Volume 11 (1865) (424 pages)

386 The Hlining and Srientific Press, Gonmanvicntions. In THs DEPARTMENT we ilivite the FREE Discussion of all roper SUnEC corey hong alone being responsible for hie idcas and theortes they advance. Mining in the Pacific States, etc, Past, Present and Prospective, , BY PROFESSOR ROWLANDSON, F. G. 3. L. MORE ABOUT THE COST-BOOK SYSTEM. It was troly remarked, in a leading article in the Inst number of this journal, that Idid not wish this community to adopt the Cornish Cost Book syetem in its entirety ; I merely recomMending it to notice, in order that the hetter part of its provisions might prove suggestive of amendmente in regard to the rules which now apply in Californin, ete., ete. The Cost Book eyetem originated in n condition of things not greatly dissimilar to what existed at the time thnt placer mining commenced in California. Read stream tin for placer gold, and the comparison holds good throughout—tin-hounding heing the equivalent to putting down a stake and notice. It is a fact, worth noting that it is customary at the present day to set up a pole at every mine in Cornwall. JI have repeatedly inquired the reason of this, hut never could glean any more eatisfactory answer than that it was a very old custom, so old that no one knew its origin. As copper mining in that country is of very recent origin, not dating earlier than the commencement of tlie seventeenth century, and originated probably in consequence of working or searching for tin, it may he safely concluded that the custom of setting upn pole at every separate mine originated hefore that period, especially as copper mining in that district scarcely acquired much economic importance, until nearly. the middle of tho eigliteenth century, its great development not occurring earlier than the latter part of the last centnory, when the great impulse was given to mining, especially where deep, by the introduction of Watts’ improved engines. In order to avoid entering on any mythical theories respecting the course pursued by “ etreamers ” in the division of the proceeds of their labor, when the Pheenicians traded to Cornwall for the tin, which probably ultimately formed part of the bronze instruments and castings found by Layard, Rawliuson, and others in the ruins of Babylon, Ninnevah, etc., T shall proceed to more particularly state than Idid in my former paper, the more recent hut somewhat primitive mode of conducting periodical meetings under this system. Ae previously related, so far as we are informed by modern tradition, periodical meetings, under the Cost Book system, were usually held monthly, eometimee at tbe mine, but more frequently at an ale-house ; the adveuturere generally consisting of well-to-do farmers, shop and storekeepers, laborers, and overseers of the mine, with, occasionally, a speculating gentleman nf landed estate, or,as sometimes happened, a henevolent person of the eame class who would take a emall risk for the eake of affording an additional source of employment to workmen resident in his vicinity. It will he easily apprehended from the description given that all euch persons would not only possess considerahle local knowledge, hut, from their pteximity to the mine, would he enahled to personally examine into its management. These were advantages which conld not he possessed hy a distant proprietory. Notwithstanding the dieadvantages under which the latter would lahor, it has rarely if ever occurred that any serious inconvenience hae arisen in consequence, excepting in cases where down-right ewindling has actuated promoting parties, aided by employees appointed by their influence. As Inining became more extensive, and the capitnl was chiefly found hy contributors who resided at a dietance, quarterly meetinge were found eufficient, hut not too frequent—in fact, practically formed the just medinm. Suhmitting what may he termed the legislative power to the body nf etockholders, in mining corporation withiu periods not exceeding three months, and the executive anthority in that of trustees or agents during’ the interval, cannot be go productive of evil as in the case of ordinary trading, banking, commercial, or manufacturing associations; in such the ex. ecutive department necessarily requires an amount of confidence not atall necessary in niining operations. In the last-named questions of credit, rise or fall in markets (excepting in a very trifliug degree), either ns respects huying in or selling off, scarcely ever arise, whilst in the first part named it will be at once secn how injurious it would be to publicly canvass such points. Mining is necessarily a slow proceeding. Setting off with the commencement of works at a new mine nnd accompanying mill, it will rarely occur that the latter will be found ready for working under twelve months, during which period all that would be requisite to be done would be to supply the funds periodically, as required ; it beiug always understood that at the commencement something like an approximately correot estimate is exhibited to the etockholders, not only of the entire cost, but also the probable time the works would require for their execution, and the sums needed at different intervals. The power of the engine to be ordered, the size of buildings, according to a plan furuished, amount of stores to be ordered, or powder, candles, etc., by way of stock, may all be legitimately discussed and legislated on by the general stockholders in meeting assembled, without injury to their common interests ; but the mnking contracts for engines or supplies, together with all matters relating to general management, may safely and properly be left to the trustees as the executive body. It will thus be seen that the executive manngement will remain with the periodically appointed officials. When a mine is about to be opened, the first duty of a superiuteudent is to lay before the trustees, nnd the latter afterwards to lay before the stoekholders, a general plan and estimate for opening the mine. Wheu executed, it can rarely happen that any serious mischief can arise in three months, either from improper sinking, or driving, or delaying either for such a period. Asa usual thing, all these matters are first designed and reported ou bya qualified suncrirtendent, and if approved at the periodical meeting, carried iuto effect without further interference of the general body. OF course, such a system implies the appointment of a qualified person or superintendent. To expect practical advice on mining and metallurgic managemeut from a euperintendent only recently called from the counter, the desk, the stage, or a ship, would he abeurd ;+ yet, from such sources hnve superintendents beretofore been appointed. Perhaps the only feature connected with the Cost Book system which may probably require serious alteration, will be tbat part of it which relates to the forfeiture of delinquent stock. The present laws which affect. the sale and forfeiture of such, are, however, so defective that some alteration must be mado ; for as they now exist, they are so parodoxical that it is almost impossible for trustess to make a legal sale of delinquent shares ; and in some cases, such ag” where the operations are carried on at distaut places, like Arizoun, time will not permit the couditions of tbe law to be complied with. As a perhaps not inappropriate pendant to this subject, it may be worthy of notice that if we compare the ancient laws relating to tinstreaming and tin-bounding, in Cornwall, of miners claiming their “meer” from the barmaster of the High-Peak, in Derbysbire, in order to work for lead, or the more recent but still ancient “ gales” for mining for coals and iron in the Forest of Dean, Gloucestershire, in Eugland, the ancient mining laws of Saxony, with the laws of placer and quartz mining in California and Australia, a great likeness exists, showing that a common pricciple of equity has pervaded and still pervades mankind in all ages and places, however remotely dissevered hy distance or remoteness of time. It might he well, perhaps, if local miuing courts could be established, euch as the stannames and harmaster courts, for settling rights and disputes in the lead district of t:e High Peat. MODES OF RENUCTION. Respecting the various feasible known modes of economically reducing silver ores,a very concise recapitulation appeared, from the pen of Professor Lanszweert, in the number of the Minine,anp Screntiric Press issued on the 2d Instant. About five years ago I published a somewhat similar statement, omitting only two of the methods detailed by Professor Lansz weert,viz., the old Hungarian and Gurlts’ process. the former is expensive, rather inefficient, and if ecrap iron is not employed, the pans of iron soon hecome useless from corrosion. Until the article of the Professor came under my notice, I was not awnre'that the use of the cbloride of copper (Gurlte’ method) ever attained the distinction of a special process. Few silver ores are found without containing some copper, which, if the ore is roasted, and common salt is afterwards snpplied, will at once convert the sulphate of cope formed by the roastiug into a chloride. it has, however, hitherto been fonod that when the chloride of copper is present, the silver har obtained ¢ontains a large admixture of copper; such is found to be the case in Saxony. It is possible, however, that in the instance jnet named, thnt the alloy of the eilver with copper is, in a great degree, the consequence of employing iron to reduce the chloride of silver, the nse of which will precipitate a proportion of the copper also. This (Gurlts’) method, however, is one worth attention, because when once put into operation, it will not require any great amount of scientific skill to maintain it in continuous working order. Whether it possesses any material efficiency as a solvent over the use of common salt alone (Augustin’s process), I am not prepared to either assert ordeny. It appears to possess advantages over what Profeseor L. terms Partode’s process—namely, the use of ammonia. Why this last-named method has been termed “ Partode’s,” I cannot imagine’ or account for, other than by the very common circumstance that the earlier proposers and discoverers of improvements not unfrequently are dead and forgotten, and their wisdom buried in oblivion, until a generntion or two have succeeded them; after which, some favornhle opportunity occurring for putting their suggestions into practical operation, up starts some pseudo discoverer or pretended inventor who claims and obtains all the honor and profit. In the letters written by me, already alluded to, I named the employment of ammonia, and I think, also, gave due credit to its first proposer, Berthier, who, about thirty years ago, wroto as Iollows : : “ Le mercure ayant maintainant on tres-hnut prix, et etant un cause de grand depense dans le traitement des minerals d ‘argent par ln chloruration, on cherce par toutes voies a se passer ce metal. Qn sait depuis longtemps qu on pourrait le remplacer par . ’ ommoninque on par le carbonate d’ammouiaquo, qui dissolvent le chlorure de’argent avec un tres grand facitite, maie on n’s pas encore fait usage de ces agents. Je crois que le moment es venn de les employee,” ete., which may be translated as follows: Mercury having maintained a very high price, and a cause of great expense in treating silver ores by chlorination, all ways have been sought toavoid the use of this metal, which, alter considerable thought, it would appear, may be replaced by ammonia or carbonate of amnionia,* which dissolves the chloride of .eilver with great facility. The use of ammonia, unless yery accutely fitting closed vessels nre employed, would be n great nuisance. ‘Ihe restoration of ammonia from the chloride formed would require the attention of a more elaborate chemical apparatus than would be generally comprehended by ordinary workmen. In fact, to keep this process in working: order, would necessitate the constant attention of a skilled person. Whether the use of chloride of ammonia iu place of chloride of sodiun (common salt) would be of advantage suflicient to more than recompense the extra outlay required by employing this more expensive material, 1 am uot prepared to state. It may, however, be remembcred that chloride of ammonia (the chenpest source of ammonia) could not be landed in Sau Francisco at a cost less than one hundred dollars per ton, above that of common salt. Ammonia and its compounds could, however, with careful attention to their manngement, he nsed over and over again, with very little loss. Where the silver is combined solefy with chlorine, or mixed with othér haloid substances asiodine or bromine, ammonia and its salts might prohahly be economically employed, as however natural chloridee are almost invariably asscciated with a greater or less proportion of sulphides and native silver, these must escape the action of ammonia and its compounds; or if any took place, it would prohably he the following reaction: the conversion of the existant native silver into a sulphide, which is insoluble in those suhstances. a shall only hriefly refer to the so-called Von Pateras’ process, partly with the the object of remarking that, like Partode’s, the title is not assigned to the proper diecoverer. Five years ngo I very fully gave the details of this method, which was the discovery of Dr. Perey, Protessor of Metallurgy in the School of Mines, London, whose elaborate works on Iron, Copper, etc., are well known. It was introduced in order the more easily to extract silver from the chlorides, chloro-iodides, and chloro-hromedes of silver, which, about twenty-five years ago, were discovered and worked at some plnoces in Chili to an immense extent, as at Chanarcillo, for instance ; eoon after its introduction,}’ Dr. William Brande, master of the British Mint, recommended the waste lime from the purifiers of gas works, as a cheap sonrce for obtaining the solvent (hyposulphite of soda) recommended by Dr. Percy. This ‘ gas lime” contains a considerable quantity of hyposulphite of lime, which, by double decomposition, *Chloride of ammonia (sal ammonia) will produco the like effect, but not so rapidly. 1 helicve I mentioned this fact in my former Ictters, 4) fFor a description of this process sce Professor LauszWeert’s papor in the Miniyg Preas of the 2d December, instant. > © can be converted into hyposulphite of eoda. Gas lime, however, ie not easily attainnhle nt the mines ; the hyposulphite of eoda can, howfever, be manufactured by other modes; hut to.do so, a8 well as to make the precipitant . (five-fold snlphide of eodium), a person possessed of some skill in chemistry wonld-be required, whose presénce, would also he generally necessary for the purpose ot seeing that { the procese was nlways in working order. The employment of hydrosulphite of soda as a solvent, ond the five-fold sulphide of sodium as a precipitant, is a most effective, and prohably the cheapest, method of reducing the natural” chlorides of eoda ; in case, however, these are mixed with sulphides or native silver, or both, te the-extent that these“exist in any ore, it will he found ineffective. l The defective pointe in these two last described methods, will be alluded to when the subject of chloridizing (one of the great sources of loss), is reviewed. Nore.—It was not until the preceding article had been placed in type that the writer discovered a serious crror, into which he had heen inadvertently Jed, by not having read with snfficient attention Professor L.’s description of Gurlts’ process, namely : the allusion to the posribility of the silver har, so obtained, being considerably alloyed with copper. The mistake arose from erroneously conceiving that Gurlts’ method was an amalgamating process, in place of simply being a humid ono. Tho differeuce is highly important. The requisito cxplapation will be given next week; to which attention is asked, as the theory of the action which takes place, as explalned hy Bonssingault, who was the first discoverer of the principle, throws much light on tho suhject of amalgamation— the Patio method, in particular. [Written for the Mining and SclJentifie Press] “Gold-Bearing Sulphurets and their Reduc: tion.” .An article published in the Minina anp Scientiric Press of Nov. 9th, under the above caption, has attrncted some attention, both by cause of the subject nnd by reason of the air of authority assumed in the signature of its author. One who signs himself a “ Metallorgical Chemist” should have respectful attention, if the title is not an assumed one; and hie opinion, when pronounced, should carry weight, if disinterested and carefully prepared, with the view of enlightening the public on a matter of science. The subject is one of grave importanco to the futuro mining prosperity of this State. Many of the most valuablo mines are almost. wholly abandoned, from the want of an efiicicnt and reliable process for freeing the precious metals, so that they can be extracted profitably. On this account, and by renson of tho wany failures of recent processes to mcet this want, the mining public scrutinize closely not only the projects of inventors, but also the reasons sct forth by those who commend them to their confidence. Had the above named article becn eimply signed “John Scott,” it would have passed without notice, as the effort of one interosted _ in promoting the “invention” which it endorses, and boldly commends to the public. This design is scarcely coucealed, though an effort to thnt effect is attempted. It may be questionable policy for an inventor to advance the success of his contrivance by condemning all other plans used or sought to bo introduced for the eame purpose; but it ie not usually deeined good taste for a professedly scientific man to publish his professional endorsement over hie own eignature, in a scientific pnper, unless he is wholly disintereeted, and then only after a thoroughly careful investigation of the merits of the new invention; and especially must it he questionable good taste, if the Professor undertakes to discredit, unfairly, all past and present processes “ seen” or merely ‘heard of,” in order to obtuin a stand-point for the commendation of a new invention. A fair and judicious discussion of provailingmethods, as also thoee proposed as eubstitutes or improvements, is must desirable; hut it is not only desirable, hut actually essential, that no professional sanction he affixed to a new method, unless upon sound reasons aud after a practical working of the proposed improve-_ ment. = If the nhove-named article be examined in . this light, it will be found sadly wanting in all the requisites of candid statement, disinterested discussion, and scientific investigation, with regard to those methods eo curtly condemned as bad, as well as to that which is so flatly commended .to the confidence of the public. The author states, seemingly in order to impress one with his peculiar ability in this

386 The Hlining and Srientific Press, Gonmanvicntions. In THs DEPARTMENT we ilivite the FREE Discussion of all roper SUnEC corey hong alone being responsible for hie idcas and theortes they advance. Mining in the Pacific States, etc, Past, Present and Prospective, , BY PROFESSOR ROWLANDSON, F. G. 3. L. MORE ABOUT THE COST-BOOK SYSTEM. It was troly remarked, in a leading article in the Inst number of this journal, that Idid not wish this community to adopt the Cornish Cost Book syetem in its entirety ; I merely recomMending it to notice, in order that the hetter part of its provisions might prove suggestive of amendmente in regard to the rules which now apply in Californin, ete., ete. The Cost Book eyetem originated in n condition of things not greatly dissimilar to what existed at the time thnt placer mining commenced in California. Read stream tin for placer gold, and the comparison holds good throughout—tin-hounding heing the equivalent to putting down a stake and notice. It is a fact, worth noting that it is customary at the present day to set up a pole at every mine in Cornwall. JI have repeatedly inquired the reason of this, hut never could glean any more eatisfactory answer than that it was a very old custom, so old that no one knew its origin. As copper mining in that country is of very recent origin, not dating earlier than the commencement of tlie seventeenth century, and originated probably in consequence of working or searching for tin, it may he safely concluded that the custom of setting upn pole at every separate mine originated hefore that period, especially as copper mining in that district scarcely acquired much economic importance, until nearly. the middle of tho eigliteenth century, its great development not occurring earlier than the latter part of the last centnory, when the great impulse was given to mining, especially where deep, by the introduction of Watts’ improved engines. In order to avoid entering on any mythical theories respecting the course pursued by “ etreamers ” in the division of the proceeds of their labor, when the Pheenicians traded to Cornwall for the tin, which probably ultimately formed part of the bronze instruments and castings found by Layard, Rawliuson, and others in the ruins of Babylon, Ninnevah, etc., T shall proceed to more particularly state than Idid in my former paper, the more recent hut somewhat primitive mode of conducting periodical meetings under this system. Ae previously related, so far as we are informed by modern tradition, periodical meetings, under the Cost Book system, were usually held monthly, eometimee at tbe mine, but more frequently at an ale-house ; the adveuturere generally consisting of well-to-do farmers, shop and storekeepers, laborers, and overseers of the mine, with, occasionally, a speculating gentleman nf landed estate, or,as sometimes happened, a henevolent person of the eame class who would take a emall risk for the eake of affording an additional source of employment to workmen resident in his vicinity. It will he easily apprehended from the description given that all euch persons would not only possess considerahle local knowledge, hut, from their pteximity to the mine, would he enahled to personally examine into its management. These were advantages which conld not he possessed hy a distant proprietory. Notwithstanding the dieadvantages under which the latter would lahor, it has rarely if ever occurred that any serious inconvenience hae arisen in consequence, excepting in cases where down-right ewindling has actuated promoting parties, aided by employees appointed by their influence. As Inining became more extensive, and the capitnl was chiefly found hy contributors who resided at a dietance, quarterly meetinge were found eufficient, hut not too frequent—in fact, practically formed the just medinm. Suhmitting what may he termed the legislative power to the body nf etockholders, in mining corporation withiu periods not exceeding three months, and the executive anthority in that of trustees or agents during’ the interval, cannot be go productive of evil as in the case of ordinary trading, banking, commercial, or manufacturing associations; in such the ex. ecutive department necessarily requires an amount of confidence not atall necessary in niining operations. In the last-named questions of credit, rise or fall in markets (excepting in a very trifliug degree), either ns respects huying in or selling off, scarcely ever arise, whilst in the first part named it will be at once secn how injurious it would be to publicly canvass such points. Mining is necessarily a slow proceeding. Setting off with the commencement of works at a new mine nnd accompanying mill, it will rarely occur that the latter will be found ready for working under twelve months, during which period all that would be requisite to be done would be to supply the funds periodically, as required ; it beiug always understood that at the commencement something like an approximately correot estimate is exhibited to the etockholders, not only of the entire cost, but also the probable time the works would require for their execution, and the sums needed at different intervals. The power of the engine to be ordered, the size of buildings, according to a plan furuished, amount of stores to be ordered, or powder, candles, etc., by way of stock, may all be legitimately discussed and legislated on by the general stockholders in meeting assembled, without injury to their common interests ; but the mnking contracts for engines or supplies, together with all matters relating to general management, may safely and properly be left to the trustees as the executive body. It will thus be seen that the executive manngement will remain with the periodically appointed officials. When a mine is about to be opened, the first duty of a superiuteudent is to lay before the trustees, nnd the latter afterwards to lay before the stoekholders, a general plan and estimate for opening the mine. Wheu executed, it can rarely happen that any serious mischief can arise in three months, either from improper sinking, or driving, or delaying either for such a period. Asa usual thing, all these matters are first designed and reported ou bya qualified suncrirtendent, and if approved at the periodical meeting, carried iuto effect without further interference of the general body. OF course, such a system implies the appointment of a qualified person or superintendent. To expect practical advice on mining and metallurgic managemeut from a euperintendent only recently called from the counter, the desk, the stage, or a ship, would he abeurd ;+ yet, from such sources hnve superintendents beretofore been appointed. Perhaps the only feature connected with the Cost Book system which may probably require serious alteration, will be tbat part of it which relates to the forfeiture of delinquent stock. The present laws which affect. the sale and forfeiture of such, are, however, so defective that some alteration must be mado ; for as they now exist, they are so parodoxical that it is almost impossible for trustess to make a legal sale of delinquent shares ; and in some cases, such ag” where the operations are carried on at distaut places, like Arizoun, time will not permit the couditions of tbe law to be complied with. As a perhaps not inappropriate pendant to this subject, it may be worthy of notice that if we compare the ancient laws relating to tinstreaming and tin-bounding, in Cornwall, of miners claiming their “meer” from the barmaster of the High-Peak, in Derbysbire, in order to work for lead, or the more recent but still ancient “ gales” for mining for coals and iron in the Forest of Dean, Gloucestershire, in Eugland, the ancient mining laws of Saxony, with the laws of placer and quartz mining in California and Australia, a great likeness exists, showing that a common pricciple of equity has pervaded and still pervades mankind in all ages and places, however remotely dissevered hy distance or remoteness of time. It might he well, perhaps, if local miuing courts could be established, euch as the stannames and harmaster courts, for settling rights and disputes in the lead district of t:e High Peat. MODES OF RENUCTION. Respecting the various feasible known modes of economically reducing silver ores,a very concise recapitulation appeared, from the pen of Professor Lanszweert, in the number of the Minine,anp Screntiric Press issued on the 2d Instant. About five years ago I published a somewhat similar statement, omitting only two of the methods detailed by Professor Lansz weert,viz., the old Hungarian and Gurlts’ process. the former is expensive, rather inefficient, and if ecrap iron is not employed, the pans of iron soon hecome useless from corrosion. Until the article of the Professor came under my notice, I was not awnre'that the use of the cbloride of copper (Gurlte’ method) ever attained the distinction of a special process. Few silver ores are found without containing some copper, which, if the ore is roasted, and common salt is afterwards snpplied, will at once convert the sulphate of cope formed by the roastiug into a chloride. it has, however, hitherto been fonod that when the chloride of copper is present, the silver har obtained ¢ontains a large admixture of copper; such is found to be the case in Saxony. It is possible, however, that in the instance jnet named, thnt the alloy of the eilver with copper is, in a great

degree, the consequence of employing iron to reduce the chloride of silver, the nse of which will precipitate a proportion of the copper also. This (Gurlts’) method, however, is one worth attention, because when once put into operation, it will not require any great amount of scientific skill to maintain it in continuous working order. Whether it possesses any material efficiency as a solvent over the use of common salt alone (Augustin’s process), I am not prepared to either assert ordeny. It appears to possess advantages over what Profeseor L. terms Partode’s process—namely, the use of ammonia. Why this last-named method has been termed “ Partode’s,” I cannot imagine’ or account for, other than by the very common circumstance that the earlier proposers and discoverers of improvements not unfrequently are dead and forgotten, and their wisdom buried in oblivion, until a generntion or two have succeeded them; after which, some favornhle opportunity occurring for putting their suggestions into practical operation, up starts some pseudo discoverer or pretended inventor who claims and obtains all the honor and profit. In the letters written by me, already alluded to, I named the employment of ammonia, and I think, also, gave due credit to its first proposer, Berthier, who, about thirty years ago, wroto as Iollows : : “ Le mercure ayant maintainant on tres-hnut prix, et etant un cause de grand depense dans le traitement des minerals d ‘argent par ln chloruration, on cherce par toutes voies a se passer ce metal. Qn sait depuis longtemps qu on pourrait le remplacer par . ’ ommoninque on par le carbonate d’ammouiaquo, qui dissolvent le chlorure de’argent avec un tres grand facitite, maie on n’s pas encore fait usage de ces agents. Je crois que le moment es venn de les employee,” ete., which may be translated as follows: Mercury having maintained a very high price, and a cause of great expense in treating silver ores by chlorination, all ways have been sought toavoid the use of this metal, which, alter considerable thought, it would appear, may be replaced by ammonia or carbonate of amnionia,* which dissolves the chloride of .eilver with great facility. The use of ammonia, unless yery accutely fitting closed vessels nre employed, would be n great nuisance. ‘Ihe restoration of ammonia from the chloride formed would require the attention of a more elaborate chemical apparatus than would be generally comprehended by ordinary workmen. In fact, to keep this process in working: order, would necessitate the constant attention of a skilled person. Whether the use of chloride of ammonia iu place of chloride of sodiun (common salt) would be of advantage suflicient to more than recompense the extra outlay required by employing this more expensive material, 1 am uot prepared to state. It may, however, be remembcred that chloride of ammonia (the chenpest source of ammonia) could not be landed in Sau Francisco at a cost less than one hundred dollars per ton, above that of common salt. Ammonia and its compounds could, however, with careful attention to their manngement, he nsed over and over again, with very little loss. Where the silver is combined solefy with chlorine, or mixed with othér haloid substances asiodine or bromine, ammonia and its salts might prohahly be economically employed, as however natural chloridee are almost invariably asscciated with a greater or less proportion of sulphides and native silver, these must escape the action of ammonia and its compounds; or if any took place, it would prohably he the following reaction: the conversion of the existant native silver into a sulphide, which is insoluble in those suhstances. a shall only hriefly refer to the so-called Von Pateras’ process, partly with the the object of remarking that, like Partode’s, the title is not assigned to the proper diecoverer. Five years ngo I very fully gave the details of this method, which was the discovery of Dr. Perey, Protessor of Metallurgy in the School of Mines, London, whose elaborate works on Iron, Copper, etc., are well known. It was introduced in order the more easily to extract silver from the chlorides, chloro-iodides, and chloro-hromedes of silver, which, about twenty-five years ago, were discovered and worked at some plnoces in Chili to an immense extent, as at Chanarcillo, for instance ; eoon after its introduction,}’ Dr. William Brande, master of the British Mint, recommended the waste lime from the purifiers of gas works, as a cheap sonrce for obtaining the solvent (hyposulphite of soda) recommended by Dr. Percy. This ‘ gas lime” contains a considerable quantity of hyposulphite of lime, which, by double decomposition, *Chloride of ammonia (sal ammonia) will produco the like effect, but not so rapidly. 1 helicve I mentioned this fact in my former Ictters, 4) fFor a description of this process sce Professor LauszWeert’s papor in the Miniyg Preas of the 2d December, instant. > © can be converted into hyposulphite of eoda. Gas lime, however, ie not easily attainnhle nt the mines ; the hyposulphite of eoda can, howfever, be manufactured by other modes; hut to.do so, a8 well as to make the precipitant . (five-fold snlphide of eodium), a person possessed of some skill in chemistry wonld-be required, whose presénce, would also he generally necessary for the purpose ot seeing that { the procese was nlways in working order. The employment of hydrosulphite of soda as a solvent, ond the five-fold sulphide of sodium as a precipitant, is a most effective, and prohably the cheapest, method of reducing the natural” chlorides of eoda ; in case, however, these are mixed with sulphides or native silver, or both, te the-extent that these“exist in any ore, it will he found ineffective. l The defective pointe in these two last described methods, will be alluded to when the subject of chloridizing (one of the great sources of loss), is reviewed. Nore.—It was not until the preceding article had been placed in type that the writer discovered a serious crror, into which he had heen inadvertently Jed, by not having read with snfficient attention Professor L.’s description of Gurlts’ process, namely : the allusion to the posribility of the silver har, so obtained, being considerably alloyed with copper. The mistake arose from erroneously conceiving that Gurlts’ method was an amalgamating process, in place of simply being a humid ono. Tho differeuce is highly important. The requisito cxplapation will be given next week; to which attention is asked, as the theory of the action which takes place, as explalned hy Bonssingault, who was the first discoverer of the principle, throws much light on tho suhject of amalgamation— the Patio method, in particular. [Written for the Mining and SclJentifie Press] “Gold-Bearing Sulphurets and their Reduc: tion.” .An article published in the Minina anp Scientiric Press of Nov. 9th, under the above caption, has attrncted some attention, both by cause of the subject nnd by reason of the air of authority assumed in the signature of its author. One who signs himself a “ Metallorgical Chemist” should have respectful attention, if the title is not an assumed one; and hie opinion, when pronounced, should carry weight, if disinterested and carefully prepared, with the view of enlightening the public on a matter of science. The subject is one of grave importanco to the futuro mining prosperity of this State. Many of the most valuablo mines are almost. wholly abandoned, from the want of an efiicicnt and reliable process for freeing the precious metals, so that they can be extracted profitably. On this account, and by renson of tho wany failures of recent processes to mcet this want, the mining public scrutinize closely not only the projects of inventors, but also the reasons sct forth by those who commend them to their confidence. Had the above named article becn eimply signed “John Scott,” it would have passed without notice, as the effort of one interosted _ in promoting the “invention” which it endorses, and boldly commends to the public. This design is scarcely coucealed, though an effort to thnt effect is attempted. It may be questionable policy for an inventor to advance the success of his contrivance by condemning all other plans used or sought to bo introduced for the eame purpose; but it ie not usually deeined good taste for a professedly scientific man to publish his professional endorsement over hie own eignature, in a scientific pnper, unless he is wholly disintereeted, and then only after a thoroughly careful investigation of the merits of the new invention; and especially must it he questionable good taste, if the Professor undertakes to discredit, unfairly, all past and present processes “ seen” or merely ‘heard of,” in order to obtuin a stand-point for the commendation of a new invention. A fair and judicious discussion of provailingmethods, as also thoee proposed as eubstitutes or improvements, is must desirable; hut it is not only desirable, hut actually essential, that no professional sanction he affixed to a new method, unless upon sound reasons aud after a practical working of the proposed improve-_ ment. = If the nhove-named article be examined in . this light, it will be found sadly wanting in all the requisites of candid statement, disinterested discussion, and scientific investigation, with regard to those methods eo curtly condemned as bad, as well as to that which is so flatly commended .to the confidence of the public. The author states, seemingly in order to impress one with his peculiar ability in this