Volume 13 (1866) (424 pages)

40 The Wining and Scientific Dress. Mining aud Scientific Yves, W. BE. EWER, 22. SENIOR Eptror. G. W. M. SMITH. W. B. EWER. A. T. DEWEY. DEWEY & CO. Publishers. Orvicr—No. 505 Clay street, corner of Sansome, 2d floor. Verms of Subseription: One copy, per annum, in advance, One copy, six months, in advance, gp For sale by Carriers and Newsdealers. 62 American and Foreien Patents,—Letters Patent for Inventors can be secured in the United States and foreign countries throush the Mixing anp Scientiric Press Parent AcEncy, We offer applicants reasonable terms, and they can rest assured of a strict compliance svith our obligations, and afaithful performance of allcontracts. For reference, we will furnish the names of numereus parties for whom . we have obtained patents during the past two years. ' San Francisco: Saturday Morning, July 21, 1866. GOLD SAVING EXPERIMENTS IN AUSTRALIA. The great loss of fine gold in the ordinary manipnlations of geld ores, is fully recognized by the Australian gold miners, where experiments have pretty conclusively proven that from twenty to twenty-five per cert. of all the gold in the ore is lost, without taking into acconnt the loss from imperfect working of the eulphurete. The current of water introduced into the hattery, and sent through the various cnotrivances for bringing the gold into contact with the mercury, in the process of amalgama. tion, keeps a large portion of the very fine gold constantly afloat, nearly all of which passes away with the water and pulp. . i In numerous experiments made with ore from Steiglitz, Ballarat and the-Ovens, by Rev. Jobn J. Bleasdale nnd Count John Dembinski, aud several times repeated, to avoid mistakes, the samples were teken, crushed and divided into eqnal parts, one-half of which was treated raw, iu the usua] manner—stamped, groundin Chile mills or pans, and subsequently treated by an amalgamation process, not deecribed in the authority before us; while the other half was roasted and submitted to the chlorine process. The mean of four experiments showed on incrense by the chlorine process of nearly thir ty-eight per cent. over the ordinary working process, with the aid of mercury. In order to still further test the loss by working procees, other experiments were performed, by mixing known nmounts of gold with ordinary sea sand, as follows: Five grains of gold, made chemicolly fine, by precipitation, were added to an equal weight of gold in a very fine state of mechanical separation ; the ten grains so preparcd were mixed with 10,000 greins of sea-sand, and the whole ground toa fine pulp. Several lots were thas prepared, ench contnining a known quantity of gold. ‘Thceee lots were then suhmitted, the one to the ordinary process, and the other to the chlorine process. The result of one of these experiments, given as an average, was the saving of 3.21 grains hy mercury ; and 4.62 by the nse of chlorine. The difference ohservahle in the two series of experiments is of couree attributable to the presence of eulphurets in the one, and their abseuce in the other. We have collected the nbove from a lengthy paper read by one of the parties mentioned, Rev. J. J. Bleasdale, before the Royal Society of Victoria, Australia; the entire series of experiments is bot an accumuletive amount of evidence of the wasteful process of gold working, usually empluyed in all gold mining regions. Drownen.—Scott Knox, an interesting lad of nine years, was drowned in the Sacramento river, near the Sacramento City Gus Works, on Thursday of last week. While hathing with other boys, he got beyond his depth, and being unahle to swim, was carried down by the etrong. current and lost. His body was recovered on Saturday, five milee below the city. The funeral took place on Snnday. His father. A. C. Knox, Esq., corresponding agent for this journal, was suddenly called by telegraph from Nevada City, to his desolated home. The afflicted parents will receive the heartfelt eympathy of all who knew the departed hoy. . to the mining interests of California. SULPHURETS AND THEIR VALUE. An increasing degree of interest is heginning to he felt in saving and working sulphurets. There is no donbt but that a large portion of the gold conteined in our quartz veins has heretofore been snffered to ran to waste in the sulphurets, with which it is so closely combined as to defy all ordinary mechanical menns for separetiog it. A few ofour mills have for severe] years adopted some rnde process for separating the sulphurets from ths great mass of the pulp,and many have saved their tailings by ronning them into large reservoirs or heaps for future treatment. Of lats qnite a number have introdnced “ separators,” chiefly such as are furnished by parties who advertise their machines in this paper. These machines are cheap, simple in their construction and working, and quite effective in separating the sulphurets from the mass of the pulp, which without eome euch contrivance must be allowed to run to waste. Assays of sniphurets show a yield verying from $50 to $500, and not uotrequently over $1,000 to the ton. The quantity saved by the saparetors from the mass of rock crushed varies with the charncter of the ores—some veins yielding not more than one ton of sulphurets in twenty tons of ore crushed ; others yielding as high as one ton of the sulphurets in every eight or ten tonsof rock. Of course the solphurets,as saved, contuin more or less of the rock—silex, from filteen to thirty or fifty per cent. ; it is not necessary or desireble even that they should contain less than about thirty per cent. of silex, as the presence of about that quentity grently facilitetes the process of desulphurizing, or “roasting,” es it is more commonly expressed. The sulpburets from any given vein usually run very regulerin their assny—the niean of three or four assays being generally considered to determine pretty conclusively their permia-. nent value. Sulphurets assayiug $100 per ton are worth in this city for shipment, about $50; those nssaying $200 are worth about $125 perton. ‘Che value of sulphurets asgnying a higher rate than $200 would depend much on . the more or less refactory nature of the ore, which would involve a greater or less per cent. age of loss in working it. During the past week a subscriber to this paper, who owns a quartz mill in the northern part of the State, and who has been working his mine for several years for free gold only, saving nothing of the refuse but his blanket woshings, called upon ns to have some of his sulphorets assayed, having noticed that we had advised qnartz mill owners to pay more attention to that portion of their ore. The result of the assay was $1,103 to the ton of sulphurets entirely free from sand. Our friend was perfectly astonished at the result, and informed us that hy the aid of the machinery recently devised for that purpose, he could save a ton per day of sulphnrets, nearly as clean as the sample he had placed in our hands for assay. Hehas thus heen ruouing away more gold than he has saved for the two or three years past! He will hereafter profit hy the lessou he bas lenroed hy reading the Mrnxixo ann Scientiric Press. This, of course, is an exceptional case ; sulphurets usually assaying from $75 to $150 to theton. There is no trouhle in eaving them,and no mill should be withont its conceutrators. With regard to working sulphurets, the process generally adopted, at present, ie that known as the “chlorine process.” The varions methods of treating sulphurete are discussed at considerable length in the Mrninc AnD Scientiric Press for December Sth and 23d, 1865. ‘The subject is too extensive for any special consideration at thie time, although we shall endeavor to speak more fully of it at au early day. A cheaper, more practicnl and more thorongh mode of treating them than any now employed, is at present a very desirable object Experiments are now iu progress in thie direction, anything of special interest is arrived ot in . this direction, we shall lose uo time in laying it hefore our readers, SULPHURETS IN CEMENT MINES. It has recently been discovered that meny of onr grave] cement mines also contain quite a notable amount of sulphurets, end several of the mills in the neighborhood of You Bet, Nevada County, are putting in appliances for saving them. We ere not informed with regard to the character of these app‘iances; but from what we have henrd, we should judge them to be quite inferior to the machinery now being mauufactured for that especial purpose in this city. Without any intention to onderrate the actnel value of the recent interesting discovery, that pnying sulphurets cnn be collected from the wills in verious parts of the State eugaged in crashing cement, we must still persist, notwithstanding we have been called to account for so doing, in assuring our readers that the statcments in some of the newspapers—the Nevada Transcript in particular—nore altogether in advance of what is warranted by such facts as have yet come to light. We notice that even the cotemporaries of thnt peper ure calling it to accountin thie relation. Nothing is gained in mining matters by overruling such interests. Capitalists hnve been so often deceived of late in such matters thot they are now becoming over-cautious ; and ag we desire their aid in the development of the mines, we should eudenvor to keep as near to facts as it is possible to do in metters of so mach uncertainty as those pertaining to mining. We have been assured, during the past week, by several intelligent, practicel cement miners from the vicinity of You Bet, that our atatements with regard to sulphurets in those mines wercas near the truth as it is possible to arrive at the present time. Our advice to both quartz and cement minere . is, that they ehould first take steps to test the value of thew snlphurcts, by careful nssnys, ond whenever they prove valuable, thot immediate measures should be taken to save them. They will rendily command their full value, either at Nevada, Grase Valley, or in this city. ‘The probability is that there will be found quite as much difference in the quantity and quality of sulphurets in the cement mincs ns in quartz mince. The value of these sulphurets can be readily escertained. ‘Ihe machinery for saving them is within the reach of all, and concentrators may be ohtnined for from $200 to $300. _ Business Cotteces—The time has come when a husinees education is indispensable. A classical educntion fits a man for the etudy of a profession. It cultivatee and polishes the mind, and wears off the rough edges of a man’e character, but it sends him into the world as ignorant of business as a bnbe. What he lacks, however, is a business education, and then he can make his mark. This want hne long heen felt by husiness men and educators, and it is now met by the establishment of Business Colleges. ‘These new institutions have heen improved from time to time, until they are now so conducted that the theory and practice of husiness life are united ; and the student gains the advantages of hoth. Young men can enter them from the workshop, the counting house and the farm without previous training ; and no young man ehould fail of epending a few months at one of them. He can thus fit himself fora successful husiness life. By the exercise of modesty, perseverence and energy, he can soon leave his nneducated fellows far in the rear. In connection with these thoughts we take pleasure in recommending the Pacific Business College, situated at 751 Market street. Students are received at all seasons of the year,and each one receives the special and personal attention of the teachers ; and on the completion of his studiee receivee a diploma. Mr. BE. P. Heald is President of this association. Among the directors, lecturere and instructors will be found some of our most worthy citizens. Tue town of Bristol, in Vermont, has a pillwhich we feel quite coufident will soon result. hox factory which employs twenty workmen, in something practical and importont. When! and uses up 300 cords of white hirch a year. SUBMARINE BLASTING, The fact has ulready heen noticed that, in the absence of any uid from Congress, the merchants of this city have nndertaken to remove the two snoken rocks in this harbor, known as Rincon and Blossom rocks ; both in the direct track of vessels, and constituting scrious ohstractions to navigation. The first is about 100 feet in length by 50 in breedth, and within about twelve feet of the surface; we are not acquainted with the dimensions of the other. The work is being done uuder the direction of 'T. D. Parkinson. No drilling is required, but the charge of powder is placed upon the surface of the rock, enclosed in en uir tight can, where it is fired by means of an insulated wire connected with a galvanic battery upon the shore. ‘The effect is produced by the force of the explosion being communiceted to the eurface of the rock by the preesure of the superincumbent water, instcad of by confiniug it with tamping, as in the case of drilling. Three blasts have alreedy been fired upon Rincon Rock. The first consisted of 125 ibs. of California powder, which was placed upon a projecting point of the rock. ‘Ihe “effect of the explosion wus to throw up a huge column of water, in the shape of an elongated cone, to the hight of nbout seventy feet, and break up the surface of the rock for many feet aronnd to such nn extent ns to increase the depth of water over the spot ten or twelve feet. The piecee were mostly thrown off into deep water, where they can do no harm. The rock is a hard slate, ond not very, eesy to blast. The first applicntion of electricity to firing submarine cherges was made by Gen. Pesley, in 1839, at Spithead, England. It was employed in removing from the chaunel the wreck of the Royal George. The effect of the explosion of gnnpowder, onder the nhove conditions, is very much like o blow froma huge hemmer. The force, exerted at the instant of explosion, is eqnivolent to about six tons per squere inch upon the surfaco exposed to the force. Count Rumford estimates the force of gunpowder at about 10,000 atmospheres. The crushing eflect of such a blow exerted over a space, say of twenty-five to thirty square feet, must be immense ; and it is uo great matter of astonishment that the hord rock should crumble beneath the blow, as Rincon Rock ie now wasting away under the repeated blows inflicted upon it by Mr. Parkinson. After that rock is demolished, or pnt out of harm's way, Mr. P. will commence the same kind of attock upon Blossom Rock, near Fort Alcatraz. Nitro-glycerine would exert a far more destructive effect than guopowder; but since the late terrihle calamity on Montgomery etreet, the city authorities have refused to al. low it to he employed anywhere within their jurisdiction. Brucgeyer'’s Roasttno Furnace—tThe prin. ciple of the application of revolving cylindere to roastiug ores appears to be reaching a decided succese. We nnderstand that one of Bruckner's furnaces, which hes recently been put up at the Central mill, near Virginia City, has been in operation some ten days on the first closs ore from the Cometock ledge, and with very favorable results. Mr. George Attwood, Superintendent of the Ophir Reduction Works and Central mill, writes to Mr. Bruckner, as follows: ‘“ Compared with the old reverberatory furnaces now in use, it consumes less wood, aud saves one-balf the labor. It also roasts in a shorter space of time. It desulphurizes remurkably well, ond chloridizes very fairly.” We don’t know of anything further that could be asked for to prove this furuace a complete succees, except a continuance to do just what it is now reported to he doing, for a reasonable length of time. We shall watch anxionsly and confidently for snch continuance of service. The experiment could not have heen entrusted to hetter hauds than Mr. Attwood’s. The success of this furnace will furnish a very sotisfactery solution to the problem for a cheap and sueceestul working of auriferous sulphurets, applicable on a small scale, and to almost any locality.

40 The Wining and Scientific Dress. Mining aud Scientific Yves, W. BE. EWER, 22. SENIOR Eptror. G. W. M. SMITH. W. B. EWER. A. T. DEWEY. DEWEY & CO. Publishers. Orvicr—No. 505 Clay street, corner of Sansome, 2d floor. Verms of Subseription: One copy, per annum, in advance, One copy, six months, in advance, gp For sale by Carriers and Newsdealers. 62 American and Foreien Patents,—Letters Patent for Inventors can be secured in the United States and foreign countries throush the Mixing anp Scientiric Press Parent AcEncy, We offer applicants reasonable terms, and they can rest assured of a strict compliance svith our obligations, and afaithful performance of allcontracts. For reference, we will furnish the names of numereus parties for whom . we have obtained patents during the past two years. ' San Francisco: Saturday Morning, July 21, 1866. GOLD SAVING EXPERIMENTS IN AUSTRALIA. The great loss of fine gold in the ordinary manipnlations of geld ores, is fully recognized by the Australian gold miners, where experiments have pretty conclusively proven that from twenty to twenty-five per cert. of all the gold in the ore is lost, without taking into acconnt the loss from imperfect working of the eulphurete. The current of water introduced into the hattery, and sent through the various cnotrivances for bringing the gold into contact with the mercury, in the process of amalgama. tion, keeps a large portion of the very fine gold constantly afloat, nearly all of which passes away with the water and pulp. . i In numerous experiments made with ore from Steiglitz, Ballarat and the-Ovens, by Rev. Jobn J. Bleasdale nnd Count John Dembinski, aud several times repeated, to avoid mistakes, the samples were teken, crushed and divided into eqnal parts, one-half of which was treated raw, iu the usua] manner—stamped, groundin Chile mills or pans, and subsequently treated by an amalgamation process, not deecribed in the authority before us; while the other half was roasted and submitted to the chlorine process. The mean of four experiments showed on incrense by the chlorine process of nearly thir ty-eight per cent. over the ordinary working process, with the aid of mercury. In order to still further test the loss by working procees, other experiments were performed, by mixing known nmounts of gold with ordinary sea sand, as follows: Five grains of gold, made chemicolly fine, by precipitation, were added to an equal weight of gold in a very fine state of mechanical separation ; the ten grains so preparcd were mixed with 10,000 greins of sea-sand, and the whole ground toa fine pulp. Several lots were thas prepared, ench contnining a known quantity of gold. ‘Thceee lots were then suhmitted, the one to the ordinary process, and the other to the chlorine process. The result of one of these experiments, given as an average, was the saving of 3.21 grains hy mercury ; and 4.62 by the nse of chlorine. The difference ohservahle in the two series of experiments is of couree attributable to the presence of eulphurets in the one, and their abseuce in the other. We have collected the nbove from a lengthy paper read by one of the parties mentioned, Rev. J. J. Bleasdale, before the Royal Society of Victoria, Australia; the entire series of experiments is bot an accumuletive amount of evidence of the wasteful process of gold working, usually empluyed in all gold mining regions. Drownen.—Scott Knox, an interesting lad of nine years, was drowned in the Sacramento river, near the Sacramento City Gus Works, on Thursday of last week. While hathing with other boys, he got beyond his depth, and being unahle to swim, was carried down by the etrong. current and lost. His body was recovered on Saturday, five milee below the city. The funeral took place on Snnday. His father. A. C. Knox, Esq., corresponding agent for this journal, was suddenly called by telegraph from Nevada City, to his desolated home. The afflicted parents will receive the heartfelt eympathy of all who knew the departed hoy. . to the mining interests of California. SULPHURETS AND THEIR VALUE. An increasing degree of interest is heginning to he felt in saving and working sulphurets. There is no donbt but that a large portion of the gold conteined in our quartz veins has heretofore been snffered to ran to waste in the sulphurets, with which it is so closely combined as to defy all ordinary mechanical menns for separetiog it. A few ofour mills have for severe] years adopted some rnde process for separating the sulphurets from ths great mass of the pulp,and many have saved their tailings by ronning them into large reservoirs or heaps for future treatment. Of lats qnite a number have introdnced “ separators,” chiefly such as are furnished by parties who advertise their machines in this paper. These machines are cheap, simple in their construction and working, and quite effective in separating the sulphurets from the mass of the pulp, which without eome euch contrivance must be allowed to run to waste. Assays of sniphurets show a yield verying from $50 to $500, and not uotrequently over $1,000 to the ton. The quantity saved by the saparetors from the mass of rock crushed varies with the charncter of the ores—some veins yielding not more than one ton of sulphurets in twenty tons of ore crushed ; others yielding as high as one ton of the sulphurets in every eight or ten tonsof rock. Of course the solphurets,as saved, contuin more or less of the rock—silex, from filteen to thirty or fifty per cent. ; it is not necessary or desireble even that they should contain less than about thirty per cent. of silex, as the presence of about that quentity grently facilitetes the process of desulphurizing, or “roasting,” es it is more commonly expressed. The sulpburets from any given vein usually run very regulerin their assny—the niean of three or four assays being generally considered to determine pretty conclusively their permia-. nent value. Sulphurets assayiug $100 per ton are worth in this city for shipment, about $50; those nssaying $200 are worth about $125 perton. ‘Che value of sulphurets asgnying a higher rate than $200 would depend much on . the more or less refactory nature of the ore, which would involve a greater or less per cent. age of loss in working it. During the past week a subscriber to this paper, who owns a quartz mill in the northern part of the State, and who has been working his mine for several years for free gold only, saving nothing of the refuse but his blanket woshings, called upon ns to have some of his sulphorets assayed, having noticed that we had advised qnartz mill owners to pay more attention to that portion of their ore. The result of the assay was $1,103 to the ton of sulphurets entirely free from sand. Our friend was perfectly astonished at the result, and informed us that hy the aid of the machinery recently devised for that purpose, he could save a ton per day of sulphnrets, nearly as clean as the sample he had placed in our hands for assay. Hehas thus heen ruouing away more gold than he has saved for the two or three years past! He will hereafter profit hy the lessou he bas lenroed hy reading the Mrnxixo ann Scientiric Press. This, of course, is an exceptional case ; sulphurets usually assaying from $75 to $150 to theton. There is no trouhle in eaving them,and no mill should be withont its conceutrators. With regard to working sulphurets, the process generally adopted, at present, ie that known as the “chlorine process.” The varions methods of treating sulphurete are discussed at considerable length in the Mrninc AnD Scientiric Press for December Sth and 23d, 1865. ‘The subject is too extensive for any special consideration at thie time, although we shall endeavor to speak more fully of it at au early day. A cheaper, more practicnl and more thorongh

mode of treating them than any now employed, is at present a very desirable object Experiments are now iu progress in thie direction, anything of special interest is arrived ot in . this direction, we shall lose uo time in laying it hefore our readers, SULPHURETS IN CEMENT MINES. It has recently been discovered that meny of onr grave] cement mines also contain quite a notable amount of sulphurets, end several of the mills in the neighborhood of You Bet, Nevada County, are putting in appliances for saving them. We ere not informed with regard to the character of these app‘iances; but from what we have henrd, we should judge them to be quite inferior to the machinery now being mauufactured for that especial purpose in this city. Without any intention to onderrate the actnel value of the recent interesting discovery, that pnying sulphurets cnn be collected from the wills in verious parts of the State eugaged in crashing cement, we must still persist, notwithstanding we have been called to account for so doing, in assuring our readers that the statcments in some of the newspapers—the Nevada Transcript in particular—nore altogether in advance of what is warranted by such facts as have yet come to light. We notice that even the cotemporaries of thnt peper ure calling it to accountin thie relation. Nothing is gained in mining matters by overruling such interests. Capitalists hnve been so often deceived of late in such matters thot they are now becoming over-cautious ; and ag we desire their aid in the development of the mines, we should eudenvor to keep as near to facts as it is possible to do in metters of so mach uncertainty as those pertaining to mining. We have been assured, during the past week, by several intelligent, practicel cement miners from the vicinity of You Bet, that our atatements with regard to sulphurets in those mines wercas near the truth as it is possible to arrive at the present time. Our advice to both quartz and cement minere . is, that they ehould first take steps to test the value of thew snlphurcts, by careful nssnys, ond whenever they prove valuable, thot immediate measures should be taken to save them. They will rendily command their full value, either at Nevada, Grase Valley, or in this city. ‘The probability is that there will be found quite as much difference in the quantity and quality of sulphurets in the cement mincs ns in quartz mince. The value of these sulphurets can be readily escertained. ‘Ihe machinery for saving them is within the reach of all, and concentrators may be ohtnined for from $200 to $300. _ Business Cotteces—The time has come when a husinees education is indispensable. A classical educntion fits a man for the etudy of a profession. It cultivatee and polishes the mind, and wears off the rough edges of a man’e character, but it sends him into the world as ignorant of business as a bnbe. What he lacks, however, is a business education, and then he can make his mark. This want hne long heen felt by husiness men and educators, and it is now met by the establishment of Business Colleges. ‘These new institutions have heen improved from time to time, until they are now so conducted that the theory and practice of husiness life are united ; and the student gains the advantages of hoth. Young men can enter them from the workshop, the counting house and the farm without previous training ; and no young man ehould fail of epending a few months at one of them. He can thus fit himself fora successful husiness life. By the exercise of modesty, perseverence and energy, he can soon leave his nneducated fellows far in the rear. In connection with these thoughts we take pleasure in recommending the Pacific Business College, situated at 751 Market street. Students are received at all seasons of the year,and each one receives the special and personal attention of the teachers ; and on the completion of his studiee receivee a diploma. Mr. BE. P. Heald is President of this association. Among the directors, lecturere and instructors will be found some of our most worthy citizens. Tue town of Bristol, in Vermont, has a pillwhich we feel quite coufident will soon result. hox factory which employs twenty workmen, in something practical and importont. When! and uses up 300 cords of white hirch a year. SUBMARINE BLASTING, The fact has ulready heen noticed that, in the absence of any uid from Congress, the merchants of this city have nndertaken to remove the two snoken rocks in this harbor, known as Rincon and Blossom rocks ; both in the direct track of vessels, and constituting scrious ohstractions to navigation. The first is about 100 feet in length by 50 in breedth, and within about twelve feet of the surface; we are not acquainted with the dimensions of the other. The work is being done uuder the direction of 'T. D. Parkinson. No drilling is required, but the charge of powder is placed upon the surface of the rock, enclosed in en uir tight can, where it is fired by means of an insulated wire connected with a galvanic battery upon the shore. ‘The effect is produced by the force of the explosion being communiceted to the eurface of the rock by the preesure of the superincumbent water, instcad of by confiniug it with tamping, as in the case of drilling. Three blasts have alreedy been fired upon Rincon Rock. The first consisted of 125 ibs. of California powder, which was placed upon a projecting point of the rock. ‘Ihe “effect of the explosion wus to throw up a huge column of water, in the shape of an elongated cone, to the hight of nbout seventy feet, and break up the surface of the rock for many feet aronnd to such nn extent ns to increase the depth of water over the spot ten or twelve feet. The piecee were mostly thrown off into deep water, where they can do no harm. The rock is a hard slate, ond not very, eesy to blast. The first applicntion of electricity to firing submarine cherges was made by Gen. Pesley, in 1839, at Spithead, England. It was employed in removing from the chaunel the wreck of the Royal George. The effect of the explosion of gnnpowder, onder the nhove conditions, is very much like o blow froma huge hemmer. The force, exerted at the instant of explosion, is eqnivolent to about six tons per squere inch upon the surfaco exposed to the force. Count Rumford estimates the force of gunpowder at about 10,000 atmospheres. The crushing eflect of such a blow exerted over a space, say of twenty-five to thirty square feet, must be immense ; and it is uo great matter of astonishment that the hord rock should crumble beneath the blow, as Rincon Rock ie now wasting away under the repeated blows inflicted upon it by Mr. Parkinson. After that rock is demolished, or pnt out of harm's way, Mr. P. will commence the same kind of attock upon Blossom Rock, near Fort Alcatraz. Nitro-glycerine would exert a far more destructive effect than guopowder; but since the late terrihle calamity on Montgomery etreet, the city authorities have refused to al. low it to he employed anywhere within their jurisdiction. Brucgeyer'’s Roasttno Furnace—tThe prin. ciple of the application of revolving cylindere to roastiug ores appears to be reaching a decided succese. We nnderstand that one of Bruckner's furnaces, which hes recently been put up at the Central mill, near Virginia City, has been in operation some ten days on the first closs ore from the Cometock ledge, and with very favorable results. Mr. George Attwood, Superintendent of the Ophir Reduction Works and Central mill, writes to Mr. Bruckner, as follows: ‘“ Compared with the old reverberatory furnaces now in use, it consumes less wood, aud saves one-balf the labor. It also roasts in a shorter space of time. It desulphurizes remurkably well, ond chloridizes very fairly.” We don’t know of anything further that could be asked for to prove this furuace a complete succees, except a continuance to do just what it is now reported to he doing, for a reasonable length of time. We shall watch anxionsly and confidently for snch continuance of service. The experiment could not have heen entrusted to hetter hauds than Mr. Attwood’s. The success of this furnace will furnish a very sotisfactery solution to the problem for a cheap and sueceestul working of auriferous sulphurets, applicable on a small scale, and to almost any locality.