o 
 LO 
 
 o 
 
Univ. ( f C-.^H 
 
NOSTRANFHCIENCE SERIES. 
 
 i. ./.WATER AND WATER SUPPLY, By 
 PROF. W. H. CORFIELD, M. A., of the 
 University College, London. 
 
 No. 18. SEWERAGE AND SEWAGE UTILI- 
 ZATION. By PROF. W. H. CORFIELD, 
 M. A., of the University College, Lon- 
 don. 
 
 No, 19. STRENGTH OF BEAMS UNDER 
 TRANSVERSE LOADS. By PROF. 
 W. ALLEN, Author of " Theory of 
 Arches." With Illustrations. 
 
 20. BRIDGE AND TUNNEL CENTRES. 
 By JOHN B. MCMASTKRS, ( 1 . E. With 
 Illustrations. 
 
 Xo. -21. SAFETY VALVES. By RICHARD H. 
 BUKL, 0. E. With Illustrations. 
 
 No. 22. HIGH MASONRY DAMS. By JOHN B. 
 
 MCMASTERS, C. E. With Illustrations. 
 \o. o;>._ THE FATIGUE OF METALS UNDER 
 
 REPEATED STRAINS, with various 
 
 I Tables of Results of Experiments. From 
 
 the German of PROF. LUDWIG SPANGEN- 
 BERG. With a Preface by S. H. SHREVE, 
 A. M. With Illustrations. 
 24 .__ A PRACTICAL TREATISE ON THE 
 TEETH OF WHEELS, with the Theo- 
 ry of the Use of Robinson's Odonto- 
 "raph. By S. W. ROBINSON, Prof, of 
 Mechauieal Engineering. Illinois In- 
 dustrial University. 
 
 No. 25. THEORY AND CALCULATIONS OF 
 CONTINUOUS BRIDGES. By MANS- 
 FIELD MERRIMAN, C. E. AVith Illustra- 
 tions. 
 
 No. 26. PRACTICAL TREATISE ON THE 
 PROPERTIES OF CONTINUOUS 
 BRIDGES. By CHARLES BENDER, C. E . 
 
 No. 27. ON BOILER INCRUSTATION AND 
 CORROSION. By F. J. ROWAN. 
 
Gninr OIP 
 
THE PRESERYATIOH 
 
 OF 
 
 TIMBER 
 
 BY THE USE OF 
 
 SAMUEL BAGSTER BOULTON, 
 
 ASSOC. INST. C. E. 
 
 REPRINTED FROM VAN NOSTRAND'S MAGAZINE. 
 
 NEW YOKE: 
 
 I). VAN NOSTRAND, PUBLISHER, 
 2B MURRAY AND 27 WARREN STREETS. 
 
 JOHN S. PRELL 
 
 Civil & Mechanical Engineer. 
 
GIFT 
 
1372- 
 
 PREFACE. 
 
 The preservation of wooden structures 
 from decay, or from the ravages of in- 
 sects, is a subject of unfailing interest to- 
 engineers. 
 
 The fact that this paper was prepared 
 for the Institution of Civil Engineers, 
 and was discussed by prominent mem- 
 bers, is a sufficient guaranty that it pre- 
 sents the facts that are best worth know- 
 ing now in the possession of practical 
 men. 
 
 Some chemical tables, appended es- 
 says, and a long bibliographical list are 
 omitted in this reprint. 
 
 M7S6010 
 
S. PRELL 
 
 Civil & Mechanical Engineer. 
 
 SAN FilAK CISCO, CAL. 
 
 THE 
 
 ANTISEPTIC TREATMENT OF TIMBER. 
 
 IN January, 1853, a paper upon Timber 
 Preserving was contributed to this Insti- 
 tution* by the author's partner, the late 
 Mr. Henry Potter Burt, Assoc. Inst. 
 C. E. Since that date, the use of Anti- 
 septics for the treatment of timber has 
 largely increased, and is year by year in- 
 creasing. For engineering purposes, the 
 process called creosoting, which consists 
 in the injection of the coal-tar oils, has 
 in this kingdom entirely, and in other 
 countries to a very considerable extent,, 
 displaced the other well-known meth- 
 ods. 
 
 Concurrently with this development^ a 
 series of remarkable discoveries in 
 chemical science has raised the manufac- 
 tures connected with the residual prod- 
 
 * Institution of Civil Engineers. 
 
nets of gas-making to a position of great 
 and growing importance. 
 
 It is proposed in the present paper, 
 to give a short account of the history 
 and development of the use of antiseptics 
 for preventing the decay of timber. A 
 reference to the processes employed in 
 coal-tar distillation will be pertinent to 
 the subject, in so far as it will indicate 
 -what are and have been the usual con- 
 stituents of the tar oils used for inject- 
 ing wood. The author proposes to add 
 some results derived from his thirty- four 
 jears' experience in connection with this 
 group of manufactures, together with the 
 outcome of some research, and of a num- 
 ber of experiments specially undertaken 
 Tvith a view to the elucidation of ques- 
 iions referred to in the paper. 
 
 EARLY HISTORY OF TIMBER PRESERVING. 
 
 Timber was naturally the first ma- 
 terial employed by man for the purposes 
 of constructive engineering. If it be 
 true that the first models of Grecian 
 architecture were copied from, and re- 
 
tained some of the distinctive features 
 of, buildings in wood, then may still be 
 seen accorded, upon the columns of the 
 five great orders of architecture, proofs 
 that the Greeks or their precursors took 
 special expedients to preserve timber 
 from decay. The wooden pillar was 
 placed upon a block of stone to pre- 
 serve it from the humidity of the soil, 
 and it was covered at the top by a slab 
 or tile to throw off the rain. These 
 contrivances are supposed to have been 
 copied in the base and capital of the 
 column, when wood came to be replaced 
 by stone. Scamozzi imagines also, that 
 the mouldings represent metal hoops, 
 placed around the wooden pillars to pre- 
 vent them from splitting. 
 
 Allusions to various substances em- 
 ployed for preserving timber and other 
 vegetable fibers from decay, are frequent 
 in the writings of the ancients. Tar and 
 pitch were used for painting or smearing 
 wood from periods of the most remote 
 antiquity. Greek and Roman authors 
 narrate, that the astringent portions of 
 
8 
 
 the oil expressed from olives (Amurca 
 16), also oils derived from the Cedar, 
 the Larch, the Juniper and the Nard- 
 Bush (Valeriana) were used for the pres- 
 ervation of articles of value from decay, 
 or from the attacks of insects. The 
 magnificent statue of Zeus by Phidias 
 was erected in a grove at Olympus where 
 the atmosphere was damp ; the wooden 
 platform upon which it stood was there- 
 fore imbued with oil. The famous statue 
 of Diana at Ephesus was of wood. If 
 its origin was believed to be miraculous, 
 no standing miracle was relied on for its 
 preservation. Pliny asserts upon the 
 authority of an eye-witness, Mucianus, 
 that it was kept saturated with oil of 
 Nard by means of a number of small 
 orifices bored in the woodwork. The 
 same author remarks that wood well 
 rubbed with oil of Cedar, is proof aginst 
 wood-worm and decay. The art of ex- 
 tracting and preparing oils, resins, tar 
 and pitch from various trees and plants, 
 and from mineral deposits, is mentioned 
 by Herodotus, and at great length by 
 
Pliny. This last author describes in de- 
 tail, the manufacture of no less than 
 fort^eight different kinds of oils. Of 
 the employment of the oxides or salts of 
 metals by the ancients, for wood preserv- 
 ing, there is no direct evidence. 
 
 EGYPTIAN MUMMIES. 
 
 Of all the methods employed by man- 
 kind for the artificial preservation of or- 
 ganized substances, there are perhaps 
 none which have equaled in success the 
 processes of the ancient Egyptians. The 
 durable results of these processes are 
 amazing, and although the topic is a 
 hackneyed one, it is nevertheless insep- 
 arably connected with the subject of this 
 paper. The descriptions by co-temporary 
 writers of the Egyptian art of embalming 
 the dead are somewhat conflicting ; 
 moreover, they do not adequately explain 
 the appearances presented by many of 
 the mummies themselves. The bodies 
 are said to have been imbued, either with 
 resinous or odoriferous gums, or more 
 frequently with bitumen or with oil 
 
10 
 
 of cedar, or commonly with natrum, 
 and often with several of these sub- 
 stances in succession. So far, these 
 statements are confirmed by modern 
 investigation. By reading Herodotus 
 and Diodorus Siculus, however, it 
 would perhaps seem that the body 
 was first steeped in the natrum for 
 seventy days, and then subjected to the 
 oily or bituminous preparation. In other 
 places it might be gathered that the oily 
 preparation came first, and the steeping 
 in natrum afterwards. Without further 
 explanation, neither of these processes 
 would appear to be practicable. At 
 ordinary temperatures, the steeping in 
 the one preparation would interfere with 
 the absorption of the other. Natrum is 
 supposed to have been a natural sub- 
 stance, obtained from some briny lakes, 
 still existing in the neighborhood of 
 Cairo, and consisting principally of a 
 mixture of sodium-sesqui- carbonate, so- 
 dium-chloride and sodium-sulphate. Rou- 
 yer, who accompanied the army of Napo- 
 leon to Egypt in 1798, expressed his 
 
11 
 
 conviction that the mummies had been 
 placed in ovens in order to eliminate 
 moisture, and to facilitate the penetra- 
 tion of the bitumen. But no ancient au- 
 thor mentions any such process, nor is 
 there any record of it amongst the 
 numerous and detailed pictorial repre- 
 sentations which have been discovered in 
 tombs and temples. 
 
 Pettigrew, in his valuable work on 
 this subject, whilst giving the results of 
 his examination of various mummies, and 
 of analyses of embalming materials, ex- 
 presses his opinion that the bodies must 
 have been subjected to a very consider- 
 able degree of heat, as even the inmost 
 structure of the bones is penetrated by 
 the antiseptics. By some it has been 
 supposed that this was effected by steep- 
 ing the body in a cauldron of heated 
 bitumen. Pettigrew's most striking ex- 
 periment was made with the heart of 
 a mummy, from which he succeeded in 
 withdrawing by maceration the preserva- 
 tive substanceR, when, after 3,000 years of 
 perfect preservation, the heart began at 
 
12 
 
 once to putrefy. This is a striking proof, 
 both of the efficacy of the substances 
 employed, and also of the fact, that the 
 immunity from decay was not due to a 
 chemical transformation produced once 
 for all, but that it depended upon the 
 abiding presence of the antiseptic. In 
 recent anatomical practice, carbolic acid 
 has been used for injecting bodies for 
 purposes of dissection. When this is 
 done, however, it is found necessary to 
 renew the process after the lapse of a few 
 weeks, a contrast to the antiseptics em- 
 ployed by the Egyptians. Pettigrew's 
 description showed that the worst pre- 
 served of the mummies are those pre- 
 pared with natrum alone, the most per- 
 fect being those in which solid resins or 
 bitumens remain incorporated. Natrum 
 is frequently found accompanying the 
 bitumen in some of the most successfully 
 preserved specimens. It is probable that 
 some astringent or other substances were 
 also used, the secret of which has 
 hitherto eluded modern investigation. 
 The author has caused some experi- 
 
13 
 
 ments to be made with pieces of timber, 
 in order to test a theory which suggested 
 itself to his mind. The wood was first 
 thoroughly impregnated with a mixed 
 solution of the three salts of sodium of 
 which the natrum brine is composed 
 Afterwards the wood was steeped in tar 
 oil, heated to 230 Fahrenheit. The heat 
 of the tar oil volatilized the water of the 
 soda solution, and the oil took the place 
 of the water. The timber remained im- 
 pregnated with the saline particles, and 
 saturated with the tar oil. May not this 
 have been the method used by the Egyp- 
 tians to impregnate both with natrum 
 and oils ? 
 
 There is no doubt that the ancients 
 had, by observation and experience, ac- 
 quired considerable practical knowledge 
 of antiseptic substances. They were 
 also of opinion that those woods lasted 
 the longest which were most odoriferous, 
 or, in other words, those which contained 
 the greatest quantity of resin. They 
 knew that timber continually kept under 
 water was less liable to decay than when 
 
14 
 
 exposed to the atmosphere. They ob- 
 served the ravages of the Teredo navalis 
 upon timber placed in the sea. But it is 
 useless to seek amongst the writings of 
 the elder Classics for any reasonable the- 
 ory in explanation of these phenomena. 
 
 Growth of theories upon the causes of 
 Putrefaction. It is not until the eight- 
 eenth century of the present era that 
 anything beyond the merest trace can be 
 detected of serious analytical research 
 into the causes of decomposition. After 
 the fanciful dreams of the alchemists 
 had been dissipated, the more solid por- 
 tion of their labors, facts arrived at in 
 the course of their experiments, remained 
 for the uses of science. Investigations 
 were undertaken respecting the phe- 
 nomena of fermentation and of putrefac- 
 tion, animal and vegetable. It was at 
 one time declared that putrefaction was 
 due to the escape of an element called 
 phlogiston, an imaginary substance which 
 was believed in by such eminent chem- 
 ists as Scheele, the discoverer of chlor- 
 ine, and Dr. Priestley, the discoverer of 
 
15 
 
 oxygen. Later on Dr. Macbrlde pro- 
 pounded a theory that carbonic acid gas 
 had a special power of promoting cohe- 
 sion, and that putrefaction was due to 
 its being given off. None of these the- 
 ories explained why putrefaction did not 
 attack the tissues until after the vital 
 movement had ceased. By the com- 
 mencement of the present century, how- 
 ever, it began to be generally believed 
 that the putrefaction, at least of vege- 
 table matter, was a species of fermenta- 
 tion, although it was not admitted that 
 ferments of any kind were the products 
 of living organisms. Little by little the 
 similarity of the natural processes con- 
 nected with the fermentation of aliment- 
 ary substances, the decay of vegetable 
 tissues, and the putrefaction of the 
 bodies of animals began to be recog- 
 nized ; and, to the great advantage of 
 scientific progress, these three classes of 
 phenomena have ever since been studied 
 in close connection with each other. 
 
 In the meantime practice stole a march 
 upon theory. About the year 1770 Sir 
 
16 
 
 John Pringle published a list of anti- 
 septics, in which example he was folio wed 
 by Dr. Macbride. Many of the substances 
 proposed by these and other theorists, 
 particularly the alkaline bodies, are abso- 
 lutely injurious to timber. But towards 
 the close of the last century and at the 
 beginning of the present, experiment 
 was greatly stimulated by the wants of 
 the British navy. During the colossal 
 struggles of Great Britain with hosts of 
 adversaries, the very existence of the 
 nation appeared to be staked upon 
 her fleets. The great prevalence of dry- 
 rot in the timbers of British men-of- 
 war assumed the proportions of a na- 
 tional calamity. It was said that a single 
 70-gun ship required for its construction 
 the oak of 40 acres of forest, and that 
 the supply would fail. It was in 1812 
 that Lukin tried, in the Woolwich 
 Dockyard, his disastrous experiment 
 with the injection of resinous vapors. 
 More practical suggestions were soon 
 forthcoming, and the use of the salts of 
 various metals began to be recommend- 
 
17 
 
 ed. Sir Humphrey Davy suggested cor- 
 rosive sublimate ; Thomas Wade (in 
 1815), the salts of copper, iron, and 
 zinc. The opinion gained ground that 
 poisons of various kinds were cor- 
 rectives to the decay of timber. 
 
 From the year 1768 up to the pres- 
 ent time, the records of the Patent 
 Office contain lists of almost every 
 conceivable antiseptic, suitable or un- 
 suitable, for the preservation of wood. 
 
 Progress during the Railway Era. 
 But it is since the birth and growth of 
 the railway system that the antiseptic 
 treatment of timber may be said to have 
 received its most important development. 
 The stone blocks and other solid sup- 
 ports, at first used for the permanent way 
 of railways, were found to be too rigid, 
 and had to be replaced by a more elastic 
 material. The wooden sleepers which 
 were substituted decayed so rapidly that 
 some artificial method for prolonging 
 their duration began to be considered as 
 an engineering necessity. By the year 
 1838, four several systems of antiseptic 
 
18 
 
 treatment werej fairly before the public, 
 and competingjfor the favor of engineers. 
 These were : Corrosive sublimate, intro- 
 duced by Mr. J. H. Kyan ; sulphate of 
 copper, by Mr. J. J. Lloyd Margary ; 
 chloride of zinc, by Sir William Burnett ; 
 heavy oil of tar (afterwards called creo- 
 sote), by Mr. John Bethell. 
 
 Corrosive Sublimate, or bichloride of 
 mercury, was successfully used by Hom- 
 berg, a French savant, in 1705, for pre- 
 serving wood from insects. It was rec- 
 ommended by De Boissieu in 1767. In 
 1730 the Dutch Government tried it upon 
 wood immersed in sea water as a remedy 
 against the Teredo navalis, but for this 
 purpose it failed. In the " Encyclopae- 
 dia Britannica," in 1824, it is recorded 
 that Sir Humphrey Davy recommends its- 
 use for timber. Ryan's first patent, for 
 the employment of corrosive sublimate 
 for wood-preserving was taken out in 
 1832. His first success was gained by 
 the preservation of the woodwork of the 
 Duke of Devonshire's conservatories. 
 Kyanizing was for a long time by far the 
 
19 
 
 most popular of the timber preserving 
 processes in this country, and the name 
 is to this day frequently applied erron- 
 eously to other systems. Used in sea- 
 water, however, by the British Admiralty, 
 this process turned out a failure, as it 
 had done under similar circumstances 
 with the Dutch government a century 
 earlier. Kyanizing has met with a con- 
 siderable amount of success in compara- 
 tively dry situations ; but in water, and 
 particularly in sea-water, it appears to 
 have invariably failed, as have all the 
 salts of metals. Corrosive sublimate is 
 somewhat volatile at ordinary tempera- 
 tures ; it also has the drawback of pro- 
 ducing injurious effects upon the work- 
 men employed in handling it. 
 
 Sulphate of copper. The use of this 
 and of other salts of copper was recom- 
 mended by De Boissieu and by Borden- 
 ave in 1767, and by Thomas Wade in 
 1815. In 1837 Mr. Margary took out a 
 patent for the use of sulphate and asce- 
 tate of copper. Sulphate of copper has 
 perhaps been the mo&t successful of all 
 
the metallic salts as an antiseptic for 
 timber. Applied in various ways it was 
 popular in France long after it had been 
 given up in this country. It is still in 
 use in France, to a limited extent, for 
 sleepers and telegraph poles. 
 
 Chloride of zinc. This was recom- 
 mended by Thomas Wade in 1815, and 
 by Dr. Boucherie in 1837 ; and a patent 
 for its application was taken out in this 
 country by Sir William Burnett in 1838. 
 The process of Burnettizing was at one 
 time much patronized by the British Ad- 
 miralty. For railway sleepers it was ex- 
 tensively adopted in France by the au- 
 thor's firm, principally on the railways 
 from Orleans to Bordeaux, and from Caen 
 to Cherbourg. It is no longer used in 
 France, but it is still employed in Hol- 
 land and in Germany. Chloride of zinc 
 is a powerful antiseptic, but its weak 
 point for wood-preserving consists in its 
 extreme solubility in water. 
 
 Heavy oils of Tar, commonly called 
 Creosote. As early as 1756 attempts 
 were made, both in England and Ameri- 
 
21 
 
 ca, as described by Knowles, to inject or 
 impregnate timber with vegetable tars or 
 with extracts therefrom. The first men- 
 tion of the products of the distillation of 
 gas- tar, to be used separately for impreg- 
 nating timber, appears to be by Franz 
 Moll. This inventor took out a patent 
 in 1836 for injecting wood in closed iron 
 vessels with the oils of coal-tar first in a 
 state of vapor, and next with the heated 
 oils in the ordinary liquid state. He rec- 
 ommended the adoption both of the oils 
 lighter than water, and of the oils heavier 
 than water, calling the former " Eupion," 
 and the latter "Kreosot." He relied 
 upon the Kreosot for its antiseptic quali- 
 ties, but proposed to use the light oils 
 separately, at the commencement of the 
 operation, for the purpose of facilitating 
 the absorption of the heavy oil. This 
 plan has never been acted upon, as it 
 would be obviously wasteful and unprac- 
 tical to inject the lighter oils, or crude 
 naphthas, which would immediately evap- 
 orate. 
 
 The practical introduction of the proc- 
 
22 
 
 ess is due to Mr. John Bethell. His now 
 celebrated patent, which is dated July, 
 1838, does not mention the words " Cre- 
 osote" or " Creosoting." It contains a 
 list of no less than eighteen various sub- 
 stances, mixtures or solutions, oleagi- 
 nous, bituminous, and of metallic salts. 
 Amongst them is mentioned a mixture 
 consisting of coal-tar thinned with from 
 one-third to one-half of its quantity of 
 dead oil distilled from coal-tar. This is 
 the origin of the so-called Creosoting 
 process. Creosote, correctly so called, is 
 the product of the destructive distilla- 
 tion of wood, and coal-tar does not con- 
 tain any of the true Creosote, which has 
 never been used for timber-preserving. 
 But a substance, since called carbolic 
 acid, or phenol, had been discovered in 
 coal-tar ; it was thought by some to be 
 identical with the Creosote of wood, 
 hence the process came to be miscalled, 
 after a time the creosoting process. It 
 is in this popular sense only that the 
 word Creosote is to be understood in the 
 remainder of this paper. The two sub- 
 
23 
 
 stances, Creosote and Carbolic acid, are 
 described and contrasted, and their vary- 
 ing properties delineated in Dr. Tidy's 
 "Handbook of Chemistry." 
 * Competition of the Processes Theory 
 of Eremacausis. In addition to the 
 four processes already mentioned, a pat- 
 ent for a fifth was taken out by Mr. 
 Charles Payne in 1846. His plan con- 
 sisted in the injection into the timber, 
 first of a solution of a sulphuret of barium 
 or calcium, and next of a solution of 
 sulphate of iron, the object being to form 
 an insoluble sulphuret in the pores of 
 the wood. This process was tried to 
 some extent both in England and in 
 France, but it was a complete failure, and 
 is mentioned only by way of reference. 
 
 From ]838 to 1853, at which last date 
 the paper of Mr. H. P. Burt was read at 
 this institution, the four processes, Kyan- 
 izing, Margaryizing, Burnettizing and 
 Creosoting had been in active competi- 
 tion. The prevailing theory at that time 
 as to the causes of the decay of timber 
 was shaped by the opinions of the great 
 
24 
 
 chemist Liebig. Liebig taught that the 
 processes of fermentation in certain fluids 
 and of the putrefaction or decay of or- 
 ganized bodies, animal and vegetable, 
 were caused by a species of slow com- 
 bustion, to which he applied the term 
 eremacausis. He held that this decom- 
 position could be produced by contact 
 with portions of other bodies already un- 
 dergoing eremacausis. That it required 
 for its ordinary development the pres- 
 ence of moisture and of atmospheric air; 
 that its action was provoked by oxygen, 
 and that its method of action was by a 
 communication of motion from the atoms 
 of the infecting ferment to the atoms of 
 the body infected. He denied that fer- 
 mentation, putrefaction and decomposi- 
 tion were caused by fungi, animalcules, 
 parasites or infusoria, although these or- 
 ganisms might sometimes be present 
 during the processes. 
 
 But he also stated that the phenomena 
 of decomposition might be suspended by 
 extreme heat or cold, that they were ac- 
 celerated by the action of alkalies, and 
 
/ 
 
 25 
 
 retarded by that of acids, and that they 
 might be arrested by the use of certain 
 antiseptics. If, however, the theory of 
 eremacausis be accepted, and if its phe- 
 nomena be due entirely to a communica- 
 tion of molecular motion, and not at all 
 to the action of living germs, does any 
 adequate explanation remain of the ef- 
 fects produced by antiseptics ? With re- 
 gard to timber, theorists were ready 
 with an answer to this question, and they 
 deduced their theories from further 
 teachings of the great German chemist. 
 Liebig, enlarging upon the views of pre- 
 vious investigators, had proclaimed the 
 identity in composition of the animal and 
 vegetable albumens. The blood of ani- 
 mals and the sap of plants are, during 
 life, the circulating media of the vital 
 growth ; after death they are the por- 
 tions of the respective bodies which pu- 
 trefy most rapidly ; both are largely com- 
 posed of albumen. The sap freshly 
 drawn from a tree will commence to pu- 
 trefy within twenty-four hours. It was 
 proclaimed (although probably not by 
 
26 
 
 Liebig), that the coagulation of the al- 
 bumen was the true specific against the 
 decay of wood. Corrosive sublimate, 
 sulphate of copper, chloride of zinc, and 
 the tar oils were all powerful agents for 
 that purpose. It was claimed for all 
 four of these processes that they coagu- 
 lated the albumen contained in the wood, 
 and that they formed insoluble compounds 
 therein, thus arresting decay. 
 
 Prolonged experience has, however, 
 proved that the salts of metals are not so 
 permanent in their effects as the tar oils. 
 The discussion which took place at this 
 institution in January, 1853, upon the 
 occasion of the reading of Mr. Burt's 
 paper, was an interesting one, and was 
 joined in by most of the leading engi- 
 neers of the country. Whilst the 
 other processes were admitted, in many 
 instances, to have done good service, 
 the Creosoting process was generally 
 held, after fifteen years' experience, to 
 have proved the most stable and reliable. 
 In many subsequent discussions, the pro- 
 longed duration of creosoted timber had 
 
27 
 
 been a matter of constant and reiterated 
 testimony. Gradually the Creosoting 
 process took the place of the others by 
 a species of "survival of the fittest,'' 
 until in England it entirely extinguished 
 its rivals. The author's last experience 
 of Kyanizing in England was carried out 
 in 1863. 
 
 In France, the Creosoting process was 
 later in establishing itself, partly owing 
 to the difficulty which at one time existed 
 in procuring Creosote in that country, 
 partly, also, to the popularity of the sul- 
 phate of copper process, enhanced, as it 
 was by the ingenuity of the method em- 
 ployed for its injection by Dr. Boucherie. 
 But it was discovered even in France, 
 and notwithstanding the theories of in- 
 soluble compounds being formed in the 
 timber, that the salts of metals were 
 gradually washed out of the wood in 
 moist situations. In 1861, the French 
 chemist Pay en reported that sulphate of 
 copper could be almost entirely removed 
 from wood by repeated washings with 
 water, and in 1867 he reported that the 
 
28 
 
 whole could be so removed. This has 
 been confirmed by the testimony of Max- 
 ime Paulet. 
 
 The experiments of Mr. Forestier, un- 
 dertaken for the French Government, 
 and the prolonged and exhaustive experi- 
 ments of the Dutch Government, are 
 conclusive as regards the efficiency of 
 creosoting against the ravages of the 
 Teredo navalis, in cases where the tim- 
 ber has been efficiently prepared, and 
 with a suitable kind of creosote. These 
 experiments are referred to in the Min- 
 utes of Proceedings of this Institution, 
 vol. xxvii. The experiments undertaken 
 by Mr. Crepin on Tbehalf of the Belgian 
 Government, and the independent testi- 
 mony of many of the leading engineers 
 of this country, have also from time to 
 time been brought to the notice of this 
 Institution, in confirmation of the success 
 of the Creosoting process against the 
 ravages of marine insects. On the other 
 hand, there are distinct and well authen- 
 ticated instances of failure. An inquiry 
 
29 
 
 into the causes of such failures is one of 
 the main objects of this paper. 
 
 Origin and properties of the Tar Oils. 
 As the tar oils gained in usefulness, 
 their varying qualities became subjects 
 of increasing interest. A brief digres- 
 sion may here be useful, in order to show 
 the process of manufacture by which 
 these tar oils are procured. It will be 
 seen that from coal, as it is carbonized at 
 the gasworks, four well known products 
 are obtained, viz., illuminating gas, am- 
 moniacal liquor, coal-tar, and coke. Gas 
 liquor, or ammoniacal liquor forms 
 the basis of a separate industry ; the 
 ammoniacal products are of no utility for 
 timber preserving. The antiseptic sub- 
 stances are all obtained from the distilla- 
 tion of coal tar, a black, viscous substance 
 of a consistency resembling treacle. The 
 tar is subjected to the heat of a furnace 
 placed beneath the still, the operation be- 
 ing aided sometimes by the injection of 
 steam, sometimes by the application 
 of an exhausting air pump. The prod- 
 ucts of distillation come over very nearly 
 
30 
 
 in the order of their respective volatili- 
 ties, those of lightest specific gravity be- 
 ing followed in succession by heavier 
 and yet heavier ones as the heat increases. 
 The temperature during the distillation 
 ranges from 180 to 758 Fahrenheit. 
 This preliminary process, although now 
 carried out with more skill and economy 
 than formerly, has not varied much dur- 
 ing the last fifty years in its main object, 
 which is to break up the tar into three 
 groups of products, viz., oils lighter than 
 water (crude naphthas) ; oils heavier than 
 water, pitch, the residuum of distillation, 
 which last product is run out from the 
 bottom of the still, and solidifies, upon 
 cooling, into a hard, black substance. It 
 is in connection with the component 
 parts of the two groups of oils, and their 
 separate and subsequent treatment, that 
 some of the best known and most bril- 
 liant discoveries of modern industrial 
 chemistry have been developed. The oils 
 lighter than water, however, have no 
 part in the preservation of timber. It is 
 not uncommon to hear inquiries as to 
 
31 
 
 whether the discovery of the aniline dyes 
 has not, somehow or other, interfered 
 with the quality of the Creosoting liquor. 
 There exists a singular and unfounded 
 prejudice on this subject. The materials 
 for the aniline dyes are not, and never 
 have been, taken from the Creosoting 
 liquor or heavy oils ; they are taken ex- 
 clusively from the oils lighter than water, 
 which last have never been employed for 
 the Creosoting process, and are value- 
 less for timber-preserving. The benzols, 
 toluols, &c., from which the aniline dyes 
 are produced, are extremely volatile, like 
 alcohol. 
 
 The heavy oils of tar, or dead oils 
 heavier than water, constitute the " Cre- 
 osote v of the timber yards. They con- 
 tain numerous substances, some of them 
 liquid, some semi-solid, varying consid- 
 erably in their properties, but most of 
 them are now recognized as antiseptics. 
 Formerly, the whole mass of these heavy 
 oils was used for timber -preserving as 
 they were collected from the still, but 
 each portion can, if required, be separ- 
 
32 
 
 ated as it comes over, according to its 
 volatility, or the solid matters can be 
 separated by filtering, for subsequent 
 treatment. 
 
 It has been seen that Mr. Bethell's 
 original patent recommended the use of 
 the mother liquor, or coal tar, thinned 
 with a portion of heavy coal-tar oil. So 
 late as 1849, Bethell's licenses for the 
 use of his patent described the process 
 as " saturating timber with the oils ob- 
 tained by the distillation of gas- tar, 
 either alone or mixed with gas-tar." 
 The author remembers how, in the early 
 days of Creosoting, inspectors frequently 
 refused to allow the thinner and lighter 
 dead oils to be used without being thick- 
 ened with tar. Tar, the mother liquor, 
 necessarily included all the substances 
 contained in the dead oils, plus the naph- 
 thas and the pitch. The reasons for not 
 adopting the tar in its entirety are simply 
 that the crude naphthas are useless as 
 antiseptics, and would immediately evap- 
 orate, whilst the pitch, from its too great 
 solidity, would form an impediment to 
 
33 
 
 the injection. The dead oils, therefore, 
 came into use alone, and there crept in- 
 to some of the specifications the contra- 
 dictory prescriptions that the wood was 
 to be Creosoted according to Bethell's 
 patent, but that the Creosote was to be 
 free from adulteration with coal tar. 
 
 The dead oils made in London, and in 
 all places where the tar is produced from 
 the carbonization of the coal of the 
 Newcastle district, are, as compared with 
 other dead oils, the richest in semi-solid 
 substances (naphthalene, anthracene, py- 
 rene, &c.), and they require a higher 
 temperature to volatilize. They are gen- 
 erally called "London oils." The dead 
 oils of the Midland Districts are lighter, 
 thinner, and more volatile, and contain 
 usually a larger proportion of the ordi- 
 nary tar acids. They are usually called 
 u Country oils/' The Scotch oils are, 
 many of them, still lighter, thinner, and 
 more volatile, sometimes lighter than 
 water. Some Scotch oils, however, have 
 been proved to be of excellent quality. 
 
 As regards the question of thick or 
 
34 
 
 thin oils, there is no doubt as to the 
 opinion and practice of the earlier intro- 
 ducers of the Creosoting process. In 
 January, 1853, Mr. Bethell stated that 
 " the product of Newcastle coal contained 
 a quantity of naphthalene, and that he 
 was an advocate for its use." In Novem- 
 ber, 1864, he said that "the Creosoting 
 process was not, as often described, a 
 chemical process entirely " ; that Creo- 
 sote did coagulate albumen in the sap of 
 the wood ; " but that was not his only 
 idea when he introduced the process : 
 his object was to fill the pores of the 
 wood with a bituminous asphaltic sub- 
 stance, which rendered it waterproof," 
 &c. 
 
 The late Mr. H. P. Burt, whoselabors in 
 connection with the preservation of tim- 
 ber will be remembered by many of the 
 elder members of the engineering pro- 
 fession, was in the habit, for many years, 
 of using, by preference, the heavy Lon- 
 don oils, mixed at times with a small per- 
 centage of the country oils, the latter as 
 solvents or diluents of the more solid 
 
/ 
 
 35 
 
 material. The author, whose connection 
 with Mr. Burt commenced in 1850, re- 
 members, among his first experiences of 
 creosoting, the solid masses of naph- 
 thalene contained in the tanks before 
 heating. 
 
 When the construction of railways 
 commenced in India in 1850 and 1 851, 
 it was speedily discovered that the tim- 
 ber found in that country was subject to 
 very rapid destruction by decay and by 
 the attacks of insects. A serious difn- 
 culty was encountered by engineers in 
 procuring suitable sleepers, and the ex- 
 periment was tried of sending creosoted 
 Baltic timber from this country. The 
 first consignment of this material was 
 sent out in December, 1851, for 
 the East Indian Railway Company. 
 The results were promising from the 
 first, and the exportation of creosoted 
 sleepers to India continually increased. 
 The Minutes of Proceedings of this In- 
 stitution contain numerous records of 
 the rapid decay of unprepared timber in 
 tropical climates, and also of the very 
 
36 
 
 great general success of creosoted timber 
 exposed to the same influences, check- 
 ered, however, with a few instances of 
 partial failure, which should be as in- 
 structive as the successes. It may be 
 interesting to refer to the two papers by 
 Mr. Bryce McMaster, upon Indian 
 Permanent Way materials, one read 
 in 1859, and the second in 1863, in 
 which the success of creosoted timber 
 in India is fully set forth. Mr. Juland 
 Danvers, in his annual report to the Sec- 
 retary of State for India for the year 
 1863, remarks that it is cheaper to send 
 out creosoted Baltic sleepers than to use 
 those of indigenous wood. The printed 
 report of the East Indian Railway Com- 
 pany for the year 1867 again records the 
 success of creosoted sleepers, after six- 
 teen years' experience of their use. 
 
 It becomes a matter of interest to as- 
 certain the kind of Creosote which was 
 used for these earlier Indian sleepers. 
 When the exportation first began there 
 was a custom's duty upon the importa- 
 tion of Baltic timber into this country 
 
37 
 
 equal to about 20 per cent, on the value 
 of the sleepers. The author's firm made 
 early arrangements for creosoting in 
 bond, and for this reason, and with tri- 
 fling exceptions, all the sleepers sent 
 abroad, although supplied by various 
 contractors, were for many years creo- 
 soted at the works of the author's firm 
 at Rotherhithe and at the Victoria docks. 
 Their books contain accurate records of 
 the origin of all the creosote used. As 
 may be anticipated, by far the greater 
 bulk was London oil, up to 1863 com- 
 paratively little country oil, and in some 
 years none at all being used. In Janu- 
 ary, 1853, Mr. Burt, in describing to this 
 Institution the process which he used, 
 spoke, as a matter of course, of Creosote 
 becoming a hard, compact mass at a tem- 
 perature below 35 Fahrenheit. Ten 
 years later, in February, 1863, speaking 
 with reference to the Creosoting of some 
 sleepers, the success of which in India 
 had just been announced, he described 
 Creosote as becoming solid at a tempera- 
 ture below 40 Fahrenheit, and added 
 
that, in consequence, he had introduced 
 a heating apparatus inside the Creosoting 
 cylinder. 
 
 With the exception of a small experi- 
 mental shipment of larch and Scotch fir, 
 all the sleepers sent to India have been 
 of Baltic fir timber from the Polish and 
 Russian ports. The shipments were of 
 the ordinary kind of wood, such as was 
 in use at first for sleepers in this country, 
 and were mostly of triangular section. 
 Amongst them, for the first three or four 
 years, were considerable quantities of 
 white-wood, a wood somewhat liable to 
 split in hot countries. Subsequently, red- 
 wood was stipulated for, and with good 
 reason, in all Indian specifications. The 
 quantity of Creosote injected into these 
 sleepers was at first from 35 to 40 gal- 
 lons to the load of 50 cubic feet, as com- 
 pared with the 50 and 60 gallons of the 
 present day. At present not only is a 
 larger quantity of Creosote injected, but 
 more care is also expended in the selec- 
 tion of the wood than was formerly the 
 case. If, therefore, the earlier sleepers 
 
39 
 
 shipped to India behaved well, it might 
 be assumed that the quality of the Creo- 
 sote, at least, was suited to the climate. 
 Such Creosote, however, as was then 
 used would now be rejected under the 
 requirements of many of the specifica- 
 tions at present in force for the prepara- 
 tion of timber for tropical countries. It 
 is a question for grave consideration 
 whether the change has been for the bet- 
 ter. 
 
 It is a matter of notoriety, that for 
 many years an increasing demand has 
 arisen for the thinner and lighter Creo- 
 sotes. " Country oil " became more pop- 
 ular, and began to be mentioned in speci- 
 fications. Inspectors preferred these 
 thinner oils ; they were injected with less 
 trouble, and the timber looked cleaner 
 and less " muddy " after the process, 
 especially in the winter, when the Lon- 
 don oils are more solid. Contrary to the 
 opinion of the introducers of Creosot- 
 ing, the thin, light " Country oil " came 
 to be considered by many as the supreme 
 type of excellence. 
 
40 
 
 This view was adopted by the late Dr. 
 Letheby, who was further influenced by 
 the growing recognition of the wonder- 
 ful antiseptic powers of carbolic acid. 
 Discovered in coal tar by Runge, a Ger- 
 man chemist, in 1834, carbolic acid had 
 gradually achieved the important position 
 which it still holds as one of the most 
 valuable of antiseptics for sanitiry and 
 surgical puposes. Carbolic acid in vary- 
 ing quantities was present in the tar oils; 
 the other constituents of those oils were 
 imperfectly understood ; some of them, 
 now well known, had not then been dis- 
 covered. The success of the creosoting 
 process was therefore by a priori reason- 
 ing attributed mainly, if not solely, by 
 Dr. Letheby to the presence of the tar 
 acids. In June, 1860, Dr. Letheby pub- 
 lished his views on this subject in the 
 "Journal of the Society of Arts." He 
 considered carbolic acid to be the most 
 effective constituent of the tar oils, and* 
 that the efficiency of the latter in pre- 
 serving timber depended ma ; nly upon 
 the percentage of carbolic acid which 
 
41 
 
 they contained. He therefore concluded 
 that the lighter poitions of the dead oils 
 were the best, viz., those portions dis- 
 tilling between 360 Fahrenheit and 490 
 Fahrenheit, as they contain the tar a^ids 
 in greatest abundance. Naphthalene and 
 para-naphthalene he desired to exclude 
 as much as possible, as he held them to 
 be of no value in the preparation of tim- 
 ber. He had found the proportion of 
 carbolic acid in tar oils to range from 6 
 per cent, down to as low as 0.5 per cent. 
 In a letter of his in the author's posses- 
 sion, dated 5th June, 1863, he alludes to 
 two samples as containing "unusually 
 large " proportions of tar acids ; the 
 "quantities were respectively 6.4 per cent, 
 and 10.1 per cent. In a lecture at Not- 
 tingham, in 1867, Dr. Letheby described 
 a specification which he had drawn up 
 for an Indian railway. This specifica- 
 tion, dated 1865, contains the following 
 stipulations : The creosote is to have a 
 specific gravity as near to 1,050 as pos- 
 sible, ranging from 1,045 to 1,055. It is 
 not to deposit naphthalene or para-naph- 
 
42 
 
 thalene at a temperature of 40 Fahren- 
 heit. It is to contain 5 per cent, of crude 
 carbolic and other coal-tar acids (by the 
 caustic potash test). It is to yield 90 
 per cant, of liquid oil, when distilled 
 from its boiling point to a temperature of 
 600 Fahrenheit. 
 
 From an examination of upwards of 
 seventy timber-preserving specifications 
 in the author's possession, ranging from 
 1849 to the present year, it is manifest 
 that a new departure was thus inaugur- 
 ated by Dr. Letheby. For the first time 
 a boiling-point is fixed, a certain percent- 
 age of tar acids insisted upon, whilst the 
 use of naphthalene and the heavier dis- 
 tillates is discouraged. This specification 
 has long ceased to be used, but its 
 stipulations have been copied, and in 
 some cases carried to greater lengths, in 
 more modern specifications, 10 per cent, 
 of tar acids being occasionally required. 
 Such specifications exclude the London 
 oils if taken in their entirety as they 
 come from the still. It is to be regret- 
 ted that, at the period mentioned, there 
 
43 
 
 is no record of experiments having been 
 made by any English chemists as to 
 the actual effects produced upon timber 
 by the various constituents of the tar 
 oils taken separately. For want of such 
 a test, it would appear that an import- 
 ant element in the question was for 
 some years overlooked in this country. 
 
 So early as 1848 the French Academie 
 des Sciences received a communication 
 from De Gemini, detailing a series of 
 experiments upon wood prepared with 
 various antiseptics. This investigator 
 endeavored to prove that timber cannot 
 be permanently preserved by the use of 
 antiseptics which are themselves soluble 
 in water, and for that reason he preferred 
 the use of heavy oils, or bituminous 
 substances. The Academie rejected the 
 conclusions of De Gemini, more especial- 
 ly as he denied that solutions of sulphate 
 of copper formed insoluble compounds 
 with woody fiber. 
 
 In 1862 Mr. Kottier presented a paper 
 to the Academie Royal e de Belgique giv- 
 ing the results of a number of experi- 
 
44 
 
 ments as to the effects upon timber of 
 the various constituents of coal-tar oil. 
 He arrived at the conclusion that al- 
 though carbolic acid (L'Acide Phenique) 
 was a very energetic antiseptic, yet that, 
 owing to its volatility, the durable success 
 of the Creosoting process was not due 
 to its agency. He attributed that suc- 
 cess to the heavier and less volatile por- 
 tions which came over at the later 
 periods of the distillation, and consid- 
 ered that the heavier they were the 
 better. 
 
 Later on this investigation was taken 
 up by Mr. Charles Coisne, who was then, 
 and still is, an engineer in the service of 
 the Belgian Government. In 1863 Mr. 
 Coisne commenced a series of experi- 
 ments, the object being to determine, in 
 a practical manner, which portions of 
 the tar oils best preserved the timber. 
 The results were so instructive, that in 
 1866 he inaugurated a new series of ex- 
 periments, still more carefully conducted, 
 which lasted until 1870. He procured 
 samples of Creosote from England, Scot- 
 
45 
 
 land, Belgium and France. Four of these 
 samples contained, respectively, 15 per 
 cent., 15 per cent., 8 per cent., and 7 
 per cent, of tar acids by the usual test. 
 The fifth was an oil of heavy specific 
 gravity, specially prepared, and contain- 
 ing no tar acids. Yet this last sample 
 produced better results than any of the 
 others. Each sample was divided into 
 portions. Wood shavings were saturated 
 with these oils in the following different 
 ways : 
 
 1st. With the Creosotes as received. 
 
 2d. With the Creosotes, supplemented 
 by additional quantities of tar acids. 
 
 3d. With the Creosotes, supplemented 
 by some of the heavier portions of the 
 same oils distilling over at a temperature 
 exceeding 320 Centigrade (628 Fahren- 
 heit). 
 
 4th. With the original Creosotes di- 
 vided into the lightest, the medium, and 
 the heaviest portions, with each of 
 which the shavings were separately sat- 
 urated. 
 
 A putrefying pit (pourrisoir) was pre- 
 
46 
 
 pared, in which the shavings were 
 placed on the 10th of November, 1866, 
 together with other shavings not pre- 
 pared. After four years' sojourn in the 
 pourrisoir, they were removed and ex- 
 amined on the 16th November, 1870. 
 The results were strikingly in favor of 
 the heavier oils, and adverse to the tar 
 acids, which last bodies appeared to have 
 been wholly ineffective. The shavings 
 which had been prepared with the light- 
 est portions of the oils, although they 
 had contained the largest portions of the 
 tar acids, were, nevertheless, in the worst 
 condition. Those prepared with the oils 
 somewhat heavier were in most cases 
 better preserved. Best of all were the 
 shavings prepared with the heaviest oils, 
 procured by distilling at the higher tem- 
 peratures even when containing no tar 
 acids ; these last were all perfectly 
 sound. The un-creosoted shavings were 
 all rotten. Mr. Coisne believed that the 
 best portions of the oils were the " green 
 oils," distilling at high temperatures. 
 These experiments are recorded at 
 
47 
 
 length in the <l Annals des Travaux 
 Publiques de Belgique," also in separate 
 pamphlets. Their results have consider- 
 ably influenced the practice of railway 
 engineers on the Continent. The Belgian 
 Government accepted the conclusions 
 arrived at by Mr. Coisne, and for many 
 years has based its creosoting specifica- 
 tions thereon, with highly satisfactory re- 
 sults. The specification for the Belgian 
 State Railways does not stipulate for any 
 tar acids ; it requires that at least two- 
 thirds of the Creosote must have been 
 obtained by distillation at a temperature 
 exceeding 250 Centigrade (482 Fahren- 
 heit), and the remainder at a tempera- 
 ture exceeding 200 Centigrade (392 
 Fahrenheit). It allows 30 per cent, of 
 naphthalene, which is calculated at the 
 ordinary temperature. In a recent cor- 
 respondence with the author, Mr. Coisne, 
 who has for more than twenty years 
 superintended the Creosoting operations 
 of the Belgian Government, confirms the 
 results of those experiments by his sub- 
 sequent experience. 
 
48 
 
 So far, the experiments and the experi- 
 ence of De Gemini, Rottier and Coisne 
 appear to be in absolute contradiction 
 with the theory that the Creosoting 
 process owes its success to the tar acids. 
 Yet the fact cannot be doubted, that the 
 tar acids are powerful antiseptics, and 
 that their presence arrests decay. What, 
 then, is the explanation of this apparent 
 anomaly ? 
 
 The authorities on the tar acids are 
 many and reliable. From amongst the 
 learned and voluminous treatises which 
 have been written respecting these 
 bodies, fifteen references have been made 
 to authors in England, Scotland, France, 
 Belgium, Germany and America. None of 
 them disagree as to the following facts : 
 That carbolic acid is volatile at ordinary 
 temperatures. That it is soluble in water. 
 That its combinations are not stable. 
 That it is a powerful germicide, but that 
 its efficacy ceases so soon as it evaporates 
 or is washed out of the substances in- 
 tended to be preserved. Professor (now 
 Sir Joseph) Lister, whose adoption of 
 
49 
 
 the antiseptic system for surgical pur- 
 poses has revolutionized hospital prac- 
 tice, speaks from his large and valuable ex- 
 perience as to the importance of carbolic 
 acid in the treatment of wounds, but he 
 also remarks that its volatility is some- 
 times an evil as well as a good. Dr. San- 
 som, whose recent work on antiseptics so 
 ably epitomizes the results arrived at by 
 previous investigators, as well as those 
 due to his own researches, speaks of it 
 as the "aerial disinfectant" par excel- 
 lence. 
 
 If this substance can be washed out 
 by water, and if its volatility is one of 
 its great merits, and occasionally a de- 
 fect, for sanitary purposes, can it at the 
 same time be considered as a durable 
 agent amongst the oils injected into rail- 
 way sleepers ? Especially can this be the 
 case in those tropical countries where 
 extreme heat or torrential rains, or 
 alternations of both, are prevalent 1 For 
 piles and other timbers used for harbor- 
 work, the comparative solubility in water 
 of the antiseptic agents employed is 
 
50 
 
 also a matter of vital importance. What 
 is true respecting carbolic acid, will also 
 apply, to a great extent, to cresylic acid, 
 the last substance being, however, some- 
 what less volatile and less soluble than 
 the former. Do these bodies become 
 stable by entering into combination with 
 woody fiber? Their instability in this 
 connection is apparently pointed out by 
 Mr. Coisne's experiments. It may, how- 
 ever, be objected that these experiments 
 were not conducted under the conditions 
 to which railway timbers are exposed. 
 This point also has been very fully in- 
 vestigated. 
 
 In 1867 Mr. Coisne obtained some 
 Creosoted sleepers which had success- 
 fully resisted decay during periods of 
 from eighteen to twenty years. The 
 wood was crushed, and the substances 
 obtained therefrom tested. He found no 
 tar acids ; if they had ever been there, 
 they were no longer present. He found, 
 however, a quantity of naphthalene ; also 
 of an oil which did not commence to dis- 
 
51 
 
 til until 230 Centigrade (446 Fahren- 
 heit). 
 
 In 1882 the author caused some simi- 
 lar experiments to be made. Through 
 the kindness of the authorities of the 
 London and North-Western Railway 
 Company, eleven pieces of old Creosoted 
 sleepers were sent from their permanent 
 way. They had been in use for the fol- 
 lowing periods : 
 
 1 specimen 16 years. 
 
 .17 
 .20 
 .22 
 .28 
 .29 
 .30 
 .32 
 
 Sleepers were also received from the 
 Taff Vale Railway, the South- Eastern 
 Railway, and the Great Eastern Railway, 
 which had been in use periods varying 
 from fourteen to twenty-three years. A 
 portion was also taken from a Creosoted 
 pale fence, which had been fixed in the 
 Victoria docks in 1855, and which is still 
 in place, perfectly sound and strong, 
 
52 
 
 after twenty-nine years' use. A careful 
 analysis of these seventeen specimens, 
 all of ordinary Baltic fir, gave the follow- 
 ing results : 
 
 1st. In no cases were any tar acids de- 
 tected by the ordinary tests. 
 
 2d. In fourteen out of the seventeen 
 specimens the semi-solid constituents of 
 the tar oils were present; in twelve of 
 them was naphthalene, this body being 
 in some cases in considerable quantity. 
 
 3d. Only small percentages remained 
 of oils distilling below 450 Fahrenheit. 
 In the majority of instances from 60 per 
 cent, to 75 per cent, of the total bulk of 
 substances retained in the wood did not 
 distil until after a temperature of 600 
 Fahrenheit was reached. 
 
 It is clear, therefore, that these tim- 
 bers had been preserved by the action of 
 the heaviest and most solid portions of 
 the tar oils, and that the other constitu- 
 ents had disappeared. 
 
 4th. In some of these specimens 
 acridine was searched for and detected. 
 This substance is one of the alkaloids or 
 
53 
 
 bases now known to exist in the Creosote 
 oils. This is probably the first occasion 
 upon which acridine has been publicly 
 mentioned in connection with the injec- 
 tion of wood ; but the author is per- 
 suaded that it will come to be recognized 
 as one of the most valuable constituents 
 of the tar oils for timber-preserving 
 purposes. It was discovered by Graebe 
 and Caro ; it is a powerful germicide, 
 and solidifies within the pores of the 
 timber, from which it neither evaporates 
 nor washes out. It is intensely acrid 
 and pungent. 
 
 Portions of the same specimens of 
 wood, fifteen in number, were sent to 
 Mr. Greville Williams, whose original 
 researches with relation to coal deriva- 
 tives have been for so many years known 
 to the scientific world. Mr. Greville 
 Williams tested the samples of wood for 
 tar acids, naphthalene, and the alkaloids. 
 For the tar acids he found all ordinary 
 tests fail, until he employed the extreme- 
 ly delicate one by bromine and ammonia. 
 In some cases, even by this test, no 
 
54 
 
 phenols could be detected, but in most 
 cases he succeeded in detecting faint 
 traces of those bodies ; generally less 
 than one part in three thousand ; minute 
 portions, probably of the heaviest par- 
 ticles of the tar acids which had been 
 incorporated and retained by the heavier 
 portions of the oils. It is needless to 
 say that these infinitesimal quantities 
 could be of no practical value in preserv- 
 ing the wood. In all the specimens,, 
 save two, he found naphthalene. The 
 presence of the antiseptic alkaloids was 
 distinctly proved, and one of these 
 bodies, called cryptidine, which he had 
 discovered in Creosote oils, in 1856, was 
 detected by him in one of the specimens. 
 Mr. Greville Williams concludes that 
 the preservative action of the Creosote 
 oils is due more to the bases or alkaloids 
 than to the tar acids, as the former re- 
 main after the latter have disappeared. 
 These researches were published in the 
 " Journal of Gas Lighting," and also in a, 
 pamphlet in the possession of this Insti- 
 tution. 
 
55 
 
 First, and most volatile of all the Cre- 
 osote oils, are the carbolic and cresylic 
 acids, which are also freely soluble in 
 water at ordinary temperatures ; they 
 come over from the still, incorporated 
 with the lightest portions of the oils. 
 Pure carbolic acid would entirely disap- 
 pear by evaporation, if not secured in a 
 stoppered bottle. Next in order comes 
 naphthalene, which is much less volatile 
 than the tar acids. It is not soluble in 
 cold water, and almost insoluble in boil- 
 ing water. As it comes from the still it 
 is of a yellowish color, and mixed with 
 the heavy oils, it gradually becomes black 
 on exposure to the atmosphere. It forms 
 the principal constituent of the thick, 
 muddy-looking substance which some- 
 times forms on the surface of Creosoted 
 timber, and which may often be seen ad- 
 hering to the ends of railway sleepers for 
 several years after they have been placed 
 in the line. When sublimed by the ac- 
 tion of heat and a current of air, it forms 
 the beautiful frost-like substance well 
 known in Creosoting yards. It becomes 
 
56 
 
 quite solid at a low temperature, and in 
 that condition would be an impediment to 
 the injection of the timber a difficulty 
 removed by heating the oils to about 100 
 Fahrenheit, at which temperature naph- 
 thalene becomes liquid. After injection 
 it solidifies, and greatly assists in filling 
 up the pores of the wood. 
 
 The following simple experiments, 
 which have been tried and repeated in 
 many different ways at the author's lab- 
 oratories during the last few years, are 
 in strict accordance with the now well- 
 known characteristics of naphthalene and 
 the tar acids : 
 
 1. If tar acids and naphthalene be 
 separately exposed either at the ordinary 
 temperature, or at the tropical heat of 
 130 Fahrenheit, the tar acids will evap- 
 orate with much more considerable ra- 
 pidity than naphthalene. 
 
 2. Injected into timber the same results 
 follow. 
 
 3. Light, thin oils, containing large 
 percentages of tar acids, evaporate more 
 quickly than heavier oils containing less 
 
57 
 
 tar acids and more naphthalene, when 
 tested by methods Nos. 1 and 2. 
 
 In weighing after these experiments 
 great care must be taken to allow for the 
 absorption of moisture from the atmos- 
 phere. The tar acids absorb moisture 
 before finally evaporating. Wood also 
 absorbs a large amount of moisture when 
 injected with oils containing these acids. 
 
 4. By repeated washings with cold 
 water, all the carbolic acid, and all or near- 
 ly all the cresylic acid, can be washed out, 
 both from country and from London oils. 
 These experiments assume especial im- 
 portance in considering the durable ef- 
 fects of various kinds of creosote for 
 protecting timber immersed in sea-water 
 from the attacks of marine insects. 
 
 Dr. Meymott Tidy has published the 
 results of his experiments upon naph- 
 thalene. He injected pieces of wood 
 with this substance, and exposed them 
 to a temperature of 150 Fahrenheit. 
 He found that the evaporation was only 
 superficial, and that it practically ceased 
 after forty-eight hours, the naphthalene 
 
58 
 
 below the surface remaining within the 
 pores of the wood. Naphthalene is now 
 recognized as an antiseptic, not so pow- 
 erful in its immediate effects as the tar 
 acids, but more durable. It is probable 
 that tar acids of a heavier and less vola- 
 tile type than carbolic or cresylic acids, 
 may be more reliable as antiseptics for 
 preserving timber. 
 
 Following in the series of distillates, 
 amongst the Creosote oils are the alka- 
 loids or bases of the quinoline or leuco- 
 line group, amongst which chemists are 
 searching, not without fair promise of 
 success, for a febrifuge similar to, if not 
 identical with, the quinine derived from 
 the cinchona plant. In this group oc- 
 curs the substance called cryptidine, al- 
 ready alluded to as one of the valuable 
 antiseptics discovered in those portions 
 of the oils which were formerly character- 
 ized as "inert.'' 
 
 Para-naphthalene, mentioned in Dr. 
 Letheby's specification, has since then 
 become the basis of one of the most in- 
 teresting chemical discoveries of the age. 
 
59 
 
 It was excluded by Dr. Letheby from 
 the oils intended for timber preserving, 
 and is probably without value for that 
 purpose. It is now called anthracene, 
 and is extremely valuable as the sub- 
 stance from which alizarine is manufac- 
 tured, thanks to the brilliant discoveries 
 of Perkin in England, and of Graebe, 
 Liebermann and Caro in Germany. Ali- 
 zarine is the coloring matter used by 
 Turkey-red dyers and printers ; for ages 
 it had been extracted from the madder 
 root. It is now made from the coal-tar 
 product anthracene, of a far higher degree 
 of purity, and at an enormously de- 
 creased cost. The madder root has gone 
 almost entirely out of cultivation. The 
 quantity of anthracene contained in tar 
 is relatively small. 
 
 Amongst the green oils, distilling be- 
 tween 550 Fahrenheit and 750 C Fahren- 
 heit, is found the acridine already al- 
 luded to as a valuable germicide and 
 stable antiseptic. Phenanthrene, carba- 
 zol, pyrene, chrysene and benzerythrene, 
 by no means complete the list, which is 
 
60 
 
 constantly being added to by new dis- 
 coveries of the numerous bodies in which 
 these dead oils are so prolific. The 
 properties of many of these heavier 
 bodies are still imperfectly under- 
 stood ; but from the fact that they will 
 not evaporate except at exceedingly 
 high temperatures, they are valuable in- 
 gredients for timber-preserving. 
 
 By the light of the evidence now ac- 
 cumulated, it may be advisable to review 
 the question as to the relative value of 
 these various bodies contained in the 
 heavy oils as regards the preservation of 
 timber. Some of them are becoming 
 valuable for other purposes. Which of 
 them should the engineer retain for in- 
 jecting wood? 
 
 Can the conclusion be resisted, that 
 for this purpose the efficacy of the tar 
 acids has been overrated, and this at 
 the expense of the more stable and en- 
 during portions of the tar oils ? The 
 London oils as they come from the still 
 are not sufficiently volatile to meet the 
 exigencies of some modern specifica- 
 
61 
 
 tions, nor do they comply with these 
 exigencies as regards the percentage of 
 tar acids. They do not, as a rule, contain 
 more than from 4 to 7 per cent, of tar 
 acids, and they will not yield 90 per 
 cent, of their bulk by distillation below 
 600 Fahrenheit. Therefore a pressure 
 is put upon the manufacturer to meet 
 the fashion by " taking out '' some of the 
 heavier portions, and in some instances 
 this is done. By this means the bulk is 
 rendered lighter, and the proportion of 
 tar acids to the diminished bulk is in- 
 creased. For these heavier portions, es- 
 pecially for the green oils, a market is 
 found for lubricating and other pur- 
 poses. But in the author's judgment the 
 efficacy of the oils as antiseptics for 
 wood is thereby diminished. The green 
 oils, after the anthracene has been re- 
 moved from them by filtration, should be 
 returned to the Creosote tank. The per- 
 centage of tar acids to be used remains a 
 contested matter of opinion. But the 
 author ventures to express the hope that 
 at least the lighter portions of the tar 
 
62 
 
 acids, and especially carbolic acid, may 
 soon be relegated altogether to their 
 important functions as sanitary antisep- 
 tics, for which they are so valuable, in- 
 stead of being wasted by the attempt to 
 use them as antiseptics for timber, for 
 which their peculiar properties render 
 them unreliable. Upon the whole it 
 would be wiser to revert, to a larger ex- 
 tent and with increased knowledge, to 
 the plan of using the London oils mixed 
 with the country oils, and encouraging 
 instead of discouraging the use of the 
 heavier portions. The whole of the 
 Creosote oils manufactured from ordi- 
 nary gas tar in this country are required 
 for preserving timber, and to exclude 
 one considerable portion of the supply is 
 to enhance unnecessarily the cost of the 
 rest. No oils, however, should be used 
 as Creosotes which are lighter than 
 water. Both bone oil and shale oil are 
 sometimes offered as Creosote oils. 
 
 In 1881 Professor (now Sir Frederick) 
 Abel and Dr. Tidy drew up a joint 
 Creosoting specification, in which, as the 
 
63 
 
 result of direct experiment, they resolved 
 to exclude no semi-solid bodies which 
 completely melt at 100 Fahrenheit. 
 They further changed the standard of 
 volatility from 90 per cent, at 600 
 Fahrenheit to 75 per cent. Subsequent 
 and prolonged investigation induced Dr. 
 Tidy to go still further in the same direc- 
 tion, and not only to withdraw the 
 clause limiting to 2o per cent, the oils 
 distilling at a higher point than 600 
 Fahrenheit, but even to require that at 
 least 25 per cent, of those non-volatile 
 oils must be present. The author's ex- 
 perience leads him entirely to agree with 
 the progress made in this direction. 
 
 CONFLICTING THEORIES ON PUTREFACTION 
 THE GERM THEORY. 
 
 If experiment and experience should 
 lead to clearer views as to the relative 
 value of various antiseptics, it may be 
 advisable to test those views by refer- 
 ence to the recent development of theory 
 upon the causes of decomposition in or- 
 ganized bodies. How do antiseptics act. 
 
64 
 
 upon timber ? Is the coagulation of 
 albumen a sufficient explanation of their 
 preservative action ? Surely not. Many 
 substances, boiling water included, which 
 will effectually coagulate albumen, will 
 not prevent the decay of wood. Coagu- 
 lation retards, but does not prevent, the 
 decay of albumen itself. Again, the 
 quantity of albumen in fir timber is ex- 
 ceedingly small, if the tree be cut down, 
 as it generally is and always should be, 
 during the season when the sap is not 
 circulating. From a number of experi- 
 ments made upon ordinary fir sleepers, 
 the author arrives at the conclusion, that 
 the quantity of nitrogenous matter or 
 albumen which they contain does not 
 usually much exceed 1 per cent, of their 
 weight. Any watery fluid containing 
 from "2 to 3 per cent, of tar acids would 
 effectually coagulate this quantity of 
 albumen. In some cases it is found 
 that a portion of this albumen is actu- 
 ally coagulated by substances naturally 
 contained in the timber. But the coagula- 
 % tion does not of itself preserve the wood. 
 
65 
 
 Leibig's theory of decomposition has al- 
 readj been alluded to. He maintained 
 that putrefaction was due to eremacausis 
 or slow combustion, produced by con- 
 tagion, the infected bodies communicat- 
 ing a molecular motion to^ the atoms 
 of the bodies with which they come in 
 contact, and that these phenomena are 
 not caused by the action of germs or 
 living organisms. 
 
 The modern germ theory distinctly 
 traverses this last assertion. Pasteur 
 affirms, that without the presence of liv- 
 ing germs, the phenomena of organic 
 decomposition do not accomplish them- 
 selves, and that these germs are the 
 veritable agents of the decomposition. 
 The laborious experiments, and the lucid 
 deductions of Professor Tyndall con- 
 firm the experiments and theories of 
 Pasteur. Professor Tyndall explains 
 that the air is laden with clouds of germs, 
 agents of decomposition, ever ready to 
 settle down and develop upon matter 
 suitable to their growth. He finds that 
 the contents of tubes filled with the 
 
66 
 
 most putrescible materials, animal or 
 vegetable, can be preserved from putre- 
 faction indefinitely, by the exclusion of 
 germs. But that it is not sufficient 
 merely to poison or neutralize one gen- 
 eration of organisms, the incursions of 
 fresh myriads must be excluded, or putre- 
 faction will ensue. 
 
 After reading the "Essays on the 
 Floating Matter of the Air," in which . 
 Professor Tyndall describes how the 
 germs gradually fell into the open tops 
 of the test tubes, let the comparison be 
 made between the mouths of these tubes 
 and the gaping orifice of a crack pro- 
 duced by the sun in a piece of timber. 
 Through it the germs will descend, and 
 if there is nothing to arrest their action, 
 and if the crack is deeper than the por- 
 tion of the wood charged with antisep- 
 tics, they will carry destruction into the 
 center of the log. But if the antiseptic 
 be of an oily or bituminous nature, it 
 will flow into the cracks when they first 
 develop themselves, and seal up the ori- 
 fices against the enemy. Examine a 
 
67 
 
 crack or a wound in the trunk of a living 
 fir tree ; it will be found that by a nat- 
 ural process, a resinous substance ex- 
 udes, which closes the wound against the 
 agents of destruction. 
 
 The bodies of mammoths preserved in 
 ice through countless ages, the trees of 
 primeval forests excluded from the air 
 beneath thick deposits of peat, the frag- 
 ments of wooden piles which have en- 
 dured undecayed for centuries when 
 driven deeply below the surface of 
 water, all confirm the experiments of 
 Pasteur and Tyndall, and prove that the 
 exclusion of germs prevents patref ac- 
 tion. Specimens are exhibited of a 
 wooden pile from the remains of the 
 bridge (destroyed by fire) which was 
 constructed by Charlemagne across the 
 Rhine at Mayence ; of pieces of piles 
 from the foundations of the bridge across 
 the Medway at Rochester, which was de- 
 stroyed by Simon de Montfort in 1264, 
 and which was probably then about one 
 hundred years old ; also from the new 
 
68 
 
 bridge erected to replace the former one 
 in 1283. 
 
 It is not for the author to draw the 
 dividing line between the decomposing 
 action of germs and the action of 
 oxidation. It is sufficient for his 
 purpose to submit that all influences 
 which either destroy or exclude germs, 
 will prevent decay so long as those influ- 
 ences endure ; but that permanent ef- 
 fects must not be relied upon from agents 
 which are not themselves permanent and 
 abiding. The germ theory then becomes 
 a severe but a salutary test in choosing 
 antiseptics for the treatment of timber. 
 Such treatment is of little value unless 
 its effects will endure for long periods. 
 Reliance, therefore, must not be placed 
 upon those germicides, however potent, 
 which will readily volatilize in air, or 
 dissolve in water. A growing skepticism 
 arises from experience as to insoluble 
 compounds being formed between woody 
 fiber and substances which are them- 
 selves soluble in water. In short, the 
 substances to be employed should by 
 
69 
 
 preference be antiseptics in a double 
 sense ; they should be both germicides 
 and germ excluders. From the long 
 list of germicides must be especially ex- 
 cluded such as injure or weaken the 
 fiber of the wood ; amongst these latter 
 must be classed all solutions with very 
 strong acid or alkaline reactions ; also 
 some of the metallic salts. It has been 
 seen, that the salts of zinc, mercury, and 
 copper have been to some extent suc- 
 cessful ; of these the author's experience 
 induces him to prefer sulphate of cop- 
 per, as less soluble in water than chloride 
 of zinc, and not volatile like corrosive 
 sublimate. Even sulphate of copper can- 
 not be permanently relied upon, when 
 exposed to the continuous action of 
 water ; but it may be found useful in 
 comparatively dry situations, or as a pro- 
 tection against dry-rot to timber under 
 cover. From its properties as a germi- 
 cide, sulphate of copper might be use- 
 fully employed in conjunction with oily 
 or bituminous fluids, even with oils 
 which do not possess great potency as 
 germicides. 
 
70 
 
 From all research and experience it 
 would, however, appear that the same 
 conclusions may be derived, viz., that the 
 best antiseptics for timber are to be 
 found amongst oils and bitumens which 
 fill up the pores of the wood. Of such 
 bodies, those which contain germicides 
 are to be preferred. And, other proper- 
 ties being equal, those which either sol- 
 idify in the pores of the wood or which 
 require an extremely high temperature 
 to volatilize them, and which are insol- 
 uble in water, must surely be the best 
 of all. 
 
 Apparatus for Timber -Preserving. 
 Of the apparatus employed for applying 
 antiseptics to wood, the most ancient and 
 the most popular is the tar brush or the 
 paint brush. During the last century, 
 and in the earlier portion of the present, 
 steeping in tanks was extensively adopted, 
 the various liquids being employed either 
 cold or heated. A marked improvement 
 was introduced in 1831 by Mr. Breant, a 
 director of the ATint of Paris, who in- 
 vented the first apparatus for injecting 
 
71 
 
 timber by means of vacuum and press- 
 ure, in a closed iron cylinder ; he em- 
 ployed, by preference, linseed oil and 
 resin. The cylinder was fixed vertically, 
 an inconvenient arrangement not neces- 
 sary to the efficiency of his process. The 
 iron cylinder and the process by vacu- 
 um and pressure were adopted by Mr. 
 Bethell, and greatly improved by him and 
 by Mr. H. P. Burt, who were associated 
 together for some years. The cylinder 
 was enlarged, its fittings strengthened and 
 simplified, and an interior heating appa- 
 ratus added. In Mr. Burt's paper of 
 January, 1853, there is a full description 
 of this machinery ; its main features are 
 still the same in the usual Creosoting 
 apparatus of the present day. These 
 cylinders, being of wr ought-iron, were 
 applicable to Creosote oils and to chlor 
 ide of zinc, but not to salts having a 
 corrosive action upon iron, such as sul- 
 phate of copper and corrosive sublimate. 
 In 1842, Mr. Timperley described to this 
 Institution a method which he had 
 adopted on the Hull and Selby Railway, 
 
72 
 
 for lining the iron cylinder, in order to 
 preserve it from the action of corrosive 
 sublimate. This method and the expedient 
 of smearing the inner surface with pitch 
 were proposed and tried for sulphate of 
 copper injections with but partial suc- 
 cess. The author had several cylinders 
 materially injured or destroyed by the 
 corrosive action of these salts. In 1857 
 Messrs. Lege and Fleury Peronnet in- 
 troduced an apparatus of which the cyl- 
 inder, trucks and pressure pumps were 
 entirely of copper, and machinery of this 
 costly description is still used for the 
 Compagnie des Chemins de Fer du Midi, 
 at Labouheyre. In 1865 the author took 
 out a patent for the following apparatus : 
 Inside the iron cylinder he placed a 
 wooden tank, which contained the timber 
 to be operated upon, and in which was 
 the sulphate of copper solution. It was 
 an open wooden tank, inside a closed 
 iron cylinder. The pressure applied was 
 that of condensed air, a condensing air- 
 pump being used, capable of maintain- 
 ing an effective pressure of 200 Ibs. to 
 
73 
 
 the square inch. By this means the tim- 
 ber was injected with the copper solu- 
 tion without injury to the iron cylinder. 
 
 The process of Dr. Boucherie was at 
 one time largely used in France. It con- 
 sisted in the injection of newly-fallen 
 timber in the forest by the vertical press- 
 ure of a column of the antiseptic solu- 
 tion, generally sulphate of copper, which 
 was conducted through a pipe from a 
 small reservoir fixed at a height of 30 or 
 40 feet. The tube was attached by an 
 ingenious arrangement to the end or 
 middle of the log ; the antiseptic liquid 
 expelled the sap from the softer parts of 
 the timber, and took its place. The 
 process is still used to a small extent in 
 France, principally for telegraph poles. 
 
 Various attempts have been made to 
 imbue timber with the vapors of oils, 
 either by employing the tensions of the 
 vapors themselves, or by the use of the 
 pressure-pump. The first experiment of 
 this kind appears to have been made by 
 Lukin, in the dockyard at Woolwich in 
 1812, when the apparatus exploded, with 
 
74 
 
 fatal consequences to the workmen em- 
 ployed, and the attempt was abandoned. 
 The patents of Franz Moll in 1836, of 
 Bethell in 1864, and other subsequent 
 patents, claim the invention of the prin- 
 ciple of injecting Creosote oils in a state 
 of vapor. If this could be conveniently 
 or safely carried out, the system might 
 possess some advantages. But there 
 is a fatal objection to its employment. 
 Timber is weakened by exposure to a 
 temperature much exceeding 250Fahren- 
 heit, whilst at 300 Fahrenheit, or a little 
 above, it commences to decompose, and 
 becomes seriously injured. Now the 
 boiling point of the Creosote oils ranges 
 from a little below 400 Fahrenheit up to 
 760 Fahrenheit. As with the steam of 
 water, so is it with the vapor of oils no 
 pressure can be obtained with them, ex- 
 cept at a temperature exceeding their 
 boiling point. The vapors of the Creo- 
 sote oils cannot, therefore, be injected 
 into timber except at temperatures, and 
 under conditions of pressure, which 
 would destroy the value of the timber as 
 
75 
 
 an engineering material. The process 
 has been tried in France, and it failed, 
 owing to the complete deterioration of 
 the timber. 
 
 A modification of this system has, 
 however, been carried into practice. 
 Super-heated steam was passed through 
 Creosote oils, and then injected into the 
 sleepers (which had been previously 
 warmed by steam) with the idea that 
 the mingled vapors of water and Creo- 
 sote might be injected into the timber 
 at a temperature of from 290 Fahren- 
 heit to 320 Fahrenheit. With this 
 modified process, the author's firm carried 
 out some extensive operations for the 
 Compagnie des Chemins de Fer de 
 1'Ouest, it being the desire of the engi- 
 neers of that company to economize the 
 Creosote, and to try whether in a finely 
 divided state, a smaller quantity might 
 not suffice by being more deeply injected. 
 The operation was supplemented, how- 
 ever, by an injection of Creosote in the 
 usual fluid state. 
 
 After prolonged trials, the first part 
 
76 
 
 of the operation was discontinued by 
 order of Mr. Bouissou, the company's 
 engineer of the permanent way. It was 
 found, whenever the cylinder was opened 
 before the second operation, that a small 
 portion of the lightest particles of the 
 Creosote had been carried over mechani- 
 cally into the cylinder by the super- 
 heated steam. Once within the cylinder, 
 however, the two fluids obeyed the laws 
 which govern their respective volatili- 
 ties : the Creosote oil sank to the bot- 
 tom of the cylinder, and the vapor of 
 water only was injected into the timber. 
 The sleepers on examination and testing 
 by the ordinary tests, contained neither 
 tar oils nor tar acids. 
 
 An analogous experiment tried at the 
 Timber Preserving Works of the Austrian 
 North- West Railway, is described in the 
 journal of the Architects and Engineers' 
 Institute of the Kingdom of Bohemia 
 for 1880, by Herr J. Seidl, and the proc- 
 ess has been condemned for very similar 
 reasons. 
 
 Condition of Timber at Time of 
 
77 
 
 Preparation. Getting Hid of Moisture 
 by Stacking or Artificially. The hy- 
 grometric condition of timber at the 
 time of injection is an important element 
 in the success of the operation, all im- 
 portant with the Creosoting process es- 
 pecially. Neglect on this point has often 
 been the cause of partial or total fail- 
 ure. Woody fiber in itself is heavier 
 than water, its specific gravity being 
 generally considered as equal to 1.5, 
 water being 1.0. It is, therefore, owing 
 to the looseness of their texture, that so 
 many kinds of timber are lighter than 
 water. The specific gravity of fir timber 
 varies ordinarily between 0.5 and 0.8 ; 
 the difference arising as often from the 
 varying density of the timber itself, as 
 from the quantity of water contained. 
 As fir timber can, under certain condi- 
 tions, absorb so much moisture as to be- 
 come water-logged, or actually heavier 
 than water, its powers of absorption can 
 be calculated from its specific gravity. 
 It can take up as much as from 60 to 150 
 gallons of water to the load of 50 cubic 
 
78 
 
 feet, the maximum quantity being, of 
 course, an exceptional possibility. Fir 
 and pine, however, frequently contain as 
 much as from 15 per cent, to 20 per 
 cent, of water, after from two to three 
 years' stacking. The question of the 
 pernicious effects of an excess of moisture 
 in the timber at the time of Creosoting, 
 has been from time to time brought be- 
 fore this Institution by Mr. Bethell, by 
 Mr Burt and by the author. Large logs 
 taken out of timber ponds, or sleepers 
 freshly imported, are not in most cases 
 in a fit condition for Creosoting until 
 after having been stacked for from four 
 to six months. The author, in common 
 with most of the earlier operators in 
 this process, has tried various methods 
 for artificially drying the timber. Steam, 
 ordinary and super heated, currents of 
 hot air, and drying stoves or ovens, have 
 been used for this purpose, but have all, 
 in this country, been abandoned. To 
 subject timber to a dry heat, elevated 
 enough to remove its moisture with the 
 necessary rapidity, will invariably result 
 
79 
 
 in injury to the wood. Timber piles 
 stoved before Creosoting, prove brittle 
 when driven. The action of the air- 
 pump in the ordinary process assists the 
 operation by withdrawing air from the 
 pores of the wood ; but it is a mistake to 
 suppose that it has much effect in with- 
 drawing moisture. 
 
 These difficulties have perplexed the 
 author for many years. He has recently 
 devised a method by which to get rid of 
 the moisture as part of the timber-pre- 
 serving process, and without injury to 
 the wood. An experiment easy to repro- 
 duce, and which explains the nature of 
 this operation, is made as follows : An 
 ordinary glass flask, in which are placed 
 some pieces of wood saturated with 
 water is connected by glass tubes with 
 an experimental air pump. By working 
 the pump the air is extracted from the 
 pores of the timber, but however effi- 
 cient the vacuum may be, no perceptible 
 moisture is withdrawn, nor would the 
 water be removed from the wood except 
 by a slow evaporation prolonged beyond 
 
80 
 
 practical limits. This represents the 
 ordinary action of the air pump upon 
 timber in a Creosoting cylinder. If suffi- 
 cient heat be now applied beneath the 
 flask, the water will become volatilized, 
 and will be withdrawn rapidly in the 
 shape of steam by the action of the air 
 pump. But the wood will be found to 
 crack, and open to an extent which is not 
 desirable. This illustrates the result of 
 applying dry heat. 
 
 Now take a similar flask with a con- 
 densing apparatus added ; moreover, the 
 flask should contain Creosote oil, in 
 which the wet timber is submerged. It 
 must be constantly borne in mind that 
 at the ordinary tension of the atmos- 
 phere, the boiling point of the Creosote 
 oils ranges from about 380 Fahrenheit 
 to 760 Fahrenheit, as compared to water 
 at 212 Fahrenheit. These boiling points 
 are, however, lowered, according to a 
 well-known law, by the effects of a 
 vacuum. Let the Creosote in the flask 
 be now heated to 212 Fahrenheit, whilst 
 the air pump is put into operation. The 
 
81 
 
 heat being communicated through an oily 
 medium will not injure the timber, from 
 which the water is volatilized, and drawn 
 out by the air pump. The Creosote oils 
 are not volatilized, as the temperature is 
 far below their point of ebullition. The 
 water is speedily and effectually removed, 
 and the Creosote takes its place. 
 
 By the ordinary and well-known proc- 
 ess, after the timber has been placed in 
 the cylinder and the air-tight door 
 closed, the air is exhausted from the 
 cylinder, the Creosote is then introduced 
 heated to a temperature of from 100 
 Fahrenheit to 120 Fahrenheit, when the 
 air pump ceases to work, and the press- 
 ure pump is put into operation. 
 
 Referring now to the new process, it 
 will be seen that a large dome is placed 
 on the top of the cylinder, to which the 
 exhaust-pipe of the air pump is attached. 
 The exhausting process is continued 
 after the Creosote has been introduced 
 into the cylinder. The Creosote during 
 this part of the operation should not be 
 allowed to rise quite to the top of the 
 
82 
 
 vessel, a free space being preserved, and 
 the dome kept empty, so that the Creo- 
 sote is not drawn through the exhaust 
 pipe. The Creosote is raised to a tem- 
 perature a little exceeding 212 Fahren- 
 heit instead of 120 Fahrenheit as here- 
 tofore. The exhausting process is con- 
 tinued until all the water is extracted 
 from the timber in the form of vapor, 
 drawn through the dome, condensed by 
 passing through the worm of the con- 
 densing apparatus, and collected in the 
 receiving tank, where the quantity ex- 
 tracted can be measured. With charges 
 of very wet sleepers, the author has suc- 
 ceeded in withdrawing water equal in 
 volume to 50 gallons per load of timber, 
 and replacing this water with an equal 
 volume of Creosote by the action of the 
 air pump alone. If necessary, however, 
 the pressure pump can be afterwards ap- 
 plied in the usual way. 
 
 A slight additional cost, and a few 
 hours' additional time are necessary for 
 dealing with very wet timber by this 
 process as compared with the ordinary 
 
83 
 
 method. But the expenditure in time 
 and money is not so great as would be 
 required by stoving the wood before 
 Creosoting. If, in the absence of arti- 
 ficial methods, timber be stacked for six 
 months, as it should be, the interest on 
 capital represents a certain expenditure 
 also. The author ventures to suggest 
 that this is not always taken sufficiently 
 into account, in giving out contracts for 
 creosoted timber. Other conditions be- 
 ing equal, dry timber is at a disadvantage 
 in the competition, as far as price is con- 
 cerned, with timber just landed. Yet a 
 small extra expenditure in this particular 
 would frequently be repaid to the con- 
 sumer twenty or thirty-fold in the pro- 
 longed duration of the wood. 
 
 Conclusion. In conclusion the author 
 would remark that with regard to certain 
 points mentioned in this paper, upon 
 which some controversy has at times 
 arisen, he has been careful to advance no 
 opinion which he has not confirmed, 
 either by the opinions and investigations 
 of eminent authorities, or by careful and 
 
84 
 
 reiterated experiments. Many hundreds 
 of experiments have been in fact carried 
 out at the laboratories of the author's 
 firm at JSilvertown during the last five 
 years, with the especial object of investi- 
 gating the properties of the tar oils and 
 other antiseptics, and their behavior in 
 contact with timber. To Mr. Koyle, Mr. 
 Bendix, and Mr. Holmes of the chemical 
 staff of his Silvertown Works he has to 
 return his best thanks for their skilled 
 assistance, and particularly to Mr. Ben- 
 dix, who has been more especially en- 
 trusted with the conduct of these experi- 
 ments. To Mr. Gabbett he is indebted 
 for the drawings exhibited. 
 
 The Treatment of Timber by Anti- 
 septic Methods has been acknowledged 
 by some of the greatest engineers of 
 this country to have been useful to the 
 art of constructive engineering. It may 
 be made even more useful in the future 
 than it has been in the past. All that 
 the advocates for its still more extended 
 development can desire to claim will be, 
 that their methods and investigations 
 
85 
 
 may be seriously examined, and from 
 time to time decided upon, in accordance 
 with the results which science and ex- 
 perience may bring to light. 
 
 DISCUSSION. 
 
 Sir Joseph Bazalgette, C. B., President, 
 said the subject of the paper was an ex- 
 ceedingly practical one. Timber, in the 
 majority of countries, was the most avail- 
 able material for constructive and engin- 
 eering purposes, and in some countries it 
 was almost the only material which could 
 be used. The great defect in its use was 
 its want of durability. Anything, there- 
 fore, which could remedy that defect, and 
 give durability to the timber, must be a 
 subject of great interest to the engineer. 
 The author in the paper had given the 
 result of thirty-four years' experience, 
 together with his researches into what 
 had been done ages before, and the whole 
 had been placed before the members in a 
 manner showing that he had devoted very 
 great ability and attention to the subject. 
 
86 
 
 Although the author was commercially 
 engaged in that branch of engineering, 
 he was sure the members would feel that 
 the paper had risen considerably above 
 the commercial element, and had clearly 
 shown that science could be, and had 
 been, brought to bear on industrial art, 
 so as to improve it and make it of great 
 value. 
 
 Mr. Boulton remarked that the subject 
 of his paper was one which had occupied 
 his attention for many years. He hoped 
 he had clearly explained the analytical in- 
 vestigations by which he had sought for 
 some clue to what was a rather complex 
 labyrinth, namely, the kind of substance 
 which was the best to put into timber for 
 its preservation. He had employed many 
 of those substances, and the conclusion 
 at which he had arrived was that, suppos- 
 ing the substance to be a good antiseptic, 
 whether, as in former times, corrosive 
 sublimate, sulphate of copper, or chloride 
 of zinc were used, or whether creosote 
 oils, there was always a close connection 
 between the durable results of the anti- 
 
87 
 
 septic and the immunity of that antiseptic 
 from volatility in the air or solubility in 
 water. Timber must be exposed to air 
 for engineering purposes, and also to 
 water ; in some cases in marine work, it 
 was in the water altogether, and there- 
 fore, the antiseptic ought not to be liable 
 to evaporation or to being washed out 
 by the action of the water. He was not 
 there to advocate the use of the creosote 
 of one district more than another, because, 
 commercially speaking, that was a matter 
 that did not affect him. He thought that 
 all honest creosotes made from coal-tar in 
 England were useful for the purpose of 
 preparing timber; but he thought that 
 some of them were more useful than 
 others, because they were more durable. 
 If, therefore, engineers would take the 
 trouble to follow out his idea, and study 
 the different constituents of the creosote 
 oils, remembering which of them were the 
 most durable and the least soluble, that 
 would give a clue to the formation of 
 fresh specifications for the preparation of 
 timber. He did not think that the pres- 
 
88 
 
 ent specifications were satisfactory in all 
 respects. Plate 6 represented the prod- 
 ucts derived from Newcastle coal, such as 
 was ordinarily carbonized in London gas- 
 works. There was, as had been explained 
 in the paper, a different series of products 
 from the Midland coals ordinarily car- 
 bonized in other parts of the country. 
 Taking the same coals those carbonized 
 in the gasworks and subjecting them 
 by carbonization to a lower temperature, 
 another class of products would be ob- 
 tained as had been pointed out by Dr. 
 Armstrong in a recent discussion. It 
 was as well that engineers should bear 
 that in mind, as they were now witness- 
 ing an inauguration of a new series of in- 
 dustries, namely, the partial carbonization 
 of coal in coke ovens, partly for the pur- 
 pose of getting the products direct, in- 
 stead of through the gasworks. Those 
 other products might be valuable, but 
 they were not the same as far as the 
 preparation of timber was concerned, for 
 they were lighter and more volatile. He 
 had taken the trouble to get some truck- 
 
89 
 
 loads of different coals used ordinarily 
 by the London gas companies ; he had 
 carbonized them on a large scale at lower 
 temperatures, and had found that he ob- 
 tained thinner and lighter oils with a 
 specific gravity of from 930 to 1,030, in- 
 stead of from 1,045 to 1,060, and he had 
 a different class of products altogether. 
 
 Dr. C. Meymott Tidy said it was twenty 
 years ago when he commenced working 
 with creosote, and he was bound to admit 
 that since that time his views had under- 
 gone considerable changes ; but he sup- 
 posed there was no great harm in that, 
 for the views of engineers, politicians, and 
 even of theologians, were constantly shift- 
 ing. The process of creosoting was of a 
 threefold nature. First, there was the 
 physiological action of rendering the 
 wood a poison, so that animals could not 
 or would not attack it; secondly, there 
 was a chemical action, consisting chiefly 
 in the coalgulation of the albumen ; and 
 thirdly, there was what he held to be 
 by far the most important action of the 
 three, namely, the simple mechanical ac- 
 
90 
 
 tion. The process of creosoting was prac- 
 tically a choking up of the pores of the 
 wood so that neither air, moisture nor life 
 could get inside. He well remembered 
 the late Dr. Letheby drawing up his orig- 
 inal specification. No doubt he was very 
 strong in his belief of the enormous value 
 of carbolic acid ; indeed, he regarded it, 
 as the author had stated, as probably the 
 most important ingredient of the tar. In 
 the last specification which he, Dr. Tidy, 
 had drawn up a year ago, and which was 
 now being employed largely, he had 
 laid down three essentials, and as they 
 practically represented the views which 
 he held on the subject at the present time, 
 he might be allowed to refer to them. 
 The first point of the specification was 
 that the creosote should be completely 
 liquid at a temperature of 100 Fahren- 
 heit, no deposit afterward taking place 
 until the oil registered a temperature of 
 93. That point was considered very 
 fully. The temperature at which creosot- 
 ing was performed was about 120. It 
 did not appear to him to matter one iota 
 
91 
 
 how solid the creosote was (and he was 
 bound to say that from his point of view 
 the more solid it was the better), so long 
 as it was liquid at the temperature at 
 which the creosoting process was done. 
 Seeing that the process was carried out 
 at a temperature of 120, he thought he 
 was right in specifying that the creosote 
 should be liquid at the temperature of 
 100. The next point was (he had left 
 out a specific-gravity clause) that, tested 
 by a certain process, the creosote should 
 yield a total of 8 per cent, of tar acids. 
 He was aware that in an earlier specifica- 
 tion drawn up by Sir Frederick Abel and 
 himself about three years ago. they speci- 
 fied 10 per cent., and of course it was 
 only fair to ask him why he had thus de- 
 generated. Having examined a very large 
 number of creosoted timbers that had 
 been prepared for at least a year, he was 
 unable to detect the slightest trace of 
 carbolic acid in them. This fact had also 
 been very prominently and excellently 
 well brought out by Mr. Greville Wil- 
 liams. But although after a short period 
 
92 
 
 there was no trace, so far as he could 
 make out, of carbolic acid in the sleeper, 
 yet the wood continued as sound as ever. 
 It was also a fact that the earlier timbers 
 were creosoted with heavy oils containing 
 only a small quantity of carbolic acid, 
 nevertheless these very sleepers laid the 
 foundation of the success of creosoting 
 at a process. Taking those two facts to- 
 gether, it appeared to him that they had 
 hitherto placed an exaggerated value up- 
 on the carbolic acid. He did not wish 
 to be misunderstood. He did not say 
 that the carbolic acid evaporated, nor that 
 it might not undergo certain chemical 
 changes in the wood; he did not know 
 what took place, and that was not the 
 place to discuss the question. It was on 
 the ground, however, he had mentioned, 
 that he had fixed the quantity of the car- 
 bolic acid as low as was consistent with 
 obtaining a genuine creosote. In other 
 words, he fixed 8 per cent, not because 
 he regarded 8 per cent, as necessary for 
 the purpose of creosoting, but because 
 he thought from a large number of an- 
 
93 
 
 alyses of London creosote, that by fixing 
 8 per cent, he should ensure the obtain- 
 ing a genuine creosote. In the other 
 part of his specification he admitted that 
 he had completely altered previous speci- 
 fications, namely, in requiring that the 
 creosote should contain at least 25 per 
 cent, of constituents that did not distil 
 over a temperature of 600. He believed 
 that up to that time almost every specifi- 
 cation had required that the oil should 
 contain at least 75 per cent, of matters 
 that did distil over 600. He entirely 
 agreed with the author that it was to the 
 heavier oils that the success of the creo- 
 soting process was due, and it was there- 
 fore by the amount of those oils that did 
 not distil over at a temperature of 600 
 that the excellence of the creosote to be 
 used for creosoting purposes should be 
 determined. It appeared to him to be 
 highly advisable to get the heaviest creo- 
 sotes for the work, and to insist upon as 
 great a quantity as possible of the creo- 
 sote being driven into the wood. 
 
 Dr. H. E. Armstrong said that, on the 
 
94 
 
 whole, he concurred in the views expressed 
 by the author. He thought that creosot- 
 ing, instead of being an operation of a 
 threefold character, as Dr. Tidy had 
 stated, was of a onefold nature. Water 
 had to be excluded, because in excluding 
 water everything was excluded which was 
 likely to be harmful. When water was 
 introduced, other things were introduced 
 with it, especially certain organisms which 
 there could be no doubt played a most 
 important part in effecting the rapid de- 
 cay of timber. He agreed with Dr. Tidy 
 that, mechanically, it was of great import- 
 ance to choke up the pores, but the ob- 
 ject was not so much to choke up the 
 pores as to prevent the perpetual moist- 
 ening of the wood. When wood was 
 moistened, and was subject to frequent 
 variations in pressure, it necessarily be- 
 came after a time reduced to a very 
 spongy condition mechanically, and its 
 quality was in that way materially affected. 
 If, therefore, the access of moisture could 
 be prevented an important point was 
 gained. The author had briefly referred 
 
95 
 
 to Pasteur's experiments, which perhaps 
 were not so well known as they deserved 
 to be. He supposed that the experiment 
 to which special reference was made was 
 that conducted with sawdust. M. Pas- 
 teur had shown that if ordinary moist 
 sawdust had air passed over it for a few 
 hours, there was obvious evidence of de- 
 cay afforded by the production of car- 
 bonic acid. But if precautions were taken 
 to kill all the organisms attached to the 
 sawdust by heating it, and if it was then 
 moistened with water deprived of organ- 
 isms, and exposed to a current of air 
 carefully deprived of organisms by filter- 
 ing through cotton wool, the current of 
 air would pass over it for hours without 
 there being any evidence of the decay of 
 the wood. That was the fundamental ex- 
 periment upon which the views of chem- 
 ists with regard to the part played by 
 organisms were based at the present day. 
 With reference to the author's remark as 
 to the difference between creosote, prop- 
 erly so-called, and coal-tar oils, he thought 
 there was a little misunderstanding on 
 
96 
 
 that point. The author stated, "Creosote, 
 correctly so-called, is the product of the 
 destructive distillation of wood, and coal- 
 tar does not contain any of the true Creo- 
 sote, which has never been used for tim- 
 ber preserving." That was not quite 
 correct, because true creosote contained 
 a considerable quantity of carbolic acid 
 and cresylic acid, which had been com- 
 monly regarded as active constituents of 
 ordinary creosote oil. With reference to 
 what was really the active constituent in 
 .creosote oils, the remarks of Dr. Tidy 
 met with his approval to a large extent, but 
 he should be inclined to predict that be- 
 fore many years Dr. Tidy would drop his 
 limit from 8 per cent, to 6 per cent., and 
 perhaps eventually sink it altogether. It 
 was very much to be hoped that that 
 would be the case, because he thought 
 that engineers were using a material for 
 creosoting that ought not to be employed 
 for that purpose, and probably the car- 
 bolic acid was practically of very little use. 
 He did not think that the coagulation of 
 the albumenoids to which reference had 
 
97 
 
 been made, took place to any large extent, 
 or was an essential part of the process. 
 That was, he thought, the only part that 
 could be assigned to the carbolic acid. 
 There could be very little doubt that, 
 within a comparatively short time, either 
 by evaporation or by being dissolved out, 
 the carbolic acid disappeared. It was not 
 there in any form, but actually went 
 away. There was no probability that it 
 would be fixed in such a way as to escape 
 attention and detection by the tests em- 
 ployed by Dr. Tidy and Mr. G. Williams. 
 He was inclined to think the action was 
 mainly a choking action as described by 
 Dr. Tidy, the access of water to the wood 
 being prevented. It was therefore simply 
 a question of obtaining an oil which would 
 do that in the best possible way, which 
 could be introduced into the wood with 
 the greatest readiness, and would remain 
 in it under ordinary conditions, for the 
 greatest length of time ; and if, as the 
 author had said, with the oil which would 
 exercise that action engineers could in- 
 troduce substances like acridine and other 
 
98 
 
 compounds of a poisonous character, so 
 much the better. 
 
 Professor A. Voelcker remarked that, 
 as had been pointed out by the author, 
 the antiseptic treatment of timber had 
 almost entirely superseded former meth- 
 ods, and justly so, for on the strength 
 of past experience there could be no 
 question that, when properly carried out, 
 the impregnation of timber with crude 
 creosote was the most efficacious, the 
 least troublesome, the most persistent, 
 and the cheapest process that could be 
 adopted. He gathered from the paper 
 that the author was rather inclined to 
 think that chemists had attached too 
 much importance to the presence of car- 
 bolic acid in creosote oil. He had point- 
 ed out that certain alkaloids in coal-tar 
 possessed antiseptic properties, even in a 
 higher degree than phenol, and had sug- 
 gested whether it would not be desirable 
 to modify somewhat the specifications is- 
 sued by the Crown Agents for the colo- 
 nies, by the War Office, and other public 
 bodies. Professor Yoelcker agreed that 
 
99 
 
 the heavy tar-oils were extremely useful, 
 and perhaps more so than the light tar- 
 oils, for preserving timber intended to be 
 used for railway sleepers. He could not 
 go so far as Dr. Tidy, who had suggested 
 (he granted somewhat vaguely) that 
 chemists had attached far too great im- 
 portance to the presence of carbolic acid 
 in crude creosote. But he would go as 
 far as to say that for preserving well- 
 seasoned old timber, it did not, perhaps, 
 matter so much whether there was a high 
 percentage of carbolic acid in the creo- 
 sote, as it mattered that there should be 
 present in it a high percentage of the 
 oils which passed over on distillation 
 above 610, because, as Dr. Tidy had 
 pointed out, the effect of these tar com- 
 pounds was to close up the pores of the 
 timber, to render it impervious to water, 
 air, and other debasing influences ; being 
 at the same time in itself, comparatively 
 speaking, an imperishable substance, like 
 all pitchy products when completely 
 dried. But it should be borne in mind 
 that it was' requisite not only to preserve 
 
100 
 
 well-seasoned old timber, from which the 
 moisture was expelled almost completely, 
 but that of late years a great deal had 
 been done in preserving telegraph-posts, 
 gate-posts, wooden fencing, hop-poles, 
 and the like, for which sapling-wood, or 
 at any rate young wood, was used. 
 There was a great deal of difference in 
 the chemical constitution of the two 
 kinds of wood. Sappling-wood was more 
 or less filled with sap, and in the liquid 
 which circulated in it there were perish- 
 able substances belonging to the class of 
 albumenoids, which acted as ferments, 
 and caused otherwise imperishable sub- 
 stances to decay. The primary causes of 
 decay of greenwood were unquestionably 
 the albumenoid substances ; and all the 
 older processes, such as the corrosive 
 sublimate, or kyanizing plan, or the im- 
 pregnation with other metallic salts, were 
 based on the principle that by those me- 
 tallic salts, notably by the bichloride of 
 mercury (corrosive sublimate), the al- 
 bumenoids were precipitated, and ren- 
 dered insoluble and incapable of acting 
 
101 
 
 as ferments. In green wood also, the 
 celluloise was in a more tender condition 
 than in old wood, where there was a 
 larger proportion of in crusting matter ; 
 there was, therefore, a greater reason for 
 preventing the first state of decomposi- 
 tion ; and he questioned whether creosote, 
 which was sometimes extremely poor in 
 carbolic acid, was the proper material for 
 preserving wooden structures of the kind 
 he had mentioned. No doubt there was 
 a good deal to be said in extenuation of 
 the qualities of creosote, for the process 
 of preserving wood in open tanks, was 
 sometimes unskillfully not to say care- 
 lessly conducted ; but, making all allow- 
 ance for the imperfections of the meth- 
 ods for preserving wooden poles in that 
 way, there could be no doubt that some- 
 times creosote answered remarkably well, 
 and in other instances the same process 
 tended to make the wood more perishable 
 than it would have been had it not been 
 creosoted at all. That seemed to be a 
 contradiction, but according to the evi- 
 dence of those who had carried on the 
 
102 
 
 process with more or less success for fif- 
 teen years or longer, the same kind of 
 creosote would answer extremely well for 
 preserving hard timber used for railway 
 sleepers, while for young wood it did not 
 answer the purpose. He had found, from 
 the examination of samples which had 
 been sent to him, that there were great 
 differences in the composition of different 
 creosotes. Not long ago he had received 
 a sample which yielded, on distillation 
 from the boiling point up to 610, only 
 39 per cent, of distillate, containing no 
 more than 3 per cent, of carbolic acid ; 
 while another sample yielded 14f per cent, 
 of a watery liquid with a little light oil, 
 the water being strongly ammoniacal ; 
 and it was well known that any ammoni- 
 acal water left in the creosote was extreme- 
 ly injurious to the timber. The same 
 sample only yielded 47 per cent, of dis- 
 tillate; including 4 per cent, of crude 
 carbolic acid. In a third sample he found 
 only 5 per cent, of carbolic acid. He 
 ventured to think that creosote contain- 
 ing as little as 5 per cent, of crude car- 
 
103 
 
 bolic acid was not a good liquid for pre- 
 serving immature wood, simply because 
 it was not strong enough to precipitate 
 or render ineffective albumenoid sub- 
 stances. Even Dr. Tidy, in the recent 
 modifications of his views, still recom- 
 mended that the creosoting liquid should 
 contain as much as 8 per cent, of crude 
 carbolic acid. A great deal had been said 
 about the specific gravity of the creosote. 
 He confessed that he did not attach very 
 great importance to specific gravity, but 
 he did attach great importance to the 
 presence of a fair percentage of phenol, 
 or crude carbolic acid, if it was wished to 
 preserve green wood, such as that used 
 for telegraph posts or hop -poles ; because 
 it was essential that the first tendency to 
 subsequent decay should be counteract- 
 ed, and that could not be done without 
 the introduction of a sufficient quantity of 
 carbolic acid. In the case of hard timber 
 the main object was to fill up the pores. 
 There was not so much albumenoid matter 
 present, and the timber would keep fairly 
 well if moisture was excluded ; that was 
 
104 
 
 effected by heavy tar oil which filled up the 
 pores, and rendered the wood very hard, 
 so that there was not the same necessity 
 for the presence of carbolic acid. He 
 could even understand that if crude creo- 
 sote contained a very small quantity of 
 carbolic acid, as in the case he had men- 
 tioned, and if there should be a large 
 proportion of the more solid constituents 
 of creosote, the pores externally at any 
 rate would be closed up, and the same 
 thing would take place by painting or 
 pitching unseasoned wood ; the solid con- 
 stituents closed up the pores of the outer 
 layers, introducing nothing to render the 
 albumenoids ineffective as a ferment, so 
 that the moisture was kept in, and in that 
 way decay was actually hastened, whereas 
 if free passage were allowed, the wood 
 would be washed out and would keep 
 longer. Engineers knew from experience 
 that green wood, when thoroughly paint- 
 ed or pitched, decayed more rapidly than 
 wood in its natural state. In order that 
 the point might be settled he would sug- 
 gest that some experiments be tried with 
 
105 
 
 creosote containing various proportions 
 of carbolic acid, not with reference to the 
 preservation of railway sleepers, but of 
 younger wood. Strictly comparative ex- 
 periments should be made with crude 
 creosote, one sample containing 5 per 
 cent., another 10 percent., and a third 15 
 per cent, that being the usual range of 
 carbolic acid in commercial creosote. 
 Some well-conducted experiments in open 
 tanks with creosote of various strengths 
 would, he thought, finally settle the ques- 
 tion. He could not help thinking that 
 it would be requisite for the proper car- 
 rying out of the process that there should 
 be something like 10 per cent, of crude 
 carbolic acid in the creosoting liquid ; at 
 any rate, without further information on 
 the subject, he should be disindined to 
 recommend anybody wishing to preserve 
 hop-poles or telegraph posts to use any 
 liquid containing a less amount than he 
 had mentioned. 
 
 Mr. H. K. Bamber said it appeared to 
 him that the whole secret of the paper 
 was to be found in the paragraph, " By 
 
106 
 
 the light of the evidence now accumu- 
 lated, it may be advisable to review the 
 question as to the relative value of these 
 various bodies contained in the heavy oils 
 as regards the preservation of timber. 
 Some of them are becoming valuable for 
 other purposes. Which of them should 
 the engineer retain for injecting wood ? " 
 Carbolic acid, if left in creosote, was 
 worth 2d. a gallon, and if taken out from 
 4s. to 40s. per gallon, according to the 
 state of purity. The author's idea ap- 
 peared to be that nothing should be left 
 in the creosote which it would pay him 
 better to take out > in fact, there should 
 be nothing left that was worth more than 
 the proverbial 2d. He did not appear to 
 see the difference in our color between 
 the two pennies and the two sovereigns. 
 The difference in the town-made tar and 
 the country tar did not arise so much 
 from the difference of coal used as from 
 the degree of heat used in making the 
 gas. In London it was desired to obtain 
 a harder coke that would do for engines, 
 .and for that purpose a much higher 
 
107 
 
 temperature was used, and the most lumi- 
 nous portion of the gas fiist formed was- 
 decomposed on coming into contact with 
 the sides of the red-hot retort, the result 
 being gas charcoal, naphthaline, and a 
 gas of less illuminating power. With re- 
 gard to Dr. Letheby's specification, that 
 very specification was advocated and rec- 
 ornmended'by Messrs. Burt and Boulton, 
 but then carbolic acid had not become so- 
 valuable when separated. Now the speci- 
 fication recommended was drawn up by 
 Dr. Tidy, and if the author could get his- 
 views adopted there would soon be a very 
 tidy specification to work from. The au- 
 thor had mentioned some experiments of 
 Dr. Tidy's with naphthaline injected into 
 wood, but he had given no facts or data,, 
 merely expressing his own opinion. 
 Again, the experiment was not similar to 
 the exposure of creosoted sleepers, which 
 were not subjected to a temperature of 
 150 Fahrenheit in a closed vessel. He 
 would give the results of two experiments- 
 that he had made in 1882, one with coun- 
 try oil, condemned by the author, and 
 
108 
 
 one with Mr. Boulton's own oil, full of 
 naphthaline. He took a piece of wood 
 (deal), 3 inches by 3 inches by 8 inches, 
 and dried at 230 Fahrenheit, until it lost 
 no more weight, so that there was no 
 water left in it to cause loss. He then 
 kept it in a vessel containing the author's 
 London creosote, heated to 180 Fahren- 
 heit, having a weight on the wood to keep 
 it under the creosote. It took up 1,020 
 grains, after being wiped from excess of 
 creosote outside. It was then, on Feb- 
 ruary 7th, 1882, placed on a mantelshelf, 
 where the temperature was never above 
 70 Fahrenheit, and generally between 
 40 and 50. It was repeatedly weighed, 
 and the loss was constant until June 5th, 
 1882, when it had lost 487 grains, equal 
 to 47.75 per cent, of the creosote put in. 
 Now, as there were only 10 per cent, of 
 crude tar acids in the creosote, what was 
 it that made up the 47.75 per cent, loss? 
 Water there was none. The loss arose 
 chiefly from evaporation of the naphtha- 
 line. At the same time he treated a simi- 
 lar piece of wood, 3 inches by 3 inches 
 
109 
 
 by 6 inches 2 inches shorter dried at 
 the same temperature, until it ceased to 
 lose weight. It was then immersed in 
 country oil, specific gravity 1,045, and 
 kept under the oil by a weight, but with- 
 out applying heat. It absorbed 1.788 
 grains of the creosote, so that the wood, 
 which was a quarter smaller, took up, 
 actually, in cold, more than double the 
 quantity that the other piece did of the 
 author's oil at 180 Fahrenheit. The 
 piece was placed side by side with the 
 other on the mantelshelf, and in four 
 months it had lost 575 grains, or 42.33 
 per cent, of the oil taken up. But that 
 was not fair to the second piece of wood, 
 for it was so saturated that some of the 
 oil drained out on the mantelshelf, and 
 of course contributed to the loss of 
 weight, although it was not by evapora- 
 tion. The oil contained about 20 per 
 cent, crude tar acids. Those were plain 
 facts, and showed that the author's 
 contention "that country oils are not 
 good for creosoting timber because of 
 their instability" was contrary to fact. 
 
110 
 
 The beautiful white substance, naphtha- 
 line, was liable to sudden changes. It 
 might at one moment be a black dirty- 
 looking substance, and, by the applica- 
 tion of a moderate heat, it became volatil- 
 ized and condensed into a lustrous sub- 
 stance. The author, by Dr. Tidy's 
 experiments, had tried to make out that 
 it was not volatile. Camphor, although 
 it could not be volatilized by heat with- 
 out decomposition, yet it was well known 
 that a piece of camphor, even when 
 wrapped in paper or any porous mate- 
 rial, would soon pass away by evapora- 
 tion ; and it was so with the naphtha- 
 line. Many attempts had been made to 
 prepare tar colors, &c., from naphthaline, 
 but as yet without success ; it was worth 
 nothing (except in small quantities in the 
 albo-carbon gas-burners) when separated 
 from the creosote ; and that was the rea- 
 son why it was so valuable, according to 
 the author, in the creosote. But if ever, 
 by chemical research, naphthaline became 
 as valuable as carbolic acid, it would then 
 become so volatile as to escape from the 
 
Ill 
 
 creosote altogether, and chemists would 
 be asked to reconsider their creosoting 
 specifications. As to the solubility of car- 
 bolic acid in water and alkaline solutions, 
 which the author said was a disadvantage, 
 he maintained that it was an advantage, 
 for it enabled the acid gradually to dis- 
 solve in the water and sap, and thus get 
 into the substance of the wood and pre~ 
 vent decay, while the other portion of 
 the creosote remained like beauty, only 
 skin-deep. To say that because carbolic 
 acid could not be found in creosoted 
 sleepers after twenty or thirty years, and 
 that therefore it had nothing to do with 
 stopping decay, was absurd. It might 
 as well be said that a few days after a 
 large fire only one or two policemen were 
 found and no fire-engines, and that there- 
 fore the policemen put out the fire and 
 not the engines. Carbolic acid was an 
 oxidizable substance, and would protect 
 the wood from oxidation or decay. It 
 instantly prevented decomposition, and 
 destroyed the life of the germs which 
 caused decay, being also poisonous to 
 
112 
 
 most insects. Dr. Tidy had mentioned 
 the number of analyses he had made, 
 and how long his experience had lasted. 
 Mr. Bamber might therefore be allowed 
 to state that he had tested samples of 
 creosote for the last twenty-five years, 
 and had practical experience in the proc- 
 ess of creosoting. It was his opinion 
 that to creosote timber properly the 
 creosote tank must not be only the 
 " waste tub " for distilling works. It 
 was easy to get good country oil with 18 
 to 25 per cent, crude tar acids, yielding 
 no deposit of that volatile substance, 
 naphthaline. He had met with some 
 samples of so-called creosote that con- 
 tained nearly half their bulk of filth, con- 
 sisting of charred oil, &c., he presumed 
 the residues from anthracene manufac- 
 ture, yet when the creosote was rejected 
 every effort was made to induce the be- 
 lief that it was some of the best creo- 
 sote. 
 
 Dr. Albert J. Berneys said that no one 
 could doubt the conclusion that the sub- 
 stances preferred should be germ ex- 
 
113 
 
 cinders as well as germicides, and those 
 contained in the oils which were heavier 
 than water. His contention would be to 
 retain, at least in part, and to the extent 
 of 2 per cent., the carbolic acid as well 
 as the naphthaline and the alkaloids. 
 The arguments in favor of carbolic acid 
 were very strong. Where the creosoted 
 timber was covered up in the ground the 
 solubility in water assisted in diffusing it 
 somewhat in the earth, and thus extended 
 its sphere of action. Nor should that 
 solubility be exaggerated. In a dry soil 
 the loss could only be by heat, and that 
 would also affect other ingredients. It 
 said much for the durability of carbolic 
 acid that, in spite of the employment of 
 heavier types of tar-creosote in early 
 days, it was distinctly present in many 
 cases recorded in the experiments of Mr. 
 Greville Williams. In one specimen 
 wood creosoted thirty years, distilled 
 with water, a distinct reaction of phenol 
 was obtained in a case where most of the 
 oil and all the naphthaline had disap- 
 peared. In another, creosoted thirty-two 
 
114 
 
 years, the phenol reaction was very 
 distinct. In a third, creosoted twenty- 
 nine years, the phenol reaction was very 
 strong when distilled with acid, but was 
 also distinctly present in a free state ; 
 whereas there was no naphthaline and 
 very little oil. In cases where no free 
 phenol was found, it was discoverable in 
 combination. The power possessed by 
 phenol for coagulating albumen could 
 not be exaggerated. He would not de- 
 scribe his own experiments ; but in his 
 hospital work he was very familiar with 
 the high antiseptic power of carbolic 
 acid. The experiments of Mr. Greville 
 Williams with the white and yolk of an 
 egg only showed that the alkaloids of 
 the tar-creosote, weight for weight, were 
 equal to the carbolic acid as germicides, 
 but certainly no more; and that the 
 .__i_th part of phenol bore no relation 
 to the amount of albumen present. If 
 all the albumen had been coagulated it 
 would not have putrefied. For Mr. 
 Williams further stated that 1 per cent, 
 of phenol and 1 per cent, of alkaloidals 
 
115 
 
 were of equal value. He believed in the 
 coagulation theory by phenol of the 
 albumen of the wood, but unless enough 
 was used it was as with disinfectants. If 
 he had a quantify of hydrogen sulphide 
 in the air of a room, and he only used 
 enough chlorine to unite with one-half of 
 the hydrogen present, where would the 
 disinfection be? It was the worst of 
 disinfectants that generally they could 
 not be used in sufficient quantities. The 
 benefit of them was (as Miss Nightin- 
 gale had said) that it was necessary to 
 open the window when they were used. 
 It was the same with phenol. If he did 
 not coagulate the albumen, of which 
 there was but little in the wood, he 
 failed. But the phenol had the property 
 and the additional advantage of volatil- 
 ity. It took a long time for even the 
 free phenol to evaporate, so much was it 
 protected and shut up by the oil and 
 naphthaline in the tar-creosote. And he 
 believed that not only was carbolic acid 
 more potent as an antiseptic than any 
 other constituent of the tar-creosote, but 
 
116 
 
 that it was present in larger quantities 
 than the alkaloids which, according to 
 Mr. Williams, were equal to it weight for 
 weight. 
 
 Mr. W. Foster regarded the question 
 brought forward by the author, as to the 
 value of alkaloidal substances, as a very 
 important one. In a paper which he had 
 recently read before the Institution, he 
 had remarked on the possibility of some 
 of the nitrogen, which he was then in 
 search of, being in tar in the condition of 
 alkalodial bodies. The author had men- 
 tioned five or six of those nitrogenous 
 bodies, and there were probably others. 
 The recent investigations of chemists 
 had shown that pitch itself contained an 
 appreciable amount of nitrogen. Acridine, 
 of which an example had been given in 
 the table, contained the lowest percent- 
 age of nitrogen, and had the highest 
 boiling-point. Having regard to the 
 pitch, it was possible that there were 
 other nitrogenous bodies which had a 
 still higher boiling-point, and a lower 
 percentage of nitrogen than in the case 
 
117 
 
 of acridine. The quantity of those 
 alkaloidal substances in the tar was very 
 small. There was no information as to 
 their relative proportions ; and as the 
 percentage of nitrogen varied from 17.7 
 to 7.8, it would not be wise to specify 
 how much of those bodies was present in 
 the tar. He thought he might say that 
 there was not more than from 3 to 4 per 
 cent. If, therefore, they had any value 
 in the preservation of wood, their effect 
 must be very powerful. He was inclined 
 to look at the question of the preserva- 
 tion of wood by the aid of some facts 
 which were a little outside the subject. 
 He might be pardoned for referring to 
 the corrosion of iron. Iron could remain 
 permanent in dry oxygen, in pure water, 
 or in pure carbonic acid gas ; in any two 
 of those it remained permanent ; it was 
 only by the conjoint influence of the 
 three that corrosion was effected. Pitch, 
 he believed, was the best preservative of 
 iron that was to be had, and if applied to 
 a clean surface free from oxide (rust), it 
 was impossible to say when the surface 
 
118 
 
 of pitch would fail to protect the iron. 
 He was of course speaking of the con- 
 tinuity of surface being preserved. Pitch 
 was a substance of a most permanent 
 character, being almost destitute of any 
 chemical attributes ; if, therefore, the cel- 
 lular structure of the wood could be 
 thoroughly permeated by it, as long as 
 the continuity was perfect, it would be 
 preserved. Of course, that could never 
 be fully realized in practice. In the case 
 of green wood, the question arose as to 
 the coagulation of albuminous matter. 
 No need to go far afield to get plenty of 
 instances showing that if water and im- 
 pure air could be kept out, the preserva- 
 tion would be prolonged. The author 
 had referred to the experiments of Petti- 
 grew ; but the inference he had drawn 
 was not the only one. If albuminous 
 matter was dried, it could be kept as a 
 horny substance for an indefinite length 
 of time. A piece of glue could be pre- 
 served intact in the same way. If white 
 of egg or glue were moistened and ex- 
 posed for a certain time, it putrefied. 
 
119 
 
 The inferences deducible from Petti- 
 grew's experiments could, he thought, be 
 traced to the removal of water from the 
 muscle (the heart), which had been the 
 subject of the experiments. The whole 
 thing might be summed up in the grave- 
 digger's reply to Hamlet, "Water is a 
 sore destroyer of the dead body." 
 
 Mr. W. Carruthers thought that the 
 botanical aspect of the question should 
 be at the basis of the inquiry ; for with- 
 out a proper appreciation of the circum- 
 stances under which vegetable tissues 
 were destroyed, it was impossible rightly 
 to appreciate the means by which that 
 destruction could be prevented. While 
 he agreed with much that had been said, 
 he felt bound to differ from a great deal 
 that he had heard. He acknowledged 
 the great importance of pitch for preserv- 
 ing the external surface of wood. But 
 wood decayed not only from chemical 
 agents, air and water ; but much more 
 from the action of parasites. He could 
 easily see that if a body was entirely pro- 
 tected externally by pitch, it would be 
 
120 
 
 preserved from chemical changes, but not 
 from the more injurious and dangerous 
 attacks of fungal parasites. They were 
 developed from spores, and the attack 
 might be made through a flaw or crack in 
 the wood. When the wood was exposed 
 to the desiccation of the air, flaws con- 
 tinually appeared, and wherever a spore 
 could get access, there would begin de- 
 velopment of the mycelium or root of the 
 fungus, which penetrated the wood wher- 
 ever nutritious materials were supplied 
 through its whole course ; so that unless 
 the wood was preserved by some sub- 
 stance which would prevent the life of 
 fungi, its destruction was certain. He 
 exhibited a specimen of wood the date of 
 the creosoting of which was not known, 
 but it had been used in a hurdle for at 
 least ten years. The lower creosoted por- 
 tion, embedded in the earth, did not show 
 the slightest injury ; but the upper part, 
 exposed to the air, and cracked, had been 
 attacked from the outside by minute veg- 
 etation. Some of the spores had obtained 
 access to the interior, which had not been 
 
121 
 
 antiseptically preserved, the fungi had 
 enormously developed, and the interior 
 had been destroyed by them. The same 
 thing had occurred in the case of two 
 specimens of telegraph poles. The ex- 
 terior of the specimen which he exhibited 
 had been fairly preserved, but the interior 
 had been destroyed. It was remarkable 
 that the interior was colored by the in- 
 jection of what he supposed he must call 
 creosote ; but it had not been sufficient to 
 serve as an antiseptic, as it had permitted 
 the free growth of fungi, which ramified 
 through the base of the pole and com- 
 pletely destroyed the cellulose or lignine, 
 leaving it a fragile skeleton. It appeared 
 to him that what was needed was a suffi- 
 cient impregnation of the wood with creo- 
 sote, and with that element in it which 
 was destructive to vegetable life. He did 
 not know from experiments what that 
 element was, but he did know that there 
 was an element in crude creosote that 
 was extremely destructive to vegetable 
 life, viz., carbolic acid. Not, however, in 
 all strengths, for Koch, a distinguished 
 
122 
 
 German mycologist, had found that certain 
 liquids, with 5 per cent, of carbolic acid, 
 would support fungi; so that the pres- 
 ence of a small percentage was not de- 
 structive to vegetable life. That was ex- 
 tremely important in relation to the ob- 
 servations of Prof. Voelcker. Another 
 specimen from a telegraph pole had been 
 completely destroyed by a fungus (He- 
 ticularia). There was on one side a 
 yellowish dust, consisting entirely of the 
 spores of the plant. But in a specimen 
 from a hurdle, which had been in use 
 since 1861, when it was creosoted, the ex- 
 terior, although it had no coating of tar, 
 still exhibited the minutest marks of the 
 tools employed upon it, and the interior, 
 which was completely saturated with a 
 brown substance, was as good and fresh 
 as if it had been creosoted yesterday, 
 without a particle of fungus. There was 
 a little greenish vegetation on the outside, 
 but it was epiphytic, and not injurious to 
 the wood ; there was no fungal vegeta- 
 tion whatever. The wood had been enor- 
 mously increased in weight, and he had 
 
123 
 
 ascertained microscopically that there 
 was no deposit in the interior of the cells. 
 The whole of the lignine and of the sec- 
 ondary deposits had been colored by that 
 material, so that the tissue had been com- 
 pletely altered. It appeared to him that 
 there had been a new combination through 
 the injected material, producing an an- 
 tiseptic condition of the wood which was 
 fatal to the fungi. There was a little 
 free carbolic acid crystallizing in the in- 
 terior of the cells, but it did not seem to 
 him that that was the explanation of it. 
 He should be glad if those who were con- 
 versant with the chemical aspect of the 
 subject, would inquire into the real na- 
 ture of the change which had produced 
 the discolored and altered condition of 
 the lignine. In his opinion nothing had 
 been introduced for preserving timber 
 that could compare with the creosote 
 used in the specimen he had exhibited, 
 which had been exposed to the air nearly 
 twenty years, and yet the ragged edges 
 of the chips on the outside had not even 
 
124 
 
 been touched by atmospheric or other 
 destructive agents. 
 
 Mr. Henry Maudslay observed that, in 
 the case of Old London Bridge, the decay 
 of the timber piles of the piers varied ac- 
 cording as they were constantly under 
 water, or exposed to water, air, and sun ; 
 or exposed especially to salt water or to 
 fresh water on the rise and fall of the 
 tide. There were many combinations of 
 circumstances that tended practically to 
 destroy timber, and it was therefore most 
 desirable to ascertain the exact position 
 that would be occupied by a solid pile 
 driven into the earth to support a struc- 
 ure whether it was to be exposed to the 
 constant action of the water below in the 
 earth, or to a change in the rise and fall 
 of the tide, or to the influence of moisture 
 gradually attacking it above the highest 
 spring-tide level. On the Arran and 
 Snowdon mountains he had been lately 
 excavating soil in order to form a reser- 
 voir, and had come across some of the 
 largest roots of red pine timber that he 
 had seen in that locality. There were no 
 
125 
 
 trees on the mountains at the present 
 time, and it must have taken many years 
 for the timber to have grown at that ele- 
 vation 1,200 to 1,500 feet above the level 
 of the sea. The timber was of a mag- 
 nificent character ; these roots had been 
 submerged perhaps centuries. The roots 
 had been found in situ covered with a 
 layer of disintegrated earth saturated with 
 water from the copper mines. They had 
 been preserved in that way by nature, 
 but now that they were being exposed to 
 the air, they were in some cases begin- 
 nin to crumble away. The props and 
 supports in old workings of copper mines 
 were preserved, and would burn with 
 great difficulty. Since the Royal George 
 had sunk in 1782, all the timber had be- 
 come saturated with sea-water, which was 
 so destructive to the cast-iron cannon, 
 that they were made as soft as plumbago ; 
 but salt water had a great effect upon the 
 preservation of the oak wood, making it 
 quite green. The timber was so hardened 
 that all the pores seemed to have been 
 filled with some material that was suit- 
 
126 
 
 able to its preservation. It still retained 
 that quality, as shown in the case of a 
 billiard table made for Her Majesty, and 
 by another now in his late father's house 
 at Norwood. This table had been made 
 by Thurston in 1860, from the wreck which 
 was raised in 1841. With regard to the 
 decay of iron, he might be permitted to 
 mention that Queen Anne's statue at St. 
 Paul's cathedral, was one of the finest of 
 London specimens of decay of iron that 
 engineers could examine. It consisted of 
 cast iron, wrought iron, lead, and stone, 
 all of which were mouldering away by the 
 action of nature, the character of the air, 
 and the water. The whole of the iron 
 work was a magnificent specimen of age 
 and deterioration. If chemists would ex- 
 amine the question as to effects produced 
 upon timber subjected to the continual 
 action of water and its components, or to 
 the rise and fall of the tide, whether salt 
 or fresh, or only to the effects of a certain 
 amount of moisture, as in the case of rail- 
 way sleepers afterwards dried by the ac- 
 tion of the sun, the practical results of 
 

 127 
 
 their investigations would be of great 
 value. 
 
 Mr. E. A. Cowper said he understood 
 that an examination of the old pieces of 
 timber successfully creosoted that had 
 been exhibited, showed they were not at 
 present protected by tar acids, and if 
 they had had any in them in the first in- 
 stance, it had long ago evaporated. The 
 unsuccessful telegraph pole exhibited by 
 Mr. Carruthers, from which a specimen 
 had been taken, had evidently not been 
 put into a creosoting cylinder, for it had 
 a mere slight covering of creosote out- 
 side. Hop-poles were often put into an 
 iron pan with a fire under it and made 
 hot, and there could be no doubt that 
 steam came out from the water evaporat- 
 ing, and the very action of which the au- 
 thor had spoken took place to a slight 
 extent. The piece of wood that was cut 
 to a taper had a little creosote in its end, 
 but on its sides the creosote did not go 
 in jig- of an inch, it was merely paint on 
 the outside; where the mortise-holes had 
 been put through the post the spores had 
 
128 
 
 entered and attacked the inside. The ef- 
 fect of a spore getting into a piece of 
 timber that had been preserved only on 
 the outside surface was no argument 
 against the preservation of timber by 
 creosote. The piece from the Victoria 
 Dock fence, which had been well creo- 
 soted, had been preserved, and was as 
 sound as it was twenty-nine years ago, 
 when it was put down. The creosote 
 had gone to the middle of the wood and 
 protected it. The other specimen had 
 not been preserved, and, therefore, it was 
 rotten. A very extensive series of ex- 
 periments had been carried out by Mr. 
 Charles Coisne, and they were of a very 
 instructive character. Samples of creo- 
 sote had been taken from England, Scot- 
 land, Belgium and France, showing 15, 
 15, 8 and 7 per cent, of tar acids, and 
 there was a fifth specimen of heavy oil 
 without any tar acid. Other mixtures 
 were made by putting in an extra quan- 
 tity of tar acids, except in the case of the 
 one kept without acid, and the result 
 showed that where the heavy oil was 
 
129 
 
 used, the wood was preserved in the best 
 manner, whilst those samples of wood 
 preserved with creosote, having an extra 
 dose of acid, were not so well preserved, 
 and that which was unpreserved was en- 
 tirely rotten. He had gone to Silver- 
 town to examine the apparatus to which 
 reference had been made. There were a 
 number of pipes in the bottom of the 
 creosote cylinder with superheated steam 
 in them. When the timber had been 
 put into the cylinder and warm creosote 
 run in upon it, the temperature was grad- 
 ually got up, and the water was as effect- 
 ually driven out of the wood by evapora- 
 tion as would be the case if water was 
 put in a boiler with a fire under it and 
 kept without any fresh supply of water. 
 A temperature of 220 or 230 would 
 evaporate every particle of moisture out 
 of the wood, more especially when a vacu- 
 um was put on. He might mention that 
 the vacuum should not be turned on sud- 
 denly, otherwise the creosote, steam, and 
 water would all boil over. Water was 
 deposited in a vessel in connection with 
 
130 
 
 the condensing pipe, together with some 
 light hydro-carbons. The creosote sup- 
 plied to the creosoting vessel being 
 heavy oil, would not commence to boil 
 until about 392. London creosotes 
 contained about 4 to 7 per cent, of tar 
 acids. He had himself tried some ex- 
 periments in coagulating and precipitat- 
 ing albumen, and he found that consid- 
 erably less than 2 per cent, of carbolic 
 acid in the creosote would precipitate 
 the largest amount of albumen found in 
 wood, so that there was amply sufficient 
 carbolic acid in the London creosote for 
 that purpose. Not only was the albu- 
 men coagulated by the two per cent, of 
 carbolic acid, but by the mere fact of its 
 being boiled. If an egg was boiled for 
 a short time the white would set, and in 
 an hour or two it would be very hard. 
 After the vacuum had been on for a suf- 
 . ficient time, and the whole of the water 
 and moisture withdrawn from the timber, 
 the cock was turned, and the pressure 
 put on with pumps up to 120 Ibs. to the 
 square inch. Not only did the pumps 
 
131 
 
 put on the pressure and force the creo- 
 sote into the wood, but directly the tem- 
 perature was lowered a little, steam con- 
 densed, and there was a vacuum in every 
 pore of the wood. The whole of the 
 wood was made a condenser; in every 
 pore that had previously contained water 
 there was a vacuum, so that the creosote 
 went in, and, besides that, there was the 
 pressure of 120 Ibs. to the square inch. 
 At the works he saw a whole range of 
 tanks, following one after the other. He 
 thought the method was a very practical 
 and mechanical one. There could be no 
 doubt about the creosote thoroughly en- 
 tering the timber. He thought the 
 thanks of the members were due to the 
 author for the admirable way in which he 
 had developed the subject. The only 
 thing wanted was a sort of skeleton 
 specification for their guidance in the 
 future. 
 
 Mr. W. H. Preece said that as the be- 
 havior of certain of Her Majesty's tele- 
 graph posts had been called in question, 
 he ought to say something in their be- 
 
132 
 
 half. For the past thirty years he had 
 devoted all the attention and skill that 
 he could command to the inquiry as to 
 the best modes of preserving timber. 
 In the telegraph service of the country 
 many millions of poles had been pre- 
 served in various ways, and one of the 
 methods that explained by the author 
 had proved to be the survival of the fit- 
 test. A great deal had been said as to 
 the various causes of decay. Reference 
 had been made to chemical and physio- 
 logical causes, but there was a third 
 cause, which might be called mechanical, 
 of the decay existing at the " wind and 
 water" line, or the ground line, where 
 the timber was exposed to incessant 
 changes of moisture and temperature. A 
 careful microscopic examination showed 
 that the process of decay was a purely 
 mechanical one, that the wood disinte- 
 grated by a process of bursting. The 
 fibers appeared to be minute boilers, and 
 the change of temperature produced 
 evaporation, minute explosion, and rapid 
 deterioration. It was a simple thing to 
 
133 
 
 meet the chemical cause by the insertion 
 of salts of various kinds, and it was pos- 
 sible to meet the physiological cause by 
 antiseptic treatment ; but the mechanical 
 cause could only be obviated by coating 
 the fibers of the wood with waterproof 
 material, and filling them with a thick, 
 viscous mass like creosote in its best 
 form. In 1844 the first line of telegraph 
 was constructed between London, South- 
 ampton and Gosport, and the posts 
 were made of the best Memel timber, 
 preserved by the burnettizing process, 
 simply impregnating the wood with zinc 
 chloride. In 1857 he made a personal 
 observation of a great part of the line in 
 different grounds, and found that in sand 
 about 40 per cent, of the posts had gone, 
 in clay about 33 per cent., and in chalk 
 about 28 per cent. In 1860 he found 
 that the proportion was much greater, 
 and in 1871 they had all failed, so that 
 they had to be removed. The burnett- 
 izing process materially added to the life 
 of the pole without rendering it inde- 
 structible. Kyanizing was tried to a 
 
134 
 
 small extent, but the poisonous charac- 
 ter of the salt deterred him from carry- 
 ing it further. The favorite process 
 about twenty years ago was that of 
 boucherizing. The authorities had pur- 
 chased whole forests, and in the middle 
 of them established the boucherizing 
 process, by which they had succeeded in 
 lengthening the life of timber consider- 
 ably. While the life of an average tele- 
 graph pole unprepared was about seven 
 years, the. life of a boucherized pole was 
 about fifteen years. In 1848 a line of 
 poles was erected from Fareham to Ports- 
 mouth, a distance of about 20 miles, and 
 all the poles, three hundred and eighteen 
 in number, were creosoted by Mr. Beth- 
 ell. It 1861 he examined them all in 
 situ, and only two showed the slightest 
 trace of decay, and they had begun to 
 decay at the top. In 1874 he had them 
 again examined, and every pole was 
 sound. Last year, owing to the require- 
 ments of the service, and the necessity 
 of increasing the number of the wires, 
 the line of poles had to be taken down, 
 
135 
 
 and although they had been put up in 
 1848, they were as sound as when they 
 were first erected. About the year 1861 
 the question of the proper mode of pre- 
 serving timber was one of great conse- 
 quence. The authorities were not satis- 
 fied as to which was the best, boucher- 
 izing or creosoting, and consequently, as 
 the Yeovil and Exeter line of the Lon- 
 don and South- Western Kailway Com- 
 pany the poles were put up alternately : 
 first a plain pole, next a boucherized pole, 
 and next a creosoted pole, the line ex- 
 tending about 40 miles. In 1870 he had 
 them carefully examined, and it was 
 found that of the plain poles that had 
 been up ten years not one existed, all 
 having decayed; while of the boucher- 
 ized poles 30 per cent, had gone, and of 
 the creosoted poles not one had decayed. 
 The result was that the Government had 
 decided for years past to creosote al] 
 their poles. He did not remember the 
 exact specification thut was used. At 
 present the millions of poles existing in 
 the country were all creosoted. It was 
 
136 
 
 true that some of them had failed, but, 
 as Mr. Carruthers had pointed out, there 
 was creasote and creosote. There were 
 unreliable firms, and others in whom con- 
 fidence could be placed ; there were in- 
 spectors who could be trusted, and others 
 who could not. There were poles about 
 the country supposed to be creosoted that 
 were rotten ; and it had been found that 
 those particular poles had not been in- 
 spected, and that they had been hastily and 
 improperly impregnated. He could state, 
 as the result of thirty years' experience, 
 that he had never seen a case of a prop- 
 erly creosoted pole showing the slightest 
 sign of decay. 
 
 The reply of Mr. Boulton upon the 
 Discussion and Correspondence is given 
 at the end of the Correspondence. . 
 
 CORRESPONDENCE. 
 
 Mr. A. Bouissou, of the Western Rail- 
 ways of France, stated that in 1859, on 
 the line from Rouen to Dieppe, sleepers 
 creosoted by the Bethell process had 
 been adopted for the first time. These 
 
137 
 
 sleepers were of beech. They had been 
 creosoted in England in the works of the 
 author's firm, and when an examination 
 of them was made twenty years later, on 
 the occasion of the Paris Exhibition of 
 1878, it was shown that not a single one 
 of them bore the slightest trace of decay. 
 Since 1864, the railway company of which 
 he was engineer of the permanent way, 
 had adopted creosoting for their sleep- 
 ers, and from that date they had ap- 
 plied it to about five million sleepers, 
 of which at least three million and a-half 
 were of beech wood. In these latter, as 
 in the trial sleepers of 1859, no sign of 
 decay has as yet been distinguished, and 
 the lasting powers of the sleepers seemed 
 only to be limited by the wear and tear 
 to which the materials were exposed. 
 Beech wood placed in the ground, with- 
 out having been prepared, completely de- 
 cayed at the end of two or three years, 
 which rendered impossible the use of 
 that wood unprepared in the form of 
 sleepers. Also sulphating, employed for 
 a long time for beech sleepers, not having 
 
138 
 
 given the good results expected, had been 
 abandoned by all the French railway 
 companies. 
 
 The employment of creosote for the 
 preservation of sleepers had given every 
 satisfaction, and its use had only been 
 limited at certain periods by the difficulty 
 sometimes experienced in procuring a 
 sufficient quantity of creosote. As re- 
 garded the quality of the creosote, he 
 simply required that it should contain 5 
 per cent, of phenic acid. 
 
 Mr. W. A. Brown remarked that a pre- 
 serving process, of which much had been 
 said and a great deal expected by engin- 
 eers a few years ago, had been referred 
 to in the latter part of that portion of 
 the paper devoted to "Apparatus for 
 Timber Preserving." This process was 
 Mr. Blyth's system of " Thermo- Carbol- 
 ization," which had been carried out by 
 Messrs. Conner & Co. at their works at 
 Mill wall, when a large number of sleep- 
 ers had been prepared for some of our 
 railways, together with telegraph poles 
 for them and for the Post Office. It be- 
 
139 
 
 X 
 
 came his duty, about four years ago, to 
 inquire into the subject, and he made 
 an investigation into the different stages 
 of the process at Messrs. Conner & Co.'s 
 works, which led him to the following 
 conclusions : 
 
 1st, that the strength of the wood was 
 impaired through some of the celluloise 
 and its incr listing materials being carried 
 off in the form of pyroligneous acid by 
 the superheated steam. 
 
 2d, that the peculiar " Creosote mix- 
 ture " used as part of the process, con- 
 tained so large a proportion of water that 
 it was not at all likely to act as a pre- 
 servative of the sleepers to which it was 
 applied. 
 
 It would be interesting to hear now 
 how the sleepers and poles thus pre- 
 pared had actually lasted in this country. 
 In Austria the experience of Mr. Seidl, 
 and in France that of the author, as re- 
 corded in the paper, appeared to confirm 
 the conclusions at which Mr. Brown ar- 
 rived in the course of his investigations ; 
 but so far as he was aware, there were 
 
140 
 
 no published results as to the process in 
 England. 
 
 Mr. John Cleminson observed that the 
 question of preparing timber against de- 
 cay was occupying more attention now 
 than formerly. It was therefore to be 
 regretted that the author had not 
 referred in detail to many good proc- 
 esses with the above object in view, 
 namely, that of Sir John MacNeill, 
 Gardner, Beer, Blythe, and others. 
 The author's remarks in reference to 
 carbolic acid as an antiseptic would 
 lead to the idea that it was necessary the 
 acid should remain when injected ; such 
 was not the case, nor was it necessary. 
 The mere fact of its presence (the most 
 powerful antiseptic known), with super- 
 heated steam, was all that was required 
 to produce coagulation of the albumen, 
 and so to render preservation practically 
 complete. With the old process of creo- 
 soting, .the surface exteriorly only was 
 preserved, the interior if unsound decayed 
 uninterruptedly. All depended upon the 
 selection of the timber. No amount of 
 
141 
 
 creosote would avail to save its destruc- 
 tion ultimately, if the interior was not 
 sound. Where sleepers were adzed, the 
 greater part, and in many instances the 
 whole of the part, penetrated by the 
 creosote was cut away, thus leaving the 
 interior open to destruction from damp 
 and other causes. The same disadvantage 
 was experienced in the case of piles, when 
 the ends were pointed for receiving shoes 
 after creosoting. With carbolic acid 
 once in contact with the albumen, and in 
 the event of any interior unsoundness, 
 the coagulation arrested decay, and pre- 
 vented it from spreading, by entirely en- 
 closing the defective part or parts. Com- 
 bined when necessary with an outer ap- 
 plication of creosote, thorough soundness 
 and preservation internally and external- 
 ly were thus secured. Blythe's process 
 was a double process. The object, pres_ 
 ervation internally and externally, in the 
 case of sleepers and piles, was most ef- 
 fectually obtained by carbolizing the in- 
 terior, and creosoting the exterior. A re- 
 sult had been obtained that had placed 
 
142 
 
 this process foremost with French en- 
 gineers for several years, and it was now 
 largely used by them. In England where 
 used it had met with much favor. The 
 author of the paper was employing this 
 process in France. 
 
 Mr. Richard Cowper remarked that the 
 value of creosote for preserving timber 
 dspended partly on the mechanical effect 
 which it had in excluding from the pores 
 of the wood air and water, and the 
 germs of destruction which they con- 
 tained, and partly on the power possessed 
 by certain of its constituents of destroy- 
 ing those germs. For the purposes of 
 germ- exclusion, it was generally admitted 
 that the heavier portions of the creosote, 
 from the less degree of solubility and 
 volatility which they possessed, and their 
 property of solidifying at ordinary tem- 
 peratures, were the more efficacious. As 
 regarded the germ-destroyers, the phe- 
 nols and the alkaloids alone need be con- 
 sidered. Phenols, namely carbolic, cre- 
 sylic, and other acid bodies occurring in 
 creosote, had long been known to possess 
 
143 
 
 remarkable antiseptic properties, but they 
 were easily soluble in water, and com- 
 paratively volatile. Much stress had 
 been laid upon their power of coagulat- 
 ing albumen, but it had been shown that 
 no stable chemical compound was formed, 
 and that the albumen thus coagulated 
 might be freed from the phenol by wash- 
 ing with water, when it would decay. It 
 had been shown by the experiments of 
 Coisne, Greville Williams, and the author 
 of the paper, on pieces of old creosoted 
 timber, that in many well preserved speci- 
 mens no phenol can be detected by the 
 ordinary test, whilst in most cases they 
 had found naphthaline, and in all cases 
 oils of the heaviest character in consider- 
 able quantity. It had been shown by Mr. 
 Greville Williams that all the old timbers 
 examined by him contained a consider- 
 able amount of alkaloids, and his experi- 
 ments proved not only that these alka- 
 loids were powerful germicides, but that 
 they were more powerful than phenol. 
 They were at the same time much less 
 soluble and volatile. Evidently if creo- 
 
144 
 
 sote containing a high percentage of 
 phenol were required, it could not con- 
 tain so high a percentage of the heavier 
 constituents, which were those possessing 
 the greatest value as germ-excluders. At 
 the same time, some of the alkaloids 
 which had been shown to be of more 
 value than phenol as germicides would 
 be removed. 
 
 Mr. W. Langdon remarked that in 1874 
 a paper by him upon the subject had been 
 read before the Society of Telegraph En- 
 gineers, in which he warmly advocated 
 the employment of creosote in preference 
 to any other preservative for timber, and 
 he had since seen no reason to alter the 
 views expressed on that occasion. Of 
 late years, however, the appearance of 
 the timber so treated had suggested the 
 belief that the oils now employed did not 
 contain that amount of tar or other 
 heavy compounds which was apparently 
 possessed by the creosote supplied in the 
 earlier eays. His attention in the appli- 
 cation of creosote to timber had been 
 more in the direction of telegraph poles 
 
145 
 
 than otherwise, which class of timber was 
 much more exposed to the weather than 
 were railway sleepers, and which might 
 in consequence be accepted as affording a 
 more complete test of the value of the oil 
 than did railway sleepers. These to a great 
 extent were buried in the soil, and had 
 but one side exposed to the influence of 
 the atmosphere. Of late years numbers 
 of the poles had presented anything but 
 the appearance of a well creosoted pole. 
 The surface had become partially or 
 wholly. bleached, and almost white. This 
 generally occurred on that portion of the 
 pole subject to the sun's rays; but it was 
 also equally marked upon that side of the 
 pole exposed to prevailing winds and wet 
 weather. It would therefore seem as if 
 the bleaching was the result both of the 
 influence of the sun and of the weather ; 
 in fact that the creosote disappeared from 
 the surface of the pole under the influ- 
 ence of the sun and of wet. If telegraph 
 poles creosoted many years back were 
 examined, as a rule the surface of those 
 poles would be found covered with a 
 
146 
 
 pitchy compound, and that mainly on the 
 side of the pole exposed to the sun. 
 There was no washing out from the 
 weather. This he thought was easy of 
 explanation. The warm atmosphere would 
 always exercise an extractive influence 
 upon any oil injected into wood or other 
 like substance ; its tendency would be to 
 bring it to the surface, where the lighter 
 portions would be evaporated, and the 
 heavier portions congealed. Creosote no 
 doubt was a strong antiseptic, but where 
 timber when felled was decayed, it could 
 not give fresh life to the decayed portion. 
 Timber, if properly seasoned, would last 
 many years if not exposed to the vicissi- 
 tudes of wind and weather, as in the in- 
 stance of many articles of furniture made 
 from the very same wood from which 
 telegraph poles and railway sleepers were 
 obtained, and which seemingly never de- 
 cayed indoors. It was here that the cre- 
 osote process enabled, an equally long 
 life to be obtained for it when employed 
 out of doors, and he imagined that the 
 heavier oils played a much higher part in 
 
147 
 
 procuring this immunity from decay than 
 the creosote oil, inasmuch as it was to 
 these heavier oils that the exclusion of 
 moisture from the timber was due. A 
 telegraph pole, or a railway sleeper, free 
 from disease, if properly seasoned, and 
 encased in such a manner as to prevent 
 moisture getting into its fiber, was prac- 
 tically indestructible from rot or decay. 
 The coating given to it by the injection 
 of these heavier oils into the fiber to a 
 depth of from 1 to 2 inches afforded the 
 timber this coating, excluded moisture, 
 and thereby secured its duration. 
 
 Mr. C. De Laune Faunce De Laune re- 
 marked that the author had attempted to 
 prove that only a very small quantity of 
 carbolic acid was necessary in creosote for 
 the preservation of wood. He approached 
 the subject with diffidence, as he lay 
 claim to no scientific knowledge, merely 
 discussing it from the purely practical 
 side ; and because he had been instru- 
 mental in extending the use of creosote 
 among landowners and farmers. The 
 author referred to his having used creo- 
 
148 
 
 sote too hot, and thereby having dam- 
 aged the wood, much in the same way as 
 if he had taken a warm bath too hot. He 
 certainly stated to the author that he had 
 used a material called creosote which 
 contained a very small percentage of 
 carbolic acid, and that the wood had 
 failed to be satisfactorily impregnated 
 with it in an open tank, even when sub- 
 mitted to a great heat ; but he scarcely 
 anticipated that he would infer that it 
 was his general custom to use extreme 
 heat, as he only wished it to be under- 
 stood that even under such conditions 
 the creosote did not perfectly penetrate 
 into the wood. The process of injec- 
 tion, in the case of telegraph poles, might 
 preserve them to an indefinite period, 
 but such a course was frequently im- 
 practicable to the former, and in the case 
 of hop-poles impossible ; wherefore an 
 open tank was indispensable. For the 
 last twenty years he had used creosoted 
 wood, and the process had always been 
 performed in an open tank. The wood 
 was first cut to the required shape, -and 
 
149 
 
 then immersed in the creosote which 
 had previously been liquefied and warmed 
 by a furnace built underneath the tank. 
 No thermometer had ever been used to 
 regulate the heat, and the only precau- 
 tion taken was to prevent the creosote 
 from boiling over, though it was suffi- 
 ciently heated to make a few bubbles ap- 
 pear on the surface. Wood of all kinds 
 had been used, and no difficulty in ap- 
 plying the creosote was at first experi- 
 enced, but he believed that the creosote 
 had gradually been becoming worse and 
 worse, and so he submitted it to Dr. Voeck- 
 ler for analysis, and got the following 
 reply: "Your creosote has a specific 
 gravity of 1.103, and on being subjected 
 to distillation yields only 61 per cent, of 
 volatile oils, of which 4 per cent, are car- 
 bolic acid." My experience in creosoting 
 timber, small as it is when compared 
 with that of public companies, is large 
 for a private individual, as I have at 
 this time 46 miles of fences where 
 creosoted wood is used ; and whereas 
 the system, when employed some years 
 
150 
 
 ago, was satisfactory, the present results 
 are as much the contrary. The pieces 
 of creosoted wood exhibited by Mr. Car- 
 ruthers were creosoted by me in 1866, 
 and, as was pointed out by him, are per- 
 fect in their preservation. Unfortunately 
 I have no analysis of the creosote then 
 used, for such an analysis would prove 
 that a material of the same constituents 
 would be suitable for preserving wood 
 in an open tank. It was obvious, there- 
 fore, that a creosote was formerly used 
 that could and did preserve inferior wood 
 in an open tank perfectly, and which 
 could be used so easily that no particular 
 precautions as to the dryness of the wood 
 were necessary, and it was in the hope of 
 ascertaining the component parts of the 
 creosote which he once used with such 
 admirable results, that he ventured on 
 these remarks ; for the creosote that he 
 formerly used for preserving wood was 
 as valuable as that which he was now us- 
 ing was useless and worthless, and all 
 he asked of manufacturers was to give 
 him material like what he had before. 
 
151 
 
 Mr. W. Lawf ord wished to inquire how 
 it was that, in the face of such undoubt- 
 ed proofs of the value of the creosot- 
 ing process, some of the large railway 
 companies, and notably the Midland, 
 had given up creosoting their sleepers ? 
 He considered it the duty of every one 
 who used timber largely to adopt either 
 this or some other antiseptic treatment, 
 since large encroachments were annually 
 made upon the timber-growing districts 
 of the world, without an adequate sup- 
 ply of timber-producing trees being 
 planted for the use of posterity. 
 
 Mr. C. Lowe, in reference to the con- 
 stituents of the creosotes employed for 
 " pickling" or preserving timber, was 
 disposed to attribute to the tar acids 
 only a very small amount of the effective 
 results obtained by the application of 
 the creosote, for the following rea- 
 sons : 
 
 1. Carbolic and cresylic acids were 
 both completely volatile even at an aver- 
 age summer temperature in England, 
 and in hot climates could not long re- 
 
152 
 
 main present (except as traces) in any 
 timber to which they had been ap- 
 plied. 
 
 2. Both these acids were readily solu- 
 ble in water, and would consequently be 
 rapidly removed from the timber in case 
 the latter, previously saturated with 
 them, was subjected to the action of 
 water in motion. He regarded the ac- 
 tion of coal-tar creosote in preserving 
 timber as presenting a two-fold char- 
 acter ; firstj a mechanical action, by which 
 the wood was rendered waterproof from 
 the filling up of the cellular tissue with 
 matter insoluble in water ; second, a 
 chemical or antiseptic action, due chiefly 
 to the presence of the tar acids. These 
 tar acids were roughly divisible into the 
 readily volatile acids soluble in water 
 (carbolic and cresylic), and the heavy, 
 almost non-volatile, acids insoluble in 
 water. The latter class had not been 
 thoroughly studied, but it was known to 
 be powerfully antiseptic, and anti-para- 
 sitic. He therefore considered the creo- 
 sote best adapted for the " pickling " of 
 
153 
 
 . 
 
 timber to be a creosote containing suf- 
 ficient solid hydrocarbon, such as naph- 
 thaline, to be solid at a temperature 
 slightly above the average climatic or 
 other temperature to which the timber 
 was to be ultimately exposed ; at the 
 same time, to prevent the attacks of 
 parasitic insects, etc., the heavy tar acids 
 should be present. No reliance should 
 be placed on carbolic and cresylic acids 
 for pickling timber, seeing they were so 
 readily removed by the action of water 
 and climatic heat. It was well known 
 that their albuminous combinations were 
 readily broken up by simple washing 
 with water; as germicides and anti- 
 septics, when retained in situ, these 
 acids were invaluable for surgical use 
 and disinfection, and to these purposes* 
 they should be relegated. 
 
 Mr. T. E. M. Marsh exhibited speci- 
 mens of timber used by the late Mr. 
 Brunei in 1839. These were fair samples 
 of the bulk of the timber of the ribs 
 of the skew bridge over the River Avon, 
 at the Bath station on the Great West- 
 
154 
 
 ern Railway. The timber was cut from 
 Memel balk, and was kyanized. It was 
 quite sound after forty years' service. 
 The kyanjzing process had been em- 
 ployed extensively by the late Mr. Brunei 
 in the early works of the Great Western 
 Railway. The permanent-way timbers 
 were thus prepared, and gave excellent 
 results as to preservation from decay, 
 as was shown by specimens cut from 
 various parts of the line, between Lon- 
 don and Bristol, after having been laid 
 from fifteen to twenty years. Mr. Marsh 
 had gained much experience in the prep- 
 aration and uses of creosoted timber, 
 both while acting for Mr. Brunei, and 
 subsequently up to the present time. In 
 the early days of the process, the tar 
 from which creosote was prepared was 
 not subjected to the extraction of so 
 many chemical ingredients as was now 
 the case, and the naphthaline, or salt 
 precipitated was comparatively small, 
 and considered of little value. No diffi- 
 culty was then experienced in getting a 
 good admixture of light and heavy oil in 
 
155 
 
 a fluid state, of satisfactory color, con- 
 sistency and taste, and complying with 
 the rough and ready tests adopted. Mr. 
 Brunei adopted the process extensively 
 from its early introduction by Mr. 
 Bethell, in bridges and permanent way, 
 and much of those timbers and struc- 
 tures remained in use at the present 
 day. It was, however, soon discovered 
 that it was of great importance the tim- 
 ber should be well seasoned and dry, 
 and that it was worse than useless to 
 creosote unseasooed, damp or wet tim- 
 ber. Some alarming cases of internal 
 decay had been discovered, attributable 
 to these causes. Of late years, on ac- 
 count of the greater demands on the 
 timber merchants, and for other reasons, 
 the preparation of creosoted timber had 
 not always had such careful considera- 
 tion. The processes were often carried 
 on, not only not under cover, but water 
 in variable quantities was generally 
 found in the tanks from which the oil 
 was pumped into the pressure-cylinders, 
 and solid salts and a mixture of mud and 
 
156 
 
 the residuum and drainage of objection- 
 able matter from the timber of preceding 
 charges, accumulated in the tanks and 
 returned again, to the detriment of sub- 
 sequent charges. It not unfrequently 
 happened that timber coming from the 
 pressure-cylinders might be found with 
 some portions presenting no trace what- 
 ever of creosote even on the surface, but 
 showing only signs of the contact of 
 dirty water, when the quantity of creo- 
 sote injected was supposed to have been 
 50 gallons to the load. Such facts, Mr. 
 Marsh asserted, were sufficient to ac- 
 count for many reported failures, with- 
 out reference to the chemical questions 
 as to the relative values of the constitu- 
 ent parts of the oil. Mr. Marsh's in- 
 structions to his inspectors for the prep- 
 aration and pickling of timber, where 
 thorough efficiency was desired, were 
 based on his own personal observa- 
 tions, and were as follows : 
 
 "The state of the tanks from which 
 the creosote is being drawn while the 
 pressure progresses, and before any 
 
157 
 
 creosoting is done, must be examined, 
 and if found to contain salty or muddy 
 sediment at the bottom, or water at the 
 top, or the nature of the creosote other- 
 wise bad, its use must be protested 
 against. Samples must be taken by a 
 tube dipped to test the liquid at various 
 depths, particularly the upper and lower 
 portions of about 12 inches of the top, 
 and the same at the bottom. This must 
 be strictly attended to. No steam shall 
 be let into the creosote anywhere. The 
 numerous pipes used for heating, and 
 sometimes hoses and joints, may give the 
 means of mixing in steam during the 
 process, and hence the condensed water, 
 which must not be permitted under any 
 circumstances. Sometimes the appear- 
 ance of the timber after creosoting will 
 show that water has been in contact with 
 it. The thorough good creosoting must 
 also be checked by a chisel at the sound 
 hearty parts of the timber, and the 
 penetration checked by weighing trial 
 sticks with each charge (these should 
 not be open sappy timbers, and they 
 
158 
 
 should be the least dry rather than those 
 to favor absorption more than the bulk 
 in the same charge). A good percent- 
 age, over 50 glallons to the load, must be 
 injected so as to allow for outside drain- 
 age when drawn out of the cylinder. In 
 weighing, 50 gallons may be reckoned as 
 550 Ibs. If the timber be not quite sat- 
 isfactory and perfectly dry, and immedi- 
 ate delivery is urgently wanted, then a 
 considerable extra quantity must be in- 
 jected, as much as 10 per cent., or fur- 
 ther drying, and under Cover, must be 
 insisted upon, but in no case must posi- 
 tively wet or damp timber be allowed to 
 go into the pressure-cylinders." 
 
 Mr. Benjamin Nickels observed 
 that he was much gratified in 
 noting that the author had drawn 
 special attention to the compound 
 acridine, pointing out, at the same 
 time, its high antiseptic value as a con- 
 stituent of creosoting materials. It would 
 appear that his impressions had been 
 based on certain marked properties ex- 
 hibited by this peculiar substance, no- 
 
159 
 
 tably its intense pungency, acridity, and 
 high antiseptic value, also its immunity 
 from loss by evaporation and the solvent 
 action of water. As little beyond a mere 
 reference to the compound had been 
 made, it might be of interest to state 
 what had been done in other directions, 
 and so far as it might corroborate the 
 views advanced by its author. In the 
 year 1882 he was induced to take out a 
 patent for a composition to be used as an 
 insecticide, and for the coating of ships' 
 bottoms and other submerged surfaces, 
 and in which acridine played an import- 
 ant part. He had, during a previous ex- 
 perience, met with many opportunities of 
 observing the painfully irritating action 
 of the heavier tar oils, arising from hand- 
 ling during the treatment and purifica- 
 tion of anthracine, due to the presence 
 of acridine, and as an outcome of the ob- 
 servation it had occurred to him that this 
 substance should constitute an effective 
 " antifoul," inasmuch as it would be al- 
 most impossible for animal life to remain 
 in contact with it. Experiment in nu- 
 
160 
 
 merous directions fully supported the 
 idea ; but the question arose, would the 
 acridine resist the prolonged solvent ac- 
 tion of water, and remain effective for a 
 lengthened period, and in the thin coat- 
 ing of any composition that could be aP- 
 plied as a paint to a ships' side? Opin- 
 ion varied considerably as to ultimate 
 success when attempted on a practical 
 scale, although laboratory trials had shown 
 that such composition was unacted upon 
 in still water. The first experiment of 
 any importance was made on a small iron, 
 barque (the "Cordova") which sailed 
 from London for the Falkland Islands 
 about the end of January, 1882, return- 
 ing at the end of October, after an ab- 
 sence of nine months, during which her 
 hull had been constantly submerged. 
 Previous to sailing, portions of her plates 
 towards the lower part of the vessel, and 
 where subjected to the greatest wash, 
 had been coated in the ordinary way of 
 applying a ship's paint with acridine 
 composition, prepared in conformity with 
 the patent referred to. He was present 
 
161 
 
 on her return to England, and upon the 
 vessel being docked for repainting and 
 repair, he made a close inspection of the 
 portion that had been originally coated 
 with the composition. He found that 
 the paint had remained intact, presenting 
 a smooth and unbroken surface ; it had 
 adhered most tenaciously to the iron 
 plates, completely protecting them from 
 the action of the sea. There was no ad- 
 hesion of barnacle or weed, and the evi- 
 dence of contained acridine was very 
 manifest on applying the tongue to por- 
 tions of the composition scraped from 
 the side of the vessel. Subsequent ex- 
 amination showed that there had been 
 little or no loss of acridine, and that the 
 prolonged and be.iting action of swiftly- 
 running and boisterous seas had failed 
 in removing or washing out the acridine 
 originally incorporated in the paint ap- 
 plied. Since the date of this experiment 
 many others had been made, and were 
 still on hand, with vessels on long sea- 
 voyages, and, as far as he was enabled 
 
162 
 
 to state, the results obtained had been of 
 a satisfactory charactei\ 
 
 It would be difficult, perhaps, to cite 
 more complete illustrations of the indif- 
 ference of a substance to severe water ac- 
 tion ; and the author might, he thought, 
 rest well assured that his statements 
 concerning this singular tar product were 
 in nowise overrated or exaggerated. As 
 regarded the antiseptic character of acri- 
 dine, he might mention that it was of 
 high value, extremely small quantities be- 
 ing sufficient to arrest the change in 
 many organic substances prone to rapid 
 decomposition. 
 
 Mr. Martin F. Roberts wished to di- 
 rect attention to a point which had in- 
 fluenced engineers in their preference for 
 the so-called " Country oil," viz., that of 
 economy. Engineers would be aware 
 that in drawing up specifications it was 
 usual to stipulate for a certain quantity 
 of creosote to be injected into a cubic 
 foot of timber, usually 6, 8 or 10 Ibs., 
 the contractor's price for creosoting be- 
 ing regulated according to the quantity 
 
163 
 
 specified ; and it thus became necessary 
 for engineers to consider whether, say 8 
 Ibs. per cubic foot of the thick, heavy, 
 London creosote penetrated as far into 
 the timber as 8 Ibs. of the thinner coun- 
 try oils. He was sure all engineers would 
 agree that it would not ; and from his 
 own experience he was able to say that, 
 with telegraph poles, in many places 
 where 8 Ibs. of London creosote per cu- 
 bic foot had been injected, it had not 
 penetrated more than half through the sap- 
 wood, whereas a similar quantity of coun- 
 try oil would have penetrated completely 
 to the heartwood, although, of course, the 
 country oil would not leave as large a de- 
 posit of solid substances in the pores of 
 the timber. It was, therefore, desirable 
 to consider whether it was better to 
 have the sap wood completely injected 
 with thin oil at a certain price, or the 
 outer portion only injected with thick 
 oil at the same cost, and his experience 
 led him to prefer the complete injection 
 by the thin oil. His ground for arriving 
 at this conclusion was that, although he 
 
164 
 
 had met with many samples of creosoted 
 timber in which a portion of the sap- 
 wood had decayed where the creosote 
 had not penetrated, he had never met 
 with a piece of timber having decayed 
 where the creosote had penetrated, except 
 in one instance in a Government tele- 
 graph pole, referred to in the discussion ; 
 and even in this case he thought it well 
 to ask if the decay had taken place before 
 or after creosoting. Engineers acquaint- 
 ed with red fir timber would remember 
 that what was called a " foxey pole " was 
 occasionally found, in which, although 
 the outer portion or all of the sapwood 
 might be quite sound, some of the inner 
 portion of the pole had decayed before 
 felling ; and it was often a difficult mat- 
 ter, even for an experienced inspector, to 
 detect such a pole. It would easily be 
 conceived that in such a case the decay 
 might be, and often was, attributed to a 
 defective quality of creosote having been 
 used, instead of to the fact that a por- 
 tion of the pole was rotten when treated. 
 The remarks made by the author un- 
 
165 
 
 der the heading of " The Conflicting 
 Theories of Putrefaction," in which he 
 spoke of the " gaping orifice of a crack 
 produced by the sun in a piece of tim- 
 ber," would appear to specially point to 
 the necessity for the use of a thin, pene- 
 trating oil, as timber would crack after 
 long exposure in the sun, even if it had 
 been creosoted with the thickest London 
 oil ; and in these cases the oil which had 
 penetrated the deepest would be more ef- 
 fective, as it was the most likely to have 
 genetrated beyond the depths of the 
 crack. If it were the practice to com- 
 pletely saturate the entire mass of tim- 
 ber with creosote, and if it were found 
 possible to do so in all cases, there would 
 then be no objection to the use of Lon- 
 don oils ; but as the question of cost had 
 to be considered, and the smallest quan- 
 tity of creosote per cubic foot which was 
 found to answer the purpose was there- 
 fore specified for, the thinner country cre- 
 osote was preferred, owing to its greater 
 penetration, weight for weight. In Mr. 
 Coisne's experiment with shavings, the 
 
166 
 
 conditions were so totally different to 
 those met with in ordinary practice, that 
 too much reliance should not be placed 
 in them. It was obviously an easy mat- 
 ter to completely saturate shavings either 
 with thick or thin creosote, but with 
 telegraph poles and railway timber the 
 creosote never penetrated completely 
 through the timber, and it could not be con- 
 tended that the exclusion of germs alone 
 prevented putrefaction, as, if so, a coating 
 of tar would prevent decay. What was 
 necessary was that the germs of decay in 
 the timber should also be destroyed, and 
 this could only be accomplished by bring- 
 ing all that portion of the timber more 
 liable to decay viz., the sapwood under 
 the influence of a creosote of consider- 
 able penetrating power. If evidence in 
 support of this assertion were needful, 
 it would only be necessary to refer to the 
 fact that engineers strictly barred the 
 use of whitewood timber for telegraph 
 poles and other purposes, owing to its 
 being found impossible in practice to in- 
 ject creosote into whitewood to a greater 
 
167 
 
 depth than J or f of an inch from the 
 surface, and whitewood timber so pre- 
 pared, either with London or country 
 creosote, was found to decay rapidly. It 
 would appear that the best system 
 of creosoting would consist in first in- 
 jecting the timber with thin "country 
 oil," then running the thin oil off and 
 filling the cylinder with London creosote, 
 which, being forced in by increased 
 pressure, would drive the thinner oil fur- 
 ther into the timber, and the thicker cre- 
 osote would hermetically seal the outer 
 pores of the timber. Failing this proc- 
 ess, owing to its increasing the cost, it 
 would appear advisable to use thin creo- 
 sote, and if it was considered that thin 
 oil did not sufficiently fill the outer pores 
 of the timber, the process, at a trifling 
 cost, could be siipplemented by giving 
 the timber a coat of hot tar. 
 
 Mr. Greville Williams stated that he 
 regarded the paper as the most valuable 
 and exhaustive contribution yet made to 
 the literature of the subject. He agreed 
 with Dr. Meyrnott Tidy and the author in 
 
168 
 
 considering that the value of the carbolic 
 acid in creosote oils had been overrated. 
 He believed that an oil from which the 
 carbolic acid had been removed would 
 sterilize wood, if thoroughly impregnated 
 with it, partly by virtue of the organic 
 alkaloids present, and partly by the pro- 
 tective influence of the heavier oils them- 
 selves. He had satisfied himself by care- 
 ful experiments that the alkaloids exer- 
 cised a potent influence in preventing the 
 development of bacteria, mould, and mi- 
 croscopic fungi in vegetable infusions. 
 He thought, moreover, that where wood 
 had to be exposed to the action of sea- 
 water, it would be advantageous to use a 
 creosote containing a high percentage of 
 the alkaloids ; this could easily be attained 
 by well-known methods. Although the 
 minute quantities of carbolic acid remain- 
 ing in old creosoted timbers were too small 
 to account for their preservation, he con- 
 sidered it right to say that, by a suffi- 
 ciently delicate method of manipulation, 
 he had rarely failed in getting evidence 
 of its presence even thirty years after the 
 
169 
 
 -wood had been creosoted. He found 
 traces of it in eleven out of fourteen 
 specimens which had been creosoted from 
 twenty- five to thirty-two years before. 
 The organic alkaloids, however, which re- 
 mained, were sufficient to allow quantita- 
 tive estimation. He thought that no chem- 
 ist, who had examined very old sleepers 
 for carbolic acid, could come to any other 
 conclusion than that the traces remaining 
 were insufficient for their protection. A 
 point, moreover, of great importance for 
 the proper comprehension of the subject, 
 was involved in this almost entire disap- 
 pearance of the carbolic acid. If the co- 
 agulation of the albumen by the carbolic 
 acid were the cause of the preservation 
 of the timber, how was it that this acid 
 almost entirely disappeared? The in- 
 stability of the compound, of albumen 
 with carbolic acid, was well known to 
 those chemists who had minutely exam- 
 ined it ; nothing more conclusively proved 
 this instability than the disappearance of 
 the carbolic acid. With regard to the 
 naphthaline, he thought it significant that 
 
170 
 
 it was only absent from two of the sleep- 
 ers he had examined. There could, he 
 considered, be no question that naphtha- 
 line, although perhaps feeble as a germi- 
 cide, properly so called, was very valuable 
 as a sterilizer ; it was insoluble in water, 
 and once in the wood, clung to it tena- 
 ciously. He was also most decidedly in 
 favor of the removal of all restrictions as 
 to maximum boiling-point, and considered 
 that, if the oils were fluid at the temper- 
 ature of injection (say 100 to 120 
 Fahrenheit), that was all that was need- 
 ful. On the whole question, he found 
 himself able to thoroughly indorse the 
 conclusions of the author and Dr. Tidy, 
 and he considered that specifications 
 which excluded the use of London oils 
 were framed under a misapprehension of 
 the true nature of the condition requisite 
 to afford a good creosote. 
 
 Mr. Boulton had been obliged to be 
 very brief in his verbal reply at the close 
 of the discussion, and as some of the 
 points then raised involved matters of 
 considerable detail, which had also been 
 
171 
 
 alluded to in the correspondence, he 
 thought that unnecessary repetition would 
 be avoided if he were to connect his re- 
 plies to both series of communications in 
 a continuous form. He was gratified at 
 the valuable support which his main 
 propositions had received. 
 
 The remarks made by Dr. Tidy, and 
 the views expressed by that gentleman in 
 his recent report to the Gaslight and 
 Coke Co. were in principle in accordance 
 with the views expressed in the paper. 
 The author, however, believed with Dr. 
 Armstrong that Dr. Tidy, who had been 
 somewhat conservative on the subject of 
 tar acids, would be led by the logic of 
 facts to accept a much lower proportion 
 than 8 per cent. The "London creo- 
 sotes " as they came from the still, honest 
 creosotes which had done excellent work, 
 and which constituted probably about 
 one half of the total supply of this king- 
 dom, did not contain so large a percent- 
 age. Some misapprehension still existed 
 on this subject, which the statement of a 
 few facts might remove. In July, 1863, 
 
172 
 
 the author sent to Dr. Letheby a sample 
 of the usual London creosotes, which he 
 was then largely using. Dr. Letheby 
 found it contained only 4.37 per cent, of 
 tar acids. Later on, and during one 
 period of seven years especially, nearly 
 the whole of the tar of the great London 
 Gas Companies, as well as tar from other 
 sources, was contracted for and distilled 
 by the author's firm. The quantity was 
 probably larger than had ever been treated 
 up to that time by any one firm or cor- 
 poration, and it therefore formed a suf- 
 ficiently broad basis for estimation. He 
 would give the quantities during three 
 ^consecutive years 
 
 1877 Gallons of tar distilled.... 14,735,404 
 
 1878 " " " .... 15,839,819 
 
 1879 " '" " .... 12,690,029 
 
 or an average of between fourteen and 
 fourteen and a half million of gallons per 
 annum. He had found, as stated in the 
 paper, that the heavy oils distilled from 
 this mass of tar contained on an average 
 from 4 to 7 per cent, of total tar acids. 
 More recent experiments which he had 
 
173 
 
 made upon a large number of London 
 tars one series in May, 1882, another in 
 August, 1882, and a third since this paper 
 had been read gave similar results. 
 Latterly, the largest of the English gas 
 companies, the Gaslight and Coke Co.,, 
 had erected works at Beckton, at which 
 they distilled their own tar. It had been 
 assumed that the list of analyses ap- 
 pended to Dr. Tidy's printed report rep- 
 resented the percentage of tar acids which 
 the London creosotes in their natural 
 condition contained. This, however, was 
 not the case. The samples analyzed by 
 Dr. Tidy contained from 8.2 to 10.2 per 
 cent, of tar acids, but they had been spe- 
 cially treated to "meet the market," cre- 
 ated by the modern type of specification 
 by removing from the creosote some of 
 its least volatile parts, those parts con- 
 taining little or none of the volatile tar 
 acids. The Gaslight Co.'s creosotes as 
 they came from the still contained on an 
 average 6 per cent, of total tar acids by 
 the ordinary caustic alkali test. The au- 
 thor had been enabled to clear up this. 
 
174 
 
 matter, of which experts would readily 
 detect the importance, owing to the court- 
 esy of the Board and Secretary of the 
 Gaslight and Coke Co. 
 
 He agreed with Dr. Armstrong in the 
 importance of M. Pasteur's experiment 
 upon sawdust, which was recorded in the 
 Comptes Kendus of the Academic des 
 Sciences for 1863. It is remarkable as 
 an early demonstration of the application 
 of the germ theory to the phenomena ac- 
 companying the decay of woody fiber. 
 Dr. Armstrong had alluded to the dis- 
 tinction between wood creosote and tar 
 creosote. Both contained tar acids, some 
 of which might be identical, or if not 
 identical, isomeric. But tar creosote, if 
 it could be so called, was a complex body ; 
 some of the tar acids it contained differed 
 essentially from either carbolic or cresylic 
 acid, being less volatile, and less soluble 
 in water than either phenol or cresol. 
 There is evidently room for much further 
 investigation in this connection ; also for 
 a more complete comparison between the 
 
175 
 
 " tar acids of the coal-tar oils and similar 
 bodies contained in other oils." 
 
 In relation to the remarks of Mr. W. 
 Foster, the author must express the hope 
 that that gentleman would continue the 
 very interesting researches of which he 
 had so recently given an account to the 
 Institution in his valuable paper on " The 
 Composition of Coal." Authentic Tables 
 as to the varying products derived from 
 different kinds of coal, and at different 
 temperatures, were becoming matters of 
 the first necessity in various branches of 
 industry. Mr. Foster had referred to 
 the experiment of Pettigrew, alluded to 
 in the paper. Pettigrew had removed 
 the embalming material from the heart of 
 the mummy by steeping it in alcohol ; 
 after which, upon exposure to the atmos- 
 phere, putrefaction took place. What 
 the author desired to point out was that 
 the previous immunity from decay had 
 not been the result of any chemical com- 
 bination between the antiseptic and the 
 tissue. 
 
 A jarring note had been struck by Mr. 
 
176 
 
 Barnber, who had represented "the whole 
 secret of the paper" to consist in "the 
 
 author's idea that nothing should be 
 
 left in the creosote which it would pay 
 him better to take out ;" an object foreign 
 to the declared aim and intention of the 
 paper. The author had not approached 
 the subject from the commercial point of 
 view a fact which the President had so 
 gracefully recognized. It might, how- 
 ever, be opportune to state that he was 
 not at present commercially interested in 
 any manufacture which caused carbolic 
 .acid to be "taken out" of the creosote 
 oils, although he was largely interested 
 in the success of prepared timber as an 
 engineering material, and therefore in 
 the choice of the best antiseptics for that 
 purpose, whether obtained from the creo- 
 sote oils or from other sources. Mr. Bam- 
 ber's figures as to the comparative com- 
 mercial values of creosote oils and car- 
 bolic acid, recalled to memory the well- 
 known comparison between the value per 
 ton of iron ore and of steel watch springs. 
 The manufacture of pure carbolic acid was 
 
. 177 
 
 a long and costly process, of which the 
 first cost of the crude material formed an 
 altogether insignificant item. Nor was 
 so low a price as 2d. per gallon for creo- 
 sote either "proverbial" or usual. But 
 it would be found in the long run that 
 the consumer had to pay the commercial 
 value for everything which the creosote 
 contained, and it was therefore best to 
 discuss upon scientific and practical 
 grounds the substances which the engin- 
 eer should require it to contain. It was one 
 of the main objects of the paper openly to 
 point out by diagrams and detailed de- 
 scriptions the principal substances con- 
 tained in the coal-tar oils, to draw atten- 
 tion to their properties, and to state their 
 uses for various manufactures, so that for 
 the purposes of timber-preserving, engin- 
 eers might be in a position to " prove all 
 things, hold fast that which is good." 
 Mr. Bamber was mistaken as to facts in 
 his allusion to Dr. Letheby's specification, 
 and that of Dr. Tidy. Dr. Letheby's 
 specification, drawn up under instructions 
 from Mr. Meadows Kendel, M. Inst. C.E., 
 
178 
 
 in 1865, for the use of the East Indian 
 Railway Company, stipulated that the creo- 
 sote was to yield to a solution of caustic 
 potash, not less than 5 per cent, of crude 
 carbolic, and other tar acids. Dr. Letheby 
 never increased that quantity. Dr. Tidy 
 had increased, and not as Mr. Bamber 
 supposed, diminished the percentage of 
 tar acids mentioned by Dr. Letheby. 
 
 Mr. Bamber complained that no facts 
 or data had been given respecting Dr. 
 Tidy's experiments on naphthaline. But 
 the paper contained a reference to a 
 printed report of Dr. Tidy, deposited in 
 the library of the Institution, wherein was 
 a full account of these experiments. They 
 were also recorded and approved of by 
 Dr. Lunge, of Zurich, in his learned work 
 upon "The Distillation of Coal Tar." 
 Amongst other authorities who after in- 
 vestigation differed from Mr. Bamber in 
 admitting naphthaline as an ingredient in 
 the timber-preserving oils, were the late 
 Mr. Bethell, Mr. Burt, Prof. Sir Frederick 
 Abel, Mr. Forestier, for the French Gov- 
 ernment, Mr. Coisne, for the Belgian Gov- 
 
179 
 
 eminent, &c. Mr. Bamber had once stated 
 to an eminent engineer, in a report upon 
 a creosote highly charged with naphtha- 
 line, that timber impregnated with such 
 an oil would, " within a very short time 
 of the timber being in India, lose 5 Ibs. 
 out of every 10 Ibs. put into the timber 
 here merely by escape of naphthaline.'' 
 Dr. Tidy's experiments with timber in- 
 jected wholly with naphthaline, and sub- 
 jected to a temperature of 130 Fahren- 
 heit, proved that these apprehensions 
 were unfounded. But it was now related 
 by Mr. Bamber that in his own experi- 
 ment a piece of wood impregnated with a 
 creosote of the type which he preferred, 
 and containing 20 per cent, of tar acids, 
 lost in four weeks 42.33 per cent, of the 
 oil taken up. Mr. Bamber' s record of his 
 own experiment was very instructive. He 
 tried two kinds of creosote against each 
 other. One, which might be called speci- 
 men A, was "full of naphthaline," but the 
 percentage of that body was not stated. 
 It contained 10 per cent, of tar acids. 
 Specific gravity not named. With this- 
 
180 
 
 oil a piece of deal 3 inches by 3 inches 
 by 8 inches was impregnated. The other, 
 which might be called specimen B, was a 
 ".country oil," specific gravity 1.045, con- 
 taining 20 per cent, of tar acids. "With 
 this oil a piece of deal 3 inches by 3 
 inches by 6 inches was impregnated. 
 Specimen A was alluded to as " Mr. 
 Boulton's own oil " and " the author's 
 London creosote ;" but to these appella- 
 tions he demurred, as he never used a 10 
 per cent, creosote unless required to do 
 so by specification, and the London oils 
 did not in their natural state contain 10 
 per cent, of tar acids. Therefore A, al- 
 though it might come from his works, 
 would be a mixture of London and Coun. 
 try oils. But, although in the author's 
 judgment too volatile, yet the 10 per cent, 
 specimen would be less volatile than the 
 20 per cent. Therefore, the author pre- 
 ferred A to B. Where a large issue was 
 staked upon a single minute experiment, 
 accuracy of result should be ensured by 
 the most minute precautions. It was not 
 explained why the two pieces of deal were 
 
181 
 
 not cut to the same size, a circumstance 
 which affected the conditions both of ab- 
 sorption and of evaporation. Nor were 
 the specific gravities of the two pieces of 
 wood stated. Of two pieces cut from the 
 same log, one piece of wood would fre- 
 quently absorb, under the same condi- 
 tions, a very much larger quantity of fluid 
 than the other. However, the results as 
 stated might be calculated as follows : 
 
 A. Piece of wood, capacity 72 cubic 
 inches, absorbed 1,020 grains of creosote 
 =3.49 Ibs. per cubic foot. 
 
 B. Piece of wood, capacity 54 cubic 
 inches, absorbed 1,785 grains of creosote 
 =8.17 Ibs. per cubic foot. 
 
 But no pressure was used, and engin- 
 eers would recognize that the experiment 
 failed to reproduce the conditions of the 
 ordinary creosoting cylinder. It was well 
 known that without pressure, light oils 
 penetrated timber more easily than heavy 
 oils. In like manner the adulterating 
 substance, bone oil, penetrated more 
 readily than creosote; solutions of me- 
 tallic salts more readily still ; and water 
 
182 
 
 more readily than all. But it was " light 
 come, light go ; " those which penetrated 
 most readily were generally the least 
 permanent. The main object of the en- 
 gineer was not to select the fluid which 
 gave the contractor the least trouble to 
 inject. He desired to select the antisep- 
 tic which was likely to be the most effi- 
 cacious and the most permanent, and he 
 required the contractor to provide effi- 
 cient apparatus, and to inject under 
 pressure a stipulated quantity by weight. 
 Sleepers and large logs of timber were 
 injected without difficulty with creosotes 
 of a heavier type than either of Mr. 
 Bamber's samples, and to the extent of 
 10 Ibs. and 12 Ibs. per cubic foot. Small 
 pieces of wood could be easily gorged 
 with creosotes. The author had recently 
 injected some fir paving blocks 6 inches 
 by 6 inches by 3 inches, with 22 Ibs. per 
 cubic foot of ordinary heavy London cre- 
 osote, containing about 5 per cent, of tar 
 acids. Mr. Batnber exposed his speci- 
 mens to evaporation on a mantelshelf at 
 a- temperature never above 70 Fahren- 
 
183 
 
 heit, and generally between 40 Fahren- 
 heit and 50 Fahrenheit. In four months 
 A had lost 47.75 per cent., and B had 
 lost 42.33 per cent, of the creosote put 
 in. If this could be taken as a normal 
 result, engineers would hesitate as to em- 
 ploying either type of creosote. No doubt 
 both were too volatile. But it should 
 also be borne in mind that the injection 
 was imperfect ; to use Mr. Bamber's " ex- 
 pression, it was only " skin deep." As 
 regarded the comparative evaporation of 
 the two specimens, hpwever, the result 
 was extremely valuable. It is well-known 
 that the evaporation of fluids (except 
 when in a state of ebullition) was in pro- 
 portion to the surface exposed, and not to 
 the bulk of the fluid. This point Mr. 
 Bamber appeared to have forgotten ; he 
 had exposed A, the creosote he disliked, 
 to a wider evaporating surface than that 
 to which he had exposed B, the creosote 
 which he preferred. The position on the 
 mantelshelf in which the pieces of wood 
 were placed was not stated. But sup- 
 posing them to have been suspended, say 
 
184 
 
 by a thread, so that all the surfaces were 
 exposed to evaporation equally, the re- 
 sults might thus be calculated : 
 
 A. Piece of wood, the sum of whose 
 superfices was 114 square inches, lost 
 487 grains = 4.29 grains per square inch 
 of exposed surface. 
 
 B. Piece of wood, the sum of whose 
 superfices was 90 square inches, lost 575 
 grains =6. 39 grains per square inch of 
 exposed surface. 
 
 If, however, each piece of wood had 
 been placed with one of its sides in con- 
 tact with the mantelshelf, so that one 
 surface was protected from evaporation, 
 the calculation became slightly modified, 
 so that A would have lost 5.41 grains, 
 and B 7.98 grains per square inch ex- 
 posed. If the specimens had been placed 
 on end, then A showed a loss of 4.64 
 grains and B of 7.09 grains per square 
 inch. Mr. Bamber had therefore been 
 mistaken as to the comparative volatili- 
 ties of naphthaline and the tar acids, as 
 proved by his own experiment. B, the 
 creosote with 20 per cent, of tar acids, 
 
185 
 
 had lost about 50 per cent, more than A, 
 the creosote with 10 per cent, of tar 
 acids and " full of naphthaline." Had it 
 been otherwise, every chemical treatise 
 describing the properties of these bodies, 
 would have to be re-written. The state- 
 ment that part of the loss of specimen B 
 was due to the fact that some of the oil 
 drained out of it, which it was said u was 
 not fair " to that specimen, gave rise to 
 the rejoinder, was it quite fair to a tim- 
 ber-preserving process that a type of an- 
 tiseptic should be recommended which 
 " drained out " with so little provocation ? 
 This part of the discussion might almost 
 appear trivial, were it not for the fact, 
 confirmed by many special instances in the 
 author's experience, that whenever these 
 light oils had been used exclusively, 
 whether for marine work or for railways, 
 complaints invariably arrived, sooner or 
 later. Oils of so light and volatile a na- 
 ture lost a large portion of their bulk, 
 which evaporated or drained out in the 
 creosoting yard, on the export ship, and 
 on the permanent way in India and else- 
 
186 
 
 where. An experiment, easy to carry out 
 without any laboratory apparatus, may be 
 tried by any one interested in this sub- 
 ject. Take three saucers or shallow 
 dishes ; place in one saucer 200 grains of 
 pure carbolic acid (crystallized), in the 
 second 200 grains of pure cresylic acid, 
 and in the third 200 grains of pure 
 naphthaline. Expose them side by side 
 in any room, and at any ordinary tem- 
 perature. The crystals of carbolic acid 
 would liquefy in a few minutes-, owing to 
 the avidity with which that body absorbed 
 moisture from the atmosphere. In a few 
 weeks' time (varying with the temperature) 
 the carbolic acid would have entirely 
 disappeared by evaporation. By that 
 time the cresylic acid would have lost 
 about half its bulk. When the whole of 
 the cresylic acid had also evaporated. 
 The naphthaline in considerable bulk, at 
 least one-half of the original weight 
 would still remain, an easy victor in the 
 trial of endurance.* The evaporation was 
 
 * This experiment was carried out on a mantelshelf 
 at the Institution of Civil Engineers in August, 1884, 
 with the result indicated by Mr. Boulton. 
 
'187 
 
 greatly retarded by the incorporation of 
 those bodies with the less volatile oils, 
 and by their being driven into the cells 
 of the timber. But the evaporation must 
 necessarily take place in proportion to the 
 respective and recognized volatilities. 
 
 Allusion had been made by Mr. Bamber 
 to " charred oil," and he presumed that 
 it was a residue of anthracene manufac- 
 ture. The author in the course of his 
 experience had never met with " charred 
 creosote," except indeed as a result of 
 over-heating in a laboratory experiment ; 
 nor was he acquainted with any ordinary 
 process of manufacture by which it could 
 be produced. Creosote oils were distil- 
 lates ; whatever the heat in the still, the 
 residuum might become carbonized, but 
 not the substances" which came over in 
 the form of vapor. Anthracene or para- 
 naphthaline had been denounced by the 
 creosote specifications of the theorists at 
 a time when it was considered worthless 
 for any purpose ; it was taken out of the 
 creosote by every tar-distiller in England, 
 whether in London or country, and was 
 
188 
 
 now of value for the manufacture of ali- 
 zarine. The removal was effected by a 
 simple process of filtration ; the resulting 
 oils were the green oils, the best part of 
 creosote for timber-preserving, fluent and 
 rich in alkaloids. How could they become 
 " charred oils ? " 
 
 In the illustration, drawn from a fire- 
 engine, it was forgotten that a fire might 
 break out a second time, and that if a 
 fresh supply of water were not available, 
 the building would be consumed. Car- 
 bolic acid evaporated rapidly from timber, 
 and it had been proved that it left no 
 permanent effects behind. When the 
 sleeper was placed in the permanent way 
 the supply of the antiseptic could not be 
 renewed, and the timber would rot if 
 more stable antiseptics were not present 
 in the shape of the heavier oils. 
 
 As regarded naphthaline colors Mr. 
 Bamber was also mistaken. They were 
 very successful as a manufacture, and 
 their use was largely increasing. He 
 accused the. author of "condemning 
 country oils," and of saying that they 
 
189 
 
 " were not good for creosoting timber." 
 In the paper the exact contrary was 
 stated. The author advocated the use of 
 both London and country oils, and he 
 habitually used large quantities of both. 
 What he condemned was the use of oils, 
 whether London or country, which were 
 so manipulated as to contain a large pro- 
 portion of volatile substances at the ex- 
 pense of the more durable, and therefore 
 for this purpose more valuable antisep- 
 tics. Were Mr. Bamber's theories carried 
 into practice, about one-half of the creo- 
 sote manufactured in England, the enor- 
 mous bulk of the "London oils," would 
 be excluded from use by the timber-pre- 
 server. Nevertheless they were precisely 
 the creosotes which had given the most 
 unmistakably good results, whether, as 
 in the case of the early Indian sleepers, 
 and of the sleepers of the Chemin de Fer 
 de 1'Ouest, the percentage of tar-acids 
 had been proved to be small, or whether, 
 as was the practice of the Belgian Gov- 
 ernment, the tar-acids had been altogeth- 
 
190 
 
 er and avowedly struck out of the speci- 
 fication. 
 
 In reply to Prof. Yoelcker, lie desired 
 to state that he had purposely abstained 
 from connecting the names of administra- 
 tive bodies with the questions of contro- 
 versy. He was not aware of any specifi- 
 cation officially issued by the War Office 
 which bore on this subject; but it was 
 known that the distinguished chemist 
 of that department had been consulted 
 by various administrations, who could 
 have had no other object in view than to 
 obtain the best engineering material. The 
 views of Sir Frederick Abel on all the 
 most important points of a creosote spe- 
 cification were substantially the same as 
 those of Dr. Tidy and of the author. And 
 what the author considered to be the 
 most important points were, 1st, that the 
 presence in considerable volume of the 
 heavier and least volatile distillates, i. e., 
 those distilling at or above 600 Fahren- 
 heit, must not merely be tolerated but 
 insisted upon. That naphthaline, and 
 the other usual semi-solid constituents, 
 
191 
 
 should be admitted, provided they were 
 completely fluid at the temperature to 
 which the creosote was raised when in- 
 jected into the wood. It was known that 
 these views had not been adopted by the 
 Crown agents for the colonies, but he 
 hoped that this discussion might be the 
 means of clearing away many misconcep- 
 tions. Respecting the point which he 
 considered subsidiary to the other two, 
 although not unimportant, viz., the per- 
 centage of tar acids, Sir Frederick Abel, 
 as well as Dr. Tidy, had recently recom- 
 mended a reduction, and the last word 
 had not been said on this question. Prof. 
 Yoelcker was mistaken in thinking that 
 Dr. Tidy had recommended 8 per cent, 
 of carbolic acid. The 8 per cent, was of 
 total tar acids, including carbolic, cresylic, 
 and all other tar acids which could be re- 
 moved by a specified solution of caustic 
 soda. Dr. Tidy, in his report to the Gas- 
 light Co., mentioned his reasons for not 
 stipulating for a fixed quantity of carbolic 
 acid. Whenever any stated quantity of 
 this body had been mentioned in specifi- 
 
192 
 
 cations by English engineers, it had been 
 fixed at one-half of the total tar acids. 
 Hence the quantity had varied from 2-J 
 per cent, to 5 per cent., the latter being 
 the largest quantity of crude carbolic acid 
 which the author had ever known to be 
 required by any specification issued in 
 this country. He might be permitted to 
 express his satisfaction that Dr. Voelcker 
 had recently joined the ranks of investi- 
 gators into the properties of creosote oils, 
 but he was sure that so distinguished a 
 chemist would be the last to depreciate 
 the experiments and experience of the 
 numerous chemists and practical men who 
 had placed the results of their labors on 
 record. It could surely have only been 
 by some misconception that Dr. Yoelcker 
 recommended an entirely new departure 
 by asking for 10 per cent of carbolic acid 
 in creosotes used for young timber or 
 sap-wood, although he admitted the prob- 
 able superiority of the heavier oils for 
 timber intended for railway sleepers and 
 other engineering purposes. Dr. Yoelcker 
 had not produced the results of any orig- 
 
193 
 
 inal experiments in support of his views. 
 The typical experiments which he asked 
 for had been tried and recorded ; they 
 proved that carbolic acid and the lighter 
 tar acids were not reliable as durable 
 antiseptics for timber. Engineers were 
 familiar with the preparation of young 
 wood and sap-wood as well as with that 
 of older timber. The same creosotes 
 were always used for both, and with com- 
 plete success. It had been clearly estab- 
 lished that the heavy oils preserved sap- 
 wood from decay. It would be remem- 
 bered by many members of the Institu- 
 tion that the late Mr. Bethell had even 
 advocated the use of young wood in pref- 
 erence to older timber, because the sap- 
 wood absorbed the creosote so readily, 
 and that Mr. (now Sir John) Hawkshaw 
 had combated this idea, not from any 
 doubt of the preservation of young wood, 
 but upon the ground that the engineer 
 must choose for many purposes the kind 
 of timber best adapted for resisting im- 
 pact or heavy strains. Amongst the nu- 
 merous successful specimens of creosoted 
 
194 
 
 wood which had been exhibited at the 
 Institution during the discussion, and 
 which f had been taken from various rail- 
 ways after periods of endurance varying 
 from sixteen to thirty- two years, nothing 
 was more striking than the perfect pres- 
 ervation of the sap-wood, although careful 
 analysis had shown that the heavy oils, 
 and not the tar acids, were the enduring 
 agents of preservation. The allusion of 
 Dr. Voelcker to telegraph poles had elic- 
 ited much practical information. Nothing 
 could be more conclusive than the evi- 
 dence of Mr Preece as to the behavior 
 of the young timber, surrounded by its 
 girdle of sap-wood, which was used for 
 telegraph poles in this country. The au- 
 thor had been responsible for the creo- 
 soting of a large portion of the poles al- 
 luded to by Mr. Preece ; these had as a 
 rule been prepared with the usual Lon- 
 don oils. But it was only right that he 
 should state another circumstance. He 
 believed that the success of the poles, 
 creosoted for the Post-office Telegraph 
 Department, was largely influenced by the 
 
195 
 
 care taken by that department in the 
 seasoning of the timber. The date of de- 
 livery of the poles, landed and stacked at 
 the creosoting yard, was a matter of con- 
 tract, but there was no fixed date for the 
 creosoting. On the contrary, the engi- 
 neer did not allow them to be creosoted 
 until he pronounced them to be dry, and 
 ready for the process. Sixteen years ago, 
 at a meeting of the Institution, he had 
 urgently recommended the adoption of 
 some* such method for ensuring the proper 
 seasoning of timber. The very interest- 
 ing and satisfactory evidence of Mr. 
 Bouissou, the Engineer of the West of 
 France Railways, confirmed the experi- 
 ence of Mr. Preece, both as to the satis- 
 factory results of creosoting, and also as 
 to the great importance of seasoning be- 
 fore creosoting; the precautions adopted 
 for the latter purpose by the French 
 company being substantially the same as 
 those of the English administration. With 
 reference to the preparation of telegraph 
 poles, a very valuable paper had been 
 contributed by Mr. William Langdon, 
 
196 
 
 M. Inst. C. E., to the Society of Telegraph 
 Engineers, on the 25th of March, 1874. 
 Mr. Langdon had also contributed to this 
 discussion, and had confirmed by his ex- 
 perience many of the views entertained 
 by the author. With regard, therefore, 
 to the observations of Dr. Yoelcker as to 
 green or unseasoned timber, the author 
 would add the results of his own long 
 and varied experience in this and other 
 countries, by saying that the attempt 
 should never be made to inject creosote, 
 or any other oily substance, without pre- 
 viously, or at the time of the operation, 
 expelling watery moisture. Timber should 
 not be felled whilst the sap was in it. 
 
 As regarded the effects of living organ- 
 isms, and the introduction of their spores 
 through cracks in the wood, the views of 
 Mr. Carruthers entirely agreed with those 
 expressed by the anthor. But what was 
 the remedy ? The botanical aspect of the 
 question had not been lost sight of, from 
 the days when Dean Buckland and others 
 discussed at this Institution the question 
 of timber preparation from that important 
 
197 
 
 standpoint, and it had not been overlooked 
 in the modern systems of injection. Exo- 
 genous trees, whose annual growth took 
 place by the formation of concentric layers 
 of vascular tissue added externally, fur- 
 nished the timber with which engineers 
 had almost exclusively to deal. The 
 softer and younger wood, containing the 
 greatest portion of albumen, was on the 
 outside ; it was more liable to decay than 
 the harder portions. It was the chief 
 merit of the system of injecting under 
 pressure that it precisely met this diffi- 
 culty. The softer parts absorbed more 
 of the antiseptic than the rest, the press- 
 ure followed the line of least resistance, 
 the antiseptic fluid gorged the sap-wood, 
 and penetrated to all cracks or shakes. 
 There was but little analogy between this 
 method and the application of a surface 
 coating of pitch, as although he recom- 
 mended by preference oils of a heavy 
 character, and containing semi-solids, the 
 whole of these bodies were perfectly 
 liquid at 100 Fahrenheit, the tem- 
 perature to which they were usually 
 
198 
 
 subjected at the time of injection. On 
 cooling, they solidified, not on the surface 
 merely, but within the pores of the tim- 
 ber, which they sealed up against the in- 
 cursion of the agents of decay. Mr. 
 Carruthers had referred to the experi- 
 ments of the celebrated Dr. Koch. The 
 researches of Koch, and of other German 
 scientific investigators, were very damag- 
 ing to the claims of carbolic acid as a 
 germicide, and as a coagulator of albu- 
 men. In his treatise "Ueber Desinfec- 
 tion," Dr. Koch deduced from his careful 
 and laborious experiments minutely de- 
 scribed, that the value of carbolic acid 
 was greatly limited as a germicide, and 
 that for the destruction of spores it was 
 altogether useless, being almost without 
 action ; but that it could be used to de- 
 stroy micro-organisms free from spores. 
 This was when used in a watery solution ; 
 still stronger was his opinion as to an 
 oily solution. He stated that in solutions 
 of oil or alcohol, carbolic acid did not ex- 
 hibit the slightest antiseptic action. To 
 this, the remarks of Dr. Sansom had al- 
 
199 
 
 ready pointed. It must be remembered 
 that it was in an oily solution, i.e., dis- 
 solved in the tar oils, that carbolic acid 
 was applied to timber. G. "Wolff hugel 
 and G. v. Knorre followed up Koch's in- 
 vestigations, and spoke of the inactivity 
 of an oily solution of carbolic acid ; of its 
 inferior powers of penetration into porous 
 solids, and of its inferiority in the de- 
 struction of fungi. F. Boillat, who fol- 
 lowed up the experiments of Koch in the 
 laboratory of Professor Nencki at Bern, 
 found that albumen, when completely co- 
 agulated with an excess of carbolic acid, 
 formed no permanent combination there- 
 with. He was able to wash out on a fil- 
 ter the whole of the carbolic acid from 
 the albumen precipitate, after which, 
 upon exposing it to the atmosphere dur- 
 ing forty-eight hours, the albumen be- 
 came putrid. Mr. Carruthers had spoken 
 of the presence of free crystallized car- 
 bolic acid in the cells of a small piece of 
 a wooden hurdle. But carbolic acid 
 would not crystallize out of the oils hold- 
 ing it in solution ; it could only be ob- 
 
200 
 
 tained in that state of purity by a long 
 and complicated chemical process, and 
 the crystals would immediately liquefy 
 when exposed to the atmosphere. The 
 minute particles seen by Mr. Carruthers 
 were probably naphthaline, or one of the 
 other semi-solids of the higher distillates 
 of coal-tar. The condition of this hurdle 
 corresponded exactly with that of enor- 
 mous masses of successfully creosoted 
 timber as typified by the samples exposed 
 during this discussion, and the author 
 thought that the final question of Mr. 
 Carruthers had been fully answered by 
 many authorities quoted in the paper. 
 
 In reply to Mr. C. de Laune, the au- 
 thor would remark that his paper had a 
 much wider object in view than the mere 
 question of carbolic acid; the presence 
 or absence of that body would not explain 
 Mr. de Laune's difficulty. No honest 
 creosote made from coal-tar, whether 
 " London" or "country" oil, whether 
 with much or little tar acid, contained 
 any ingredient which could injure timber ; 
 the only question was, which of those in- 
 
201 
 
 gradients was most efficacious and most 
 durable. The question as to which was 
 the easiest to put into the timber was of 
 much less importance. Some small pieces 
 of hurdles, &c., had been shown during 
 the discussion, and alluded to by Dr. 
 Voelcker, Mr. Carruthers, and Mr. de 
 Xiaune ; Mr. E. A. Cowper had detected 
 the reason why one had succeeded and 
 the other failed. The first had had plen- 
 ty of creosote put into it ; the others but 
 very little. Mr. de Laune had made a 
 detailed statement to the author, which 
 was briefly as followed: That he had 
 been in the habit of preparing different 
 kinds of timber of various densities, and 
 frequently in a wet or unseasoned state 
 by boiling the wood in creosote in open 
 tanks and without a thermometer; and 
 that he did not keep the timber in the 
 tanks more than twelve hours, as a long- 
 er operation rendered it brittle a very 
 significant fact. He said that he had not 
 latterly superintended these operations 
 personally, and that he did not regard 
 the process as a scientific one, but thought 
 
202 
 
 that it could be carried out by odd hands, 
 old men, or boys. A good many years 
 ago, the author had had considerable ex- 
 perience in preparing timber in open 
 tanks with corrosive sublimate, sulphate 
 of copper, and also with creosote. The 
 time for leaving the timber in the tank, 
 to be injected by the metallic salts in 
 watery solution, which penetrated more 
 readily than creosote, was generally cal- 
 culated at about twenty-four hours 1'or 
 every inch in thickness of the wood. 
 With the creosoting process it was essen- 
 tial that the water in the timber should 
 be first got rid of ; the presence of the 
 water prevented the entrance 6f the cre- 
 osote oils. Even with the cylinder-proc- 
 ess, where the oil was driven in under 
 pressure, engineers insisted upon the 
 timber being dry, and they weighed it- 
 before and after the operation, to check 
 the quantity of creosote injected. "With 
 the open- tank system more care, and not 
 less care, was necessary than with the 
 superior apparatus. But soft young 
 timber, if properly seasoned and then 
 
203 
 
 subjected to creosote at a moderate heat, 
 could without difficulty be made to im- 
 bibe a sufficient quantity of creosote of 
 any kind manufactured in this country. 
 But if the timber was wet, it was not 
 amenable to treatment by creosote in 
 open tanks at a moderate temperature, 
 and if the creosote was raised to a tem- 
 perature even approaching to its boiling- 
 point, which was about 400 Fahrenheit, 
 it would cause the timber immersed in it 
 to become as brittle as a carrot. Timber 
 should not, under any circumstances, be 
 subjected to a higher temperature than 
 250 Fahrenheit. It would, therefore, ap- 
 pear that Mr. de Laune's difficulties were 
 to be explained by his methods of oper- 
 ation. He had told the author that he 
 had for many years procured all his creo- 
 sote from the same works, a small local 
 manufactory, where the tars of the dis- 
 trict were distilled. It had been ascer- 
 tained that the creosotes manufactured at 
 the works in question had not essentially 
 varied in type, whilst even as regarded 
 carbolic acid, if the analysis quoted by 
 
204 
 
 Mr. de Laune was correct, the quantity 
 contained in the sample was considerably 
 above the average, although this was a 
 point to which the author attributed but 
 little importance. He was surprised to 
 find, in the report accompanying the an- 
 alysis alluded to, a statement to the ef- 
 fect that "good creosote should yield 
 quite 75 per cent, of volatile oils (sic) 
 containing 10 to 15 per cent, of crude 
 carbolic acid." No creosotes used for 
 timber-preserving, under any specifica- 
 tion, had ever been required to contain 
 more than from 2^ to 5 per cent, of crude 
 carbolic acid. The recommendation of 
 " volatile oils " was a mistake which was 
 obvious to all experts ; but it might have a 
 bad effect in encouraging the use of some of 
 the worst adulterants, substances sold as 
 creosote which were not derived from coal 
 tar at all. The report, although issued 
 from the laboratory of the Royal Agricul- 
 tural Society, was signed for, but not 
 by, Dr. Voelcker. The author had un- 
 derstood that Dr. Voelcker was at the 
 time absent owing to illness ; he would 
 
205 
 
 not therefore have alluded to it but for 
 the fact that this report had been brought 
 so prominently into notice by Mr. de 
 Laune, and that extracts from it had 
 been published in an agricultural journal. 
 
 The author had used creosoting for 
 farm purposes, for fences, hurdles, and 
 for many years also, for piles and fences 
 for his wharves. He always used for him- 
 self the type of creosote he recommended 
 to others, and it had proved invariably 
 successful in his own case. 
 
 The author was asked by Mr. Clemin- 
 son why he had not alluded to the proc- 
 ess of Mr. Blythe. If by Blythe's process 
 was meant the attempt to introduce the 
 creosote oils, or any part of them into 
 timber in the form of vapor, the subject 
 had been fully treated in the paper. For 
 the operations described as having been 
 carried out for the Compagnie des Che- 
 mins cle Fer de 1' Quest, the apparatus 
 u'sed was supplied by Mr. Blythe. The 
 experiments of Mr. Seidl were described 
 by him as having been carried out by 
 "Blythe's process." Engineers in Eng- 
 
206 
 
 land had recently had an opportunity of 
 witnessing similar experiments at the 
 works of Messrs. Connor, at Millwall. 
 After the dismantling of these works, the 
 author had purchased the greater part of 
 the machinery for the purpose of adapt- 
 ing it to his own processes, so that he 
 had again had an opportunity of studying 
 the question. By slow evaporation, fluids 
 gradually volatilized at temperatures much 
 below their boiling-points. But pressure 
 from their vapors could only be obtained 
 at temperatures exceeding their boiling- 
 points. Thus water gradually evaporated 
 even from a frozen surface, but no tension 
 of its vapor could be produced except at 
 a temperature exceeding its boiling-point, 
 212 Fahrenheit. The boiling point of 
 the creosote oils ranged from about 400 
 to 760 Fahrenheit, that of carbolic acid 
 when separated from these oils being 360 
 Fahrenheit, and of cresylic acid 390 
 Fahrenheit. Now, it was well known 
 that timber for the purposes of the en- 
 gineer was injured and rendered brittle 
 and unsafe at a temperature much ex- 
 
207 
 
 s 
 
 ceeding 250 Fahrenheit. How then 
 could those tar products be introduced 
 under pressure into the timber as vapor, 
 whether accompanied or not by super- 
 heated steam, without injuring the tim- 
 ber? Either the temperature must be 
 raised above danger point for the wood, 
 or nothing but the vapor of water would 
 be driven into it. This applied to the first 
 part of the process. Of course, if it was 
 followed up by an injection of the creo- 
 sote oils in the usual manner, this second 
 part of the process covered the deficien- 
 cies of the first operation. The presence 
 of any of the components of the tar-oils 
 could be detected in the timber by chem- 
 ical tests. When specimens of wood had 
 been produced, which had been prepared 
 by the injection of tar-oil vapors in suffi- 
 cient quantity to have a practical value in 
 the preservation of timber, and at a tem- 
 perature not exceeding 250 Fahrenheit, 
 the author would be very glad again to 
 give his best attention to this part of the 
 subject. 
 
 He was glad to be able to reply to the 
 
208 
 
 question of Mr. Lawford, with regard to 
 the Midland Railway Company. In 1866, 
 at a meeting of the Institution, Mr. Cross- 
 ley, the engineer of that company an- 
 nounced that, although he admitted that 
 creosoting stopped decay, he had given 
 up that process from a calculation of 
 economy based on the assumption, that 
 with very heavy traffic like that which 
 prevailed over the lines of his company, 
 the sleepers were worn out by hard work 
 before they had time to decay. The au- 
 thor would suggest that incipient decay 
 of unprepared sleepers often set in at a 
 very early period of their service, especi- 
 ally through cracks and bolt-holes ; the 
 fastenings of the chairs thereupon became 
 loosened, and the mechanical destruction 
 of the sleepers hastened. But Mr. Law- 
 ford would be glad to hear that the Mid- 
 land Railway Company had again adopted 
 creosoting ; they had had large quantities 
 of sleeper creosoted during the last few 
 years. 
 
 In reply to Mr. Roberts, the author 
 had never found any difficulty in com- 
 
209 
 
 pletely saturating the sap-wood with the 
 London oils where the timber had been 
 sufficiently dry. Mr. Coisne's experience 
 with shavings were for the purpose of as- 
 certaining what kind of creosote lasted 
 best, and he effected a complete satura- 
 tion both with the thin oils and with 
 thick oils. The thinnest oils did not pre- 
 serve the woody fiber from rotting, even 
 with so good an injection, whilst the 
 heavier oils did. A fortiori, the thinner 
 oils would be, by themselves, still more 
 unreliable with the inferior injection car- 
 ried out in practical operations with tim- 
 ber. It must also be borne in mind that 
 Mr. Coisne did not stop at these experi- 
 ments, but had confirmed them by twenty 
 years' subsequent treatment of timber on 
 a very large scale, for the Belgian State 
 Railways. The chapter in Mr. Coisne's 
 1871 pamphlet, upon the choice of creo- 
 sote oils was a most interesting and prac- 
 tical one. 
 
 With reference to the author's process 
 for removing water from the timber at 
 the time of creosoting, the following ex- 
 
210 
 
 perinaent had been carried out at his 
 works since the paper had been read. 
 
 Six square fir-sleeper blocks, each 8 
 feet 11 inches by 10 inches by 10 inches, 
 saturated with moisture, were cut into 10 
 inches by 5 inches sleepers. One sleeper, 
 
 A, from each block was prepared by the 
 new method, the corresponding sleeper, 
 
 B, from the same block, by the old meth- 
 od, so that in each instance the results 
 with the two halves of the same log 
 could be contrasted. Care was taken to 
 choose -blocks having the heart in the 
 center, and with the texture of the two 
 halves as nearly as possible similar. 
 
 From the six sleepers, A, water was 
 withdrawn by the new process to the ex- 
 tent, ascertained by weighing the water, 
 of 120 Ibs. ; yet the sleepers, when with- 
 drawn from the cylinder after the process 
 was completed, weighed 155 Ibs. more 
 than when put in, thus showing that they 
 had absorbed 275 Ibs. of creosote. As 
 their total cubic contents were 18.57 
 cubic feet, their average loss of water 
 was 6.45 Ibs. per cubic foot ; their aver- 
 
211 
 
 age gain of creosote was 14.8 Ibs. per 
 cubic foot. 
 
 The six sleepers, B, were creosoted by 
 the ordinary process. Being, like the 
 others, very wet, and having no moisture 
 extracted from them, the results of their 
 being weighed before and after creosot- 
 ing showed an absorption of 116 Ibs. of 
 creosote only, or an average of 6.29 lbs 
 per cubic foot. The separate absorp- 
 tions of these six sleepers were as fol- 
 lowed : 9.04 Ibs., 4.52 Ibs., 2.9 Ibs., 6.13 
 Ibs., 9.36 Ibs., and 5.49 Ibs. per cubic 
 foot respectively, thus illustrating the 
 uncertain results of creosoting timber 
 when too wet by the ordinary method. 
 They were placed in the cylinder with a 
 charge of ordinary dry sleepers, which 
 took up on the average rather more than 
 10 Ibs. of creosote per cubic foot. 
 
 The result with sleepers A was inter- 
 esting, as it showed that by the new 
 process wet timber could have its mois- 
 ture at once removed, and a large quan- 
 tity of creosote injected without difficulty. 
 All twelve sleepers, both A and B, were 
 
212 
 
 afterwards cross-cut at 6 inches, 9 inches, 
 12 inches, and at 4 feet 6 inches from 
 their ends, the corresponding section of 
 A and B being constrasted and photo- 
 graphed. The sleepers A were found not 
 only to have absorbed a large quantity of 
 creosote, but the creosote was much more 
 evenly distributed than was the case with 
 sleepers B. 
 
 Might the author be permitted to sum 
 up the evidence which had been produced 
 during the discussion as to the best class 
 of antiseptics for timber? Both engi- 
 neers and chemists would probably agree 
 with him that after forty-five years' dis- 
 cussion of this engineering problem the 
 time had gone by for dogmatic assertion, 
 unsupported either by experiment in the 
 laboratory or by recorded experience in 
 engineering works. In the paper he 
 had called the germ theory a severe 
 but salutary test for these antiseptics. 
 As a matter of fact, the subject had 
 received valuable elucidation from the 
 labors and discoveries of a number of 
 eminent men, who had studied the physi- 
 
213 
 
 ology of the bacteria. In the application 
 of the remedies, however, the operations 
 of the timber-preserver diverged from 
 those of the physician to the human body. 
 In combating those terrible enemies the 
 bacteria, which were pathogenic to ani- 
 mal life, the great difficulty was that 
 many of the remedies effectual against 
 the bacteria intefered with the vital func- 
 tions of the patient. On the other hand, 
 the physician could repeat remedies when- 
 ever the malignant symptons reappeared. 
 Therefore antiseptics, more or less vola- 
 tile, were sometimes more useful to the 
 physician than others of a more perma- 
 nent character, because they did not accu- 
 mulate in the system of the patient. In 
 preserving timber, the problem differed 
 materially. The vital functions of the 
 plant had ceased ; stronger poisons, and 
 substances which clogged up the cells and 
 tissues, could be employed, provided al- 
 ways that they were of such a nature as 
 not to injure the structure of the wood. 
 But the remedy must be applied once for 
 all. In the majority of cases where tim- 
 
214 
 
 ber was once placed in engineering works 
 the supply of the antiseptic could not be 
 renewed. Therefore the very first condi- 
 tion was that the antiseptic should be of 
 a permanent constitution. Let this rule 
 be applied to the evidence offered during 
 the discussion. Antiseptics for timber 
 had been described: 1st, as coagulators 
 of albumen ; 2d, as germicides ; 3d, as 
 sterilizers, rendering the cells of the wood 
 unfit for the development of fungi or 
 bacteria ; 4th, as germ-excluders, closing 
 the entrances against the intrusions of 
 the enemy. 
 
 Was not too much value still attached 
 by some to the coagulation of the albu- 
 men in wood ? Albumen formed an ex- 
 tremely small portion of the wood ; in fir 
 it varied from 0.5 to 0.9 per cent. Those 
 parts of timber containing the smallest 
 portions of albumen were nevertheless 
 liable to decay ; the mere coagulation of 
 the albumen did not protect the bulk of 
 the timber from destruction. Did coagu- 
 lation preserve even the albumen itself 
 from destruction? Sansom, Angus Smith, 
 
215 
 
 and other authorities found that it did 
 not. The author took a hard-boiled egg, 
 a very complete specimen of coagulated 
 albumen, removed the shell, and exposed 
 it to the sea breezes on a high point of 
 the Atlantic shore of the island of Mull. 
 In a few days signs of putrefaction were 
 visible; in eight days the albumen was 
 coated with various species of micrococ- 
 cus, cromogenes and other agents of de- 
 struction. The egg had become a mass 
 of corruption. Coagulation had not pro- 
 tected albumen from putrefaction. What 
 was the result when coagulation was pro- 
 duced, not by heat, but by the action of 
 an antiseptic body 1 ? Did not the result 
 depend mainly, if not altogether, upon 
 the germicide properties of the antiseptic, 
 and upon its abiding presence ? Or, thus 
 produced, did coagulation per se effect a 
 new combination with permanent results I 
 In the case of carbolic acid, a host of in- 
 vestigators said, No. Their experiments 
 appeared to prove that carbolic acid was 
 volatile in the air, soluble in the water, 
 and that its compounds were not stable. 
 
216 
 
 Boillat, in his experiments, realized the 
 extreme conditions desired by those the- 
 orists who thought that carbolic acid had 
 a permanent effect upon timber ; he pro- 
 duced a perfect coagulation of albumen 
 with an excess of carbolic acid. Yet a 
 mere washing with water removed the 
 whole of the carbolic acid, and the albu- 
 men putrefied on exposure to the air. 
 Carbolic acid, therefore, would appear to 
 have had no permanent effect upon albu- 
 men. The author agreed with Dr. Ber- 
 nays that if coagulation by carbolic acid 
 were desirable, 2 per cent, of that body 
 might be retained ; but having in view 
 the foregoing evidence, what was the 
 value of the coagulation theory at all as 
 applied to timber-preserving ? There had 
 been some idea that carbolic acid lin- 
 gered in the timber in some unrecognized 
 form. The author had had occasion to 
 test sleepers a few weeks after creosoting ; 
 if this were done before the carbolic acid 
 had time to evaporate, it could be found 
 in the wood by the ordinary tests, and a 
 quantitative analysis made. On the other 
 
217 
 
 hand, Dr. Tidy, who was not unwilling to 
 find it in combination, had searched for it 
 after twelve months, and had not found it 
 by the ordinary tests, that is, in sufficient 
 quantity to have any practical result. But 
 whenever it was present there were tests 
 subtle enough to detect it, even in such 
 infinitesimal quantities as to have no 
 practical value, as was evidenced by the 
 experiments of Mr. Greville Williams. 
 Notwithstanding theories and experi- 
 ments, did carbolic acid, when put into 
 timber, do any good there ? Mr. Coisne, 
 Mr. Greville Williams, and the author, 
 not only never found it to have contrib- 
 uted to the success of old creosoted tim- 
 ber, but Mr. Coisne's experiments went 
 further still. He injected woody fiber 
 with light oils and an excess of tar acids, 
 and the woods rotted, whilst the woods 
 creosoted with heavy oils, and without 
 any tar acids, were preserved. 
 
 There was one point respecting which 
 there had been a consensus of opinion on 
 the part of all who had taken part in the 
 discussion, namely, that for the prepara- 
 
218 
 
 tion of timber, creosoting had been un- 
 deniably more successful than corrosive 
 sublimate, sulphate of copper, or chlor- 
 ide of zinc. Could this be at all due to 
 carbolic acid? How was this possible, 
 when a host of authorities proved that 
 carbolic acid was less permanent in its 
 effects than the three metallic salts al- 
 luded to, and very considerably less pow- 
 erful as a germicide than corrosive sub- 
 limate or sulphate of copper. In a valu- 
 able work upon bacteria by Magnin and 
 Sternberg there was a long list of anti- 
 septics, with a statement as to their com- 
 parative potency as germicides, compiled 
 from the latest authorities. Carbolic 
 acid. was low in the scale. Dr. Sternberg 
 gave the strength of solutions of differ- 
 ent kinds which had been found efficacious 
 in preventing the development of the 
 septic micrococcus, the following amongst 
 many others : 
 
 Corrosive sublimate. . .1 part in 40,000 
 Sulphate of copper. .. .1 " 400 
 
 Chloride of zinc 1 " 200 
 
 Carbolic acid 1 " 200 
 
219 
 
 These were in watery solution. To this 
 must be added the statements that in oily 
 solution the antiseptic power of carbolic 
 acid was diminished, according to San- 
 som and Angus Smith ; altogether it was 
 nil according to Koch. It was evident 
 that there was a vast accumulation of sci- 
 entific evidence in confirmation of the 
 continually reiterated statements of those 
 practical men, who had had the largest 
 and longest experience in preparing tim- 
 ber, to the effect that it was not to car- 
 bolic acid, but to other substances con- 
 tained in the tar oils, that the superiority 
 of the creosoting process over the other 
 three methods was due. Mr. Lowe was 
 well known as one of the highest scien- 
 tific and practical authorities upon the 
 tar acids, and he had given much valu- 
 able information in his communication to 
 the Institution. On the other side, the 
 absence of evidence was even more re- 
 markable than many of those interested 
 in this subject would perhaps have an- 
 ticipated. No chemist had brought for- 
 ward even a laboratory experiment in 
 
220 
 
 proof of any permanent effect of carbolic 
 acid upon albumen. No practical man 
 had produced a proof that that substance 
 had had any lasting effect upon timber. 
 The author submitted that the claims of 
 carbolic acid as an antiseptic for timber 
 had not been proven. 
 
 What, then, were the substances in the 
 creosote oils which had insured the supe- 
 riority of that process over the others? 
 If the author were asked the question, 
 he would remark that the object being 
 the prolonged preservation of timber, 
 antiseptics should be chosen which re- 
 mained longest in the timber. That the 
 different constituents of the creosote oils, 
 showed a gradation from the lightest and 
 most volatile bodies at the carbolic, or 
 left-hand end of the scale, up to the least 
 volatile and most permanent bodies at 
 the right-hand end. Divide the bulk of 
 the oils roughly in half. Would the con- 
 stituents of the right-hand half of them- 
 selves insure the preservation of the tim- 
 ber? Yes, excellently well. They con- 
 tained germicides and solidifying mate- 
 
221 
 
 rials ; they were both sterilizers and 
 germ-excluders ; they would not evapo- 
 rate, except at an enormously high tem- 
 perature. Nevertheless in their united 
 bulk they were perfectly fluid at a tem- 
 perature of 100 Fahrenheit ; they were 
 insoluble in water ; they could be injected 
 into timber, in quantity exceeding the 
 maximum which any engineer had as yet 
 required. Would the other, or left-hand 
 part of the group, taken by themselves, 
 preserve timber? Much less perfectly, 
 as they were more volatile. "Would a still 
 further fractioning to the left, if it were 
 practicable, insure a better result ? Not 
 so, but a worse one still ; for the lightest 
 oils, which contained the greatest portion 
 of the tar acids, were, like the tar acids 
 themselves, the most volatile portions of 
 all. 
 
 The author trusted that he had made 
 clear his reasons for specially objecting 
 to large percentages of tar acids. Take 
 an honest heavy cresote, free from adul- 
 teration, free from mutilation, containing, 
 say, 5 per cent, of tar acids. If this 
 
222 
 
 sample were refused because it did not 
 contain 8 or 10 per cent., the tar-distiller 
 was induced to remove a large portion of 
 the heavier constituents of the bodies to 
 the right hand of the scale, in order to 
 make the proportion of tar acids larger 
 in the portion remaining. He believed 
 that those heavier portions were the best. 
 He thought that, provided the oils were 
 sufficiently fluid at the temperature at 
 which they were injected, there should be 
 no restriction as to maximum specific 
 gravity or maximum boiling-point. If 
 larger and stronger doses of germicides 
 were desired, it would be far better to 
 put them into the wood in the shape of 
 corrosive sublimate or sulphate of copper, 
 in addition to the heavy oils. This could 
 be done by a double process of prepara- 
 tion, with respect to which he had been 
 lately experimenting. 
 
 Timber preserved by antiseptic treat- 
 ment was an engineering material com- 
 peting with other materials, both as to 
 price and durability. Members of the 
 Institution would appreciate the endeav- 
 
223 
 
 ors of the author to emancipate an im- 
 portant industry from the effects of any 
 theories which, themselves unproven, 
 might stand in the way of improvement, 
 either as to diminished cost or increased 
 efficiency. 
 
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