Volume 12 (1866) (428 pages)

Ghe Blining and Scientific Press, Gommmurications, In rH1s DEPARTMENT we luvito the FREE Discussion of all ate au bict leaping ents alone belng responslble for he ideas and theories they advance. [Wrltten for the Mining and Scientific Press] THE AGE OF GOLD-BEARING ROOKS, BY PROFESSOR ROWLANDSON, F. G. 8. Le ad \S Wo. Ix. (conTINvED FRom PaGz 402, VoL. x1.) SIR RODERICK MURCHISON’S VIEWS — HONOR AWARDED WHERE HONOR IS DUE. Before quoting the views expressed hy this world-renowned and justly celebrated geologist, I take the opportunity of publicly expressing my grateful thanks for’ the deep obligation which I personally feel towards Sir Roderick Murchison, for the great nmount of labor undergone, and ahility displayed hy him in drawing up his “ Silurian System ;” for, although I had entered upon the inquiry of the age of gold-hearing rocks somewhat simultaneously with the commencement of Sir Roderick’s lahorers in Siluria, my researches on this question were commenced from a starting point different from that taken hy the distinguished geologist alluded to—mine was taken chiefly from a chemico-metallurgic hasis—Sir Roderick’s from palceontological and stratagraphic evidence. It is only due to Sir Roderick to state, that op to the period when he published the views contained in the following quotations, all the evidence previously gathered tended not only to show the soundness of his generalization, as hased on the facts which had been up to that time positively ascertained in regard to the palceontology of gold regions, but also from their persistency, as far as was then known, necessarily led to a belief, amounting to conviction, that the views originally propounded hy Sir Roderick would hold good the world over. In regard to the latter point, I think Sir Roderick will find it necessary, from the evidence supplied hy California, to modify his theory to some extent, as to the Age of Gold Bearing Rocks, especially those lying adjacent to this part of the Pacific coast, and possihly some other parts of the world to which attention will he drawn hereafter. To respectfully drawing the attention of geologists, generally, and that of Sir Roderick Murchison, in particular, to the fact that gold bearing quartz lodes are, on tolerahly good evidence, fonnd to exist over a large extent of country, in this and adjoining States, amidst rocks of secondary, and possibly of tertiary age, I feel certain that however much such a view may he in opposition to a very frequently and strongly expressed theory of Sir Roderick, Do one more readily than himself will cheerfully admit the soundness of any new view, when reasonahly supported, however much that may differ from his own, as previously expressed ; and further, that he will ost willingly lend all the aid which his position and just influence enables him to so extensively exercise in order to ascertain the true theory of this interesting subject, to the end that it may, if possihle, he turned to economic aceount. The condition of geology at the time when Sir Roderick Murchison published his “ Silurian System,” eince which nearly a gcneration has heen called into existence and passed away, was eomething tike that of chemistry, as applied to agriculture, etc., when Liehig, only avery few years later, reduced chaotic and dispersed masses of‘ valuahle matter and experiments into system. The world is indehted to Sir Redcrick Murchison for like valuable agsistance in regard to geology, and it would he difficult to imagine or describe the debt of gratitude that is duc to that gentleman from the present as well as hy future generations. Individually, Tngain tender to Sir Roderick my acknowledgiments of the personal advantagee which I have derived in studying geology trom an early perusal of his Silurian System. As hrevity is said to he the soul of wit, I hope that iu thue curtly according my thanks to him a like hrevity will he accepted as the essence of sincerity. SIR RODERICK MURCHISON’S VIEWS ON GOLDBEARING ROCKS. Sir Roderick states, at page 474 of his third edition of Siluria ; « Tet us first reflect upon the genernl fact, that, whilst all the stratified formations are composed either of crystalline and paleozoic rocks, or of secondary and tertiary deposits, gold has never heen found in any appreciable quantity in either of the two last-menutioned classes of strata. The vast areas, therefore, which are covered hy all such younger formations are excluded from the application of onr reasoning ; and every one who lives in tracte the subsoil of which consists of such rocks, may at once be assured, that he can never profitahly extract gold from them. Having laid down this generalization, which affirms that hy far the largest portion of land ou the face of the globe never contains gold, we proceed to consider the nature and limits of the gold-hearing rocks, nnd then indicate how the chief wealth is derived from superficial auriferous drifted materials or gravel. Appealing to the structure of the different countries which at former periods have afforded or still afford any notahle nmount of gold, we find in all a general agreemeut. Whether, referring to the ancient history, we cast our eyes to the countries watered hy the Pactolus of Ovid, to the Phrygia and Thrace of the Greeks, to the Alps* nnd golden I’ gns of the Romans. to the Bohemia of the Middle Ages, to tracts io Britain which were worked in old times, and hove either heer: long abandoned or are now scarcely at all productive, or to to those chains in America and Australia which, previously uusearched, have, in our times, proved so rich —we invariably find the same constants in nature. In all these lands, gold has been imparted abnndantly to one class only of those ancient rocks whose order and succession we have traced, or to the associated eruptive rocks. The most nsual, original position of the metal is in quartzose veinstones that traverse altered Silurian slates (chiefly Lower Silurian), frequently near their junction with eruptive rocks. Sometimes, however, it is partially diffused through the body of rocks of igneous origin.” “Seeing. on the one hand, that the oldest rock, and, on the other, the medinl and youngest deposits never contain gold, and that yet (as will he shown) the metal ie of recent accumulation ex masse, it might seem to follow that there existed in those original deposits which have since become largely auriferous, the elements out of which gold was subsequently hrought together in rich veinstones. It is indeed a tact, ns will hereafter he shown, that there are fine-grained old schistose sediments in which gold is so impalpahly disseminated, that it ie difficult to imagine how this diffusion could have occurred if the original menstruum had not contained the elements of the ore. In that diffused state the gold may have remained long after the consolidation of the sediment, until, in ages long posterior, it was run together into metallic veinstones by metamorphic action, or segregated into the lumps and filaments in which it now occurs. But, however we may account for them, the facts are those which I have for many years exposed—viz., that a certain geological zone only in the crust of the globe has heen rendered richly auriferoust}. *In truth, as above expressed, every old country of Europe, where tho rocks were onco aurifcrous, bas long ecased to yleld any yaluable amount of gold. In referenco to the Alps, 1am indebted to my learued friend Mr, J. W. Cowell for pointing out to me the following passage iu Strabo (Book iv. ch. 6, sect. 12), by which it appears that even Imperial Rome was at ovo timo inundated with a glut of goid from her Northorn mountains —* Polybius says that in bis lime the gold mines were so rich about {oorth of ?] Aquileia, but especially in the country of the Taurise: Norici, that if you dug but two feet below the surface you found gold. and that the diggings (generally) were not deeper than 15 feet ; that in some instances the gold was found pure, in lumps of the size ofa bean or a lupin, and which lost ouly one-eighth in smelting, in others it required more smelting. but was very profituble. Jtaljansaiding the barbarians intho working for two months, gold becamo forthwith oue-third cheaper over the whole of Italy ; and tho Turisci discovering this, drove the associate Italians away and monopolized it themsolves. At present all gold mines belong to the Romans.” + When preparing this work for press, Ireccived a letter from Mr, Lieber, the State Geologist of South Carolina, which, being explained by 2 second letter from that gcntleman, in reply to ono which Taddressel to him, conlains a little tahle which cloarly expressos bis views as derivod from hig experience in South Carolina and the Bruzils, Tracing out the peculiar features of the “ itacolumite ” and its associated rocks of * itaberite” and “ specular irou scbist,’? and a compound of tale und magnetic irou, which he terms “ entawhberite,” Mr. Lieber afirms, that*these rocks, together with clay and taleoso slates, are chiefly auriferous, and that none of the recks above them ever bear gold, whilst the miea slates bencath aro mue!: less productivo of the ore, Ho consequently clussifies the whole in ascendiug order, xs Sub-auriferous, Aurilerous, and Post-auriferous—a mineral classification which is in accorfance with the data 1 have long endeavored to establish by geological and paleontological proofs, To se ResuneD.—The line of steamers hetween New Orleans and San Francisco, susnended hy the Rehellion,is to he again in operation. On the Ist of Jannary, the Pacific Mail Stenmship Company isto place a steamcr on the line from New Orleans, via Havana, to Aspinwall, connecting at the latter place with the steamers to and from San Francisco. Some of the principal New York hotels talk of raising the price of hoard to $6 per day. There are families in the Fifth avenue who give $500 or $600 a week for their mere lodging and hoarding privilege, while their extras” will reach $300 or $400 more. a [Wrltten for the Mining and Scientlfic Press.} Gold Bearing Sulphurets and their Reduction.” REPLY £0 “A STUDENT OF METALLUOICAL CHEMISTRY.” Messrs. Eprrors :—I notice in your issue of the 23d ultimo,a communication signed “ A Student of Metallurgical Chemistry,” in which the motives of my contrihution to yonr‘journal, of Decemher 9th, are unjustifiahly attacked, and the positions assumed by me attempted to he controverted. : I would premise my reply to the author hy hinting thatthe perusal of the gentleman's communication, without the signature, conveys evidence that it is written by a student, and certainly one not very far advanced in his studies. My ohject is not concealed, nor is any at-. tempt made at the same. It was written for . the benefit of the mining community of Caliples ofichemistry, claiming to be competent to sextract the precious metals from their ores. abandoned, miners ruined, public confidence shaken in all mining operations, and the production of the precious metals limited to about one-third of what it ought to he. The method invented by myself for the reduction of the precious metals from the goldbearing salphurets was not “nbandoncd as impracticable.” On the contrary, it is available for treating sulphurets rich in gold, especjally some of those at Grass Valley, hut not for those holding so small an amount as $20 per ton where labor is high. ‘ I did not condemn the common reverberatory furnace—these are my words : “ By means of this method the precioue metals are “ freed” wheu contained in hi-sulphide of iron ;” neither was! ignorant that condensing chamhers form an essential part of said furnace ; alluding to the mechanical loss of gold, I said, “ it is loss unless some means be employed for its collection.” In copying the manuscript, I inadvertedly omitted the following to complete the paragraph: “This method is too slow and expensive for California.” (did not disapprove of reverheratory fornaces for the purpose of chlorination. Reterring to the “ Chlorination “Process,” I spoke of oxidation heing performed iu theni previous to the treatment of the mase hy chlorine, ete., @ process it would appear the “ Student” is unacquainted with. IL did not discredit the methods of the distinguished Metallurgists, Agustin, Ziervogel and Von Patera; these employ said furnaces for a purpose foreign to the suhject in question. My remarks were confincd solely to the treatment of gold hearing sulphurets, a euhject I profess to undcrstand. I have nothing to retract concerning “ inventions in the shape of furnaces ;” two of the said inveutors have admitted to me that their iuventions did not answer their expectatiuns. Iam uot at liberty to pablish their reasons. , Regarding the peformance of “ The Gold and bilver Separating Company’s Furnace” (Dr. Hagan’s) the “ Student” seems to intimate that thecrade sulphurots taken for assay did not represent the “ mass mixed” from which the third assay wns made; I will endeavor to eulighten him on this point, thanking him ip the first place for correcting a typographical error. It seeins the gentlemanis an arithmetician, as well as a student of metallurgy. Assuy fist is the mean of five assays made on as fair a sample of the ernde mineral as could he ohtuined ; they not disagreeing wore than some $30 ahove, nor $11 per ton less than the meau (not an oucomimon occurreuce). Assay third is likewise the mean of five assays made on the mass after treatincnt, obtuined ina like manner to that hy which the sainple from which assay firs? was made; these disagreed from $45 above to $26 per tou helow the mean, thas showing that a fair sample was ohtaincd. Siath assay of the tailings ; this was an assay of the “refuse” nfter amalgamation ; had I made no series of them (1 considered it unnecessaiy to do so), “the agerecate of the extraction and that left inthe tailings” night have equalled the amount as per nssay third; as itis, I consider assay sixth sufficiently exuct forall pructical purposes; from these results, along with those of the otncr threc experiments. I considered myself justified in arriving at this fair conclusion, omitting fractions of a per cent., viz: 55 per cent., de-. sulphurized ; 16 per cent., lost ; 52 per cent. . extracted and 32 percent. left in the tailinge. The treated mass was ainalgamated, and the amaleam carefully separated hy a“ Workman” without any apparent loss. Again, the * Student” is unwilling to admit that there was any loss of gold during treatment. I maintain that ‘there was, knowing that fair eamplee were ohtained for aseay hoth before and after treat. ment. He says: “ But aside from this, add the . fixed, positive data obtained hy the extraction -of $205.12 to that ehown by assay remainuin in the tailings, and we have $205.12+146.12 =$351.24. Now, suhtracting this Inst sum from the assay of the crude sulphurets=$395. 48—351.24—=44,24 per ton, or not quire twelve per cent. loss.” This quasi admitted loss from a 55 per cent. desulphurization, or rather say what is warranted by the “ Student’s” arithmetic, 11.19 per cent., added to 9.15 per cent., corresponding to the complemeut (45) of 100 per cent., would make 20.34 per cent. loss, provided the whole of the mineral had heen desalphurized; so it would appear that the minimum mechanical loss of gold mentioned in my communication (20 per cent.) wonld have heen experienced had the farnace heen capable of i . doing what it is represented to do, fornin, who have heen so often imposed npon j/ hy persons entirely ignoraut of the first princi} sulphide of iron. 1 cannot see the analogy hetween decarhonizing carhonate of lime aud desulphurizing biThe first isa proto-sall, the second alernary compound. Heat decomposes the former, whereas it does not separate the What has heen the result? Vnolunhle mines 1 E whole of the sulphur from the latter. I do not advance this by way of proof to show that hisulphide of iron cannot he deselphurized in lumps, hut merely to show the fallacy of the « Student’s ” reasoning. But the “Student” is continually harping on the “ effectual method,” and naively says: “This method is mainly commended to our confidence, from the circumistance of his being requested to examine the performance of this furnace {using his own words) in my professional capacity.” Verily, this is arriving at a conclusion with a vengeance. Experiments were niade hy me years ago on sulphorets in lnmps, both with steam and without it, for the purpose of desulphurizing them. I nlways obtained a negative result. On the contrary, I have experimented on *‘ tolerably fine crushed ” sulpharets in an arrangement similar to Mr. White’s, on the same principle, and obtained desulpharization of tho mineral, with the exception of some milliemes of sulphur that was found associated with iron and oxygen ; this small portion was not inimical tothe extraction of the precious metals from the oxidized mineral by amalgamation. I am aware that Mr. White's furnace was exhihited to the public at Newark, New Jersey, about eighteen wonthe ago. Several chemists and persons engaged in the husiness of testing ores witnessed its performauco. Some of them gave certificates regarding its merits. One “student ’ was nmoug the number. Any competent investigator will find no difficulty in pertorming experiments to satisfy himself that what I have stated regarding the two tarnaces (Dr. Hagan’s aud Mr. White's) is true. Certainly no candid person will deny that the objections urged hy the “student ’’ against the comnion reverheratory furnaces are overcome in Mr. White’s, viz :—*‘ the expense of huilding and keeping them in repair, the trouble and cost of working the ore properly, and the constant drend of careless and indifferent workmen, upon whom the successful working of the ore chiefly depends.” The cost of Mr. W.’s is less in proportion thau the common furnnces, considering the amount of work it is capahle of perlorming. The attendance of one workman is only required to keep up the requisite degree of heat, and feed the hopper with the ground mineral, which discharges itsclf at the other end, the wear and tear being trifling, while the coil of pipe in the chimney, from which jets of cold water are ejected, acts the part of a condensing chamher, thus securing a compact apparatus as wellasacheap method. . There is an old adage—* The greatest thief always calls thief first.” So the “ Student’s ” communication, accusing me of interested motives, will readily convey conviction to the mind of the most uhtuse reader, that his object is to holster up a process that had sunk into ohscurity, aud is now attempted to he revived under a new patent. The “ Student” appears not to confine his glowing intellect to the study of metallurgy only; bat assumes to occupy the chair of a modern Chesterfield, and read me lessons upon taste and propriety; yet as I have already lived the greater part of a long life, I would suggest to him that his labors in this hehalf are not appreciated. I would also suggeet to him that in the scientific world, at least, the names of individuals heing given is, to some extent, a guarantee of good faith; and if the “Stadent” has heen more than three months in this city, and is of sufficient age to have. experience in the matters in controversy to give weight to his opinions, it might be well tor him to shake off his cloak of modesty and let your readers know to whom they are indehted for

Ghe Blining and Scientific Press, Gommmurications, In rH1s DEPARTMENT we luvito the FREE Discussion of all ate au bict leaping ents alone belng responslble for he ideas and theories they advance. [Wrltten for the Mining and Scientific Press] THE AGE OF GOLD-BEARING ROOKS, BY PROFESSOR ROWLANDSON, F. G. 8. Le ad \S Wo. Ix. (conTINvED FRom PaGz 402, VoL. x1.) SIR RODERICK MURCHISON’S VIEWS — HONOR AWARDED WHERE HONOR IS DUE. Before quoting the views expressed hy this world-renowned and justly celebrated geologist, I take the opportunity of publicly expressing my grateful thanks for’ the deep obligation which I personally feel towards Sir Roderick Murchison, for the great nmount of labor undergone, and ahility displayed hy him in drawing up his “ Silurian System ;” for, although I had entered upon the inquiry of the age of gold-hearing rocks somewhat simultaneously with the commencement of Sir Roderick’s lahorers in Siluria, my researches on this question were commenced from a starting point different from that taken hy the distinguished geologist alluded to—mine was taken chiefly from a chemico-metallurgic hasis—Sir Roderick’s from palceontological and stratagraphic evidence. It is only due to Sir Roderick to state, that op to the period when he published the views contained in the following quotations, all the evidence previously gathered tended not only to show the soundness of his generalization, as hased on the facts which had been up to that time positively ascertained in regard to the palceontology of gold regions, but also from their persistency, as far as was then known, necessarily led to a belief, amounting to conviction, that the views originally propounded hy Sir Roderick would hold good the world over. In regard to the latter point, I think Sir Roderick will find it necessary, from the evidence supplied hy California, to modify his theory to some extent, as to the Age of Gold Bearing Rocks, especially those lying adjacent to this part of the Pacific coast, and possihly some other parts of the world to which attention will he drawn hereafter. To respectfully drawing the attention of geologists, generally, and that of Sir Roderick Murchison, in particular, to the fact that gold bearing quartz lodes are, on tolerahly good evidence, fonnd to exist over a large extent of country, in this and adjoining States, amidst rocks of secondary, and possibly of tertiary age, I feel certain that however much such a view may he in opposition to a very frequently and strongly expressed theory of Sir Roderick, Do one more readily than himself will cheerfully admit the soundness of any new view, when reasonahly supported, however much that may differ from his own, as previously expressed ; and further, that he will ost willingly lend all the aid which his position and just influence enables him to so extensively exercise in order to ascertain the true theory of this interesting subject, to the end that it may, if possihle, he turned to economic aceount. The condition of geology at the time when Sir Roderick Murchison published his “ Silurian System,” eince which nearly a gcneration has heen called into existence and passed away, was eomething tike that of chemistry, as applied to agriculture, etc., when Liehig, only avery few years later, reduced chaotic and dispersed masses of‘ valuahle matter and experiments into system. The world is indehted to Sir Redcrick Murchison for like valuable agsistance in regard to geology, and it would he difficult to imagine or describe the debt of gratitude that is duc to that gentleman from the present as well as hy future generations. Individually, Tngain tender to Sir Roderick my acknowledgiments of the personal advantagee which I have derived in studying geology trom an early perusal of his Silurian System. As hrevity is said to he the soul of wit, I hope that iu thue curtly according my thanks to him a like hrevity will he accepted as the essence of sincerity. SIR RODERICK MURCHISON’S VIEWS ON GOLDBEARING ROCKS. Sir Roderick states, at page 474 of his third edition of Siluria ; « Tet us first reflect upon the genernl fact, that, whilst all the stratified formations are composed either of crystalline and paleozoic rocks, or of secondary and tertiary deposits, gold has never heen found in any appreciable quantity in either of the two last-menutioned classes of strata. The vast areas, therefore, which are covered hy all such younger formations are excluded from the application of onr reasoning ; and every one who lives in tracte the subsoil of which consists of such rocks, may at once be assured, that he can never profitahly extract gold from them. Having laid down this generalization, which affirms that hy far the largest portion of land ou the face of the globe never contains gold, we proceed to consider the nature and limits of the gold-hearing rocks, nnd then indicate how the chief wealth is derived from superficial auriferous drifted materials or gravel. Appealing to the structure of the different countries which at former periods have afforded or still afford any notahle nmount of gold, we find in all a general agreemeut. Whether, referring to the ancient history, we cast our eyes to the countries watered hy the Pactolus of Ovid, to the Phrygia and Thrace of the Greeks, to the Alps* nnd golden I’ gns of the Romans. to the Bohemia of the Middle Ages, to tracts io Britain which were worked in old times, and hove either heer: long abandoned or are now scarcely at all productive, or to to those chains in America and Australia which, previously uusearched, have, in our times, proved so rich —we invariably find the same constants in nature. In all these lands, gold has been imparted abnndantly to one class only of those ancient rocks whose order and succession we have traced, or to the associated eruptive rocks. The most nsual, original position of the metal is in quartzose veinstones that traverse altered Silurian slates (chiefly Lower Silurian), frequently near their junction with eruptive rocks. Sometimes, however, it is partially diffused through the body of rocks of igneous origin.” “Seeing. on the one hand, that the oldest rock, and, on the other, the medinl and youngest deposits never contain gold, and that yet (as will he shown) the metal ie of recent accumulation ex masse, it might seem to follow that there existed in those original deposits which have since become largely auriferous, the elements out of which gold was subsequently hrought together in rich veinstones. It is indeed a tact, ns will hereafter he shown, that there are fine-grained old schistose sediments in which gold is so impalpahly disseminated, that it ie difficult to imagine how this diffusion could have occurred if the original menstruum had not contained the elements of the ore. In that diffused state the gold may have remained long after the consolidation of the sediment, until, in ages long posterior, it was run together into metallic veinstones by metamorphic action, or segregated into the lumps and filaments in which it now occurs. But, however we may account for them, the facts are those which I have for many years exposed—viz., that a certain geological zone only in the crust of the globe has heen rendered richly auriferoust}. *In truth, as above expressed, every old country of Europe, where tho rocks were onco aurifcrous, bas long ecased to yleld any yaluable amount of gold. In referenco to the Alps, 1am indebted to my learued friend Mr, J. W. Cowell for pointing out to me the following passage iu Strabo (Book iv. ch. 6, sect. 12), by which it appears that even Imperial Rome was at ovo timo inundated with a glut of goid from her Northorn mountains —* Polybius says that in bis lime the gold mines were so rich about {oorth of ?] Aquileia, but especially in the country of the Taurise: Norici, that if you dug but two feet below the surface you found gold. and that the diggings (generally) were not deeper than 15 feet ; that in some instances the gold was found pure, in lumps of the size ofa bean or a lupin, and which lost ouly one-eighth in smelting, in others it required more smelting. but was very profituble. Jtaljansaiding the barbarians intho working for two months, gold becamo forthwith oue-third cheaper over the whole of Italy ; and tho Turisci discovering this, drove the associate Italians away and monopolized it themsolves. At present all gold mines belong to the Romans.” + When preparing this work for press, Ireccived a letter from Mr, Lieber, the State Geologist of South Carolina, which, being explained by 2 second letter from that gcntleman, in reply to ono which Taddressel to him, conlains a little tahle which cloarly expressos bis views as derivod from hig experience in South Carolina and the Bruzils, Tracing out the peculiar features of the “ itacolumite ” and its associated rocks of * itaberite” and “ specular irou scbist,’? and a compound of tale und magnetic irou, which he terms “ entawhberite,” Mr. Lieber afirms, that*these rocks, together with clay and taleoso slates, are chiefly auriferous, and that none of the recks above them ever bear gold, whilst the miea slates bencath aro mue!: less productivo of the ore, Ho consequently clussifies the whole in ascendiug order, xs Sub-auriferous, Aurilerous, and Post-auriferous—a mineral classification which is in accorfance with the data 1 have long endeavored to establish by geological and paleontological proofs, To se ResuneD.—The line of steamers hetween New Orleans and San Francisco, susnended hy the Rehellion,is to he again in operation. On the Ist of Jannary, the Pacific Mail Stenmship Company isto place a steamcr on the line from New Orleans, via Havana, to Aspinwall, connecting at the latter place with the steamers to and from San Francisco. Some of the principal New York hotels talk of raising the price of hoard to $6 per day. There are families in the Fifth avenue who give $500 or $600 a week for their mere lodging and hoarding privilege, while their extras”

will reach $300 or $400 more. a [Wrltten for the Mining and Scientlfic Press.} Gold Bearing Sulphurets and their Reduction.” REPLY £0 “A STUDENT OF METALLUOICAL CHEMISTRY.” Messrs. Eprrors :—I notice in your issue of the 23d ultimo,a communication signed “ A Student of Metallurgical Chemistry,” in which the motives of my contrihution to yonr‘journal, of Decemher 9th, are unjustifiahly attacked, and the positions assumed by me attempted to he controverted. : I would premise my reply to the author hy hinting thatthe perusal of the gentleman's communication, without the signature, conveys evidence that it is written by a student, and certainly one not very far advanced in his studies. My ohject is not concealed, nor is any at-. tempt made at the same. It was written for . the benefit of the mining community of Caliples ofichemistry, claiming to be competent to sextract the precious metals from their ores. abandoned, miners ruined, public confidence shaken in all mining operations, and the production of the precious metals limited to about one-third of what it ought to he. The method invented by myself for the reduction of the precious metals from the goldbearing salphurets was not “nbandoncd as impracticable.” On the contrary, it is available for treating sulphurets rich in gold, especjally some of those at Grass Valley, hut not for those holding so small an amount as $20 per ton where labor is high. ‘ I did not condemn the common reverberatory furnace—these are my words : “ By means of this method the precioue metals are “ freed” wheu contained in hi-sulphide of iron ;” neither was! ignorant that condensing chamhers form an essential part of said furnace ; alluding to the mechanical loss of gold, I said, “ it is loss unless some means be employed for its collection.” In copying the manuscript, I inadvertedly omitted the following to complete the paragraph: “This method is too slow and expensive for California.” (did not disapprove of reverheratory fornaces for the purpose of chlorination. Reterring to the “ Chlorination “Process,” I spoke of oxidation heing performed iu theni previous to the treatment of the mase hy chlorine, ete., @ process it would appear the “ Student” is unacquainted with. IL did not discredit the methods of the distinguished Metallurgists, Agustin, Ziervogel and Von Patera; these employ said furnaces for a purpose foreign to the suhject in question. My remarks were confincd solely to the treatment of gold hearing sulphurets, a euhject I profess to undcrstand. I have nothing to retract concerning “ inventions in the shape of furnaces ;” two of the said inveutors have admitted to me that their iuventions did not answer their expectatiuns. Iam uot at liberty to pablish their reasons. , Regarding the peformance of “ The Gold and bilver Separating Company’s Furnace” (Dr. Hagan’s) the “ Student” seems to intimate that thecrade sulphurots taken for assay did not represent the “ mass mixed” from which the third assay wns made; I will endeavor to eulighten him on this point, thanking him ip the first place for correcting a typographical error. It seeins the gentlemanis an arithmetician, as well as a student of metallurgy. Assuy fist is the mean of five assays made on as fair a sample of the ernde mineral as could he ohtuined ; they not disagreeing wore than some $30 ahove, nor $11 per ton less than the meau (not an oucomimon occurreuce). Assay third is likewise the mean of five assays made on the mass after treatincnt, obtuined ina like manner to that hy which the sainple from which assay firs? was made; these disagreed from $45 above to $26 per tou helow the mean, thas showing that a fair sample was ohtaincd. Siath assay of the tailings ; this was an assay of the “refuse” nfter amalgamation ; had I made no series of them (1 considered it unnecessaiy to do so), “the agerecate of the extraction and that left inthe tailings” night have equalled the amount as per nssay third; as itis, I consider assay sixth sufficiently exuct forall pructical purposes; from these results, along with those of the otncr threc experiments. I considered myself justified in arriving at this fair conclusion, omitting fractions of a per cent., viz: 55 per cent., de-. sulphurized ; 16 per cent., lost ; 52 per cent. . extracted and 32 percent. left in the tailinge. The treated mass was ainalgamated, and the amaleam carefully separated hy a“ Workman” without any apparent loss. Again, the * Student” is unwilling to admit that there was any loss of gold during treatment. I maintain that ‘there was, knowing that fair eamplee were ohtained for aseay hoth before and after treat. ment. He says: “ But aside from this, add the . fixed, positive data obtained hy the extraction -of $205.12 to that ehown by assay remainuin in the tailings, and we have $205.12+146.12 =$351.24. Now, suhtracting this Inst sum from the assay of the crude sulphurets=$395. 48—351.24—=44,24 per ton, or not quire twelve per cent. loss.” This quasi admitted loss from a 55 per cent. desulphurization, or rather say what is warranted by the “ Student’s” arithmetic, 11.19 per cent., added to 9.15 per cent., corresponding to the complemeut (45) of 100 per cent., would make 20.34 per cent. loss, provided the whole of the mineral had heen desalphurized; so it would appear that the minimum mechanical loss of gold mentioned in my communication (20 per cent.) wonld have heen experienced had the farnace heen capable of i . doing what it is represented to do, fornin, who have heen so often imposed npon j/ hy persons entirely ignoraut of the first princi} sulphide of iron. 1 cannot see the analogy hetween decarhonizing carhonate of lime aud desulphurizing biThe first isa proto-sall, the second alernary compound. Heat decomposes the former, whereas it does not separate the What has heen the result? Vnolunhle mines 1 E whole of the sulphur from the latter. I do not advance this by way of proof to show that hisulphide of iron cannot he deselphurized in lumps, hut merely to show the fallacy of the « Student’s ” reasoning. But the “Student” is continually harping on the “ effectual method,” and naively says: “This method is mainly commended to our confidence, from the circumistance of his being requested to examine the performance of this furnace {using his own words) in my professional capacity.” Verily, this is arriving at a conclusion with a vengeance. Experiments were niade hy me years ago on sulphorets in lnmps, both with steam and without it, for the purpose of desulphurizing them. I nlways obtained a negative result. On the contrary, I have experimented on *‘ tolerably fine crushed ” sulpharets in an arrangement similar to Mr. White’s, on the same principle, and obtained desulpharization of tho mineral, with the exception of some milliemes of sulphur that was found associated with iron and oxygen ; this small portion was not inimical tothe extraction of the precious metals from the oxidized mineral by amalgamation. I am aware that Mr. White's furnace was exhihited to the public at Newark, New Jersey, about eighteen wonthe ago. Several chemists and persons engaged in the husiness of testing ores witnessed its performauco. Some of them gave certificates regarding its merits. One “student ’ was nmoug the number. Any competent investigator will find no difficulty in pertorming experiments to satisfy himself that what I have stated regarding the two tarnaces (Dr. Hagan’s aud Mr. White's) is true. Certainly no candid person will deny that the objections urged hy the “student ’’ against the comnion reverheratory furnaces are overcome in Mr. White’s, viz :—*‘ the expense of huilding and keeping them in repair, the trouble and cost of working the ore properly, and the constant drend of careless and indifferent workmen, upon whom the successful working of the ore chiefly depends.” The cost of Mr. W.’s is less in proportion thau the common furnnces, considering the amount of work it is capahle of perlorming. The attendance of one workman is only required to keep up the requisite degree of heat, and feed the hopper with the ground mineral, which discharges itsclf at the other end, the wear and tear being trifling, while the coil of pipe in the chimney, from which jets of cold water are ejected, acts the part of a condensing chamher, thus securing a compact apparatus as wellasacheap method. . There is an old adage—* The greatest thief always calls thief first.” So the “ Student’s ” communication, accusing me of interested motives, will readily convey conviction to the mind of the most uhtuse reader, that his object is to holster up a process that had sunk into ohscurity, aud is now attempted to he revived under a new patent. The “ Student” appears not to confine his glowing intellect to the study of metallurgy only; bat assumes to occupy the chair of a modern Chesterfield, and read me lessons upon taste and propriety; yet as I have already lived the greater part of a long life, I would suggest to him that his labors in this hehalf are not appreciated. I would also suggeet to him that in the scientific world, at least, the names of individuals heing given is, to some extent, a guarantee of good faith; and if the “Stadent” has heen more than three months in this city, and is of sufficient age to have. experience in the matters in controversy to give weight to his opinions, it might be well tor him to shake off his cloak of modesty and let your readers know to whom they are indehted for