
 Moreover, the velocity, v, is supposed to be o at the beginning 
 of the time, /. 
 
 Equations for Acceleration, Distance Travelled, Velocity Ac- 
 quired, Force, Work, and Kinetic Energy, with the Absolute 
 C. G. S. System of Units, 
 
 the dyne being the unit of force and the erg being the unit 
 of work and of energy. 
 
 v 
 
 1 i ) a = acceleration -, or v = a /. 
 
 (2) d distance travelled = - X / = - a / 2 . 
 
 2 2 
 
 (3) v~ 2 a d t from (i) and (2). 
 
 (4) f= = m a, where v is the velocity given to the mass 
 
 m by the force f in the time t. 
 
 (5) w work =fd. 
 
 When w is entirely spent in giving kinetic energy 
 to m, we have 
 
 m v 
 X 
 
 2 2 
 
 (6) k. e. = kinetic energy w =fd - X - / = mv*. 
 
 Corresponding Equations with the Gravitation C. G. S. 
 System of Units, 
 
 the gram-force, a force equal to the pull of gravitation on a 
 gram mass, being the unit of force and the gram-centimeter 
 being the unit of work and of energy. 
 
 v 
 
 (1) a = acceleration = -, or v = a t. 
 
 (2) d = distance travelled = - X t - a / 2 . 
 
 (3) z/ 2 2 a d, from (i) and (2). 
 
 (4) / = a, where v is the velocity given to the mass 
 
 g* g 
 
 m by the force/" in the time /. 
 
ON THE PRESENTATION OF DYNAMICS 347 
 
 (5) w work fd. 
 
 When w is entirely spent in giving kinetic energy 
 to /, we have 
 
 m v v mv z 
 
 (6) k. e. = kinetic energy = w =fa*= X - / = . 
 
 gt 2 2g 
 
 With the Absolute Foot-Pound-Second System, 
 
 in which the poundal is the unit of force and the foot-poundal 
 is the unit of work and of energy, we have precisely the same 
 equations as with the absolute C. G. S. system. 
 
 With the Gravitation Foot-Pound-Second System, 
 
 in which the pound-force, a force equal to the pull of gravita- 
 tion on a pound mass, is the unit force and the foot-pound is 
 the unit of work and of energy, we have precisely the same 
 equations as with the gravitation C. G. S. system. 
 
 Many engineers, in this country at least, keep to the gravi- 
 tation English unit of force, and yet write 
 
 force mass X acceleration. Mass in the 
 
 Language of 
 
 This is as if we should write equation (4) of a En s* neerin e- 
 
 gravitation system in the form /= , and call ~ the mass. 
 
 S S 
 
 That is, the engineer calls the mass of 10 pounds of iron 
 io^-. It is to be hoped that in time there will be agree- 
 ment between physicists and engineers as to the meaning of 
 so important a term as mass. 
 
CHAPTER XII 
 
 PLAN AND EQUIPMENT OF A LABORATORY 
 
 LET us suppose the school, for which we are to provide a 
 laboratory, to be one of considerable size. 
 
 We have elsewhere, see Chapter VII., seen reason to believe 
 that, for the best results, the laboratory sections should number 
 not more than fifteen, though we may well make provision for 
 slightly larger sections in view of emergencies. 
 
 We will consider first the laboratory tables. Very short 
 tables are comparatively expensive ; very long ones are too 
 Working much in the way when one has to go around them. 
 Tables. The width should be such as to give plenty of 
 
 room for a row of pupils on each side, with somewhat bulky 
 apparatus before them, and without the necessity of crowding 
 Bunsen burners and steam-boilers, for example, into close 
 proximity with other articles which might suffer from the 
 association. A good size for the table is TO feet by 4 feet, 
 the height being 3 feet. Such a table will give working room 
 for six pupils, three on a side. Fig. 18 shows such a table in 
 elevation and Fig. 19 shows it in plan. In Fig. 18, gg is a gas- 
 pipe having six outlets downward for Bunsen burner connec- 
 tions, and four short horizontal branches (see also Fig. 19) for 
 ordinary illuminating jets. In the same figure, 18, bb is a 
 wooden bar, attached to the end posts by means of clamps, 
 and adjustable at any height above the table between the gas- 
 pipe gg and the tops of the posts. From this bar six brass 
 rods project horizontally (see Fig. 21), each i foot long and 
 each provided with a miniature vise, a thin saw-cut i inch 
 deep, crossed by a pinching screw. This vise is not, perhaps, 
 important, but the brass rods are very convenient for making 
 
PLAN AND EQUIPMENT OF A LABORATORY 349 
 
 suspensions, of spring-balances, for -example, in careful weigh- 
 ing. The scale of Figs. 18 and 19 is i cm. for i foot. Few, 
 if any, features of this table are original with me. 
 
 I 
 
 FIG. 18. 
 
 The four small circles shown in the table-top in Fig. 19 
 indicate holes bored through for suspension of pans bearing 
 weights in a certain exercise on the bending of rods. The 
 
 
 o 
 
 . 
 
 
 
 b \ 
 
 1 b 
 
 
 ^:\ 
 
 I 1 
 
 ~T 
 
 IIMIltffi 
 
 , * *. 
 
 /P *-.* 
 
 FIG. 19. 
 
 line rr indicates the position of a rod under observation, / 
 being position of index. Two holes at mid-length of the table- 
 top are not shown in Fig. 19. 
 
350 PLAN AND EQUIPMENT OF A LABORATORY 
 
 The table should be so made as to keep a reasonably flat 
 top, as in some exercises a level surface is very desirable, and 
 therefore it should have as many as six legs. Pine and ash 
 are good materials. Oak is objectionable on account of its 
 tendency to warp. 
 
 If the plan of the course to be given involves furnishing each 
 member of the class with a particular set of apparatus, which 
 he alone is to use and for which he must be responsible, it may 
 be necessary to provide drawers or lockers in or under the 
 tables ; but such a plan of work is, I believe, uncommon, and 
 I greatly prefer plain tables with no such receptacles ; for these 
 latter interfere with certain uses of the tables and, being neces- 
 sarily without glass fronts, hide whatever may be within them. 
 
 Let us suppose that we have three of these tables, accommo- 
 dating, if need be, eighteen pupils in individual work. 
 
 If now we had a very long room lighted on one side, we 
 might put all the tables in line near the windows; but this 
 The Labora- would not be a very good arrangement, for it would 
 toiy Room. p ut one ii ne O f p U pil s w ith their backs to the light, 
 and the other line with their faces to the light, a disposition 
 of the class unfavourable in some exercises to those facing the 
 windows ; for sometimes the parts of the apparatus demanding 
 their most critical observation would be in the shadow of other 
 parts. We will suppose the room (see A in Fig. 20) to be 
 oblong, lighted on one side and one end, and will place the 
 tables, i, 2, 3, crosswise of this room, with one end of each 
 distant about 3 feet from the lighted long side. A shelf sup- 
 ported by brackets on the wall is very useful, and we will sup- 
 pose such, a shelf, 15 inches wide, to run along the lighted end 
 of the room at the height of the working tables. See 7. Our 
 room should contain also a large soapstone sink, 5a, with an 
 adjacent slop-table, 5, for holding battery materials, etc., a table 
 for reference books, 4, another, 6, for demonstration apparatus, 
 a wall blackboard, 9, and a long row of cases, 8, for storing ap- 
 paratus. Ample provision of space for all these things, arranged 
 as in Fig. 20, A, gives us a room 35 feet long and 25 feet wide. 
 
PLAN AND EQUIPMENT OF A LABORATORY 351 
 
 * 
 
 The apparatus cases should be about 2 feet deep, easy range 
 for the adult arm, and the top not more than 6.5 feet above 
 the floor. Much bulky apparatus, of such a nature Apparatus 
 as not to be easily injured, can well be placed on Cases etc - 
 top of the cases. The shelves should be adjustable at various 
 heights, unless some one knows the apparatus well enough to 
 place them in advance. The highest shelf should not be more 
 than 5 feet above the floor. 
 
 A few drawers, for cork-stoppers, rubber tubing, small hard- 
 ware, etc., and a few cupboards for glassware, crockery, record 
 books, and other things more useful than sightly, can be placed 
 in, or under, the tables for books and demonstration apparatus. 
 
 Nothing has yet been said here in regard to the height of the 
 laboratory ceiling, or the number and dimensions of the win- 
 dows. It goes without saying that the room should be well 
 lighted. Fig. 20 indicates seven windows, each 4 feet wide. 
 As to the height of the ceiling, there are few experiments which 
 demand greater height than that of the ordinary room in a mod- 
 
352 PLAN AND EQUIPMENT OF A LABORA TORY 
 
 ern, well constructed, school building, and it would be hardly 
 justifiable to make an exceptional height for the sake of these 
 few experiments. 
 
 We must presently consider the lecture-room and the prepa- 
 ration-room, or workshop. As the latter is a necessary adjunct 
 
 to both the laboratory and the lecture-room, it may 
 Workshop. J 
 
 well be placed between them, if this arrangement 
 
 is consistent with the general plan of the school-building, of 
 which we assume the rooms for physics to be a part. A common 
 form for such a building, in the case of public schools, is a long 
 main body, with rather broad hall-ways, or passageways, run- 
 ning along its rear, and with a wing at each end. At the end 
 of a passageway (see E, Fig. 20), and in line with it, there is 
 likely to be a long narrow space, sometimes utilized as a coat- 
 room. This space, which I shall assume to be 10 feet wide, 
 will here be taken as a workshop and general utility room (B, 
 Fig. 20). Circumstances must determine whether the lecture- 
 room or the laboratory shall occupy the rear of wing. 
 
 The plan shown in Fig. 20 does not undertake to provide 
 for instruction in the use of tools, or for the manufacture of 
 much apparatus, but only for such operations of construction 
 and repair as the energetic teacher must be prepared to under- 
 take. This equipment should include a work-bench and a lathe, 
 with tools for working in both metal and wood, an emery wheel 
 for sharpening tools, and facilities for soldering and glass-blow- 
 ing. The last two operations may use a blast lamp in common, 
 and should therefore be carried on near each other. The blast 
 of air for the lamp can be furnished by means of a Richards 
 pump, with compression chamber, placed in a sink. From 
 such a pump, with a good head of water, a sufficient current of 
 air for the lamp can be carried many feet through a half-inch 
 pipe. The teacher should have also at his service an outfit for 
 photographing and for blue-printing, and the dark room for 
 developing may well be placed at the inner end of the work- 
 room. Of course there should be shelves and a case of drawers 
 for stock and tools. 
 
PLAN AND EQUIPMENT OF A LABORATORY 353 
 
 All these things being placed, and also an .electric motor for 
 i power, which may be on the floor or on a platform above the 
 i rest of the machinery, there will remain in room B a consider- 
 i able amount of space available for storing the lecture-room 
 | apparatus. The most convenient way of getting such apparatus 
 I into the lecture-room, C, is through a door in the middle of the 
 i wall behind the lecture- table. 
 
 The width of the lecture-room, as shown in Fig. 20, is 35 feet. 
 The depth I leave undetermined, as that should depend on the 
 number of pupils it will be required to hold. The Lecture- 
 common practice of making the width of a lecture- Room ' 
 room much greater than its depth is unfortunate. The front 
 seats at the sides in such a room are undesirable, for they give 
 a very oblique and therefore indistinct view of things on the 
 blackboard which is behind the lecture-table. 
 
 The lantern-screen is also supposed to be behind this table, 
 on a roll which draws it up out of sight when it is not needed ; 
 but, if the ceiling is high, the wall space above the blackboard, if 
 finished smooth and white, serves exceedingly well as a screen 
 for projections. The lantern itself is supposed to be at the 
 rear of the room. The one window shown in the wall of C 
 is supposed to be on a level with the lecture-table, so that 
 a mirror placed at this window will put the sun's rays at the 
 service of the lecturer, provided this window has a southerly 
 outlook. 
 
 At the lecture-table sink it is well to have two faucets, one of 
 which should end in a screw, so as to admit of ready connec- 
 tion with an aspirator. It is well to provide the Some 
 table with a horizontal adjustable bar carried by Equipments, 
 end posts, like the bar and posts of the working-tables (see 
 Figs. 18 and 19) ; but as these objects might sometimes obstruct 
 the view of something on exhibition beyond them, the posts 
 should be so attached to the table as to be easily removed or 
 replaced. 
 
 For a source of low voltage electricity, which one needs to 
 use occasionally at the lecture-table, the arrangement illustrated 
 
 23 
 
354 PLAN AND EQUIPMENT OF A LABORATORY 
 
 by the following diagram (Fig. 21) is to be recommended: 
 Si and S 2 are two storage cells of the ordinary type, connected 
 with each other in series through the binding-posts b 2 and 
 b 8 . These cells are charged by a battery, DD, of six large 
 gravity Daniell cells connected with each other in series. The 
 connections here shown are maintained all the time, so that the 
 storage cells are always ready for use. If two volts are needed 
 for use in any experiment, connection is made with the binding- 
 posts bi and b 2 , or with b 3 and b 4 . If four volts are needed, 
 connection is made with b L and b 4 . All the cells should be 
 covered so as to diminish evaporation. 
 
 Fig. 21 
 
 A convenient and useful device for controlling strong currents 
 by variation of resistance is in the form of a column of carbon 
 plates, each about four inches long and \ inch thick, held in a 
 frame between two thick end plates of brass, one of which can 
 be pressed against the adjacent carbon plate by means of a 
 screw passing through one end of the frame. The greatest 
 defect of this device is that one cannot tell, without some sup- 
 plementary measuring instrument, how great its resistance is at 
 any given instant. 
 
 The reflecting galvanometer (see Figs. 15 and 16, Chapter 
 VIII.), if the lecture-room is provided with such an instrument, 
 can be placed, when in use, on a shelf just below the blackboard, 
 the inclined screen being placed above the blackboard, or the 
 whole outfit can be put in one corner of the room in place of 
 the triangular apparatus case, 22 of Fig. 20. 
 
 If the school is one in which the physics class is small, the 
 
PLAN AND EQUIPMENT OF A LABORATORY 355 
 
 laboratory room, with little or no change from its plan as already 
 given, can be used as a lecture-room. 
 
 I have said little in this book in regard to the general body 
 of apparatus with which the physics department of a well 
 equipped school should be provided, and I shall 
 not now undertake to treat of this matter at length. pparatus ' 
 Accompanying the Harvard Descriptive List of laboratory 
 exercises is a detailed list of apparatus for these exercises, 
 which is the product of years of experience and suggestion and 
 gradual development. Much of this apparatus, which is simple 
 and inexpensive, would be useful in any beginner's course of 
 laboratory physics, looking toward college or not looking 
 toward college. Moreover, several manufacturers of school 
 apparatus keep the articles of the Harvard list in stock and 
 know these articles by the numbers they bear in that list, a fact 
 which facilitates ordering from them if one has the Harvard 
 list at hand. 
 
 As to the apparatus for lecture-room purposes, almost any 
 modern descriptive text-book is a fairly good guide, though of 
 course one should compare various books and various catalogues 
 of dealers in apparatus before making any large purchase. 
 
CHAPTER XIII 
 
 PHYSICS TEACHING IN OTHER COUNTRIES 
 REFERENCES. 
 
 Board of Education of the English Government. Special Reports 
 on Educational Subjects. 
 
 British Association Reports, in many places ; for example, in 1889 and 
 1890, " Suggestions for a Course of Elementary Instruction in Physical 
 Science." 
 
 Delalain Freres, 115 Boulevard Saint-Germain, Paris, official pro- 
 grammes of primary and secondary instruction in France. 
 
 Russell, J. E. German Higher Schools. New York and London, 
 Longmans, Green & Co. 1899. ^P- 4^7- 
 
 Sharpless, I. English Education. New York, Appleton & Co. 
 London, E. Arnold. 1892. Pp. 193. 
 
 WITHOUT undertaking an examination of the state of elemen- 
 tary physics teaching in all European countries, we may well 
 inquire what it is in Germany, England, and France ; for these 
 are the countries to which, rightly or wrongly, Americans are in 
 the habit of looking for suggestion and instruction. 
 
 Germany has a well established system of physics teaching in 
 her schools as well as in her universities, and this system, if it 
 is not the cause of her eminence in physical research and her 
 success in commercial scientific undertakings, is at least con- 
 temporaneous with these achievements. England has for a 
 number of years studied German methods of secondary educa- 
 tion in science, hoping thus to find and profit by the secret ol 
 her dangerous commercial activity. It is well, therefore, that 
 we should look first at these same methods as they are found 
 in German schools below the universities. The numerous 
 
PHYSICS TEACHING IN OTHER COUNTRIES 357 
 
 quotations given below, from Russell's German Higher Schools?- 
 make this task easy. 
 
 It should be said in advance that in both classes of the 
 higher schools, the classical gymnasiums and the ra*/-schools, 2 
 the full course of study is nine years, which, beginning with the 
 year of the lower class, are numbered thus, sexta, quinta, quarta, 
 unter-tertia, ober-tertia, unter-secunda, ober-secunda^ unter-prima, 
 ober-prima. Many pupils, however, leave the schools at the 
 end of six years, there being a well defined break in the course 
 at that point. 
 
 (From p. 330.) " The chief aim of all instruction in the 
 natural sciences [ including physics ] is to cultivate the habit of 
 keen and accurate observation, to strengthen the pupil's reason- 
 ing powers and to increase his ability of expressing clearly what 
 he sees and thinks. The acquisition of a fund of systematic 
 knowledge or useful information is a secondary consideration." 
 
 After remarking (p. 333) that "the science work in the Real- 
 schools is taken more seriously than in the Gymnasien," the 
 author gives, " as a type of what is done in Prussia the course 
 of study prescribed in the Konigstadtisches Realgymnasium of 
 Berlin." The physics of this course is, 
 
 " Unter-secunda. [Sixth year]. Physics, 3 hours [per week]. 
 First semester : Frictional electricity and phenomena out of 
 [taken from] the domain of magnetism and galvanic electricity. 
 Acoustics and optics. Second semester : Mechanics of solid, 
 liquid, and gaseous bodies. General properties of matter. 
 Parallelogram of forces and of motion. Laws of falling and 
 vertically projected bodies. The simple machines. Text-book, 
 Jochmann, Grundriss der Experimental Physik" 
 
 " Ober-secunda. Physics, 3 hours. First semester : Mag- 
 netism and galvanic electricity. Second semester: Heat, 
 repetition and extension of mechanics, especially of oblique 
 projection and of central motion. Text-book, same as in 
 Unter-secunda . ' ' 
 
 1 Longmans, 1899. 
 
 2 The Realgymnasien and the Obtrrealschulm. 
 
358 PHYSICS TEACHING IN OTHER COUNTRIES 
 
 " Unter-prima. Physics, 3 hours. First semester : Wave 
 theory, acoustics and optics. Second semester : Mechanics. 
 In both semesters, reviews and more thorough mathematical 
 treatment of particular parts of the earlier work. Solution of 
 problems. Text-book, same as in Unter-secunda. (Physical 
 laboratory exercises, 2 hours, optional.) " 
 
 " Ober-prima. Physics, 3 hours. First semester : Optics. 
 Second semester : Mechanics. In both semesters, reviews and 
 more thorough discussion of parts of the earlier work, especially 
 quantitative determinations and methods of measurement. 
 Text-book, same as above. (Physical laboratory exercises, 2 
 hours, optional.) " 
 
 (From p. 345.) " According to the Prussian syllabus of 1892, 
 the course in physics is divided into two parts. The first part 
 is intended to give the pupil some notion of the fundamental 
 principles of the subject as exemplified in the ordinary and 
 more familiar manifestations of nature ; it is concluded 
 with Unter-secunda. The continuation of the course aims to 
 give those who may pass on to the university a more compre- 
 hensive understanding of physical laws and their applications. 
 This division is in strict accord with a prevailing idea of the 
 Berlin Conference [in which the present Emperor figured so 
 prominently], that those leaving school at sixteen should have 
 as symmetrical a training as it is possible to provide. Only the 
 most important principles are taught in the first part of the 
 course, and much stress is put upon the application of these to 
 the practical affairs of every-day life. 1 
 
 " The advanced course is first of all a repetition and exten- 
 sion of the earlier work, and in the second place a more 
 extended mathematical treatment of the subject. This latter 
 phase of the work can be done successfully only in the Real- 
 schools, inasmuch as the mathematics taught in most Gymna- 
 sien is insufficient for the purpose." 
 
 1 " Full information of what may be accomplished in this preliminary 
 course may be found in the Zeitschrift fur den physikalischen und chem- 
 ischen Unterricht, JahrgangN, Heft 4 (April, 1892)." 
 
PHYSICS TEACHING IN OTHER COUNTRIES 359 
 
 (From p. 346.) " A text-book is always employed in teach- 
 ing physics and chemistry, precisely in the same manner as in 
 teaching natural history. But, unlike the methods commonly 
 used in American and English schools, German teachers invari- 
 ably use these books for reference only. It is not expected, 
 however, that they will take the place of the elaborate compen- 
 diums found in each school-room ; they are mere outlines of the 
 subject, intended to assist the pupil in making scientific classi- 
 fications, not for purposes of recitation. In fact, as we have 
 repeatedly observed, the German teacher never assigns a lesson 
 in advance to be studied at home. Recitations, therefore, at 
 least in the American sense, are unknown. 
 
 "A typical lesson always includes a review of the principles 
 and experiments of past lessons which have a direct bearing 
 upon what is next to be presented. The teacher explains the 
 nature of the apparatus with which he is to deal, and places it 
 upon his desk in full view of the entire class. . . . Certain 
 conditions are stated, and the class questioned as to what results 
 may reasonably be expected. This preliminary discussion hav- 
 ing carefully prepared the way for a right understanding of 
 the experiment, the demonstration by the teacher follows. The 
 students are required to make note of the apparatus used, the 
 principles involved, the conditions under which the reaction 
 occurred and the results obtained. By means of a running fire 
 of questions, the teacher keeps himself informed in regard to 
 the menial state of his class ; for it is his duty to see not only 
 that all understand the trend of the experiment, but also that its 
 significance is realized. 
 
 " German practice is always consistent in its adherence to the 
 idea that good teaching never leaves the pupil in doubt. In 
 mathematics he is not assigned a problem to wrestle with by 
 himself alone," etc. 
 
 " Every principle worth demonstrating is illustrated in class. 
 But the teacher does more than demonstrate ; he teaches as 
 well. And successful teaching requires that present impressions 
 be definitely related to past experiences. Wrong relationships, 
 
360 PHYSICS TEACHING IN OTHER COUNTRIES 
 
 or none at all, are an inevitable consequence of misapprehension. 
 For this reason the German teacher counts it his duty to prevent 
 his students drawing wrong inferences. They have not yet 
 arrived at the stage of independent study ; that comes in the 
 university. In secondary schools no time should be wasted in 
 beating about the bush. The ability to make an occasional 
 lucky guess is in nowise identical with sustained logical thought. 
 
 " At the conclusion of a lesson topic, the pupil is directed to 
 consult his text-book and afterward write up his notes. This 
 done, the teacher inspects the book at his leisure. 
 
 " Laboratory exercises, if required at all, are introduced at 
 this point, in order that students may themselves duplicate the 
 experiment performed by the teacher or make other demonstra- 
 tions putting to practical test the knowledge just acquired. The 
 function of laboratory practice, as will be seen, is to make appli- 
 cation of facts already learned, not at all for the purpose of pre- 
 senting new truths or arriving at new deductions. Inasmuch as 
 laboratory practice is optional, and the exigencies of the time- 
 card usually place it out of school hours, few students enter for 
 it." 
 
 (From p. 348.) " Probably the best adducible evidence of 
 the relative value of the various studies, as popularly estimated, 
 is the part each plays in the final examination. Judged in this 
 way, the sciences take a low rank. Physics may be counted as 
 a fourth part of mathematics in the gymnasial examination ; in 
 the J?#z/-schools, one problem is assigned in physics and one in 
 chemistry. 1 The worst of it is that, ' nothing short of a miracle,' 
 to quote a German teacher, ' can prevent the promotion of the 
 most deficient member of the class, provided his attainments be 
 satisfactory in other subjects.' " 
 
 There is much to be commended in the physics instruction 
 which the German boy receives. It does not attitudinize, does 
 
 1 A foot-note here gives problems set at the final examination (Ar- 
 biturientenprlifung) of a Realgymnasium. The problems in physics are 
 simple, involving the use of Ohm's law, the tangent galvanometer and 
 Wheatstone bridge. 
 
PHYSICS TEACHING IN OTHER COUNTRIES 361 
 
 not call itself by a name which it cannot live up to ; it drives 
 straight and hard at some of the most important objects of 
 study, a useful knowledge of physics and a useful habit of look- 
 ing at and thinking about those physical phenomena which are 
 presented to the pupil's view. I do not feel disposed to criti- 
 cise German school-teaching as too little " inductive " or " heur- 
 istic," though possibly it may be so. Its chief defect, and a 
 serious one, seems to be that it does not give the pupil labora- 
 tory work for his own hands, and therefore leaves him wanting 
 in that actual experience of apparatus which is so important for 
 any one who must conduct or devise experiments or make any 
 objective use of physics. Transported to America, where the 
 incentives to scholarly effort on the part of young pupils are at 
 present much less strong, and where teachers are less thoroughly 
 equipped, than in Germany, the German school system of 
 physics teaching would probably not work well. 
 
 When we turn from Germany to England, and attempt to 
 realize the state of science teaching in the schools of the latter 
 country, the field of view grows suddenly obscure. For, as 
 compared with Germany, England can hardly be said to have 
 a system of education : she has rather a state of development, 
 and in some respects a rapidly changing state, the changes 
 being as rapid in science instruction as in any other. 
 
 The Special Reports on Educational Subjects issued by the 
 English Government 1 contain a good deal of interesting matter 
 relating to instruction in science. In volume 6 (1900) Mr. 
 Archer Vassall, Assistant Master at Harrow, writes as follows : 
 
 " In Public Schools [the endowed schools like Rugby, 
 Eton and Harrow] the teaching of science has only recently 
 begun to take reasonable shape, and ceased to be a series of 
 fireworks, or isolated physical phenomena, presented in a 
 casual and indigestible manner to the pupil ; while there has 
 been so little of it in the Preparatory Schools [preparatory to 
 
 1 Vols. 1-3 by the " Educational Department," later volumes by the 
 " Board of Education." 
 
362 PHYSICS TEACHING IN OTHER COUNTRIES 
 
 the endowed Public Schools] that its past and present state in 
 these institutions does not require any long exposition. 
 
 "Nevertheless, now that the large number of subjects in- 
 cluded under the head of Science are more reasonably taught 
 to elder boys and others, there has arisen a fairly widespread 
 feeling, amongst both parents and schoolmasters, that some 
 elementary information on scientific subjects should be given 
 to boys whilst still at Preparatory Schools, and that these sub- 
 jects afford valuable material for educating the minds of such 
 boys. To their credit be it said, Board Schools and Girls' 
 Schools have for some time realized this fact, and in many of 
 them scientific subjects find a place in the curriculum. 
 
 " In .Preparatory Schools the result of this inclination has 
 been that several tentative efforts in scientific instruction have 
 been made, and are still in progress at many of them, though 
 nothing approaching the systematic ' nature study' of the 
 young American has as yet been achieved." 
 
 Mr. Vassall's opinion, as shown in this article, is in favour of 
 physics, for preparatory schools, rather than chemistry, and 
 strongly for laboratory work combined with lectures, rather 
 than lectures alone. 
 
 Volume 2 of the Reports contains (pp. 389-413) an article 
 on " The Heuristic Ifethod of Teaching or The Art of Making 
 Children Discover Things for Themselves," by Professor Arm- 
 strong. The " British Association Scheme " of science instruc- 
 tion, to which he frequently refers, was the outcome of the work 
 of a committee of the association, which was appointed in 1887 
 and reported in each of the three following years. In 1889 
 and 1890 the committee printed in its reports Suggestions for 
 a Course of Elementary Instruction in Physical Science, by 
 Professor Armstrong, who was a member of the committee. 
 It is evident that these reports have had much influence in 
 England, and Professor Armstrong, in the article named above, 
 claims a very marked degree of success for teaching inspired 
 by the methods and principles set forth in " The British Asso- 
 ciation Scheme." He states in this paper that in 1897 this 
 
PHYSICS TEACHING IN OTHER COUNTRIES 363 
 
 scheme " was in operation in no fewer than 40 of the London 
 Board Schools." 
 
 In general terms this scheme, as originally set forth, is to 
 train the pupil from childhood to observe, think about, and 
 experiment on, common things, air and common liquids and 
 earthy materials, for example, not with a view to making him 
 by and by a specialist in chemistry or physics, but for the 
 purpose of forming certain important habits and cultivating 
 certain important powers, while giving a considerable amount 
 of directly useful information. It is admitted that progress 
 will be slow, as it is in all the other important studies of child- 
 hood, but great things in the way of preparation for the inevi- 
 table and unending conflict of nations, in commerce, industry, 
 and war, are hoped for by the advocates of this scheme of 
 instruction, if it is undertaken and persistently carried out. 
 
 The title of Professor Armstrong's paper should be read in 
 the light of the following passage (p. 407), by which it appears 
 that the " method of discovery " by individual pupils is not 
 rigidly adhered to. " No books will be used, but the class will 
 gradually write its own book and so come to understand how 
 books are written ; for whenever an object has been properly 
 studied, the teacher, instead of dealing with the scholars in- 
 dividually, will call them to order as a class, and by judicious 
 questioning will then elicit all that is needed for the description 
 of the work done. The simplest possible account will be 
 written on the blackboard as the questioning proceeds, and at 
 the close of the lesson a senior pupil will copy this with a 
 typewriter, and each member of the class will afterwards receive 
 a copy, which will at once be pasted in a book, to be kept for 
 reference and used as a reader." 
 
 Appendix A to the paper of Professor Armstrong gives the 
 " Course of Instruction in Elementary Science adopted [in 
 1896] by the Incorporated Association of Headmasters" of 
 secondary schools l for pupils commencing the study of physics. 
 
 1 According to Sharpless, EnglisJi Education (Appleton, 1892), " Sec- 
 ondary education [in England] is now in the hands of a number of 
 
364 PHYSICS TEACHING IN OTHER COUNTRIES 
 
 Professor Armstrong speaks of this syllabus as " based on the 
 British Association scheme." It is worthy of careful examina- 
 tion. The headings under Elementary Physics are : 
 
 1. Measurement of Length. 
 
 2. Measurement of Area. 
 
 3. Measurement of Volume. 
 
 4. Measurement of Mass. 
 
 5. Measurement of Density. 
 
 6. Measurement of Thrust and of Pressure, of Pull and of 
 Tension. Distinction between solids, liquids, and gases. 
 
 70 Measurement of the force which a liquid exerts upon 
 a body immersed in it. 
 
 8. Measurement of Temperature. 
 
 9. Measurement of Quantity of Heat. 
 
 10. Measurement of Vapour Pressure. 
 
 11. Measurement of Force in pounds or grams weight, and 
 their Graphic Representation. 
 
 12. Resolution of Forces. 
 
 13. Equilibrium of Three Forces. 
 
 14. Equilibrium of Four or more Forces. 
 
 15. Parallel Forces. 
 
 1 6. Centre of Gravity. 
 
 17. Principle of Moments, Levers. 
 
 1 8. Simple Machines. 
 
 According to Professor Armstrong (p. 397) the Oxford 
 and Cambridge Local Examination Authorities have tried to 
 make examinations suited to the science syllabus of the Head- 
 masters' Association. " Unfortunately, however, their instruction 
 in no way whatsoever imply or involve heuristic teaching ; and 
 it is only too clear that that which is fundamental in the recom- 
 mendations of the British Association scheme has not been 
 understood." This was printed in 1897-1898 ; things may be 
 different now. 
 
 private schools of all degrees of goodness and badness, of a few non- 
 conformist denominational schools which are usually good, and of the 
 endowed schools for boys" (Public Schools and Grammar Schools). 
 
PHYSICS TEACHING IN OTHER COUNTRIES 
 
 The general tendency of Professor Armstrong's writing seems 
 to be to discourage the use of printed books and to make the 
 pupil distrust accounts of what has not been seen by himself or 
 his classmates. American teachers should, I think, be slow to 
 follow this suggestion. The ordinary American boy is only too 
 willing to act on the hint not to study books on physics. He 
 will do laboratory work cheerfully enough, even when he has 
 only the dimmest idea what it is all about, but he shrinks from 
 the, to him, painful effort of getting from a book the definitions 
 and the reasoning necessary to make the laboratory work intel- 
 ligible. This is not because he has any predilection for the 
 " heuristic " method ; for he delights to be told things by word 
 of mouth instead of seeking them out for himself, and, if not 
 persistently discouraged from the practice, will habitually stand 
 with an open book before him and ask for information that is 
 plainly given on the printed pages beneath his eyes. Nor does 
 the disinclination to reading necessarily disappear with youth. 
 It often persists into manhood and renders fruitless the labour 
 of years. 
 
 Is it not quite possible that the scientific pre-eminence of the 
 Germans as a race is due largely to their habit of reading widely 
 and thoroughly, of mastering by reading not only the bulky 
 treatises and periodicals of their own language, but also the 
 scientific publications of foreign tongues? Consider the signif- 
 icance and influence of such a journal as the BEIBLATTER to the 
 ANNALEN DER PHYSIK. What testimony it gives to the zeal 
 of the Germans in the study of science through the printed 
 page. 
 
 The completeness with which the educational system of 
 France has been worked out by a thoughtful and ingenious 
 people makes it worthy of study. The official programmes of 
 primary and secondary instruction, with which we are concerned, 
 are set forth in considerable detail in frequent publications 
 issued by Delalain Freres, 115 Boulevard Saint-Germain, Paris. 
 Any one can by reading these programmes get a fair idea of 
 
366 PHYSICS TEACHING IN OTHER COUNTRIES 
 
 what is being done in schools of any given class throughout 
 France. 
 
 In examining with considerable care the parts relating to 
 physics in the official programmes of the various kinds of schools, 
 I have found nothing anywhere which seems to require or to 
 provide for experimental work to be done by pupils, though I 
 am informed that laboratories for pupils in physics do exist in 
 some lycees. Indeed, for students taking the classical course 
 I find ^nothing under chemistry, even, which seems to make 
 provision for laboratory work by pupils until the Classe de 
 Mathcmatiques Specials, for young men who have completed 
 the ordinary lycee course, is reached. Here twelve chemical 
 " manipulations," each, apparently, occupying the student four 
 hours, are strictly prescribed. 1 In the " modern " course of the 
 lycees there is some little provision for laboratory work in 
 chemistry in the third class, the second class, and the first class 
 (sciences], about eighty hours in all. 
 
 In the elementary primary schools there are object lessons 
 (lemons de chases). Although the object of the primary school 
 instruction is frankly and emphatically utilitarian, an attempt is 
 made to cultivate the philosophical imagination of the pupils. 
 " In all instruction, the master, at the beginning, makes use of 
 tangible objects, has the children see and touch the things, puts 
 them in the presence of concrete realities ; afterward, little by 
 little, he exercises them in getting at the abstract idea from the 
 
 1 An official order relative to these exercises, which order was written 
 in 1854, and is apparently still in force, runs thus: "The pupils ought 
 never to be left to themselves during the manipulations. These should 
 always be preceded by a conference, in which are set forth, with all 
 necessary details, the operative processes relative to the manipulations 
 which the pupils are to perform. In describing these operations the 
 professor executes them, making use of the same apparatus which the 
 pupils are to use. Finally, the apparatus, mounted in advance, is dis- 
 played before their eyes, which indicates all the dispositions which they 
 will have to observe in the arrangement of the pieces which compose it." 
 This order affords a good example of the care and precision with which 
 official instructions are issued to teachers in the public schools in France. 
 
PHYSICS TEACHING IN OTHER COUNTRIES 367 
 
 objects, in comparing and generalizing, in reasoning without 
 the aid of material examples." 
 
 In the higher primary schools for boys we find 
 
 " Physics and Chemistry. (Two hours a week [for both, not 
 for each] during the three years.) General Remark. In each 
 year the course in physics and chemistry will be essentially ex- 
 perimental." That is, the lessons are to be illustrated by 
 lecture-table experiments. 
 
 " Physics. FIRST YEAR. Heat. In general, bodies expand 
 under the influence of heat. Simple experiments. They 
 expand unequally. 
 
 " Temperature. Mercury thermometer. Graduation. 
 Centigrade Scale, degree centigrade. Maximum and mini- 
 mum thermometers," etc. 
 
 The general course is the same for all three sections, com- 
 mercial, industrial, and agricultural, but with applications vary- 
 ing from one section to another, "according to the special 
 needs of each." 
 
 In the higher primary schools for girls the physics of the 
 first two years is identical, so far as the official programmes 
 of topics show, with that of the same years in the corres- 
 ponding schools for boys, but the like is not true of the third 
 year. 
 
 As the time allowed for physics and chemistry together 
 in these schools for girls is only one hour a week for the 
 three years, just one -half as much as the time given to the 
 same subjects in the corresponding school for boys, it is evi- 
 dent that the instruction received by girls is comparatively 
 superficial. 
 
 In the first three years, " Division Elcmentaire" of the course 
 in the lycc'es and colleges for boys, there are object lessons, one 
 hour a week, which include a little physics. A note of instruc- 
 tion given in connection with the science of the preparatory 
 
368 PHYSICS TEACHING IN OTHER COUNTRIES 
 
 class, and repeated over and over again with reference to the 
 science of subsequent classes, up to the Classe de Rhetorique, 
 is the following : " Professors are especially charged to spare no 
 pains to make the demonstrations and the relations of facts well 
 understood, and not to dictate their courses. They may, if they 
 think it best, put into the hands of the pupils an autographic 
 text or a book which will relieve them from the necessity of 
 developing personally all parts of the course." 
 
 During the next three years, Division de Grammaire, there is 
 in the classical course, and also in the " modern" course, a 
 little of zoology, of botany, and of geology, but there is nothing 
 of physics, as such, or of chemistry, in either course. 
 
 Indeed, there is in the classical course of the lycees no study 
 of physics under its own name until the Classe de Rhetorique, 
 the ninth year of the course, is passed ; then the student has, in 
 the Classe de Philosophie, five hours a week divided between 
 physics and chemistry, or, in the Classe de Mathematiques 
 Elementaires , in addition to some study of elementary mechan- 
 "ics, six hours a week divided between physics and chemistry. 
 Of course the physics work done in these classes is elementary, 
 a fact sufficiently illustrated by the following list of " Comple- 
 ments" with which the physics programme of the Classe de 
 Mathematiques Elementaires ends : 
 
 " Laws of falling bodies. Atwood's machine. Morin's 
 machine. 
 
 " Proportionality of forces to accelerations. Mass. Its 
 measure by means of weight. 
 
 " Pendulum. Applications. 
 
 " Very elementary notions of work, vis viva, energy, the 
 mechanical equivalent of heat. 
 
 "Various forms of energy. Principles of the conservation 
 of energy. 
 
 " The steam-engine. Condenser. Expansion." 
 
 This brings the student in the classical course to his bacca- 
 laureate. His opportunities to learn physics have been, appa- 
 
PHYSICS TEACHING IN OTHER COUNTRIES 369 
 
 rently, about the same as those afforded by American colleges 
 having the old-fashioned non-elective course. 
 
 In the " modern course " of the lycces, physics, as such, is 
 taken up earlier, three hours a- week being divided between it 
 and chemistry in the Classe de Troisieme, the seventh year. 
 The spirit -in which it is to be taught is indicated by the fol- 
 lowing official extract from some report : " The professor of 
 sciences will not lose sight of the fact that the object of his 
 instruction is not solely to teach his pupils a certain number of 
 acquired facts, but that it is also, particularly in the course of 
 modern studies, where the sciences hold a large place, to con- 
 tribute to the general culture of the mind. He will, therefore, 
 so act that the high educative virtue peculiar to science, which 
 those profit by who give themselves up to it, shall be in force 
 as much as possible in his teaching." This precept is meant 
 to apply to the science teaching in general ; but under the head 
 of physics and chemistry the following direction is given : "To 
 the demonstration of scientific truths the professor will add 
 upon occasion the exposition of methods [of measurement or 
 research] and the history of discoveries." The physics of this 
 third class consists of the elementary study of gravity and heat. 
 In the next year, second class, when four hours a week are 
 divided between physics and chemistry, the work deals with 
 electricity, magnetism, acoustics, and optics. 
 
 On leaving the second class (eighth year) the student may 
 enter the first class (letters) in which there is no physics, the 
 first class (sciences), in which four hours a week are divided be- 
 tween physics and chemistry, or the Classe de Mathematiques 
 Elementaires, in which, as we have already seen, six hours a 
 week are divided between physics and chemistry. So far as one 
 can see by the official programme, the physics course of this last 
 class is precisely the same for those who have come through 
 the modern course as for those who have come through the 
 classical course, although it has been preceded by considerable 
 physics study in the modern course, and by almost none in the 
 classical course. 
 
 24 
 
370 PHYSICS TEACHING IN OTHER COUNTRIES 
 
 In the lycees and colleges for girls there is no physics, as 
 such, until the third year, when the pupils are about four- 
 teen years of age. In this year two hours a week are di- 
 vided between physics and chemistry, the former science, 
 apparently, having the greater part of the time. The subjects 
 taken up in physics are all under the headings Gravity and 
 Heat. 
 
 In the next year, the fourth of the course, one and a half 
 hour per week is given to physics and chemistry, the physics 
 topics treated being all under the headings Acoustics and Optics. 
 In the next year, the last year of the regular course, physics and 
 chemistry together have two hours per week, the physics relating 
 to magnetism and electricity. 
 
 The total time, then, for physics and chemistry in the lyde 
 course for girls amount to five and a half hours a week for 
 one year. This is about one-quarter of one year's work, the 
 total number of hours of stated instruction being twenty-one per 
 week in the third year and twenty-four per week in each of the 
 two following years. 
 
 It appears, then, that the physics work of French schools 
 is light and expansive, descriptive, somewhat historical, some- 
 what philosophical. It is, no doubt, skilfully conducted. Yet 
 we need not be surprised that philosophers 1 have little respect 
 for it, as a means of sound discipline, in comparison with Latin 
 and Greek ; for it is evidently intended to be an entertaining 
 and informing rather than a formative study. 
 
 On the whole, it appears that the best secondary schools in 
 America, in trying the experiment of teaching physics by means, 
 in part, of laboratory work done by the pupils, have little or 
 nothing to learn from the corresponding schools in France, 
 Germany, or England. For France has apparently never 
 dreamed of such an undertaking, Germany has never seri- 
 
 1 See Fouillee, Education from a National Point of View, Chapter II. 
 
PHYSICS TEACHING IN OTHER COUNTRIES 3/1 
 
 ously considered it, and England is no farther along with it 
 than we are in America, if indeed she is as far. If we make 
 a final and permanent success of this venture, as we seem likely 
 to do, Europe will have an opportunity to learn from us, and 
 we may in this way be able to repay in some small measure the 
 educational debt which we have owed to her so long. 
 
Index 
 
 [CHEMISTRY, pp. 1-227. PHYSICS, pp. 229-371.] 
 
 ACADEMIC and formal treatment, 
 61, 64. 
 
 Acceleration test of mass, dis- 
 cussion of observations on, 
 283- 
 
 Accidents in the laboratory, 125. 
 
 Action and reaction, discussion of 
 observations on, 284. 
 
 Affinity, 147. 
 
 Allotropism, 145. 
 
 America, chemical instruction in, 
 21, 57, 60. 
 
 Ann Arbor, influence of in Physics, 
 272. 
 
 Apparatus (Chemistry), blanks 
 for, 196; care of, 199; dealers 
 in, 199; for lectures, 201; list 
 of, 197. 
 
 Apparatus (Physics), arrangement 
 f> 33 > general, 355 ; redupli- 
 cation of, 291 ; teacher's record 
 of, 302. 
 
 Apparatus cases, 351. 
 
 Application to every-day matters, 
 importance of (Chemistry), 68, 
 74, 129, 138, 177. 
 
 Applications (Physics), 314. 
 
 Arithmetical blunders of pupils, 
 287. 
 
 Armstrong, Prof. H. E., on heuris- 
 tic teaching. 105, 106, 362. 
 
 Arnott's Elements of Physics, 268. 
 
 Arrangement, principles of, his- 
 torico-systematic, 55, 59; nature 
 study method, 53, 54, 56; theo- 
 retical, 53, 54, 58. 
 
 Articulation of school and college 
 
 work, 44-48. 
 Atomic theory, 79, 81, 154-162, 
 
 164. 
 
 Atomic weight, definition of, 165. 
 Avogadro's hypothesis, 54, 61 ; 
 
 incomplete discussion advisable, 
 
 76. 
 
 BALANCES, 116, 195, 255, 257, 
 285. 
 
 Battery, theory of, 169. 
 
 Bending, discussion of observa- 
 tions on, 281. 
 
 Bibliography (Chemistry), 219; 
 (Physics), 324 (see also refer- 
 ences at heads of chapters and 
 sections). 
 
 Book-learning, indirectness of, 93. 
 
 Britain, chemical instruction in, 
 !9 57- 
 
 Brookline high school, physics in, 
 
 337- 
 Burns, treatment of, 126. 
 
 CALCULATION, by pupil, on labo- 
 ratory work, 298. 
 Cause, 150. 
 
 Change and variety, need of, 251. 
 Child's experimental knowledge, 
 
 3 T 7- 
 
 Characteristics, of chemical 
 change, 69-75 5 f work in sci- 
 ences, 8-16, 50-52. 
 
 Charts, 202. 
 
 Chemicals, 192. 
 
374 
 
 INDEX 
 
 Chemistry, reasons for the study 
 
 of, 17. 
 
 Classroom, fittings, etc., 200; in- 
 struction in, 128. 
 College Entrance Examination 
 
 Bonrd, 47, 183, 333. 
 College entrance (Chemistry), 38, 
 
 39, r 7<5. 
 College entrance (Physics), 327 ; 
 
 history of the N. E; A. report on, 
 
 328. 
 College requirements, stimulus 
 
 from, 336. 
 
 Combining weights, law of, 75-79. 
 Committee of Nine, 46, 60, 85, 
 
 183. 
 Committee of Ten, 29, 39, 46, 
 
 '33- 
 
 Committee on college entrance re- 
 quirements, 39, 48, 183, 327. 
 
 Conservation of matter, 173. 
 
 Coulter, Prof. J. M., self-elimina- 
 tion in scientific work, 12. 
 
 Crystals, 205. 
 
 DEGREES, academic, 241, 247. 
 
 Demonstrations, 133; experiments 
 for, 134, 167, 169, 170. 
 
 Density of air, discussion of obser- 
 vations on, 285. 
 
 Desks, laboratory, 189. 
 
 Detailed list of laboratory exer- 
 cises, 330-333. 
 
 Diagrams, 202. 
 
 Difficulties with which chemistry 
 contends, 22-27. 
 
 Difficulty, intrinsic, of chemistry, 24. 
 
 Difficulty with words, 317. 
 
 Double decomposition, 168. 
 
 Drawing, 243. 
 
 Dynamics, presentation of, 341 ff. 
 
 ELECTROLYSIS, 167. 
 Electro-motive series, 169, 202. 
 Eliot, President, on the study of 
 
 science, 83 ; on the profession of 
 
 teaching, 234. 
 
 Ends for which chemistry is taught, 
 64-66, no. 
 
 Energy, matter and, 152. 
 
 Engineering study, 243. 
 
 England, teaching in (Chemistry), 
 57, 105; (Physics), 361. 
 
 Equations, how they are made 
 (SO 2 ), 78-80 ; time for, 83 ; 
 writing, 82. 
 
 Equilibrium, chemical, 169. 
 
 " Even front " progression in labo- 
 ratory work, 290. 
 
 Every-day matters, application of 
 chemistry to, 68, 74, 129, 138. 
 
 Expansion of air, preparation of 
 apparatus for measuring, 259. 
 
 Experiments, qualitative and quan- 
 titative, 312 (see under quantita- 
 tive). 
 
 Explanation, 129; equals descrip- 
 tions, 147. 
 
 FALLACIES, 145. 
 
 Faulty reasoning, 88, 89. 
 
 Form, care for, 251, 315. 
 
 Formulae, their meaning, 78-82. 
 
 Fouillee, Alfred, Education from a 
 
 A T atio?ial Point of View, 370. 
 France, physics teaching in, 365. 
 
 GAGE'S Elements of Physics, 269. 
 Galvanometer for lecture room, 
 
 reflecting, 310. 
 General chemistry, importance of, 
 
 208. 
 
 Generators for gases, 195. 
 Germany, teaching in (Chemistry), 
 
 20; (Physics), 356. 
 Glass-working, 113, 243. 
 Grammar of science, 146. 
 Grammar schools, quantitative 
 
 laboratory work in, 320. 
 
 HARVARD action on physics for 
 
 admission, 270, 271. 
 Harvard Descriptive List, 255, 259, 
 
 271, 329. 
 
INDEX 
 
 375 
 
 Harvard influence on chemical in- 
 struction, 19 ; outline of require- 
 ments, 69, 184. 
 
 Heat of solution, 146. 
 
 Heuristic teaching, 19, 54, 56, 105, 
 362. 
 
 High schools, what they should do 
 in physics, 336. 
 
 History of physics, 244. 
 
 History of the teaching of chemis- 
 try, 1 8. 
 
 Hofmann, experiments of, 134, 201. 
 
 Hoods, laboratory, 191. 
 
 IDENTIFICATION, exercises in, 178. 
 
 Illustration, abuse of, 142, 143; 
 absorption, 141 ; application of 
 generalizations to every-day mat- 
 ters, 129, 138; Bunsen flame, 
 89 ; burning hydrogen, 63 ; dis- 
 sociation of ammonium chloride, 
 88 ; heuristic method, 107, 108 ; 
 making of an equation, 78 ; mak- 
 ing of chlorine, 131 ; manufac- 
 ture of aluminium, 139; metals 
 and acids, 31, 109 ; need of, 129, 
 140, 141 ; origin of valency, 163; 
 oxidation and reduction, 140; 
 potassium iodide and sulphuric 
 acid, 102 ; potassium persul- 
 phate, 81 ; properties of chlo- 
 rine, 95 ; use of the imagination, 
 131 ; water of crystallization, 96, 
 144. 
 
 Imagination in science, ir, 131. 
 
 Individual work and group work, 
 
 293- 
 
 " Inductive and deductive," 274. 
 
 Intensive rather than extensive 
 work, 62, 101. 
 
 Introductory work, 49-84; qualita- 
 tive characteristics, 69; quantita- 
 tive characteristics, 73 ; summary 
 of, 68. 
 
 KNOWLEDGE-MAKING, 9, 23, 24, 
 87. 
 
 LABORATORY (Chemistry), direc- 
 tions for use in, 94; equipment 
 for, 193; furniture for, 189; in- 
 struction in, 85 ; store-room of, 
 195; structure of, 187; supplies 
 for, 195. 
 
 Laboratory (Physics), plan and 
 equipment of, 348 ff. 
 
 Laboratory exercise, length of, 
 
 2 93- 
 
 Laboratory manual, use of, 294. 
 Laboratory sections, size of, 292. 
 Laboratory work alone not enough, 
 
 34- 
 
 Laboratory work (Chemistry), di- 
 rections for, 94; general value, 
 87 ; psychology of, 91 ; value in 
 chemistry, 90. 
 
 Laboratory work (Physics), prepa- 
 ration for, 294 ; record of, 296- 
 301. 
 
 Language and science study con- 
 trasted, 10, 49, 89, 92, 102, no. 
 
 Law, in natural science, 148 ; of 
 precipitation, 146. 
 
 " Laws/' inaccuracy of some, 279 ; 
 search for, 282. 
 
 Lectures and recitations, 304 ff. 
 
 Lecture experiments (Chemistry), 
 134, 167, 169,170; (Physics) 308. 
 
 Lecture-room, 353. 
 
 Length of course, 40-42. 
 
 Liebig's course of instruction in 
 chemistry, 18. 
 
 Liquid pressure, 313, foot note. 
 
 MACGREGOR, Prof. J. G., on knowl- 
 edge-making, 9, 23, 24, 49. 
 
 Mach, Prof. Ernst, on the study of 
 science, 9. 
 
 Manipulation, need of directions in 
 regard to, 97, 112. 
 
 Manual labor, relief from, 302. 
 
 Mass, acceleration test of, 283; in 
 language of engineering, 347. 
 
 Mathematics, 235, 241, 242, 
 
 Matter and energy, 152. 
 
376 
 
 INDEX 
 
 Method of inquiry, 278. 
 Method of verification, 277. 
 Methods, report on, 289. 
 Middle States Board, action of, 333. 
 Mineralogy, 204. 
 Misleading words, 144. 
 
 " NATURE STUDY," 316. 
 
 Nichols, Professor, on research by 
 
 teachers, 216, 248. 
 Note-book, 123-125, 298. 
 Numerical problems (Chemistry), 
 
 135, 136; (Physics), use of, 307. 
 
 OBSERVATION, directions to assist, 
 98 ; involves creation of subject 
 of study, 36, 98 ; must be supple- 
 mented by text -book, 19, 136; 
 what it implies, 87. 
 
 Observation, habit of, 243, 249. 
 
 Observations, pool ing of, 281-285. 
 
 PACKARD, J. C., physics course de- 
 scribed by, 337. 
 
 Perkin and Lean, characteristics 
 of their book, 56. 
 
 Physical chemistry, 165-171; value 
 to the teacher, 166, 170. 
 
 Physical observation, chemistry 
 founded on, 17, 30-33, 39, 69. 
 
 Physics, before or after chemistry, 
 29-37 ; is chemistry simpler than, 
 
 34-37- 
 
 Physics Teachers, Eastern Associ- 
 ation of, 289 ff. 
 
 Picton, Prof. H., on heuristic teach, 
 ing, 108. 
 
 Platform-balance, 257, 285. 
 
 Portraits, 203. 
 
 Preparations, inorganic 21 1. 
 
 Problems, 135 ; collections of, 136. 
 
 Projecting lantern, 311. 
 
 QUALITATIVE analysis, 171-178; 
 history of its use in introductory 
 work, 18; in training of teacher, 
 209, 212; substitute for, 178. 
 
 Qualitative or quantitative work 
 for lower schools, 318. 
 
 Quantitative analysis, its value, 210. 
 
 Quantitative experiments, benefits 
 of, 120; degree of exactness of, 
 114; equipment for, 115; ex- 
 amples of, 78, 117; historical, 
 115; objections to, 121 ; time and 
 method of use, 119. 
 
 Questions, collections of, 133; 
 good and bad, 132. 
 
 Quiz, 128; abuse of, 306. 
 
 READING, books and journals, 218- 
 227, 248; original papers, 214. 
 
 Reagents, 192. 
 
 Reciprocal proportions, law of, 75. 
 
 Recognition of unknown bodies, 
 exercises in, 136. 
 
 Repetition of exercises, 288. 
 
 Research, 216, 247. 
 
 Reversible actions, 169. 
 
 Rowland, Professor, 247. 
 
 Russell, J. E., German Higher 
 Schools, 357. 
 
 SATURATION, 145. 
 
 Science, objections to the study of, 
 1 6 ; reasons for the study of, 
 8-16, 239; Spencer's reasons for 
 the study of, 6, 13. 
 
 Secondary schools, essential differ- 
 ence in, 335. 
 
 Self-elimination in scientific work, 
 12. 
 
 Solution tension series, 202. 
 
 Specialization in the secondary 
 school, 42-44. 
 
 Spencer, Herbert, his reasons for 
 the study of science, 6, 13. 
 
 Spring-balance, 255. 
 
 Stability, 144. 
 
 Steam baths, 194. 
 
 Strong acids, 130, 144, 145. 
 
 TABLES for laboratory work 
 (Physics), 348. 
 
INDEX 
 
 377 
 
 Teacher, defects in training of, 22 ; 
 demands on his time, 135; ex- 
 perimental work for, 134, 167, 
 169, 170, 216; his development, 
 214; his preparation, 207-214, 
 238 ; his private room, 206 ; his 
 reading, 218; need of his pres- 
 ence, 122, 125. 
 
 Teachers College, 245. 
 
 Teachers, number required, 123. 
 
 Teaching, study of the art of, 244. 
 
 Text-book, choice of, 184 ; need of, 
 99, 101, 136; types of (Physics), 
 268 if. 
 
 Torrey, Joseph, characteristics of 
 his book, 58. 
 
 Trowbridge's New Physics, 270. 
 
 Tyler, Prof. J. M., use of the 
 imagination, n. 
 
 UNIFICATION, need of, 143. 
 University of the State of New 
 
 York, syllabus of chemistry, 
 
 183- 
 
 VALENCY, 162-164. 
 
 Vassall, Archer, on physics in 
 
 English preparatory schools, 
 
 361. 
 
 WATER of crystallization, 96, 144. 
 Water-proofing, 253. 
 Weighing, method of, 112, 258. 
 Workshop, 352. 
 
 Worthington's Physical Laboratory 
 Practice, 270. 
 
 YEAR of curriculum for chemistry, 
 37-40. 
 
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