IN 
 Arthur Eaton 
 
PRACTICAL OBSERVATIONS 
 
 ON 
 
 THE MECHANICAL STRUCTURE, 
 
 MODE OF FORMATION, 
 THE REPLETION OR FILLING UP, 
 
 AND 
 
 THE INTERSECTION AND RELATIVE AGE 
 
 or 
 
 MINERAL VEINS ; 
 
 WITH THE 
 
 APPLICATION OF 
 
 SEVERAL NEW THEORETICAL PRINCIPLES 
 
 TO 
 
 THE ART OF MINING. 
 BY JOHN LEITHART, 
 
 <U 
 MINE AGENT. 
 
 WITH NUMEROUS ILLUSTRATIONS. 
 
 LONDON: 
 
 JOHN WEALE, 59, HIGH HOLBURNv 
 NEWCASTLE: 
 
 < UKRIK AND BOWMAN. 
 
 1838. 
 
PRINTED FOR THE AUTHOR, BY J. BLACKWELk 
 AND CO., NEWCASTLE UPON TYNE. 
 
TO 
 
 JOHN BUDDLE, 
 
 OF WALLSEND, ESQ., 
 
 FELLOW OF THE GEOLOGICAL SOCIETY, 
 MEMBER OF THE INSTITUTION OF CIVIL ENGINEERS, 
 WHOSE EXPERIENCE AND ABILITY 
 
 AS A MINING ENGINEER 
 IS ONLY EQUALLED BY HIS DESIRE TO ENCOURAGE 
 
 THE EFFORTS OF OTHERS WHO ARE 
 EMPLOYED IN THE INVESTIGATION OF 
 SUBJECTS PRACTICALLY CONNECTED WITH THE 
 PROGRESS OF MINING, 
 
 THE FOLLOWING OBSERVATIONS 
 
 ON MINERAL VEINS 
 
 ARE, WITH PERMISSION, 
 
 RESPECTFULLY INSCRIBED, 
 
 BY THE AUTHOR, 
 
 ALSTON MOOR, AUGUST 10, 18:i8. 
 
 690895 
 

 Pago 1 0, line 8 from top, read bent up, instead of rent up ; and line 9 
 
 bent down ; line 19, for bent, read fissure. 
 Page 24, line 12 from top, for correct, read erect. 
 . Page 39, line 1 1 from bottom, read immediate, for intermediate. 
 Page 47, line 2 from bottom, for salt, read salts. 
 Page 49, line 1C from top, for intersection, read interduction. 
 Page 55, line 12 from bottom, for hermo, read thermo; and at line 11, 
 
 for discharged, read discharge. 
 Page 57, line 3 from top, read on, for or ; also, line 12, for or, read on ; 
 
 also, line 19, read flowing towards A., instead of flowing in 
 
 at M. towards A. 
 
 Page 59, line 8 from bottom, for angles, read angle. 
 Page 62, line 1 1 from bottom, read with the, for with this ; and at line 6, 
 
 read current is moving, instead of current in its moving. 
 Page 64, line 5 from top, read on, for or. 
 Page 70, line 2 from top, read miner, for miners. 
 Page 72, line 14 from top, read east and west fissures, instead of east 
 
 and fissures. 
 
 Page 73, line 7 from bottom, for where even, read where ever. 
 Page 83, line 3 from bottom, for principles that which will, read which 
 
 will. 
 
PREFACE. 
 
 THE circumstances which first directed the Author's 
 attention to the phenomena of strata and mineral 
 veins are detailed in a paper on the Stratification of 
 Rocks, submitted to the Geological Section at the 
 Meeting of the British Association, held at New- 
 castle, in August, 1838 ; it may suffice here to men- 
 tion that being a native of, and having always lived in, 
 the interesting mining district of Alston Moor, a large 
 portion of his time, from his infancy, was spent in the 
 mines. He had not the good fortune to obtain the 
 usual advantages of education, and would perhaps 
 have remained altogether uninstructed as regards 
 literature, but for the active and generous aid and 
 friendship of the late John Dickinson, Esq., of Low 
 Byer, to whom he owes a deeply-felt and lasting gra- 
 titude. A Sunday School, promoted by Mr. Dickin- 
 son, and which, nearly to his dying day, at an ad- 
 vanced age, had the advantage of his constant and 
 zealous superintendence, was the only school (in the 
 ordinary acceptation of the word) that the author ever 
 attended. Opportunities of reading were afforded to 
 the miners by Mr. Dickinson, who not only lent 
 books to them, but afforded, by kind and judicious 
 
O PREFACE. 
 
 advice, and by a life of unwearying and active be- 
 nevolence, a constant example of upright principles, 
 of diligent research, and of plain and unpretend- 
 ing manners. These opportunites in some measure 
 compensated the want of the ordinary benefits afforded 
 by day schools for general learning. In the mean- 
 time the perusal of various works had given the author 
 a desire for knowledge, and the sciences of Astro- 
 nomy and Geology particularly attracted his attention. 
 In the latter he had daily opportunities of witnessing 
 the actual phenomena of veins when at work as a 
 miner. About ten years ago he had many opportunities 
 of becoming well acquainted with the exact relative 
 position of all the known veins in the manor of Alston 
 Moor and adjacent districts, by assisting in the exten- 
 sive Mining Surveys then in progress by Mr. J. Dickin- 
 son and Mr. Thomas Sopwith, and by drawing seve- 
 ral of the Mining Plans and Sections in their Office. 
 Being much employed as a mining agent, and occa- 
 sionally visiting distant districts, he became anxious to 
 apply theory to practice, but found many and often insu- 
 perable difficulties. At length several speculations on 
 electrical and galvanic phenomena seemed to open a 
 new field for explaining many subterranean pheno- 
 mena, and, after some years of patient investigation, 
 which formed a recreation for his leisure hours, he at 
 length arrived at some definite experimental results 
 respecting the formation of strata, and the struc- 
 ture of mineral veins, as well as on several other 
 subjects. At the recommendation of Mr. Sopwith, 
 
PREFACE. 7 
 
 he has been induced to submit his observations on the 
 formation of stratified rocks to the British Associa- 
 tion, and also to offer his views respecting mineral 
 veins to the public in the present volume. It remains 
 only to be mentioned that Mr. Buddie, who is ever 
 anxious to encourage a spirit of enquiry, has, with his 
 accustomed liberality, given the author his friendly aid 
 and encouragement. 
 
 The suggestion to publish the present volume 
 having been made only a few weeks previous to the 
 meeting of the British Association at Newcastle, 
 the time has not admitted of a careful revision of the 
 press by the Author. From the same cause Mr. 
 Buddie has not had an opportunity of attentively 
 perusing the work, and his patronage of it must there- 
 fore be considered as being given to it as the investi- 
 gations of a practical miner, without having had the 
 means of fully considering how far the principles 
 advanced by the Author are in accordance with the 
 phenomena from which they are deduced. In con- 
 clusion, the Author trusts he may venture to say that 
 many of the actual phenomena of mineral veins are 
 here presented to view that the plans and sections 
 of veins, drawn from actual observation, are more de- 
 tailed and minute than have yet been given to the 
 public. He has at all times been willing to impart to 
 others whatever information he has obtained ; and 
 while he offers his views with a strong confidence as 
 regards practical facts, he is fully sensible of the dif- 
 ficulty of attempting the solution of the difficult problem 
 
8 PREFACE. 
 
 presented by the phenomena of mineral veins. 
 His speculations, he trusts, will at least invite a spirit 
 of enquiry, and it will indeed afford him a high grati- 
 fication if he shall be considered as having advanced 
 even a single step towards a further connection of the 
 physical sciences with the art of mining. He may 
 perhaps be allowed to observe, that the circumstances 
 already mentioned may plead in his behalf for any 
 occasional errors or defects of composition. The 
 condemnation of generous criticism will in some mea- 
 sure be softened towards the literary imperfections of 
 an Author whose only book-learning was that of a 
 Sunday School, and whose mathematics were chiefly 
 studied by using only a mining shovel and a piece of 
 chalk. On the other hand, as regards facts and prac- 
 tical deductions, the Author can claim no such indul- 
 gence, for in respect to them his education has been in 
 the best of all schools the mine itself. 
 
INTRODUCTION. 
 
 IN none of the sciences, perhaps, have we a greater 
 number of phenomena, or a wider range of research, 
 than in the science of geology ; yet in none have we 
 less of clear and certain knowledge. What appears 
 to be the main obstacle to our progress in this depart- 
 ment of knowledge is, that the agents which nature 
 employs in the production of geological phenomena, 
 are either placed beyond the reach of observation, 
 or are so slow and minute in their operation as to 
 elude it. This being the case, the changes which 
 the earth's surface appears to have undergone, as 
 well as the agents that have produced them, are as 
 yet imperfectly comprehended. Another obstacle to 
 our progress in geological science is, the great diver- 
 sity of the phenomena it embraces, and proposes to 
 explain. In some parts of the earth's surface, we 
 have a regular order of succession in the beds or layers 
 forming its crust ; in others, the materials are tum- 
 bled together in great confusion. In some parts of 
 it, the beds have their planes of stratification parallel 
 to the horizon, in others they are perpendicular to it. 
 In some parts the strata are rent into innumerable 
 fragments; while, in other parts, they are in an 
 
 A 
 
INTRODUCTION. 
 
 entire state. In particular parts and strata, these 
 rents or fissures are filled with matter of a rocky 
 character ; in other parts and strata, with the ores 
 of the different metals* and other crystalline earthy 
 minerals ; and, lastly, some of the fissures are filled 
 with the bounding rocks in a decomposed state ; 
 others with clay, sand, gravel, &c., with a multitude 
 of other phenomena, which no geological theory 
 has yet fully embraced, or which have been clearly 
 explained by any admitted system of science. 
 
 All Geological theories must, from the very na- 
 ture of the subject, be in a great measure conjectu- 
 ral. For we have a system of things presented to 
 our view, evidently the work of agents acting at 
 distant intervals of time, and this, apparently, not 
 in any regular progression or harmony. The opera- 
 tions of each successive era obscuring, or partially 
 destroying, the productions of the preceding; so 
 that we have not before us the perfect result of any 
 one concurring system of natural operations, but a 
 mass of confusion and disorder, having rather the 
 character of ruin than a perfect structure ; yet we 
 admit that the simple materials of the earth's crust, 
 and the laws of nature, have continued the same in 
 all ages the great advances in physical science, 
 and the extensive researches into the natural his- 
 tory of the earth already made, render it highly 
 probable, that before long, the causes and methods 
 of all these changes will be fully determined. As 
 the architect, having learned certain rules and pro- 
 
INTRODUCTION. 3 
 
 portions by the study of the less dilapidated re- 
 mains, can reconstruct the mouldering fragments 
 of a ruined temple ; give a correct idea of its 
 form and extent, and can restore, even in detail, 
 its ornaments in all their pristine beauty ; and as 
 the naturalist, having found a single bone of an 
 animal, the whole species of which may have been 
 for ages extinct, can tell not only what were its ha- 
 bits and its external appearance, but can even de- 
 tail the structure of its internal organs : so the 
 geologist, having made himself acquainted with the 
 known laws of nature, and the phenomena exhibited 
 in the various formations which constitute the crust 
 or surface of the earth, endeavours to restore them, 
 in idea, to their primeval state ; and by the relative 
 position of their disjointed parts, or any other dis- 
 cernible marks of change, to trace out the causes 
 of these great convulsions of nature, or the agents 
 in those more minute and protracted operations by 
 which the present state of the earth's surface has 
 been induced. 
 
SECTION I. 
 
 ON THE MECHANICAL STRUCTURE OF 
 MINERAL VEINS. 
 
 MINERAL Veins are spaces in the rocks, consti- 
 tuting the surface of the earth, filled with various 
 materials which are different in general from the 
 substance of the rocks which they traverse. 
 
 In this definition we have two distinct objects of 
 inquiry the formation of the spaces in the rocks % 
 and the subsequent filling up of them. The former 
 of these subjects, viz., the formation of the spaces, 
 will constitute the first object of inquiry. 
 
 The formation of mineral veins, both as regards 
 the advancement of science and its practical utility, 
 is one of the most interesting and important depart- 
 ments of geological inquiry. As might, therefore, 
 be expected, much has already been written on the 
 subject, and different theories have been advanced; 
 yet it is a sufficient stimulus to further investigation 
 that none of these theories have been approved by 
 any large majority, either of scientific geologists or 
 practical miners. 
 
 The first requisite in attempting to establish any 
 theory is to give a full view of the phenomena to 
 be accounted far, so far as they are known. 
 
STRUCTURE OF MINERAL VEINS. 5 
 
 Of the spaces in which the contents of mineral 
 veins are found, there are a great variety, both as 
 regards their form and position ; and names have 
 been given to them by miners, expressive of these 
 varieties, as Rake vein, Pipe vein, Flat vein, 
 Strings, &c. They may be classed under two gene- 
 ral heads the Fissuriferous Vein (or mineral fis- 
 sure), and the Tubular ( Tube vein), the first includ- 
 ing those which have the appearance of a fissure, 
 or rent in the strata, extending to a great length, 
 and generally to an unknown depth: the second, 
 those that have the form of an irregular tube or 
 perforation, either being nearly horizontal in one 
 stratum, or passing more or less obliquely from the 
 surface downwards, to an unknown depth. 
 
 OF THE FISSURIFEROUS VEIN, 
 
 OR MINERAL FISSURE. 
 
 Fissuriferous veins are the most prominent, and 
 the phenomena presented by them are the most 
 various and complicated. These veins, therefore, 
 demand particular attention, especially as the phe- 
 nomena have as yet been but partially exhibited, 
 and for many of them no rational explanation has 
 even been attempted. 
 
 The longitudinal course or bearing of these veins 
 or fissures is seldom, if ever, in a perfectly straight 
 line ; but, though crooked in detail, they, for the 
 most part, preserve in general a direct average 
 
 A 3 
 
O STRUCTURE OF MINERAL VEINS. 
 
 bearing through their whole course, as in Fig. 1 ; 
 yet occasionally considerable deviations take place 
 in the general bearing, as in Fig. 2. 
 
 As it regards the direction of veins, though 
 divided into two classes North and South veins, 
 and East and West veins, accordingly as their gene- 
 ral bearing approaches to these directions yet in 
 the same district variations are found running in 
 every possible direction. 
 
 The width of the vein or fissure is not uniform 
 throughout its whole length. Some veins, at suc- 
 cessive intervals, open out to a width of from two 
 or three feet to as many yards, and then contract 
 to a mere joint or crack in the strata, as in Fig. 3 ; 
 others continue with little variation in width 
 through their whole course. 
 
 The beginning or termination of a vein or fissure, 
 longitudinally, is seldom explored. Where this has 
 been done, the vein appears to commence at the 
 one end abruptly, and after continuing for a greater 
 or less distance in an entire state, it begins to send 
 out small veins, or strings, as the miners call them, 
 from either side, at acute angles ; and, finally, to 
 terminate, or be lost in a number of these strings, 
 as shown below. 
 
 The downward course of veins varies from the 
 perpendicular to an angle of 45 ; but their inclina- 
 
STRUCTURE OF MINERAL VEINS. *J 
 
 tion to the horizon, or hade, as it is commonly call- 
 ed, is not uniform. In an alternating series of 
 strata the hade is greater ; that is, the vein inclines 
 more towards a horizontal position in the soft strata 
 than in the hard, as shown in Fig. 5 ; and it some- 
 times occurs that the vein, in passing a stratum of 
 coal, or soft clay, takes the direction of the stratum 
 for a greater or less distance, as in Fig. 5 ; the 
 vein being much contracted, and sometimes almost 
 entirely disappearing, in this horizontal part of its 
 course. As the vein descends deeper into the earth, 
 where the strata, being under great pressure, are 
 harder, and where the strata differ less in induration 
 and density, the inclination or hade becomes less, 
 and more uniform. 
 
 Veins sometimes give off strings in their vertical 
 course, as well as in their horizontal ; and sometimes 
 a string of this kind goes off from the overlying 
 side of the vein, and returns into it again in the 
 form of a segment of a circle, as is shown below 
 at ABC. 
 
 The strata on one side of a vein are generally 
 found at a higher level than on the other : and most 
 frequently the underlying side is on a higher level 
 
8 STRUCTURE OF MINERAL VEINS. 
 
 than the overlying side, as in Fig. 5, &c. In this 
 case, if the hade or inclination is not uniform, as in 
 Fig. 4, but varies, as in Fig. 5, in an alternat- 
 ing series of strata, the vein has a greater width in 
 the hard strata, or those in which it has a more erect 
 position, than in the soft, where it is more in- 
 clined. 
 
 Sometimes, though rarely, it occurs that the 
 strata on the overlying side are on a higher level 
 than on the underlying ; and when the hade or in- 
 clination is not uniform, as in Fig. 6, but is vari- 
 able, as in Fig. 7> the ve ^ n & of greater width in 
 the soft strata, where it is more inclined than in 
 the hard, where it has a more erect position. 
 
 To distinguish these two kinds of fissuriferous 
 veins the former, or those which are more capa- 
 cious in the hard strata, may be called hard, or erect 
 Capacious Veins ; and the latter, which are more 
 capacious in the soft strata, may be called soft, or 
 inclined Capacious Veins. 
 
 This distinction is entirely new; and though, 
 perhaps, of little consequence as regards geological 
 science, it is of the utmost importance in mining. 
 The hard, or erect capacious veins, are by far the 
 most numerous, as well as the most productive of 
 metallic ores ; the soft, or inclined capacious veins, 
 being generally of a poor and deceitful nature, and 
 when productive of ore, it is not found in the same 
 strata as in the hard, or erect capacious veins. By 
 a due attention to these facts, an immense amount 
 
STRUCTURE OF MINERAL VEINS. 9 
 
 of the capital which has been thrown away in useless 
 trials might have been saved. 
 
 The strata forming the sides of the vein or fis- 
 sure are not only on a different level, but immedi- 
 ately adjacent to the vein they have a different 
 position, being bent upwards on the one side, and 
 downwards on the other, as shown in Fig. 8. 
 This may be called the bur of the vein. In some 
 veins the bur is very conspicuous ; but in others it 
 is partially or wholly obscured by the extensive 
 chemical, and mechanical changes which have taken 
 place in the rocks at the sides of the veins. 
 
 It is to be observed, that the above illustrations 
 apply only to the formation of the original fissure. 
 Both its form and capacity are very considerably 
 modified, as will hereafter be explained. 
 
 The bur, and throw or displacement of the strata, 
 as well as the capacity of veins, are found, with few 
 exceptions, to be greatest at or near the surface, 
 and gradually decrease in descending into the 
 earth ; and though a vein may never have been 
 traced so deep that the bur and throw wholly 
 disappeared, yet, from their regular decrease, it is 
 presumed there must be a point where they come to 
 nothing : whether the vein may terminate at the 
 same point, will probably for ever remain matter of 
 conjecture. 
 
 The bur and throw of veins, or the displacement 
 of the strata, are not to be conceived as an absolute 
 
 K 
 
 shifting of them, but the effect of a mechanical 
 
10 STRUCTURE OF MINERAL VEINS. 
 
 agitation of the particles of the strata on the one side 
 of the fissure different to that on the other, and also 
 to a different degree of pressure. 
 
 The structure of veins or fissures may be further 
 distinguished from the position which the strata 
 have near to them. 
 
 When the vein, Fig. 8, has the strata on the un- 
 derlying side rent upwards, and on the overlying 
 side rent downwards, it may be called a bur vein. 
 
 When the vein, Fig. 9 has the strata on the 
 underlying side on a higher level, and inclined to 
 it, as at H A and G F, and on the overlying side 
 on a lower level, and declining from it, as at A I and 
 F G, it may be called an overlying subsident vein. 
 
 When the vein, Figs. 10 and 11, has the 
 strata on the overlying side on a lower level, and 
 inclined to it, as at I A and G F, and on the under- 
 lying side on a higher level, and either having an 
 inclined or horizontal position, as at W A, Fig. 
 10, and H A, Fig. 11, it may be called an under- 
 lying subsident vein. 
 
 When the vein, Figs. 12 and 13, has the strata on 
 the overlying side on a lower level, and declining 
 from it, as at A J and / g, and on the underlying 
 side the strata on a higher level, and either horizon- 
 tal or declining from it, as at A W, Fig, 12, and 
 A H, Fig. 13, it may be called an underlying heave 
 vein. 
 
 When the vein, Figs. 14 and 15, has the 
 strata on the overlying side on a higher level, 
 
STRUCTURE OF MINERAL VEINS. 11 
 
 and either horizontal or declining from it, as at F V, 
 Fig. 14, and / g and a g, Fig. 15, and on the 
 underlying side on a lower level, and having a posi- 
 tion inclining to it, or horizontal, it may be called 
 an overlying heave vein. 
 
 In order to illustrate how this difference of width 
 or distance between sides of veins in different strata 
 takes place when they traverse an alternating se- 
 ries of hard and soft strata, let the straight line 
 A B C D E F, Plate 3, Fig. 16, be a rent, having 
 an uniform inclination or hade in both the hard and 
 soft strata. Then, if on the underlying side of the 
 fissure the strata are bent up over the points H 
 and G, and on the overlying side are bent down 
 over the points I and J, in this case, the sides of 
 the fissure will be in contact throughout ; that is, 
 in both the hard and soft strata, or in other words will 
 be mathematically divided. But if the vertical course 
 of the vent be inflected, as in Fig. 24, and hav- 
 ing the strata bent up on the underlying side, and 
 bent down on the overlying side, then will the sides 
 of the fissure be only in contact in those parts in 
 which it has the greatest inclination, that is, in the 
 soft strata. For if the point G be drawn into the 
 position a A, then the point m will be drawn into 
 b B ; the point n into c E ; the point o into e E ; and 
 the point/* into/F; and hence in the hard strata 
 A B, C D, and D E, will be formed the fissile 
 cavities w and s. 
 
 Again, if the fissure has a uniform inclination, as 
 
12 STRUCTURE OF MINERAL VEINS. 
 
 in Fig. 17, and the overlying side be moved down 
 from v' to V, or (which is the same thing) from U' 
 to U, in the line of direction of gravity, the sides of 
 it will be in contact throughout, that is, in both the 
 hard and soft strata, as has been shown in the case 
 of Fig. 16. But if the vertical course of the 
 fissure be inflected, as in Fig. 25, then the sides of 
 the fissure will only be in contact in those strata in 
 which it has the greatest inclination, that is, in the 
 soft ; as has been shown in the case of Fig. 24. 
 
 Again, if the fissures, as in Figs. 18, 19, 20, 
 and 21, have a uniform inclination, and their over- 
 lying sides on a lower level than the underlying, 
 then the sides of the fissures will be in contact 
 throughout ; that is, in both the hard and soft strata, 
 as has been shown in the case of Fig. 16. But 
 if the vertical course of the fissures be inflected, as in 
 Figs. 26, 27, 28, and 29, then will the sides only 
 be in contact in those strata in which the fissure 
 has the greatest inclination ; that is, in the soft 
 strata, as has been shown in the case of Fig. 24. 
 
 Again, if the fissures, as in Figs. 22 and 23, have 
 a uniform inclination, and the overlying side on a 
 higher level than the underlying, then will there 
 be formed between their sides the fissile gashes, or 
 chasms, s s, of uniform width from top to bottom, 
 provided the overlying side possesses such a degree 
 of rigidness as not to crush. But if the vertical 
 course of the fissures be inflected, as in Figures 30 
 and 31, then will the irregular formed cavity s w s, 
 
STRUCTURE OF MINERAL VEINS. 13 
 
 be produced between the sides of the fissures ; 
 the cavities being much larger in those parts which 
 have the greatest inclination, that is, the soft strata, 
 than in the hard, or those in which the fissure has 
 the most erect position. 
 
 An important consequence deducible from the 
 fact of veins having a more erect position in the 
 hard strata than in the soft, when they traverse an 
 alternating series of them, is, that in a homogeneous 
 mass of rock (such as the primary rocks) the ver- 
 tical course will be curvilineal. For the increase 
 of induration and density in a homogeneous mass 
 of rock cannot take place suddenly, but must 
 gradually increase with the depth below the surface ; 
 therefore veins in their downward course through 
 the primary rocks are bent or deflected in each 
 element of their route from the surface towards the 
 perpendicular, and hence must be more or less cur- 
 vilineal. So that if it be admitted that a difference 
 of level of the corresponding parts of rocks on the 
 opposite sides of the fissuriferous vein, be a gene- 
 ral property of it, then will veins in the primary 
 rocks have the following mechanical characters. 
 
 In order to illustrate the mechanical structure of 
 veins in the primary rocks, admitting the correspond- 
 ing parts of the rocks to be on different levels on 
 the opposite sides of them, and that their verti- 
 cal courses are curvilineal, let A B, Fig. 32, 
 be the vertical course of the vein ; then if the 
 rock on the underlying side is bent up, and on 
 
14 STRUCTURE OF MINERAL VEINS. 
 
 the overlying side is bent down, there will be formed 
 between the sides of the fissure the meniscous 
 shaped cavity s, the sides of it being in contact at 
 both the superior and inferior extremities of the 
 fissure. Then if veins in the primary rocks have 
 their corresponding parts on the overlying sides on 
 a lower level than on the underlying side, as is the 
 case with them in the secondary strata, there will 
 be formed between the sides of the fissures the 
 meniscous shaped spaces s s, &c., in each of the 
 Figs. 33, 34, 35, 36, and 37, similar to that of s in 
 Fig. 32. But in case the fissure has its overlying 
 side on a higher level than the underlying side, as 
 in Figs. 38 and 39, then will there be formed the 
 concave-shaped chasms s and s, which are open both 
 at the superior and inferior extremities. 
 
 Having, in the foregoing remarks, pointed out the 
 most obvious mechanical features of Fissuriferous 
 Veins, I shall conclude this description by referring 
 to a diagram which exhibits the phenomena which 
 they present in traversing the strata in the mining 
 district of Alston Moor. Plate 6 is a section of the 
 strata in the above district, from the top of the 
 Whin-sill to the top of the Fell-top limestone, in 
 which is presented the vertical course and mechani- 
 cal structure of a hard, or erect capacious vein, Fig. 
 
 40, and of a soft, or inclined capacious vein, Fig. 
 
 41, each having the strata on one side of it four 
 yards higher than on the other. The phenomena 
 which these veins present in traversing each stratum 
 
STRUCTURE OF MINERAL VEINS. 15 
 
 have been stated in treating of the general properties 
 of this species of vein. 
 
 Having described the structure of the fissuriferoirs 
 vein, I shall now point out the mechanical structure 
 of the common pipe or tulndar vein, the radiated 
 pipe vein, and the lateral embedded, or fiat vein. 
 
 In the common pipe or tubular vein, there are 
 two species, the embedded and the disruptive. The 
 former, or embedded, has a position conformable 
 with that of the stratum in which it is found, as in 
 Fig. 42 ; and the latter, or disruptive, has a 
 position more or less vertical, so as to pass through 
 the different strata, as in Fig. 43 : both this and 
 Fig. 42, being longitudinal sections of the vein. 
 
 The most prominent mechanical features which 
 the common pipe vein presents, are its zig-zag 
 longitudinal course and variable size, and also its 
 leaping off from its preceding course first to one side 
 and then to the other, in the most capricious manner. 
 The usual form of the embedded pipe vein is an 
 elongated ellipsoid, as in Fig. 44 ; and that of the 
 disruptive an irregular cylinder, as in Fig. 45, both 
 of which are sections across the veins. 
 
 The next order of vein is the radiated pipe vein, 
 Fig. 46. This vein appears to be composed of 
 the two preceding orders of veins, viz., the fissur- 
 iferous and the common pipe vein. It may either 
 be the result of the intersection of several short fis- 
 suriferous veins at one point, or it may be formed 
 by the rending of the circumscribing rock at the 
 
16 STRUCTURE OF MINERAL VEINS. 
 
 time of the formation of the common pipe vein. 
 The mechanical structure of this order of veins may 
 be studied by referring to what has been stated with 
 regard to the two preceding orders. 
 
 The last order of veins is the lateral embedded, 
 or flat vein. This vein is never met with but in 
 connection with some fissuriferous vein, and has 
 always a position conformable to that of the stratum 
 (most commonly limestone) in which it is em- 
 bedded. In order to illustrate the mechanical fea- 
 tures and connection of the flat vein with the 
 fissuriferous, let C D be a part of such vein 
 traversing the limestone stratum M N, Fig. 4/7; 
 then are the wedged-shaped cavities n o and p q on 
 the one side of the fissuriferous vein, and r s and 
 t v on the other, the lateral embedded, or flat 
 veins, extending to a limited but variable distance 
 from the fissuriferous vein. From what has been 
 stated of the flat vein, it is plain that it is not a regular 
 stratiform mass, as its length, breadth, and thick- 
 ness are variable, as, likewise, from its not always 
 being found to accompany the fissuriferous vein. 
 
SECTION II. 
 
 ON THE FORMATION OF THE FISSURES, OR 
 SPACES OF VEINS. 
 
 HAVING examined the principal features of the me- 
 chanical structure of veins, we are next, from these 
 data, to enquire by what kind of force such effacts 
 could be produced. It would not accord with the 
 limits or the object of this work, to enter into a 
 formal review of all the theories which have been 
 proposed to account for the formation of veins, but 
 it may be deemed necessary to notice a few of the 
 most popular. 
 
 Some geologists have entertained the idea, that 
 the rocks traversed by veins were in a humid state, 
 and that veins are cracks or rents formed by a dimi- 
 nution of their volume in drying. 
 
 That from desiccation and other causes of a dimi- 
 nution of volume, the strata might be separated 
 into blocks, or fragments, is beyond doubt. And 
 it is found that they are so divided by cracks, called 
 cutters, joints, or backs ; but the form and size of 
 these block?, and consequently, the direction, as 
 
18 FORMATION OF VEINS. 
 
 well as the number of the joints, varies in the dif- 
 ferent strata, each evidently following its own pecu- 
 liar law of consolidation, and there does not appear 
 to be any connexion between those which occur in 
 one stratum and those of another. How, then, can 
 we conceive that the cracks or joints in each stra- 
 tum, should happen to come so exactly under those 
 of the stratum immediately above, and should run 
 exactly in the same direction for miles, so as to 
 form a continuous fissure through a hundred beds 
 of different strata ? 
 
 Again, no crack or opening could take place in 
 any stratum, until it had attained such a degree of 
 rigidity, as would prevent it from yielding to the 
 superincumbent pressure ; for it is impossible that a 
 space could be formed in a mass under pressure, 
 while the compressing force was capable of causing 
 its molecules to move among themselves. And as 
 the strata are all under pressure, increasing from the 
 surface downwards, each stratum must have acquir- 
 ed a certain degree of induration, according to its 
 depth, before any space or open fissure could be 
 formed in it. 
 
 Hence, we might expect the rents to be much 
 more numerous, and more open near the surface 
 than below ; also larger and more numerous in the 
 hard strata, than in the soft. And this condi- 
 tion of the rocks corresponds exactly with that 
 which they assume from the joints or backs 
 
FORMATION OF VEINS. 19 
 
 before mentioned, which are altogether distinct 
 from the structure of mineral veins. But besides this, 
 a mere cracking of the strata Jrom desiccation, or 
 any other cause, will afford no explanation of the 
 bur, the throw, and others of the more striking 
 phenomena presented by mineral jveins. 
 
 Another idea entertained respecting the forma- 
 tion of veins, is, that they are cracks consequent 
 upon the subsidence of a mass of the strata, either 
 from the unequal yielding of the inferior parts, or 
 the withdrawal of some other support from beneath 
 them. Though the unequal resistance of the infe- 
 rior strata to the superincumbent pressure, while 
 the whole was in a humid state, might very naturally 
 account for the inequalities in the thickness of beds, 
 which so frequently occur, and also for their waved, 
 or undulating positions, yet neither that, nor the 
 sinking down of the strata from any other cause, 
 will account for the phenomena which veins present 
 in their mechanical structure. 
 
 A subsidence might cause a mass of the surface 
 to be detached, and to slide down, as is shown in 
 Fig. 4 ; but in this case, the difference between 
 the level of the strata on one side, and that of the 
 same strata on the other, that is, the throw of the 
 vein, would be the same from the top to the 
 bottom of the vein ; but this is not the case ; see 
 Fig. 5, a case of frequent occurrence, which could 
 never be explained on this supposition. 
 
 Another theory is, that by an expansion of the 
 
20 FORMATION OF VEINS. 
 
 interior parts of the earth, by heat or some other 
 cause, the crust of the earth has been forced 
 upwards, and thus cracked and broken. Then, as 
 the mechanical action of this upward pressure is 
 exactly the reverse of that considered in the last 
 paragraph, the same arguments will apply to both. 
 
 There are, indeed, fissures, or faults, which might 
 rationally enough be referred to a simple sliding 
 down of a mass of the strata on one side, or the 
 forcing of it up on the other ; but no motion of a 
 mass of the earth's surface, either upwards or down- 
 wards, can account for the existence of a point 
 (where the fissure lies in a stratum, see Fig. 5,) in 
 a vein where is no throw, while there is a throw 
 above and below that point. 
 
 Seeing then that no mere cracking of the strata 
 from desiccation, internal heat, or any other cause 
 of expansion, or contraction ; nor yet any sinking 
 down, or forcing up of the earth's. surface, will satis- 
 factorily account for the formation of the fissures 
 called veins ; the question arises, whether there be 
 any known force sufficiently powerful to produce 
 such, and the modus operandi of which corresponds 
 with the complicated phenomena to be explained. 
 
 Some of the phenomena, as the zig-zag nature of 
 the downward course of veins, the bur, as also several 
 others, and likewise the chemical changes which 
 have taken place in the adjacent rocks, bear a 
 striking analogy to the course and effects of a 
 powerful Electrical discharge ; and it is the 
 
FORMATION OF VEINS. 21 
 
 object of the following pages to show that such an 
 agency is competent to afford a fair and rational 
 explanation of the phenomena detailed in the pre- 
 ceding section, on the mechanical structure of 
 veins. 
 
 That the electric fluid pervades all material 
 bodies, and is extensively concerned in the opera- 
 tions of nature, has long been acknowledged. The 
 most brilliant of modern discoveries in chemistry 
 are those which have developed its influence in the 
 atomic combinations of matter; and attributing to it 
 the formation of the fissures or other spaces occu- 
 pied by the contents of mineral veins, would be but 
 another step in the generalization of its agency in 
 the economy of nature. 
 
 The way in which the electric fluid is accumu- 
 lated in the interior of the earth, and its discharge 
 effected, is an inquiry of great interest and import- 
 ance ; and in an attempt to explain it, the structure 
 of the earth's superficies must be first known. 
 
 The earth's crust is, for the most part, composed 
 of beds or strata, piled one over the other, of greater 
 or less thickness; and at the divisions between them, 
 or where one stratum ends and another begins, there 
 is always a thin layer of some soft, tenacious, and 
 flexible matter, having a laminated texture, the 
 prevailing constituents of which are clay, talc, and 
 mica, all of which are either very inferior, or non- 
 conductors of electricity ; so that these thin layers 
 will act as insulators to the dissimilar electric masses 
 
 B 3 
 
22 FORMATION OF VEINS. 
 
 of strata, in -which strata, particularly those near to 
 the surface, the electric fluid will be accumulated 
 until its intensity becomes so great at some point as 
 to burst asunder the insulating mediums. 
 
 On the eruption first occurring, large areas, or 
 even oceans, of the electric fluid would be sud- 
 denly liberated and brought into action, which 
 would rush through the rent with immense force 
 and violence, not only tearing the strata asun- 
 der, but also causing a violent vibration among 
 their particles ; and as the opposite sides of the 
 rent will be subject to a difference, not only of me- 
 chanical agitation of their particles, but also of 
 pressure, the one side will have its corresponding 
 parts depressed below that of the other, the diffe- 
 rence of level being greatest at the surface. 
 
 Having shown the way in which electro-mechanical 
 action may be brought into play in the interior of 
 the earth, I shall now proceed to show the most 
 striking analogies between the effects of a discharge 
 of electricity, and the phenomena of mineral veins, 
 considered in regard to their mechanical structure. 
 
 The effects of an electric discharge through an 
 imperfect conducting substance ar.e such as would 
 be produced by a material agent being ^driven 
 through it with great force and velocity, separating 
 the particles of the body in the line of its course, 
 thereby producing either a perforation, or a rent, or 
 both, according to the nature of the discharge and 
 of the substance. 
 
FORMATION OF VEINS. 23 
 
 The sides of veins, when undecomposecl, are 
 not in a ragged state, as if the strata had been 
 slowly and progressively torn asunder, but are, in 
 general, well defined, as if they had been split by a 
 sharp instrument, or by the instantaneous operation 
 of an immense impulse. 
 
 The course of an electric discharge through a sys- 
 tem of bodies of different conducting powers is in 
 a zig-zag direction, and leaping sideways at the se- 
 veral surfaces of junction of the bodies. 
 
 For as bodies of inferior conducting power oppose 
 greater resistance to its passage through them than 
 those of superior conducting power, therefore in 
 passing out of a body of superior into one of infe- 
 rior conducting power it will be deflected outwards 
 from the line of its previous route when the plane 
 of position of the bodies is not perpendicular to the 
 route of the electricity ; but in passing out of a 
 body of inferior into one of superior conducting 
 power, it will be bent inwards from the line of its 
 previous route: for the momentum of impulse of 
 the discharge may be resolved into two forces one 
 acting in the direction of the plane of separation of 
 the compound conductor, the other perpendicular 
 to that plane consequently the greater the differ- 
 ence in the conducting power of the parts of the 
 compound conducting body, the greater will be the 
 inflections in the line of the route of the electricity. 
 This property of electricity is exemplified in the 
 crooked course of lightning through the air, and in 
 
4 FORMATION OF VEINS. 
 
 its irregular and seemingly capricious route when it 
 strikes buildings, &c. 
 
 To apply this to the course of veins. The cal- 
 careous strata being earthy salts, are better con- 
 ductors of electricity than the siliceous ; and the 
 siliceous are in general better conductors than the 
 argillaceous. And each of these species of strata 
 have their conducting power increased in some cer- 
 tain ratio to the increase of their induration. It 
 has been observed, page 7> that in an alternating 
 series of beds of limestone, sandstone, and shale, 
 or plate, the veins have a more correct position in 
 the limestone (hard), than in the sandstone (softer), 
 and also more correct in the sandstone than in the 
 plates (softest) ; it appears, therefore, that the zig- 
 zag character of the vertical course of veins through 
 an alternating series of strata of different conducting 
 powers, is exactly similar to the course of electricity 
 under similar circumstances. Another cause which 
 would concur with the difference in the conducting 
 powers of the strata to produce the inflected condi- 
 tion of the vertical course of veins, is that of a dif- 
 ference of their electric state the shales, or plates, 
 being, for the most part, positive as regards the 
 sandstones, and the sandstones positive as regards 
 the limestones. 
 
 Again, veins have a greater inclination in strata 
 
 'which are near the surface, than they have in the 
 
 same, or similar strata at a greater depth ; and in a 
 
 homogenous mass of rock of great thickness, such 
 
FORMATION OF VEINS. 25 
 
 as the clay, slates, &c., a vein in its downward course 
 is deflected towards the perpendicular in each ele- 
 ment of its route, its course being curvilineal : 
 the nature of the curve depends on the increase 
 of induration, which is in exact accordance with the 
 law, that the conducting power of rocks increases in 
 some certain ratio with their increase of induration 
 and density. 
 
 The passage of electricity produces an expan- 
 sion of the parts of a body in the line of its route. 
 When a discharge is sent through a card, the edges 
 of the perforation are bent or burred, the part form- 
 ing the margin of the perforation being expanded ; 
 and, consequently, forced outwards, and the protru- 
 sion is always greater on the side of the card next to 
 the negative pole. If the discharge be sent through 
 a quire of strong paper, the amount of the effect will 
 be found to be different at different depths from the 
 surface. One edge of the perforation being burred 
 in one direction, and the other edge being burred 
 in the opposite direction, as if it had been made 
 by drawing two threads through in opposite direc- 
 tions. 
 
 These effects bear a striking resemblance to the 
 bur of veins ; and a little further consideration will 
 suffice to shew, that the throw and displacements of 
 the strata, in the neighbourhood of veins, may be 
 accounted for on this principle. It appears that the 
 immediate effect of a discharge of electricity through 
 a substance, is to excite a commotion among the 
 
26 FORMATION OF VEINS. 
 
 particles of the substance in the line of its route; and, 
 consequently, to cause an expansion and displace- 
 ment of the parts relatively to each other. The 
 magnitude of the effects of this action from an equal 
 discharge, will vary considerably in different sub- 
 stances, being greatest in those of small conducting 
 power. Suppose a violent commotion and expan- 
 sion of this kind to have taken place in the rocks, 
 forming the immediate walls of veins at their forma- 
 tion, it is evident that the parts thus expanded, 
 and occupying a greater space, must have been 
 forced out of their former position in one way or 
 another ; and this would necessarily give rise to a 
 bending of rocks in opposite directions, they being 
 raised up on the one side of the fissure, and thrust 
 down on the other, which is in exact accordance 
 with the phenomena they present. 
 
 Another phenomenon, accompanying the pas- 
 sage of electricity through bodies of low conduct- 
 ing power, is the evolution of heat, which is a 
 phenomenon that veins frequently present in their 
 walls. 
 
 In order to shew the relative proportion of the 
 compressing force exerted on the overlying side, to 
 that on the underlying side, when the fissure has not 
 an erect position ; 
 
 Let A B D C (see the accompanying Diagram,) 
 be a fissure ; and A, b, d, f, and h, five points at dif- 
 ferent depths in it ; then, at the point h the total 
 pressure will be g h ; at the point f, ef; at the 
 
FORMATION OF VEINS. 
 
 point d,cd; at the point &, a b ; and at A, no 
 thing. 
 
 p g e c a AC 
 
 B//D 
 
 But as the direction of the pressure is oblique to 
 the vertical course of the fissure, it may be resolved 
 into two forces, the one acting vertically, and the 
 other horizontally ; or on the plane C D. Then, 
 if there be drawn g q, e p, c o, and a n, each per- 
 pendicular to the plane of the fissure A B, and there 
 also be drawn q z, p y> ox, and n x, each parallel to 
 A <?, or the horizon. Then from the law of the re- 
 solution of forces, z k will be the part of the total 
 pressure g k, acting on the overlying side A B G F, 
 at the point h ; and #/will be the part of the total 
 pressure e f, acting on the same at the point// 
 and in like manner, will x d and w b be the respective 
 parts of the total pressures c d and cib, acting on the 
 same side at the points d and b. Again, in agree- 
 ment with the law of the resolution of forces, will 
 z g be the part of the total pressure g h> acting on 
 
28 FORMATION OF VEINS. 
 
 the underlying side at the point h ; and y e will be 
 the part of the total pressure e f acting on it at 
 the point f; and, likewise, will x c and w a be the 
 respective parts of the total pressures c d and a b, 
 acting on it at the points d and b. 
 
 Consequently, if the total pressures g h 9 &c. be 
 the diameter of a circle, the compressing force acting 
 on the overlying side is to that acting on the underly- 
 ing side, at any point, as the versed sines of the 
 angles which the plane of the fissure makes with 
 the horizon, viz., as the versed sine of the angle 
 E C D is to that of the angle FAB. Hence, 
 the reason why the strata on the overlying sides of 
 veins, are (with few exceptions) on a lower level 
 than on the underlying side ; also, why the throw 
 of veins, or the difference of level in the correspond- 
 ing strata on the opposite sides of them, are variable ; 
 generally decreasing progressively as the depth in- 
 creases. 
 
 Having examined the most striking analogies 
 between the effects of electricity, and the mechani- 
 cal structure of the fissuriferous veins, the tubular 
 or pipe veins are next to be considered. 
 
 The difference of structure between the fissuri- 
 ferous and tubular, or common pipe vein, may be 
 explained from the nature of the electric discharge 
 being different at their formation, the formation 
 of the first being the result of the discharge taking 
 place from a large surface ; the latter, to its taking 
 place from a point. For when electricity is dis- 
 
FORMATION OF VEINS. 29 
 
 persed over a large surface, and a discharge takes 
 place from it, the body is rent, and the direction of 
 the fractures is generally rectangular to each other ; 
 as for instance, when the electricity forces a passage 
 for itself through the substance of an over-charged 
 jar, or a plate of glass ; but if the discharge is effected 
 by a point, a perforation is produced ; if, however, 
 the discharge from the point be not effectually 
 restrained from dispersion, (by some non-conduct- 
 ing substance, as oil, resin, &c.) the perforation 
 will have a number of small fractures proceeding 
 from its margin. Therefore, according to the man- 
 ner in which the discharge is produced, we will 
 have, as the effect, a fracture, or the fissuriferous 
 vein ; a simple perforation, or the common pipe vein ; 
 or a splintered perforation, or the radiated pipe 
 vein. 
 
 Another phenomenon, which the two latter spe- 
 cies of vein present in their structure, analogous to 
 the mechanical effects of electricity, is the twisted 
 character of their longitudinal courses, like that of a 
 corkscrew. 
 
 The last species of vein, the formation of which 
 is to be considered, is the lateral, embedded, or flat 
 vein. The position and connexion of this vein 
 with the fissuriferous is strikingly analogous to 
 what, in electrical science, is called the lateral dis- 
 charge, viz., to the tendency which a high charge 
 of electricity has to diverge, or spread out side-wise, 
 when circumstances admit of it, from the direct line 
 
30 FORMATION OF VEINS. 
 
 of its route ; more particularly, when much ob- 
 structed in its passage.* 
 
 I have thus pointed out the most striking analo- 
 gies which subsist between the mechanical effects 
 of electricity, and the phenomena which mineral 
 veins present in their structure, in both the second- 
 ary and primary strata ; and the resulting pheno- 
 mena in both are so exactly similar, or perfectly 
 identical, to those of electricity, as to lead to the 
 conclusion, that the formation of the spaces, which 
 the contents of veins occupy, is the effect of elec- 
 trical agency. 
 
 But if any other argument were wanting to establish 
 the electrical theory of the formation of mineral 
 veins, it is furnished by the fact, that there is no 
 other single known agent in nature, whose power 
 and mode of action are competent to the production 
 of the vast and complicated phenomena which veins 
 present in their mechanical structure. 
 
 It may not be amiss, in this place, to notice some 
 other geological phenomena connected with the pre- 
 sent inquiry, which may be explained in a more 
 
 * In the limestone strata, at least at the random, or position in 
 which the flats occur, the limestones in those parts are of a 
 cavernous character and columnar texture, while above and be- 
 low the flat beds they have always a laminated and compact 
 texture. In those limestones in which this property is 
 wanting, there have not as yet been any flats discovered ; but 
 there are instances of this property in limestones where no flats 
 occur. 
 
FORMATION OF VEINS. 31 
 
 satisfactory way from electrical agency, than from any 
 other cause. 
 
 The fact which first presents itself to notice, is the 
 occurrence of the short, devious, and thin veins, so 
 common in limestone and other strata. That these 
 small calcareous sparry veins in limestone strata, 
 may have been the result of a disturbance in the 
 electrical equilibrium of the limestone in its progress 
 of consolidation, is at least highly probable, and 
 easily comprehended. And in no way can the crys- 
 talline and sparry texture of veniform masses, en- 
 veloped in rocks, be so satisfactorily explained as 
 from electro-molecular action. 
 
 Another fact worthy of notice is the broken, 
 twisted, expanded, and bulged condition of the strata 
 in particular parts, more especially the coal strata. 
 
 This condition of the coal and accompanying 
 strata, is, I believe, generally called by colliers 
 a shake, or broken. This shake is not an actual 
 breach or separation in the strata, but a kind of 
 lineal space, of more or less width, in which the 
 coal and other strata are 'in a bruized, expanded, and 
 bulged state, and having the strata close to it fre- 
 quently tilted out of their regular position. Another 
 form of this shake is, that, for a limited circular space, 
 the strata are in a twisted, broken, and mingled con- 
 dition. In both these shakes, the condition of the 
 strata in general very much resembles the effect 
 produced in a piece of rather dry clay, through 
 which an electrical discharge has been sent. Then, 
 
32 THE CONTENTS OF VEINS. 
 
 since the lineal shake may be called a kind of im- 
 perfect fissuriferous vein, so may the circular shake 
 he called a kind of imperfect disruptive pipe vein. 
 
 SECTION III. 
 
 ON THE REPLETION, OR FORMATION OF THE 
 CONTENTS OF MINERAL VEENS. 
 
 Having, in the two preceding sections, explained 
 the mechanical structure and formation of the spaces 
 which the contents of veins occupy, the next subject 
 of inquiry is, by what agency and modus operandi 
 the repletion, or formation of the contents of veins 
 has been effected. 
 
 The contents of veins may be divided into two 
 classes, the Transmutive and the Foreign. 
 
 The first includes riders, douks, and other sub- 
 stances, which appear to have been formed from the 
 rocks formerly occupying the place where they are 
 found, by a process of decomposition, or impregna- 
 tion. 
 
 The second includes clays, spars, metallic ores, 
 and substances, the appearance of which denotes 
 them to be the result of subsequent mechanical 
 and chemical deposition. 
 
 First, of the transmutive contents of veins, riders, 
 douks, &c. 
 
THE CONTENTS OF VEINS. 33 
 
 By the term rider, is to be understood a part of 
 the rock forming the sides or walls of veins ; the 
 nature and appearance of which have been changed 
 in consequence of its oxidation, and impregnation 
 with some metallic oxide, or salt, or other substance, 
 whereby both its colour and induration are rendered 
 more or less different from that of the rock in its 
 native state. The metal with which the rocks 
 forming the walls of veins are most frequently im- 
 pregnated, is the oxide and different salts of iron ; 
 occasionally, however, a rider impregnated with zinc 
 is found where that metal prevails. There are four 
 different kinds of riders, the grey, the brown, the 
 black, and the red, which difference of colour is 
 probably owing to a difference in the oxidation 
 of the iron, &c. The rocks most susceptible of 
 being converted into riders, are those of a calcare- 
 ous character ; next to them are the siliceous, and 
 least of all, those of an argillaceous nature. In 
 general, the dark grey rider is the hardest, viz., when 
 the rock is impregnated with the silicate of iron ; 
 next to it in hardness is the brown rider, when it is 
 impregnated with oxide or salts of zinc ; then the 
 black, when it is impregnated with the black oxide 
 of iron ; the red always being the softest, is formed 
 by the rocks being impregnated with the red oxide 
 or carbonate of iron. 
 
 By the term douks, is to be understood a part of 
 the rock, forming the walls or sides of veins, which 
 has been changed in its nature and appearance from 
 
 c 
 
4 THE CONTENTS OF VEINS. 
 
 decomposition, and is in such a soft state as will 
 form a paste with water, without having to be 
 pounded; therefore the douks will have various 
 colours and character, according to the kind of 
 rock of which they are formed* and the elements 
 abstracted from it, which are generally siliceous. 
 The rocks most susceptible of such decomposition, 
 or of being converted into douk, are those whose 
 base is of an argillaceous nature. 
 
 Second, of the Foreign Contents of Veins, 
 Clays, Spars, Metallic Ores, &c. 
 
 By the term clay, is to be understood all those 
 soft pasty substances which are the result of mecha- 
 nical deposition ; of course this soil will differ in its 
 character according to the nature of the deposition, &c. 
 
 By the term spar, is to be understood all those 
 earthy and alkaline mineral substances which assume 
 some regular determined figure, and have a crystal- 
 line texture. These mineral substances are very 
 numerous ; the most common are quartz, calcareous 
 and fluor spar ; the external characters of which are 
 generally so well known, as to need no particular 
 description in this place. 
 
 By the term ore, is to be understood metals in 
 a state of union with sulphur, carbon, oxygen, &c., 
 which assume in general some regular figure, and 
 have also a crystalline texture. 
 
 There are not any mineral substances that exclu- 
 sively belong to any particular species of vein, they 
 being found indifferently in all. 
 
THE CONTENTS OF VEINS. 5 
 
 / 
 
 It has already been shewn, that a discharge of 
 electricity is the most rational mode of accounting 
 for the phenomena which the spaces occupied by 
 the contents of veins present, in regard to their me- 
 chanical structure, &c. It will now be assumed 
 that electricity, in its galvanic form, is the agent 
 employed by nature in effecting the changes in the 
 rocks by which the transmutive contents of veins 
 are formed, and also that by which the foreign con- 
 tents have been selected, carried to, and arranged 
 in those spaces ; and the same systematic mode of 
 proof will be employed as in the former case. 
 
 The first fact assumed to account for the reple- 
 tion of mineral veins, is, that the electric fluid per- 
 vades and penetrates the earth, more particularly 
 those parts near to the surface. It is an acknow- 
 ledged fact in the science of electricity, that the 
 electric fluid is capable of moving through either 
 the pores or actual substance of all material bodies, 
 with greater or less facility according to their con- 
 ducting powers. And the fact of the magnetic 
 effects resulting from the experiments of Dr. Bar- 
 low, in coiling wires round an artificial sphere, and 
 passing currents of electricity through them, being 
 exactly similar to those of terrestrial magnetism, 
 renders it highly probable that electrical currents do 
 actually circulate in the different parts of the earth, 
 more particularly in its external layers. 
 
 In what way electrical currents are generated 
 and set in motion in the rocky substances forming the 
 
 c c > 
 
36 THE CONTENTS OF VEINS. 
 
 crust of the earth, is an enquiry of great importance 
 and difficulty ; and, consequently, various opinions 
 have been advanced on the subject, but no very 
 clear and satisfactory explanation has been given of 
 it the opinion of some philosophers being, that 
 they are generated by solar influence ; others, that 
 they proceed from the rotation of the earth on its 
 axis : and others, that they result from a chemical 
 action going on in the interior of the earth, more 
 particularly near to its surface. 
 
 It being a fact that galvanic currents are gene- 
 rated and set in motion by combinations of various 
 substances, besides those of a metallic nature ; and 
 as the external parts of the earth are disposed for 
 the most part in beds, or layers of different 
 kinds of rock, piled one over another ; it is there- 
 fore assumed, that under this condition of its sur- 
 face, the strata will form a galvanic pile or battery, 
 giving rise to various local accumulations, and cur- 
 rents of electricity, the energy of which will depend 
 on the nature and superposition of the strata, and 
 the conducting power of the medium uniting the 
 poles of the battery. 
 
 The order of superposition of the strata in 
 Alston Moor and neighbourhood, being, with few 
 exceptions, exactly similar to the arrangement of 
 the elements in the galvanic pile of Volta, a sec- 
 tion of this district, as the strata actually occur, 
 is given in Plate 6. In this section, the hazles 
 or siliceous strata may be taken to represent the 
 
THE CONTENTS OF VEINS. 37 
 
 wetted card ; the limestone or calcareous and 
 coaly strata the plate of one metal ; the plate beds 
 or argillaceous strata the other plate of metal 5 
 and the water or other conducting substances filling 
 the fissures, the uniting wire by which the circuit 
 is completed. The electrical currents, in circulat- 
 ing through the strata, will take their route through 
 the fissures ; as, immediately on their formation, 
 they would, at least near the surface, be filled with 
 water, which is a much better conductor of electri- 
 city than the strata. And it being a general law 
 when the electric equilibrum is disturbed, and there 
 are open for the fluid several different routes, that it 
 always takes the best conductors, although the course 
 through them be more circuitous. 
 
 Therefore, from the positive pole, or strata 
 which are in a positive electrical state, there will 
 be a current of electricity flowing from them into 
 the fissure ; and from the fissure into the negative 
 strata or pole. Hence, wherever chemical decom- 
 position is the result of the currents thus generated, 
 and circulating through the strata and in the fissures 
 traversing them, the elements in union with the 
 currents will be deposited in such open parts of the 
 fissure as are in accordance with the peculiar law of 
 their relative electrical states. 
 
 In referring the spaces which the contents of 
 veins occupy to perforations, fissures, &c., it is to 
 be borne in mind that, in their original condition of 
 perforations and fissures, as in Plate 6, they were 
 
 cS 
 
38 THE CONTENTS OF VEINS. 
 
 mere fractures ; and that their present size, and the 
 condition of the rocks forming their walls, are the 
 result of the electric power communicated to the 
 walls at their formation, from the rocks being forci- 
 bly and suddenly torn asunder, and the electrical 
 currents subsequently circulating in them, the 
 effects of which would be the disintegnation, de- 
 composition, or impregnation of the walls. 
 
 The objection brought against the idea of veins 
 having been perforations, fissures, &c., however nar- 
 row they might be at their formation, from the impos- 
 sibility of such perforations and fissures being kept 
 open, may be answered by the fact that the strata, 
 particularly the harder, are divided by joints or 
 cutters into a multitude of blocks, and that in many 
 cases, the joints or cutters are found quite as 
 large in width as the original size of veins appears 
 to have been where there has been no mechanical 
 or chemical change effected in their walls. Those 
 joints or cutters are always either empty, or only 
 filled with a soft clay, which can be of no service 
 as a support to their sides. It is also a fact, that 
 veins appear only to have remained open in those 
 strata, or parts of them, in which they have an 
 erect position ; while in those strata or parts in 
 which they have a great slope, or hade, the sides are 
 always found to be in contact. 
 
 It is not a necessary condition of the theory here 
 advanced for the repletion of veins, that the spaces 
 which their contents occupy were, in their primitive 
 
THE CONTENTS OF VEINS. 39 
 
 state, of the size in which they are now found ; but 
 that they were in their primary state fractures, in 
 which the separated parts have not been re-united 
 or healed up, whether the walls were in contact or 
 not ; nor that they have, subsequently to their form- 
 ation, been opened by any slow and progressive 
 mechanical force to their present size, but their en- 
 largement, and the changes which the rocks forming 
 their walls have undergone, are the result of electro- 
 chemical agency. 
 
 From whence the metals and other substances 
 filling veins were originally derived, is, like all en- 
 quiries into the origin of things, inexplicable. But as 
 the metallic ores occur disseminated in many rocks, 
 particularly in those at a considerable depth below the 
 surface, it is highly probable that the immediate 
 source from which they are conveyed into the veins is 
 the rocks in the substance of which they exist, either 
 mechanically mixed or chemically combined. 
 That the intermediate sources from which the 
 metallic ores, &c. filling veins are derived, are 
 the enclosing rocks, is to be inferred from the 
 fact, that when veins traverse an alternating series 
 of strata, the strata forming the sides of veins, 
 in many cases, both above and below a stra- 
 tum in which they have been found productive, 
 appear to have always been in close contact, so as 
 to prevent their having been filled, either by infil- 
 teration from above, or by injection from below. 
 It is also further to be inferred, from the fact of 
 
40 THE CONTENTS OF VEINS. 
 
 strata in which veins are productive alternating with 
 those in which they are completely barren they 
 being generally productive in the strata in which 
 they have an erect position, and barren in those in 
 which they have a great inclination or hade : there- 
 fore the contents of veins are either derived from, 
 or very intimately connected with, the nature of the 
 rocks which they traverse. 
 
 Since every known substance, either aeriform, 
 liquid, or solid, can be reduced in bulk by pres- 
 sure,, it follows, that the particles or atoms of all 
 bodies are not in actual contact, but are separated 
 by pores or interstices, of greater or less size ac- 
 cording to the state in which they exist ; then, as 
 the particles, even of solid bodies, are not in actual 
 contact, it is conceived that their pores, or the in- 
 terstices, must be filled up with some highly elastic 
 fluid (as caloric, or electricity, or both) ; for it is 
 inconceivable how the molecules of matter can act 
 upon each other without some medium of commu- 
 nication to connect them together. 
 
 From the mobility of gases and liquids, we are 
 prepared to admit of their particles changing their 
 relative positions among themselves, and situations 
 in space ; their molecules being in perpetual mo- 
 tion among themselves, not only from impressed 
 forces, but also from their ever-varying state as to 
 temperature and electrical condition. But it is not so 
 easily to be conceived, that the like motions should 
 be induced among the molecules of solid substances 
 
THE CONTENTS OF VEINS. 41 
 
 by these agencies, where the particles appear (to 
 the senses) to be absolutely fixed ; yet as the par- 
 ticles of solids are not in actual contact, it must 
 be admitted that even the molecules of solid sub- 
 tances must be ever changing their relative posi- 
 tions among themselves, and also their situation in 
 space when operated on by forces such as those 
 above stated, possessing a greater intensity. 
 
 It is found in all subterraneous operations (as min- 
 ing) where the rocks in which excavations are 
 made are soft, but so tenacious as not to crush, 
 that the excavations diminish very rapidly in size, 
 so as to become a measureable quantity in a short 
 time, and that even the hardest rocks through which 
 subterraneous operations have been carried, are 
 found to diminish in size in long periods of time. 
 Now this gradual diminution in the size of excava- 
 tions made in rocks, cannot take place except 
 through an intestine motion among the particles of 
 the rocks, changing not only their relative positions, 
 but also their situations in space. The extent to 
 which this motion in the particles of the rocks may 
 be communicated, it would be difficult to assign 
 limits to. 
 
 Heat appears to have great influence in modify- 
 ing the arrangement of the particles of solid bodies 
 as it in many instances dissolves the existing ar- 
 rangement of the particles, and gives to them a 
 new one, without destroying the integrity of the 
 bodies as a whole. It is "found that prismatic 
 
THE CONTENTS OF VEINS. 
 
 crystals of sulphate of nickel, exposed to a sum- 
 mer's sun in a close vessel, had their internal struc- 
 ture so completely altered without any external 
 change, that when broken open, they were compos- 
 ed internally of octahedrons with square bases. 
 Now the original aggregation of the internal particles 
 had been dissolved, and a disposition given to 
 arrange themselves in a crystalline form."* Crystals 
 of sulphate of magnesia and sulphate of zinc, 
 gradually heated in alcohol till it boils, lose their 
 transparency by degrees, and when opened are 
 found to consist of innumerable minute crystals, 
 totally different in form from the whole crystals ; 
 and prismatic crystals of zinc are changed in a few 
 seconds into octahedrons by the heat of the sun. 
 Other instances might be given of the influence of 
 even moderate changes of temperature in modifying 
 molecular attraction in the interior of substances. 
 
 That the contents of veins and other mineral 
 substances can be dissolved and transferred, may be 
 inferred from the fact of substances being found in 
 the moulds, and taking the form of the moulds whose 
 crystallization is different to that of the substance of 
 the models. There are many instances where the 
 first-formed substance on the sides of the vein is 
 fluate of lime, and the second quartz, and hence 
 this second formation at its base, taking the form 
 of crystallization of the first, or fluor spar, and vice 
 
 * Connexion of the Physical Sciences, by M. Somerville. 
 
THE CONTENTS OF VEINS 43 
 
 versa. That where the spaces which the crystals of 
 the first formation had occupied are found empty, 
 and in others either partially or entirely filled with 
 a third substance, having the form of the mould of 
 the first, or removed substance, points out clearly 
 the dissolution and transference of mineral sub- 
 stances. Then, as we meet with cavities having a 
 peculiar form in veins, but empty, and know that 
 bodies having the form of these cavities do exist in 
 the vicinity where the cavities are found, we natural- 
 ly infer that the cavities are the result of these 
 models ; but when it is considered that specimens 
 are frequently found having exactly the same form- 
 ation, but from which the model has not been 
 removed, the inference is established beyond doubt. 
 The dissolution and transference of material atoms 
 is further proved from the various casts of animal 
 and vegetable remains found in the rocks from which 
 the animal and vegetable matter has been removed, 
 and its place supplied by mineral matter. 
 
 It has been proved by innumerable experiments 
 on bodies, both in solution and fusion, that the 
 chemical affinity is only a consequence of the 
 electric condition of the particles, or atoms of 
 bodies, and that their composition and decomposi- 
 tion are the result of electrical agency. 
 
 Therefore, it is highly probable that no portion 
 of inorganic matter is in a perfect state of rest, 
 but that its molecules are not only perpetually in 
 motion among themselves, but are constantly chang- 
 
44 THE CONTENTS OF VEINS. 
 
 ing their situations in space ; which perpetual 
 molecular motion in matter, presents to us the con- 
 stitution of solid bodies quite in a new light ; even 
 the particles in them obeying the various laws of 
 chemical affinity, electical attraction, polar concre- 
 tion, &c. The immediate tendency of these 
 chemical, electrical, and polar forces, is to occasion 
 like particles to separate from the general mass, 
 and to group together in more homogenous por- 
 tions, such as regular crystalline masses, definite 
 layers, nodular concretions, &c., assuming it as 
 admitted that the strata, in consequence of their 
 order of superposition, form a galvanic pile or bat- 
 tery, in which there is a development of electricity, 
 the currents of which traverse the fissures which 
 cut through the rocks, and that mineral substances 
 can be disolved, transferred, and recombined 
 in various ways by electrical agency. I shall now 
 proceed, from these data, to explain the mode in 
 which the repletion of veins has been effected. 
 
 It is not to be inferred, from what has been 
 above stated, that the electric action is continued 
 through a whole series of alternating strata ; for it 
 may be confined to a small number of them. And 
 I am strongly persuaded, from many observations 
 on the conditions of veins in different strata, 
 that in many cases certain classes of strata, and 
 the parts of the fissures contained in them, 
 have exclusively their own electrical conditions 
 and currents circulating in them. 
 
THE CONTENTS OF VEINS. 45 
 
 It is a well attested fact, that the surfaces of sub- 
 stances in general, from which electricity is evolved, 
 or is positive, have their attraction of aggregation 
 destroyed, or are chemically dissolved, as is the case 
 with the zinc in our common batteries. It is also 
 a well-attested fact, that the surfaces of substances 
 in general into which electricity is entering, or is 
 negative, are precipitating and aggregating surfaces, 
 as is the case with the copper in our common bat- 
 teries ; not even the most solid aggregates, nor 
 firmest compound bodies, being capable of resisting 
 the dissolving action of a current of electricity. 
 Its operation may be slow, but the results are cer- 
 tain ; and sooner or later, all compound bodies 
 are, by its agency, resolved into their elemental 
 form. 
 
 That veins possess some peculiar power in de- 
 termining to, and retaining the metals, spars, &c., 
 filling them, may be inferred from the fact, that the 
 joints, or cutters of the strata, never contain any of 
 the vein substances, even when they are open, and 
 directly communicate with the veins. Had not the 
 veins possessed some attractive action for, and re- 
 straint over, the substances filling them, we should 
 certainly have met with some instance of the vein 
 matter being deposited in the cracks or joints by 
 which the strata are divided into blocks. Nor can 
 it be said that these joints, &c. have been formed 
 subsequently to the formation and filling up of the 
 veins, as the nature and quantity of the contents 
 
46 THE CONTENTS OF VEINS. 
 
 of veins are in many instances greatly modified by 
 the joints, &c., at their junction with the veins ; 
 while in some cases they pass straight through 
 the veins, without suffering any interruption. 
 
 In case any stratum, or class of strata, which a 
 fissure traverses, is in a positive electrical state, or 
 evolving electricity, and a contiguous stratum or 
 class of strata is in a negative state, or absorbing 
 electricity, and the fissure traversing them be filled 
 with water or other conducting medium ; then, 
 whenever electro-chemical action is in operation, 
 the elements separated from the strata forming the 
 positive walls of the fissure will be carried into that 
 part of it in which the enclosing strata forming the 
 walls are negative, and there deposited, and viceversa; 
 then, as has been already observed, the plate beds 
 being generally positive in regard to the sandstones, 
 and the sandstones positive in regard to the lime- 
 stones, hence the currents in general will be from 
 both the plate beds and sandstones towards the lime- 
 stones, and from the plate beds towards the sand- 
 stones singly ; which direction of the currents, as a 
 consequence of theory, is in exact accordance with 
 the phenomena presented by the walls of veins in 
 these strata; the walls of veins in the plate beds 
 being generally in a decomposed or douky state ; 
 the walls in the sandstones exhibiting the mixed 
 conditions of impregnation and decomposition ; and 
 the walls in the limestones most generally present- 
 ing the condition of impregnation alone. 
 
THE CONTENTS OF VEINS. 47 
 
 As the plates or shales generally have dissemi- 
 nated in them both iron and zinc, a portion of them 
 will be eliminated ; and when they are in solution, 
 will be strongly determined to the negative pole or 
 rock ; hence the reason of the walls of veins in the 
 limestones being in general impregnated with these 
 salts, or converted into riders ; the walls of veins in 
 the sandstones being occasionally the same. 
 
 And as the metals in general are found dissemi- 
 nated in the rocks, and when in solution are electro- 
 positive, they will be determined to the negative 
 rocks, and there precipitated, together with such 
 other substances as may be eliminated along with 
 them. In case the rock be highly electro-negative, 
 the walls of the vein will be much ridered, and the 
 metals, &c. more or less blended or disseminated 
 in the rider : but if the rock be only moderately 
 electro-negative, the walls will only be in a slightly 
 ridered state, and the metals, &c. precipitated, ad- 
 hering to them in plates or ribs. 
 
 If one side of a fissure in any stratum be in a 
 positive electrical state, or evolving electricity, and 
 the other negative, or absorbing electricity, and the 
 fissure be filled with a fluid, as water, with which the 
 upper strata usually abound, then this arrangement 
 is exactly similar to the simple galvanic circle, in 
 which case chemical action would be brought into 
 play. Should the water, &c. filling the fissure, hold 
 alkaline, earthy, or metalic salt in solution, the so- 
 lution would be decomposed, and the metal, &c., 
 
48 THE CONTENTS OF VEINS. 
 
 precipitated on the negative wall, and the oxygen, 
 &c. on the positive. 
 
 With regard to the depth to which the walls of 
 veins are changed in their nature from the enclosing 
 rocks, it may be said generally to be from three to 
 four feet, and very rarely to exceed ten. In the 
 primary rocks the changes produced in the walls of 
 veins appear to extend to greater depths into the 
 rocks than in the secondary strata ; and where they 
 are decomposed, the matter eliminated is generally 
 the siliceous, the argill being reduced to douk, or 
 clay. 
 
 In order to illustrate, in as clear a manner as the 
 complicated nature of the subject will admit, the 
 seemingly-capricious disposition of the contents of 
 veins, as presented to us in the operations of min- 
 ing, I shall state a few general laws of electrical ac- 
 tion by which the phenomena may be explained. 
 
 First. That bodies electrified, either positively 
 or negatively, repel those in the same electrical 
 state, and attract those in the opposite electrical 
 state. 
 
 Second. That bodies either in a positive or nega- 
 tive electrical state, attract those in a neutral state, 
 by the law of induction. 
 
 Third. That bodies in a highly-active electrical 
 state, whether positive or negative, attract very small 
 bodies, or the atoms of bodies, when in the vicinity 
 of the highly-active electrified body, which are in 
 the same electrical state, by the law of induction. 
 
THE CONTENTS OF VEINS. 4Q 
 
 Then, as oxygen, chlorine, iodine, and fluorine, 
 and the substances in which their properties predo- 
 minate, are naturally in a negative electrical state, 
 they will be attracted by positively electrified bodies, 
 and repelled by those which are negatively elec- 
 trified. 
 
 And as the metals, and all other substances in 
 their elementary state, are naturally in a positive 
 electrical state, they will be attracted by nega- 
 tively electrified bodies, and repelled by those posi- 
 tively electrified ; but small bodies, or atoms of 
 bodies, are attracted by large bodies in the same 
 electrical state as themselves. 
 
 From the above principles and laws of electrical 
 action, may be explained, in a clear and rational 
 manner, not only the intersection and arrangement 
 of veins, but also the sudden and apparently capri- 
 cious changes that occur in their nature and dispo- 
 sition. For instance, suppose the rock forming the 
 walls of a vein to be electrified negatively, in this 
 case they will attract to them the electro-positive 
 elements of matter, as the metals, &c. ; but when 
 these electro-positive elements are accumulated on 
 the walls to some certain thickness, the action of 
 the rock will become null, and the positively polar- 
 ized substances planting the walls will act as elec- 
 tro-positive surfaces, and attract to them, or polarize, 
 the electro-negative elements, as oxygen, fluorine, 
 &c., or substances in which they predominate, as 
 quartz, fluate of lime, &c.; these alternations being 
 
 D 
 
50 THE CONTENTS OF VEINS. 
 
 repeated till the vein is filled up, if the electrical 
 action continue. 
 
 Again, if the rock forming the walls of a vein be 
 positively electrified, it will attract, or polarize, 
 the electro-negative substances, as quartz, fluate 
 of lime, &c., and when these substances are 
 accumulated on the walls to some certain thickness, 
 they will become the polarizing surfaces, and will 
 attract to them, or polarize, the electro-positive sub- 
 stances, as the metals, &c. ; these alternations being 
 repeated in the inverse order to the former till the 
 vein is filled up, if the electrical action is conti- 
 nued. 
 
 If, at the same time, one part or point in a vein 
 be in an electro-negative state, while another is in 
 an electro-positive state (which is no uncommon 
 condition with simple substances), the one part will 
 be attracting to it matter of a different nature to 
 that of the other ; and in case these alternate posi- 
 tive and negative states of the vein are only separat- 
 ed by very short intervals, the contents of it must 
 be disposed in a very mixed state, and present a 
 seemingly capricious arrangement if arrangement 
 it can be called at all, in the ordinary acceptation of 
 the word ; yet the position of each particle is the 
 result of the same definite agency as that by which 
 the most exact chemical effects are produced. 
 
 This law of differently electrified surfaces, or 
 points, in collecting on them oppositely electrified 
 particles, or atoms of bodies, is very elegantly and 
 
THE CONTENTS OF VErNS. -&1 
 
 clearly illustrated by an experiment devised by Pro- 
 fessor Lichtenberg. 
 
 With the knob of a jar charged with positive 
 electricity, trace on the surface of a smooth plate of 
 glass, or any resinous substance, various lines, at 
 pleasure ; then, with the knob of a jar charged nega- 
 tively, draw several other lines in the same way, and 
 set the plate vertically on its edge ; by the friction, 
 &c., produced by triturating red lead and sulphur 
 together in a mortar, the red lead is rendered posi- 
 tive and ,the sulphur negative ; then, if the powder 
 be projected in its mixed state against the plate by 
 a powder puff, or blown from the barrel of a quill, 
 the sulphur will attach itself to the positively elec- 
 trified lines, and the red lead to those negatively 
 electrified, forming a series of yellow and red lines : 
 there not being a particle of red lead attached to the 
 positively electrified lines, nor of sulphur to those 
 negatively electrified. 
 
 When the ore contained in a vein is scattered 
 through the vein substance in nodular masses, I am 
 fully persuaded, from the most attentive observation, 
 that this disposition of the ore in many cases is the 
 result of a concretionary action or coalition of mi- 
 nute particles previously disseminated through the 
 vein substance. 
 
 If it be admitted, as a principle in the repletion of 
 veins, that all the mineral substances which consti- 
 tute them, were originally disseminated through, and 
 immediately derived from, the enclosing rocks, then, 
 
52 THE CONTENTS OF VEINS. 
 
 in this case, veins ought to be of the greatest mag- 
 nitude, and most productive, at or near those points 
 in which they cross each other, and also where there 
 are a number of parallel contiguous veins, with small 
 veins or strings falling into them from either side or 
 both ; which consequence of theory is in exact ac- 
 cordance with fact. 
 
 It being conceived that the earth derives its mag- 
 netism from electrical currents circulating in it, in a 
 direction at right angles to the magnetic meridian, 
 they will, in some cases, concur with the local cur- 
 rents of the strata, and in others be antagonist to 
 them ; from which concurrence or antagonism of 
 the currents will result a variation in the internal 
 condition of veins. 
 
 In conclusion, it may be stated, that the electric 
 currents will have their routes through the veins in 
 various directions. In case they have a horizontal 
 set, their route will be from and towards all points 
 of the compass ; when they have a vertical set, 
 their route will sometimes be from below upwards, 
 but as the deep strata are in general negative in re- 
 gard to the upper, the positive current will generally 
 have a tendency downwards. It is not to be infer- 
 red from these remarks, that currents of electricity 
 traverse each fissure or vein throughout its whole 
 extent in length and depth, but that their genera- 
 tion and circulation are local, and not the result of 
 general, but special conditions in the strata. 
 
SECTION IV, 
 
 ON THE PHENOMENA OF THE INTERSECTION 
 OF VEINS, AND THEIR RELATIVE AGES. 
 
 HAVING, in the first section of this work, explained 
 the mechanical structure of veins ; and in the se- 
 cond, from these data, traced the formation of the 
 spaces which contain the substances that constitute 
 veins to a discharge of electricity, or fo electricity 
 in its coerced form ; and, in the third, traced the 
 filling up, or repletion of these spaces to 
 electro-chemical agency, or to electricity in its 
 free or galvanized form ; it is now intended, in 
 the present section, to trace up, and explain from 
 electro-dynamics, or the action of one current 
 of electricity on another, the phenomena which 
 veins present at their intersection ; and to deter- 
 mine their relative ages. 
 
 The correctness of the hypothesis here advanced 
 to explain the phenomena of the intersection of 
 veins, &c. must depend on, and be judged by, the 
 agreement between the principles of the science of 
 electro-dynamics ; as likewise, the agreement be- 
 tween the theoretical deductions involving them, 
 
 D 3 
 
INTERSECTION OF VEINS. 
 
 and the actual phenomena which veins present to 
 us in traversing one another, &c. 
 
 In no department of geology have the causes 
 assigned by geologists, for the explanation of any 
 particular class of phenomena, appeared to me 
 to be so inadequate to it, as those proposed to 
 explain the phenomena of the traversion of veins, 
 and their relative ages ; nor in any are the facts 
 more mis-stated, or the deductions more incorrect. 
 
 The principles in the science of electro-dyna- 
 mics on which it is proposed here to explain the 
 phenomena of the traversion of veins, &c. are, that 
 when two electrical currents are inclined to each 
 other at any angle, they are always naturally repul- 
 sive when one of them approaches to, and the 
 other recedes from, the summit of the angle, OF 
 point of intersection or coalescence. That, on the 
 contrary, they mutually attract each other when they 
 both approach to, or both recede from, the summit 
 of the angle, or point of intersection or coalescence. 
 And that the intensity of the action of each current 
 on the other, is inversely as the square of the dis- 
 tance, and is exerted in a direction perpendicular 
 to their routes. 
 
 It has been shown in the last section that cur- 
 rents of electricity traverse veins in all directions. 
 That when the set of the current is longitudinally 
 through the vein, it may pass in either direc- 
 tion through it ; for instance, if a vein have an east 
 and west course or bearing, the current (positive) 
 
INTERSECTION OF VEINS. 55 
 
 may have its routes through the vein either from 
 east to west, or from west to east ; and when the 
 set of the currents is vertically through the vein, it 
 may be either from below upwards, or from above 
 downwards. 
 
 Then, in order to render the application of 
 electro-dynamic action to the explanation of the 
 phenomena of the traversion of veins, &c., as intel- 
 ligible as the complicated nature of the subject will 
 admit ; let A B, Plate 8, Fig. 49, be the longitu- 
 dinal course of a prior formed fissure or vein having 
 a current (positive) of electricity moving through 
 it from A to B, or from right to left ; and let 
 C G H be a posterior formed vein, the discharge 
 or coerced current by which it was formed having 
 its origin in the point C, and its uninterrupted 
 course being C G H. Then, since the current of 
 electricity passing through the prior formed vein 
 A B, is either hydro or hermo-electric, it will be a 
 continuous current, and that of the discharged or 
 coerced current originating at C, being a sudden 
 electrical irruption, it will be a discontinuous cur- 
 rent. Hence the discharge, or coerced current 
 C, in its route from C to G, will be situated wholly 
 on the one side of the continuous current A B, 
 and in its course from G to H it will be wholly si- 
 tuated on the contrary side of the continuous cur- 
 rent A B. Therefore the effect produced by 
 a prior formed vein, or one of posterior forma- 
 tion, will be similar to the effect that a fixed 
 
56 INTERSECTION OF VEINS. 
 
 extended electrical current produces on an unstaid 
 terminated current. Hence, according to the hy- 
 pothesis here advanced to explain the phenomena 
 which- veins present to us at their intersection, 
 the supposition that all. veins were not formed at 
 the very same instant of absolute time, must agree 
 in all details with the electro-dynamic effects 
 of a fixed extended electrical current on an unstaid 
 terminated current. Then, in Fig. 49, let A G 
 and B G be made equal to each other, let there 
 be drawn A C and B C, and let the direction of 
 the current moving in the fixed channel of the prior 
 formed vein be from A to B. Then, since the 
 part of the continuous fixed current moving in 
 the prior formed vein A B from A to G, and the 
 part of the discontinuous unstaid current of for- 
 mation of the posterior vein C H, from C to G, 
 are both approaching to the summit of the angle, 
 or point G of intersection or coalescence of the 
 veins ; hence, agreeably to the law of electro-dy- 
 namics expressed at page 54, they will attract each 
 other, which attractive action let C w represent. 
 But, as the part of the continuous fixed current 
 moving in the prior formed vein A B from G to B, 
 is receding from the summit of the angle, or point 
 of intersection or coalescence ; and that of the 
 current C, from C to G, is approaching to it, they 
 will repel one another ; which repulsion let C x 
 represent. Then let w z and x z be drawn parallel 
 to C x and C w 9 and then draw C z, which will be 
 
INTERSECTION OF VEINS. 57 
 
 the resultant of the attractive and repulsive action 
 of the continuous fixed current moving in the prior 
 formed vein A B, or the discontinuous unstaid cur- 
 rent of formation of the posterior vein from C to 
 G, which is perpendicular to the course of the 
 vein, according to the law of electro-dynamics 
 expressed in page 54. 
 
 Then, let there be drawn parallel to C z the 
 several arrows, 1, 2, 3, 4, 5, &c., which will repre- 
 sent the direction of the force exerted by the con- 
 tinuous fixed current moving in the prior formed 
 vein from A to B, or the discontinuous unstaid 
 current of formation of the posterior vein from C 
 to G. Hence, the posterior, or traversed vein on 
 the side C G, will, at and near to the point of 
 intersection or coalescence, be more or less deflected 
 and drawn along the channel of the prior formed, 
 or traversing vein, in a direction contrary to that in 
 which the current is flowing in at M towards A ; 
 and it will intersect or be found at the point N 
 instead of at G, in the traversing vein, and either 
 pass straight through from N to P, or continue to 
 follow the course of the traversing vein before leaving 
 it, to some point, M, according to the intensity of the 
 discharge at C. 
 
 Then, as regards the effect of the prior formed or 
 traversing vein, or the posterior or traversed vein, 
 on its leaving the traversing vein on the other side, 
 G H. We have in this case, according to the law 
 of action in electro-dynamics, the current A M or 
 
58 INTERSECTION OF VEINS. 
 
 A P approaching to the point of intersection, or 
 coalescence of the veins, and the current M D or 
 P D receding from that point ; hence the action 
 of the fixed continuous current A M or A P on the 
 unstaid discontinuous current M D or P D will 
 be repulsive, which repulsion let H of represent. 
 Then, since the current M B or P B is receding 
 from the point of intersection of the veins, and also 
 as the current M D' or P D is also receding from 
 the point of intersection, the action of the fixed 
 continuous current M B or P B on the unstaid 
 discontinuous current M D' or P D will be attrac- 
 tive, which attraction let H w' represent. Then 
 let there be drawn w' z' and x z r parallel to H x' 
 and H w' ; and also draw H ^, then will H z be 
 the resultant of the repulsive and attractive action 
 of the fixed continuous current moving in the prior 
 formed vein A B, from A to B ; on the unstaid 
 discontinuous current M D or P D from M to D' 
 or P to D, which is perpendicular to both, to the 
 original and deflected course of the vein G H and 
 M D or P D* which is agreeable to the law of 
 electro-dynamics. Page 54. 
 
 Then let there be drawn parallel to H z' the 
 several arrows 10, 11, 12, 13, &c., which will re- 
 present the direction of the power exerted by the 
 fixed continuous current in the prior formed vein 
 
 * The original course of the vein has been used in the dia- 
 gram instead of the deflected one, for the purpose of uniformity, 
 as the result is exactly the same. 
 
INTERSECTION OF VEINS 59 
 
 A B, on the unstaid discontinuous current C in its 
 route of formation of the posterior vein, from M to 
 D' or P to D. Therefore the posterior or tra- 
 versed vein, on the side G H of the traversing 
 vein, will, at or near its point of intersection with 
 it, be deflected or curved in the direction in which 
 the current in the prior formed vein is flowing, viz. 
 towards B, as represented at V. 
 
 A popular, but very apt, illustration of the 
 influence which an electrical current passing 
 along a prior formed vein longitudinally on the cur- 
 rent of formation of a posterior vein, may be con- 
 ceived by imagining the path or tract of a block of 
 wood, or other light body, being projected along 
 the surface of smooth water, obliquely to its banks, 
 with great rapidity, and at the same time having a 
 rope attached to it of which a person has hold, and 
 so placed on the opposite bank as always to be at 
 right angles to its projection, hauling or pulling the 
 block towards him. 
 
 This species of deflection in veins (or shift as it 
 is generally called) being in the direction of the 
 acute angles of the intersection of the veins ; there- 
 fore it may be called an acuteangled deflection 
 (or shift). 
 
 Now, let the electrical current in the prior 
 formed vein, instead of moving from A to B or from 
 right to left, move from B to A or from left to right, 
 as represented in Fig. 50. And let the discharge C, 
 or current of formation of the posterior vein be the 
 
60 INTERSECTION OF VEINS. 
 
 same as in the last case from C to H. Then as 
 has been demonstrated in the preceding case, Fig. 
 49*> C s will be the attractive action of the parts 
 of the continuous currrent B G of the prior formed 
 vein, on the part C G of the unstaid discontinuous 
 current C in its route from C to G. And also will 
 C P be the repulsive action of the part of the fixed 
 continuous current of the prior formed vein G A, 
 or the unstaid discontinuous current C, in its route 
 from C to G. Then let p v and s v be drawn 
 parallel to B C and A C, and join C v, so will 
 C v be the resultant of the attractive and repul- 
 sive action of the fixed continuous current moving 
 in the prior formed vein from B to A, or the un- 
 staid discontinuous current C in its route from C 
 to G. 
 
 Then if there be drawn parallel to C v the several 
 arrows 15, 16, 17, 18, &c., which will represent the 
 direction of the force exerted by the continuous 
 fixed current moving from B to A, or the unstaid 
 discontinuous current C in its route of formation 
 of the posterior vein from C to G. Hence it will 
 be deflected, or take the channel of the prior formed 
 vein, in a direction contrary to the flowing of the 
 current, viz., towards B. And it will intersect the 
 
 * It is only intended to give the results of the electro-dynamic 
 action of the fixed continuous current moving in the prior 
 formed vein, or the unstaid discontinuous current of formation 
 of the posterior vein, in the succeeding cases, the same chain of 
 reasoning applying to all the cases. 
 
INTERSECTION OF VEINS. 61 
 
 prior formed vein at O instead of at G, and either 
 pass straight through from O to R, or take the 
 course of the traversing or prior formed vein for a 
 geater or less distance, as to S, according to the 
 intensity of the discharge at C. 
 
 Then as regards the action of the current B A 
 in the prior formed vein, or the current of formation 
 of the posterior vein in its route from R to E' or S 
 to E ; we have in this case H p' its repulsive action, 
 and H s' its attractive action, and H v' the resul- 
 tant of these repulsive and attractive actions. 
 
 Then if there be drawn parallel to N v the seve- 
 ral arrows, 21, 22, 23, 24, &c., they will represent 
 the direction of the force exerted by the conti- 
 nuous fixed current of the prior formed vein moving 
 from B to A, or the unstaid discontinuous current 
 C, in its route from R to E or S to E'. So shall 
 the posterior vein on its receding side R E or S E 
 of the prior formed or traversing vein near to its 
 intersection with it, be more or less bent in the 
 direction in which the current of the prior formed 
 or traversing vein is flowing, as at v and V. This 
 species of deflection in veins (or shift, as it is com- 
 monly called) being in the direction of the obtuse 
 angle of intersection of the veins, therefore it may 
 be called an obtuse-angled deflection (or shift). 
 
 In the preceding popular illustration, the person 
 who was supposed to be hauling the block to him 
 was placed on the opposite bank from which the 
 block was projected, and hence giving to it a more 
 
62 INTERSECTION OF VEINS. 
 
 direct course to the bank. But in this case, the 
 person is placed on the same bank from which the 
 block is projected obliquely to the banks, and hence 
 dragging it to the said bank, thereby increasing the 
 obliquity of its course to the bank, from which 
 cause, combined with the obliquity of the projec- 
 tion, the deflection may become so great as that the 
 path of the block may coincide with the channel of 
 the water; hence, a posterior formed vein under 
 these conditions may, at its junction with a prior 
 formed vein, be so much deflected, that its course 
 may coincide with the course of the prior formed 
 vein, or deviate so slightly from it as to continue 
 embodied with the prior formed vein, from such a 
 distance as to set aside all identity of parts on the 
 opposite sides of the prior formed or traversing 
 vein. 
 
 When the current of formation of a posterior 
 vein, at its junction with a prior formed vein, unites 
 with this current of the prior formed vein instead of 
 passing through it, in mining language the posterior 
 vein is said to be cut out, or off, by the prior form- 
 ed vein. 
 
 When the course of the posterior vein is at right 
 angles to the course of the prior formed veins, as in 
 Fig. 51, then, as has been demonstrated in the case 
 Fig. 49, we will have C N P D, or C N M D', the 
 course of the posterior vein, instead of the straight 
 course C G H, when the current in the prior 
 formed vein is moving from A to B, or from right 
 
INTERSECTION OF VEINS. 63 
 
 to left ; but when the current in the prior formed 
 vein is moving from B to A, or from left to right, 
 Fig. 52, the course of the posterior vein will be 
 C O R E, or C O S E, as has been demonstrated 
 in the case Fig. 50. The action of the fixed conti- 
 nuous current moving in the prior formed vein on 
 the current of formation of the posterior vein on the 
 side C N, or when approaching to the point of in- 
 tersection, is in a direction contrary to the motion 
 of the current moving in the prior formed vein A B, 
 viz., towards the right, as shown by the arrows 1, 2, 
 3, 4, 5, &c., which are parallel to C Z, the result- 
 ant of the attractive and repulsive action of A B or 
 C G ; but when the current in the prior formed 
 vein is moving from B to A, its action on the cur- 
 rent of formation of the posterior vein on the side 
 approaching the point of intersection will be towards 
 the left, as is shown by the arrows 15, 16, 17, 18, 
 &c., which are parallel to C V, the resultant of the 
 attractive and repulsive action of B A or C G. 
 
 The action of the fixed continuous current, mov- 
 ing in the prior formed vein, on the current of for- 
 mation of the posterior vein, in receding from the 
 point of intersection, or on the side G H, when the 
 current in its moving from A to B will be in the di- 
 rection in which the current is flowing, as shown by 
 the arrows 10, 11, 12, 13, 14, &c., Fig. 51, which 
 are parallel to H Z, the resultant of the repulsive 
 and attractive action of A B, or P D, or M D', 
 which will be bent at or near to the points P and M 
 
4 INTERSECTION OF VEINS. 
 
 inwards to the original course G H ; and the arrows 
 21, 22, 23, 24, &c., Fig. 52, which are parallel to 
 H V', the resultant of the repulsive and attractive 
 action of B A, when the current is moving from B 
 to A, or R^E, or S E, which is also inwards to the 
 original course H G. 
 
 Should the prior formed vein A B, fig. 53, have 
 no electrical current traversing it at the place which 
 the current of formation of the posterior veins inter- 
 sects it, then will the current of formation of the 
 posterior vein pass straight through the prior form- 
 ed vein, as shewn in Fig. 53, without interruption, 
 let the angle of intersection be what it may. 
 
 In Fig. 55, let A G B be the vertical course of 
 the prior formed vein underlying to the right ; and 
 C G H the vertical course of a posterior vein under- 
 lying the same way, but with a much greater incli- 
 nation. 
 
 Should the current traversing the prior formed 
 vein have a downward set, and the current of forma- 
 tion of the posterior vein be also downwards, then 
 will the fixed continuous current of the prior formed 
 vein draw to it the current of the formation of 
 the posterior vein so as to meet it at the point O 
 instead of the point G, and will be deflected for a 
 greater or less distance, as to S, and thence pro- 
 ceed to E, the deflection O S being what is called 
 the upheave. The effect will be the same when 
 the veins underlie in opposite directions. 
 
 But should the current traversing the prior 
 
INTERSECTION OF VEINS 65 
 
 formed vein have an upward set, as in Fig. 56, and 
 the current of formation of the posterior vein a 
 downward set ; then will the fixed continuous cur- 
 rent of the prior formed vein push from it the cur- 
 rent of formation of the posterior vein, so as not to 
 meet it at the point G, but at -the point O, and 
 then take the course of the prior formed vein from 
 O to S, and from thence to E ; the deflection 
 O S being what is called a down-heave. The 
 effect will be the same if the veins underlie in con* 
 trary directions. 
 
 Therefore the phenomena which veins present at 
 their intersections may be explained in a clear and 
 satisfactory way, even in their most minute details, 
 from the action of a fixed, extended, or continu- 
 ous electrical current, or an unstaid terminated or 
 discontinuous current. And all the theoretical 
 conclusions deduced from the hypothesis are in 
 exact accordance with the phenomena disclosed to 
 us in mining. 
 
 I am aware that in this hypothesis it is the poste- 
 rior formed vein which is made the deflected or 
 shifted vein ; whereas all Geologists who have no- 
 ticed the subject (so far as I know) have inferred 
 that the shift belongs to the prior formed vein, 
 which has had its corresponding parts displaced by 
 the movement which the rocks underwent at the 
 formation of the posterior formed vein. But this 
 view of the production of the displacement or 
 shift is singularly unhappy, as it is in effect 
 
66 INTERSECTION OF VEINS. 
 
 asserting that the cause is a consequence of the 
 effect. 
 
 It is quite impossible to explain the fact of two 
 prior formed veins in the vicinity of each other, and 
 which both underlie the same way, Fig. 54, being 
 shifted to different distances, in contrary directions, 
 from any movement impressed on the rock, either 
 sideways, downwards, or upwards. For whatever 
 movement the rock may have had impressed on it, 
 on the opposite sides of the posterior vein, at its 
 formation, the prior formed veins must have both 
 been moved in the same direction, and retain their 
 relative distance on each side to one another. 
 
 Nor can the fact of the union, or splitting of a 
 prior formed vein be explained by a posterior vein 
 cutting it in two ; or the fact of a prior formed vein 
 changing its throw, or tilting down different sides 
 on the contrary sides of a posterior vein by its being 
 cut in two by the more recent formed vein ; with a 
 number of others which the limits of this work will 
 not admit of being noticed ; but all of which facts 
 can be explained in the most clear and satisfactory 
 manner by electro-dynamics. 
 
 Since all prior formed veins, which have not a 
 vertical position, but are inclined to the horizon; 
 which are cut through by a posterior formed vein, 
 which at its formation was accompanied with an 
 elevation or depression of one side, must be re- 
 moved out of their downward course, according to 
 their inclination, and the elevation or depression of 
 
INTERSECTION OF VEINS. 67 
 
 the rock accompanying the formation of the poste- 
 rior formed vein ; 
 
 The effects resulting from a depression or eleva- 
 tion of the strata in displacing the downward course 
 of a prior formed vein according to its position to 
 the horizon, may be observed and studied in Figs. 
 57? 58, and 59. But since the shift of a prior 
 formed vein from any transverse lineal elevation, or 
 depression of the strata, is as the tangent of the angle 
 which its downward course makes, with a vertical 
 line, when the elevation or depression of the line is 
 made radius. And as veins in general have a to- 
 lerably erect position, and the throw or difference 
 of level of the strata on the opposite sides of them 
 is generally only small, the effect of a posterior 
 formed vein in shifting or displacing a prior formed 
 vein must, in most instances, be quite inappre- 
 ciable- 
 
 The electro-dynamical hypothesis here advanced, 
 to explain the phenomena of the intersection, and 
 relative age of veins making the more recent 
 formed vein the traversed or dislocated vein, and 
 the traversing or uninterrupted vein the more an- 
 cient, which is not in unison with the generally 
 received opinion on the subject, it may not be 
 amiss to notice a few facts which are not connected 
 with the electro-dynamical theory, but which corro- 
 borate the solution given by it of the relative age of 
 veins. 
 
 It is a rule to which there are very few exceptions 
 E 2 
 
68 INTERSECTION OF VEINS* 
 
 thai those veins which have a great and uniform 
 inclination traverse those that have a more inflected 
 and vertical downward course. Now it is a very 
 natural inference to suppose that the first formed 
 fissures would, from the more uniform and less in- 
 duration of the strata, have a greater and more uni- 
 form inclination than those subsequently formed 
 svhea the .conditions of .the strata were greatly 
 changed. 
 
 Again, with few exceptions, these veins whose 
 contents are of the most mechanical nature traverse 
 those whose contents are of a more chemical cha- 
 racter. It is also very natural to suppose, as the 
 strata were more soft when fissures begun to be 
 first formed in them, they would also be less distinct 
 in their chemical characters. Hence, mechanical 
 deposition would prevail more than that of chemical, 
 and give to the first formed veins their sedimentary 
 character. 
 
 Again, with few exceptions, those veins whose 
 chemical contents are of a simple earthy or alkaline 
 character traverse those whose contents are more 
 compounded and metalliferous. From this fact it 
 is very natural to suppose, as the strata approach 
 more and more to their distinct chemical characters, 
 their electrical action would become more intense ; 
 and hence the fissures then formed, or remaining 
 unfilled, as the substances carried to and precipitated 
 from them, would be more numerous, that their con- 
 tents would be more various and metalliferous. 
 
SECTION V, 
 
 THE APPLICATION OF THE THEORETICAL 
 CIPLES CONTAINED IN THE PRECEDING 
 SECTIONS TO THE ART OF MINING. 
 
 HAVING, in the preceding sections, explained the* 
 mechanical structure, the mode of formation, the 
 filling op, and the relative age of veins, I purpose, 
 in the present, to apply the theoretical deductions 
 propounded in each to the art of mining. 
 
 It is a general rule, to which there are few excep- 
 tions, that particular species of vein, and also 
 particular parts of the same vein-, are more especially 
 filled with some particular mineral substance than 
 others. This position being admitted, it would be- 
 desirable, for the interests of mining, if the circum- 
 stances which influence, and are indicative of the 
 prevalence of any particular mineral substance ins 
 veins could be pointed out, more particularly those 
 which influence, and are indicative of the prevalence 
 of metallic substances viz., to point out in what 
 respects the veins that are more metalliferous dif- 
 fer from those whose contents are of a more earthy 
 and alkaline nature. For any thing, how little so 
 ever, that can be done in this respect, must be 
 acceptable, as tending to advance the art of mining; 
 the searching for, and the extracting of metals 
 
 E 3 
 
70 APPLICATION TO MINING. 
 
 from veins, constituting the profession and business 
 of the metalliferous miners. 
 
 Veins in mining are divided into two classes, the 
 metalliferous or quick, and the non-metalliferous 
 or dead ; and the metalliferous or quick, into two 
 species the rich and the poor. A rich vein being 
 one, in which is found a considerable quantity of 
 the ore of some metal, without any reference to the 
 quantity of any other mineral substance it may con- 
 tain. A poor vein is one in which the quantity of 
 ore found in it is scarcely worth extracting, and has 
 no reference to the quantity of the other mineral 
 substances it may contain. 
 
 Therefore, the chief business or object of the 
 application of any theory of mineral veins to the art 
 of mining must be, to explain^ from the principles 
 of the theory, the peculiarities of those veins that 
 are generally quick, or very fruitful, from those 
 that are dead, or extremely barren, as fully and 
 clearly as the complicated nature of the subject 
 will permit. 
 
 The first remarkable fact with respect to the dif- 
 ference in the nature of the contents of veins, is> 
 that those which have a north and south direction 
 or bearing, or one slightly deviating from it, are, 
 in general* less metalliferious or quick than those 
 which have an east and west direction or bearing, 
 or one slightly deviating from it. Both the me- 
 chanical and chemical contents of the north and 
 south veins being more generally of an earthy and 
 
APPLICATION TO MINING. ?1 
 
 alkaline nature, and having their walls in a more 
 decomposed and disintegrated state than the east 
 and west veins. A few other remarkable differences 
 between the condition of the north and south and 
 east and west veins are as follows : First, that the 
 longitudinal courses of the north and south running 
 veins are in general more straight, of greater 
 length, have fewer strings or small veins branching 
 from them, and in general have a greater and more 
 uniform inclination than those having an east and 
 west direction. Second, That the north and south 
 veins present in their walls a more writhed, wither- 
 ed character, and in general traverse and shift 
 those having an east and west direction. 
 
 Now the conclusion to which all those differences 
 between the condition of the north and south, and 
 east and west veins lead is, that at the time of the 
 repletion of the north and south veins the strata 
 were more soft, less distinct in their chemical cha- 
 racters, less energetic in their electrical action, and 
 more diffused in their effects. 
 
 It has been demonstrated, in the last section, that 
 the traversing veins are of prior formation to those 
 traversed ; and as the north and south, in general, 
 traverse the east and west veins, therefore, the north 
 and south veins are of prior formation to the east 
 and west. 
 
 Hence the electrical currents circulating in the 
 earth from east to west, to which it is supposed its 
 magnetism is due, would pass transversely through 
 
7 APPLICATION TO MINING. 
 
 or cross the north and south veins in a feeble and 
 diffused state. But after the formation of the east 
 and west veins took place, these general currents 
 would have a tenxlency to converge and form dis- 
 tinct streams, and take the course of the east and 
 west veins in rotating the earth, in which concen- 
 trated condition of the general electrical currents 
 would give full scope to the strata to develope their 
 electric- action, the* result of which action would be 
 the generation of numerous local currents in the 
 strata ; and from the electro-dynamic law, that elec- 
 tric currents moving the same way attract each 
 other, the strata currents would be determined to 
 the east, and fissures or veins rather than to those 
 having a north and south direction. 
 
 Therefore, if all the substances constituting veins 
 were originally disseminated in the enclosing rocks, 
 and have been conveyed into the veins from electro- 
 molecular action ; then not only the metals, &c. 
 contained in the rocks, but also those previously 
 deposited in the north and south veins, would be de- 
 termined towards the east and west veins. 
 
 Whence the electrical theory of veins here ad- 
 vanced, affords a rational and clear explanation why 
 the east and west veins are more metalliferous than 
 those having a north and south direction ; and also, 
 why north and south veins are always more metal- 
 liferous at and near their junction with an east and 
 west vein, than in those parts which are distant from 
 the coalesence. 
 
\.-PLlCATION TO MINING, 7$ 
 
 By following out the theoretical consequences 
 deduced already, they afford a clear and intelli- 
 gible explanation why east and west veins are fre- 
 quently more pioductive near their intersection by 
 north and south, or cross veins; and also, where 
 strings on, small veins are falling into them from 
 either side, than in those parts which are not so 
 circumstanced. 
 
 In order to render these deductions complete, 
 there is still wanting some rational explanation of 
 the tendency of the first fissures or veins to a north 
 and south, rather than to an east and west direc- 
 tion ; and this can be done in the most satisfactory 
 manner from electro-dynamics. 
 
 The earth being an oblate spheroid, and the 
 solar influence greatest under the equator, the elec- 
 tro-magnetic currents rotating in it from east to 
 west, would have the greatest intensity at the equa- 
 tor then, as currents of electricity moving the same 
 way, attract each other with a force in proportion 
 to their intensity, the currents on each side of the 
 equator would be attracted or determined to it in 
 lines nearly coinciding with the terrestrial meridians. 
 Therefore, where even an accumulation of electri- 
 city might first be formed, the discharges, in the 
 northern hemisphere, would be from north to south, 
 and in the southern, from south to north ; the coer- 
 cive force being least in these directions. After 
 the earth's crust was thus torn into a number of 
 thin slabs, the coersive force to the discharges 
 
7 APPLICATION TO MINING. 
 
 would then become least in an east and west direc- 
 tion ; and hence, a second class of fissures or veins 
 having a course transverse to the first formed, or in 
 a direction from east to west. Hereafter, the fis- 
 suring of the fragments would become so compli- 
 cated, that no theory could be relied on to specify 
 any exact order of precedency of formation that 
 would generally prevail. 
 
 Another remarkable fact, with regard to the dif- 
 ference in the nature of the contents of veins is, that 
 the hard capacious vein, Fig. 40, or that which 
 overlies the side in which the strata are on a higher 
 level, are more metalliferous, than the soft capa- 
 ceous vein, Fig. 41, or which overlie the side in 
 which the strata are on a lower level. 
 
 The difference in mechanical structure, which 
 distinguishes soft from hard capacious veins has 
 never received, by miners, that attention which it 
 ought to command, not only from the former being 
 less metalliferous than the latter, but also from 
 their being metahferious in different strata. 
 
 Of the soft capacious species are, Crag Green 
 North Vein, and Stow Crag Vein ; of the hard 
 capacious species, are the small Cieugh, the Rani- 
 gill, the Brownly Hill, the Grass Field, and the 
 Hudgill Burn Veins, in Alston Moor. 
 
 The strata, in which theory assignsthe soft capa- 
 ceous vein to be productive, are thin hard shales or 
 platen, and thin soft sandstones immediately under- 
 lying a limestone. The strata, in which theory assigns 
 
APPLICATION TO MINING. 75 
 
 the hard capaceous vein to be productive, are thick 
 beds of limestone, and sandstone immediately under- 
 lying soft shales, or plates, which is in accordance 
 with fact 
 
 Another remarkable fact, with respect to veins 
 (at least in the secondary strata) is, that they are 
 not only less metaliferous, but the ores are of poorer 
 quality in the deep strata, than those near to the 
 surface. That this fact has been disputed by some 
 geologists is known, but its truth has been proved 
 in such a vast variety of circumstances and situations, 
 to the great loss and discomforture of the adven- 
 turers, that few, if any, practical miners, can now be 
 induced to engage in a speculation, the object of 
 which is a trial of a vein at a great depth below the 
 surface, however productive it may have been in 
 the upper strata. That there are occasionally to be 
 found patches of metal, &c. at a great depth in 
 veins, (generally disseminated in the enclosing 
 rocks,) it is not intended here to question ; but, 
 in general, the quantity is so small, as not to pay 
 the expense of extracting, independent of the 
 increased cost of working mines at a great depth. 
 The explanation which theory offers of this condi- 
 tion of veins, and the strata at a great depth below 
 the surface, is, that the strata are highly electro- 
 negative to the veins. 
 
 A fact, worthy of notice, respecting the useful 
 metals is, that they belong to particular formations 
 of rocks, some of them being indigenous to certain 
 
7(> APPLICATION TO MINING. 
 
 rocks, while others are aliens to them. In general, 
 gold and tin are found in the greatest quantity in 
 granite, and the rocks immediately reposing on it , 
 copper, in the various slate formations, which repose 
 on the former series ; lead, in the mountain lime- 
 stone formation 5 iron, in the coal strata 5 and silver,, 
 in all these formations, it being in general found 
 forming a natural alloy with the other metals r more 
 particularly lead. Above the coal strata, not any of 
 the metals, I believe, have been found m such 
 quantity as to lead to any mining operations being 
 established for their extraction. 
 
 Another condition, which has considerable influ- 
 ence on the productiveness of veins, is, that when a 
 vein is quite insulated, viz. at a great distance from 
 any other vein on either side of it, nor has falling 
 into it any strings or small veins, (called by miners 
 feeders) it will, in general, be unproductive. But 
 when there are a number of parallel veins in the 
 vicinity of each other, in general, one or more of 
 them will be productive ; also, when a vein is inter- 
 sected by another at an acute angle, or another 
 vein falls into it from either side, either one or both 
 will generally be productive at the point of junction. 
 The relation in which veins thus stand to each other 
 bears a striking resemblance to the galvanic appa- 
 ratus ; and their being more productive when thus 
 connected would appear to be the result of a more 
 energetic electro-chemical action in the strata. 
 
 The prevalence and productiveness of mineral 
 
APPLICATION TO MINING. 77 
 
 veins appear to be very intimately connected with 
 the proximity or junction of dissimilar rocks, where 
 it may be supposed the electro-molecular, and elec- 
 tro-chemical actions are most energetic. In Corn- 
 wall, I believe, it is at or near the junction of the 
 killas (clay slate), with the granite, or of the killas, 
 with the elvan courses ; or phorphyritic beds or 
 dykes, that the veins are most productive. In 
 Cumberland, Northumberland, Durham, Westmor- 
 land, Yorkshire, and Derbyshire, in consequence 
 of the limestones and sandstones being interstra- 
 tified with basalt, chert, and shale ; and of the prox- 
 imity of the rocks to, and having a position to the 
 ast of the primary slate formations in these districts. 
 In Flintshire and Shropshire, in consequence of the 
 limestones and sandstones being interstratified with 
 shale ; and of the proximity of the rocks to, and 
 having a position in these districts to the east and 
 north east of the primary slate formations, &c 
 
 It has been noticed before when veins traverse an 
 alternating series of strata, that in those in which 
 they have a great inclination, the walls are in 
 general in close contact, and their contents are 
 composed of the rocks in a decomposed or douky 
 state. But in the strata in which they have an 
 erect position, the walls are separated from each 
 other, and the cavities thus formed are in general 
 filled with some foreign substances. 
 
 In stratified districts, as in the north of England, 
 the throw of veins, or the difference of level of the 
 
78 APPLICATION TO MINING. 
 
 corresponding strata on the opposite sides of them, 
 is a matter of great importance, as it materially 
 influences their productiveness. 
 
 In Alston Moor, and neighbouring districts, the 
 country is chiefly composed of limestone, sandstone, 
 plate, or shale. In the two former, the veins pro- 
 duce ore, but they are more productive in the lime- 
 stones than in the sandstones; but in the plate beds 
 or shales, they are in general unproductive. Hence 
 the throw should not exceed three yards, so that the 
 sides or walls of the veins should be of similar stra- 
 ta ; viz., limestone facing limestone, and sandstone 
 facing sandstone, and shale opposite to shale. 
 
 When the throw is very considerable, as the 
 limestones and sandstones are in general not more 
 than from four to eight fathoms in thickness, the 
 unproductive beds are brought in opposition to 
 those which are productive, in which case the veins 
 are generally unproductive, the hanging wall being 
 composed of soft shale or plate, is in a crushed and 
 decomposed condition, and hence in contact with 
 the limestones, &e. 
 
 Then, since the mechanical structure of the hard 
 capacious vein, when its throw is only small, will 
 have both its walls formed of the same strata, and 
 also as the walls in the limestones and sandstones 
 are more or less separated, and in the shales are in 
 close contact, hence probably the reason why veins 
 are more productive in the limestones and sand- 
 stones, or those strata in which they have an erect 
 
APPLICATION TO MINING. 79 
 
 position, than in the shales, &c., or those strata in 
 which they are much inclined to the horizon. 
 
 When both the cheeks or walls of a vein are in 
 a negative electrical state, there will in general be 
 little, if any change, produced in the enclosing 
 rocks ; and if they are filled with any foreign sub- 
 stances, it will be either some metallic ore, or some 
 mechanical deposition, as clay, or both in a mixed 
 condition. 
 
 But if both the cheeks or walls of a vein are in a 
 positive electrical state, the enclosing rocks where 
 they are in contact will in general be in a deconij- 
 posed or douky state, and where they are separated 
 from each other, the enclosing rocks will be in a 
 ridered state, as the substances in which oxygen, 
 &c. prevail (as the salts of iron, &c.) are always 
 attracted by positively electrified surfaces, and re- 
 pelled by those negatively electrified ; and the ore, 
 when the vein is productive, will be disseminated 
 or scattered through the rider forming the walls of 
 the vein. 
 
 In most cases where the sides or cheeks of veins 
 are in a ridered state, they present very marked dif- 
 ferences in their appearance and character; the 
 rider when formed by the red oxide of iron being 
 in general, in a soft, withered, and carious condi- 
 tion, and having a reddish brown colour. And where 
 it has crumbled to dust, it forms the mineral soil 
 that so much resembles in appearance rappee snuff, 
 which is considered by all miners as the most favour- 
 able indication of a vein being productive. 
 
APPLICATION TO MINING. 
 
 It is a fact that the contents of veins have been 
 found in many instances to be partly or entirely 
 mechanical, when the strata forming the cheeks or 
 walls of veins were in such a soft and fragile state 
 that on the smallest excavation being made in the 
 veins, the rock would have tumbled into, and filled 
 it up. Then, in what way, it may be asked, were 
 the sides of veins in this case kept apart until the 
 vein was filled ? In answer to this, it may be stated, 
 that this condition of the rock forming the walls of 
 veins is not its natural one, but has been the result 
 of electro-chemical action, disintegrating and decom- 
 posing the rock subsequently to the existence of 
 the veins, as mere fractures or fissures. 
 
 That the mechanical contents of veins are in 
 many instances the result of the disintegration and 
 decomposition of the rocks forming their walls, by 
 electro-chemical agency, and that they have not in 
 all cases been introduced into them by currents of 
 running water, may be inferred from the condition 
 in which they are placed in some cases. There are 
 many instances of matter having a sedimentary cha- 
 racter, being enclosed in cavities in the flat veins 
 to which there was no egress for the sediment, but 
 through the solid rock ; the cavities not having 
 (sensibly) the most minute crack leading into them. 
 Therefore it cannot be conceived that the sedimen- 
 tary matter inclosed in these close cavities had 
 been washed into them by water, but had been 
 formed from the disintegration and decomposition 
 of the rock forming the walls of the cavities. 
 
APPLICATION TO MINING. 81 
 
 When the cavities contain no loose matter, the 
 rider forming their sides is in general in a very 
 high state of induration ; and they have no regular 
 form, but their appearance very much resembles the 
 effect of a chemical solvent, on a solid differing 
 much in its solubility ; and the foreign substances, 
 when any, attached to the surface of the cavities 
 are in a very perfect state of crystallization, and have 
 a brilliant lustre. In some cases, large masses of 
 rider, with the foreign substances on them, have 
 been detached from the surface of the cavities, not 
 only from the top, but also from both the bottom 
 and sides. In other cases the detached masses are 
 small, resembling the scales detached from hot iron 
 in hammering it ; which scaly condition of the de- 
 tachments is called by miners shiver. In this shivery 
 condition of the cavities their internal surface in 
 general very much resembles the leafy or scaly 
 structure of the exterior of a wasp's nest when it is 
 ruffled up. 
 
 The way in which these close and insulated cavi- 
 ties have been carved out, and the elements of the 
 rock, either in part or entirely conveyed away, and 
 other substances have been introduced into them, 
 is, perhaps, not so easily comprehended as the in- 
 troduction to, and filling up of, the fissuriferous 
 vein with foreign matter ; yet their formation and 
 repletion are equally consistent with the law and 
 mode of action of electricity. 
 
 That electricity in motion possesses the power to 
 
82 APPLICATION TO MINING. 
 
 select, and a momentum to convey, the elements 
 and finer particles of matter through masses of other 
 matter is fully established by many experiments. 
 For we know nothing of electricity, except as it is 
 presented to us in connexion with matter in a solid, 
 liquid, or uniform state. And likewise, as we have 
 no knowledge of matter separate or apart from elec- 
 tricity, and as both analogy and observation lead to 
 the conclusion that they are co-existent, there- 
 fore, if electricity be the agent employed by nature 
 in the reduction of compound bodies to their ele- 
 ments, each particle of it will, in its most simple 
 state, contain a portion of electricity. Hence, 
 when the electrical equilibrium is disturbed, and a 
 current of electricity is set in motion, the elements, 
 or atoms of matter incorporated with it, will be 
 carried to their respective polar stations, and there 
 deposited. 
 
 It is a fact established by many experiments in 
 electro-chemical science, that elements or atoms of 
 one chemical or electrical quality in solution may 
 be passed through elements or atoms of a different 
 chemical or electrical quality without interruption, 
 or an union taking place between them ; and solid 
 substances, as glass, sulphate of baryta, fluor spar, 
 carbonate of lime, &c., when moistened and placed 
 between surfaces connected with the opposite poles 
 of a voltaic apparatus are decomposed, and their 
 elements carried to their respective polar positions. 
 
 That metallic ores of lead, copper, and iron, in the 
 
APPLICATION TO MINING. 83 
 
 state of sulphurets, are disseminated through the 
 substance of the deep strata quite apart from veins 
 in Alston Moor, has been fully established in the 
 instance of Nentforce level, and some other deep 
 drivings carried through them for discovery, &c., 
 the lead and copper ores always occurring in thin 
 leaves or scales, and the iron in cubes. 
 
 Although the theory here advanced for the forma- 
 tion, filling up, &c., of mineral veins has no con- 
 nexion with the transmutation of matter, or that of 
 a contemporaneous formation of veins with the 
 enclosing rocks, or that of a deposition of the con- 
 tents of them from solution, or that of their sublima- 
 tion or injection into them from below, yet it 
 embraces in it principles that which will supply 
 all the conditions required in the above theoretical 
 modes of explaining the phenomena of mineral 
 veins. 
 
NEWCASTLE : PRINTED BY J, BLACKWELL AND CO. 
 
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 UNIVERSITY OF CALIFORNIA LIBRARY