Volume 24 (1872) (424 pages)

358 SCIENTIF IC' PRESS: [June 8, 1872. —— The Eberhardt:and Aurora. It is unfortuuate that-such a differeuce of opinion should have arisen in the management of this mine, as haa existed for the past few months. The retiroment of Mr. Ridsdale from the position of Chairman of the Board of Di-. rectors, was no doubt, a serious misfortune—as is freely admitted on all sides—and it is, perhaps, equally unfortunate that such a persistent controversy, should be kept up, as.has 6x-, isted since that gentlemans’ retirement, While we have no Gispositon to take any part in this unhappy difference, we have thought it might be iuteresting and iustructive to many of our readers to peruse the following letter from Mr. Ridsdale, written for private circulation among the stockholders, but, which has found its way into the columns of the London Mining World. In his preliminary remarks, Mr. R. observes:— . ‘«Wheu I left your board, the proportion of silver extracted at your,mills from the crushed ore, or pulp, was only 65 per cent. of the assay value of that pulp, the percentage having gradnally fallen from 85 per cent, (which was obtained under Mr. George Atwood’s management), to that low and disastrous figure; and as the extractiou of the bulliou is of far more importeuce than the mere indication of its existence by the pulp assays, because if ib is not got ont you get no dividend, I purpose to examiue the process pursued at your International Mill in detail; theu to examine that pursued at the Stanford Mill, compare the two, and make sundry suggestions therefrom for the ‘better extraction of your bullion for the future. I will begin with the ore after it has been crushed in the battery, and passed throngh the sieves when it is termed pulp.” Process at Intsrnational Mill. About 2,300 Ibs. cf pulp, with water enough added to keep it in a tolerably thick condition, . is oharged into each pan; one per cent. of salt, or about 25 Ibs., is then added, with two ounces . of sulphurie acid and from one-half to one. pound weight of sulphate of copper. (‘The temperature of the pulp should be about 160) deg. Fah.; thisis maintained by the introduction . of steam into the false bottoms underneath the . paus). The mullers are kept down and the pans grind for three hours; at the end of this. time about 150 to 200 lbs. of merenry are ad-! ded; grinding goes on theu for three hours long-' er; the mullers are then raised and about 2 lbs. of carbonate of soda, for ‘‘ cleaning’? the mereury, added; amalgamation goes on for tivo’ hours; the contents of the pans are theu run off; into the settlers, and left to settle for abont, three-quarters of an hour; the settlers are then, filled with water, aud let cool down, before! mnning off, when at the proper température,. the plugs are pulled and run off, a stream of cold water being introduced all the time. The} pans run eight hours; settlers four. The pans ruu at about sixty revolutionsa minute; settlers, atten. The tailings after leaving settlers pass! into agitators and from thence to the reservoirs. About 60 per cent. of the.ore treated contains. its silver in the state of chloride, the remaining} silver existing in state of sulphide, or in com-. bination with base metal ores; the gangue_ be-. ing quartz, largely mixed with carbonate lime. The reasons given for the addition of these, chemidals dre as follows: Oxyde mauganeése, heiig present in the ore, the addition of sul-. phnric acid actiug on it,aud the salt introduced, evolves free chlorine, which helps to chloridize the base metals presént. Sulphate of iron, is also produced by thé solution in ‘this acid’ ofj the iron from the shoes and dies of the ‘pan,) and also by that coming from the wearing o the shoes and dies of the battery, whilst crushing the ore. The sulphate of iron’ this “pro4 duéed with the stilphate of copper added, forms “magistral.’” The action of tho salton this “magistral,’’ as in the Mexican ‘‘patio’’ pro; cese, producing the chlorides of both copper and iron which further chloridizes the sil¥c1 existitig withthe basé metals. ‘This chloride:of silver,' together with, that previously existing, is reduced to-the metallic state by the iron of the pan, and then amalgamates with the mereury.’ The carbonate “of soda added merély cleans the mereury. i Now it is very doubtful whether, even i these -reasons are. sound, this process is th best that could be desired for the treatment of our ores ; for it is clear, that on the ‘addition of sulphuric acid, by far the greater part must be converted at once iuto sulphate of lime, from ths presence of large quantities of carbonate of lime in’theore, and the sulphate of oopper would be at once redticeed by the iron of the pans ; the liberated copper thus formiug an amalgam with the mercury, and finally passing into the bulliou. if: ‘ In the ‘‘patio” process considerable time is allowed for the action of the, sulphate of copper and salt on each other, so as effectually to chloridize the sulphide of silver and ‘other hase silver ores before the addition of any meroury, and there is no substance present before the ad-. dition of méreury which can act as a reducin; agent and liberate the copper. This chemical, therefore, has a fair chance for operating, which it cannot have in the pan process. The addition of ‘carbonate of “soda to'‘‘clean”’ the meréury, so far as experience. of its use. ip! tas gold niiling and amalgamating, has afforded, is. of very doubtful advautage at all. Cyanide of potassium is the best chemical for sharpeuing ™) the affinity of the mercury’ for, amalgamation, where sodium-amalgam is not used ; and nothing is more important in miling than that the mercury should be clean and lively. Many practical mill men cousider that if efficient pans be driven at good speed, the pulp being properly heated by, steam, the action of the iron of the pan, in the presence. of the salt, with clean, lively mercury, through circulation ‘of the pulp being ensured, will ‘compete suecssfully ‘with any one.of-thé chemical-receipts. Itis alleged that the heat, and) frictiou, in presence of the iron of the pans, salt, and mercury, give rise to an eléctro-galvanic action, Which has a good deal to do with the decomposition’ of silver minerals.: If so, by fixing'strips of zinc on the wooden sides of the pans, a galvanic battery would be formed, ‘which would much increase this action; ‘whether this is the case'or not, it would cost hut’ little to try it. It is probably on account of this action that many metallurgists consider . zinc-amalgam 10 be very superior to mercury lin its amalgamating powers. The Stanford Mill Process 'Ts far more efficacious thin the one ‘followed at the International Mill (the pansare smaller). Charge, 1,600 to 1,800 Ibs. of pulp, half per cent: of salt, and about a quarter pound of cyauide potassium to the ton. Grind for 4% hours, then add to each pan 200'Ibs. mercury, griud for 1144 hours longer; raise mullers and amalmagate two hours. About one hour before ruuuiug off pan into settler, add some perfectly clean lively mercury, so as to collect together the ‘flonred”’ mercury. Whilst runuing off settler, a stream of cold wateris allowed to flow into it. The coarse .eand, etc, is shovelled out of the settlers and worked over in pans ‘every 48 hours. Now the advantages of this process are, that the cyanide of potassium entirely does away with the use of acid, sulphate of copper, aud oarbonate of soda, whilst the mercury is kept in much _ better condition, and the out-turn of silver is larger. Iu August last, the Stanford Mill. crushed our ore, guaranteed us 85 per cent. of the assay value of the pulp, charged 15 dollars for milling, and made a handsonme profit; onr sheets, so far as they-are reliable (for the figures never agree); showed only 65 per cent. of the assay value of the ore as having been realized in bullion, at the time TI left'the Board. With rich ore, defects of management are not so vital in affecting the interests of a company as when you have to treat ore of a low grade. Then defective management frequently leads to irretrievable rnin. On a comparisonmade hetween the two mills when ruuningon the same quality . of ore, assaying 38 dollars to the ton, the tail. ings at the International mill averaged 13 dol-; lars per ton, whilst the tailings at the Stanford mill ranged between seven and eight. Importance of Careful Mining, Now every dollar per ton that goes away ; with the tailings of our mill represents a loss on the yearly amount of ore crushed of 21. peri cent. on the whole capital of the company, and) therefore is so much lost for distribution as . dividend. That is the way tolook atit. One dollar per ton on 80 tous crushed per day for 830 days, supposing the mill to run so long, taking our capital as 265,0001., is 5,300/, Supposiug this difference to persist throughout the! whole year, that I have shown to exist between) the silver lost in the tailings of our mill, and) that of the Stanford, when 7d on the same grade of ore, that differeuce of 5 dollars be; tween eight and thirteen, represents a differen \{ tial loss of over 26,0002. per annum, or ten per cent. ou the whole capltal.of the company, that would otherwise be available for dividend! a! rather heavy:price to pay per annum for wan of adequate scientific supervision in.our mill. Are shareholders content that this is to g on? It is littlo use paring down wages or economizing trumpery petty expenses, such as, those reported at the last meetiug to have been effected, when from want of proper scientific supervision, your property is subject to such, gigautic drains as . have indicated. Yourmanager goes oumonth after mouth running your) Oasis Mill upou ‘‘tailings.” (Vide last report for January.) It costs atleast five dollars aton! .to work tailings at all, and you ought never to have tailings that pay you to re-work ; you would not have were your amalgamation properly couducted. : The late Board of Management, at my in+ stauce, sent out a competent metallurgist to supply the place of Mr. George Atwood (who possessed the requisite metallurgical skill, hut whose services are now unfortunately lost to us), Mr. R. J. Frecheville, of the Royal School of Mines. Itis to this gentleman thatI am in+ dehted for the only accurate and reliable scientific information respecting our property that has yet reached this side of the water. Mr. Phillpotts has hitherto declined to avail himself of his services, not having been previously con+ sulted iu the appointment. ; ; In Further Discussing the Subject of Milling, ° I wish to observe that there is reason to believe that enough attention is not paid to keeping the, mereury inaclean ative condition, aud the. heavy sand that accnmulates in the eettlers and agitators does not appear to be shovelled out regularly and worked over in paus, as at the Stanford. This is professed to be attended to at our mill, but I have reason to believe that it is not doneregularly;indeed, some of our pans have beenknown to be running for a long time without grinding, and this was only found out atlast by ‘accident; nor:is it clear that any attempts are made to save the large ‘quautities' of merenry that escape from the mill, ranging from % to 1 ib. per ton. The average charge of our pans is '2,300 bs.; time of treating, 8 hours; thus 3 ‘charges-are worked per day per pan. “Now, lookiug at the high assay value of the tailings, as before ‘shown, it is a question whether the pans are not overloaded, and if a (lesser quantity, say 1,8001bs. per pan were used for 6 hours, four twies a day, probably better results would be dbtaiued thanfrom the larger charges run 8 hours 3 times per day. Thereis, however, in the International Mill scarcely pan ‘power sufficient for the large number of stamps. ‘The excellent practice pursued atthe Stanford \Mill, of adding clean ively mercury to the pans (just before running off, is not followed at the International. There is another point consnected with the question of , : ~The Enormous Loss of Mercury : ‘At our mill, to which I desire to direct attention. The amalgam, after being ‘cleaned and strained, is retorted; the mercury which distils off is led ,through a pipe, kept cold by water circulating round it, into a receiver containing water, and thus condensed to the metalha state, so'as to be again available for use at the mill.: The, crude bullion produced generally amounts to one-fifth or one-sixth of the amalgam operated upon; this erade bullion is theu taken to the assay office and melted into bars. Of course as it always unavoidably contains more or less quicksilver and foreign matters, there is necessarily a discrepancy between the:weight of the crude bullion and the weight of the bars produced from it; but the discrepancy at our millis far larger than it should be, and this is owing to imperfect retorting, . — . -Inone of the largest miuing companies on the Comstock lode, I'find that this loss averaged only 168-100 per cént. for the year ; our loss is frequently 10 per eent., and it has iu an extreme ease even reached 26 per cent. Now, the great bulk of this loss is mercury, and mercury costs 90 cents per pound. The whole figures in detail are before me. Ifthe retorted silver was melted iu pots with alembiec heads, 2 great part of this loss in mercury might be avoided. There are a number of other minor metallurgical details that require careful attentiou in this department. The mines belonging to this company, particularly the North Aurora, appear to have fully borne out all that the experts (employed at the, time of the salé of these mines,) reported of} them. ‘The largest and richest deposits of ore, run close up to the north line of the South. Aurora, which claim ison that portion of the! vein lying between the Eberhardt and North’ Aurora mines. : Whatever may have heen the fault in the Eberhardt Co’s management, indeed if any, it, contrasts very favorably when cdémpared with, that of the South Aurora. Where they have wasted vast sums of money in useloss out-door work, and neglected to develop and follow their, rich ore deposits, thereby bringing discredit on’ the district. By réfereuce to the files of the White Pine News, also to our summary of last week, it will be soen that the developments all the way on! the line of the ‘* Treasure Hill Vein,” from the Hidden Treasure to the Eberhardt, are of the most encouraging and satisfactory character. ' The Emerald Mines of Muzo. The mountains of Muzo, New Grenada, says the Jour. Soc. Arts, like those of the wholo cen, tral Cordillera of the Andes, belong to the lower formation of chalk. In the mines now worked, the emeralds occur in two distinct layers,—the . first, or npper one composed of a bitumen which is hlack and friable; the second, lower down, also of calcareous bitumen, but hard and compact. ,These two layers are generally sep; arated from each other from 17 to 22yards. In the upper layer, the emerald occurs in nests, in . the lower, iu what approaches nearer to veins: Nests df emeralds are seldom found in the latter, hut the gem is more easily extracted. The presence of well crystallized fiuorspar denotes proximity to the emerald, and the occurrence of rock erystal or parisite is also a good sign. ’ The mine of Muzo is worked hoth by galleries aud iu the open air, the latter method, although more expensive, being preferahle on account of the greater ease of finding the emeralds. All the gems now extracted are sent to Pa 2. to be cut, The aunual prodnetion is not made pubke. ’ "There are indications that the mountains of ‘Whizo are'rich in emeralds, and~it is thought that the stores of this precious stone have hardly been touched. But 1 1864, the Columbia Government in return for an annual paytnent of $14,700, granted to a French company Jia lease of the mines at Muzo for ten years, together with a monopoly of all emeralds in_CoTumbia, binding itself to prohibit the working of any other minés in the Uniou, This lease, which expires in 1874, will probably not be renewed. . ‘Evidently the mines of Muzo were known ‘long before the discovery of America, The Spaniards in 1553 found the Indians in possession of a large quantity of the stones. After the arrival of the Lee ee the mines were extensivelv worked, but, for some unknown reason, were abandoned ahout the middle of the 18th century. .After the War of Indepeudonce, the Repuhlic todk possession of the mines an let them out to individuals and to companies. '-with a considerable curvature. Increasing the Vigor of Growth in Plants. A very important announcemeut has lately been made in Frauce as to the effect produced upon the luxuriance of vegetation by the disturbanée of thé natural position of the branches. It has been known for some time that if two branches of a fruit-tree bo selected of about the same size, and the same upward inclination to the horizontal plane, and one of these be bent downward toward this plane, it appears to lose its vigor, while the other gains in a like ratio. Itis now annonuced as the discovery of an iguorant peasant on the Dauuhe, named Hooibreuk, that this law holds good only up to the horizontal position; aud that if tho hranch is depressed still further, and below the horizontal, it becomes characterized by much greater vigor than hefore, and, in fact, will put out leaves and branches to an astonishiug and unheard-of degree. But this depends upon keepiug the hranches as nearly as possible in a straight line, the effect being measurably lost In this case, only the buds which occupy the top of the arc are developed completely, at tho oxpense of the rest, which remain in their original condition, contributing neither to the extension of foliage ‘nor of fruit. Duchesne Toureace, in communicating these facts to Les Mondes attempts to show the causes which seem to determine so great 1 flow of sap to the brauches inclined below the horizontal line, and thinks that the explanation is to be found in the establishment of a siphon arrangement, by means of which the juice is carried over the bend from the main stem in excessive flow. Be this as it may, the fact remains, as illustrated by an experiment prosecuted by this geutleman. In early spring, when the sap was rnuuiugin the vines, he took four plants of about the samosize, and trimmed them so as to leave one stem to each, these beiug arranged vertically, obliquely upward; horiizontally and obliquely downward. He then cut off the stems, and collected aud measured what exuded, and found the amount from the, branch inchned downward was more than three times greater than that from the others. Something About Wool. The San Joaquin Valley Argus complains of the want of discrimination exhibited by purchascrs of wool, and says: ‘‘The great desideratum seems to be quantity—quality being of comparatively little or no importance. An apt illustration of this point was furnished last ‘year in the case ahove referred to. The party in question had 2,300 yearliugs, the fleece from which was considered next to worthless, being short aud oxceediugly foul—the owner estimating at least oue pouud of dirt to every five ponnds of wool. It was baled separately, and with many misgivings as to the result forwarded to market, n fnll statement of the ease being made to the commission merchant to whom it ‘was consigued. It was sold at 2944 cents per pound, while tho fleece from the older sheep, which was long and silky, and almost entirely free from dirt—with which extra care’ had been exercised in shearing, baling, etc.,—brought in tho same market 3144 cents— a difference of only two cents per pound in favor of the finer quality. This heing the case, what encouragement is there for the wool-grower to improve ‘the grade of his sheep, or to exercise . . more than ordinary diligence in the preparation of his wool for market? Cotswolds and Southdowns to the dogs—give us scrubs! The more dirt the more money, seems to be the role; and as the benefits of any system are to be judged by the practical results, we conclude that all efforts to impreve the grade of sheep by crossing stock, etc., must necessarily prove futile, and the time spent therein worst than wasted. Money is what the producer is after—the largest return for a given amouut of labor. Jet him, therefore,. cease his efforts at improvement, and tnru his attention to scruhs aud dirt. The latter will pay—the former won’t—and that’s ‘what wo know about wool.’ ”’ California Butter vs. Eastern Butter. From the tone of the Eastern Press we find that California is in a fair way of securing better prices for butter thau Eastern States do for their own production. A reliable exchange says: ‘The highestcoloris all that is sought for by hoth the local and shipping trade, and prices for such are cousequeutly well sustained, selling at 80@31c., whereas the other grades mentioned are difficult to dispose of at prices varying from 20@26c. There is some increase in the receipts of Ohio, with a slight inprovement in quality, hut the greater portion of it is yet very poor stuff iudeed, and despite the very best offorts of receivers to clear their houses of it, itis too inferior for the market men, and there is no other trade tocarry it off. The reports from New Orleans are not flattering for extreme prices for butter this season, and shippers, except on orders, are buying but . sparingly. The result of this will be 2 gradual weakening of prices, not so much, however, as to deter the Western Reserve from forwarding what is needed’’. , The car load of California butter shipped to the East a few days since, is receiving marked complimeuts from the Atlantic papers; they pronounce Dpou it in Bostou ‘‘as perfectly delicious.”’ If eastern butter isin such disfavor as the ahoye remarks seem to indicate, our shipments will command excellentprioces, for wesend agoodarticle, which is fullyappreciated.

358 SCIENTIF IC' PRESS: [June 8, 1872. —— The Eberhardt:and Aurora. It is unfortuuate that-such a differeuce of opinion should have arisen in the management of this mine, as haa existed for the past few months. The retiroment of Mr. Ridsdale from the position of Chairman of the Board of Di-. rectors, was no doubt, a serious misfortune—as is freely admitted on all sides—and it is, perhaps, equally unfortunate that such a persistent controversy, should be kept up, as.has 6x-, isted since that gentlemans’ retirement, While we have no Gispositon to take any part in this unhappy difference, we have thought it might be iuteresting and iustructive to many of our readers to peruse the following letter from Mr. Ridsdale, written for private circulation among the stockholders, but, which has found its way into the columns of the London Mining World. In his preliminary remarks, Mr. R. observes:— . ‘«Wheu I left your board, the proportion of silver extracted at your,mills from the crushed ore, or pulp, was only 65 per cent. of the assay value of that pulp, the percentage having gradnally fallen from 85 per cent, (which was obtained under Mr. George Atwood’s management), to that low and disastrous figure; and as the extractiou of the bulliou is of far more importeuce than the mere indication of its existence by the pulp assays, because if ib is not got ont you get no dividend, I purpose to examiue the process pursued at your International Mill in detail; theu to examine that pursued at the Stanford Mill, compare the two, and make sundry suggestions therefrom for the ‘better extraction of your bullion for the future. I will begin with the ore after it has been crushed in the battery, and passed throngh the sieves when it is termed pulp.” Process at Intsrnational Mill. About 2,300 Ibs. cf pulp, with water enough added to keep it in a tolerably thick condition, . is oharged into each pan; one per cent. of salt, or about 25 Ibs., is then added, with two ounces . of sulphurie acid and from one-half to one. pound weight of sulphate of copper. (‘The temperature of the pulp should be about 160) deg. Fah.; thisis maintained by the introduction . of steam into the false bottoms underneath the . paus). The mullers are kept down and the pans grind for three hours; at the end of this. time about 150 to 200 lbs. of merenry are ad-! ded; grinding goes on theu for three hours long-' er; the mullers are then raised and about 2 lbs. of carbonate of soda, for ‘‘ cleaning’? the mereury, added; amalgamation goes on for tivo’ hours; the contents of the pans are theu run off; into the settlers, and left to settle for abont, three-quarters of an hour; the settlers are then, filled with water, aud let cool down, before! mnning off, when at the proper température,. the plugs are pulled and run off, a stream of cold water being introduced all the time. The} pans run eight hours; settlers four. The pans ruu at about sixty revolutionsa minute; settlers, atten. The tailings after leaving settlers pass! into agitators and from thence to the reservoirs. About 60 per cent. of the.ore treated contains. its silver in the state of chloride, the remaining} silver existing in state of sulphide, or in com-. bination with base metal ores; the gangue_ be-. ing quartz, largely mixed with carbonate lime. The reasons given for the addition of these, chemidals dre as follows: Oxyde mauganeése, heiig present in the ore, the addition of sul-. phnric acid actiug on it,aud the salt introduced, evolves free chlorine, which helps to chloridize the base metals presént. Sulphate of iron, is also produced by thé solution in ‘this acid’ ofj the iron from the shoes and dies of the ‘pan,) and also by that coming from the wearing o the shoes and dies of the battery, whilst crushing the ore. The sulphate of iron’ this “pro4 duéed with the stilphate of copper added, forms “magistral.’” The action of tho salton this “magistral,’’ as in the Mexican ‘‘patio’’ pro; cese, producing the chlorides of both copper and iron which further chloridizes the sil¥c1 existitig withthe basé metals. ‘This chloride:of silver,' together with, that previously existing, is reduced to-the metallic state by the iron of the pan, and then amalgamates with the mereury.’ The carbonate “of soda added merély cleans the mereury. i Now it is very doubtful whether, even i these -reasons are. sound, this process is th best that could be desired for the treatment of our ores ; for it is clear, that on the ‘addition of sulphuric acid, by far the greater part must be converted at once iuto sulphate of lime, from ths presence of large quantities of carbonate of lime in’theore, and the sulphate of oopper would be at once redticeed by the iron of the pans ; the liberated copper thus formiug an amalgam with the mercury, and finally passing into the bulliou. if: ‘ In the ‘‘patio” process considerable time is allowed for the action of the, sulphate of copper and salt on each other, so as effectually to chloridize the sulphide of silver and ‘other hase silver ores before the addition of any meroury, and there is no substance present before the ad-. dition of méreury which can act as a reducin; agent and liberate the copper. This chemical, therefore, has a fair chance for operating, which it cannot have in the pan process. The addition of ‘carbonate of “soda to'‘‘clean”’ the meréury, so far as experience. of its use. ip! tas gold niiling and amalgamating, has afforded, is. of very doubtful advautage at all. Cyanide of potassium is the best chemical for sharpeuing ™) the affinity of the mercury’ for, amalgamation, where sodium-amalgam is not used ; and nothing is more important in miling than that the mercury should be clean and lively. Many practical mill men cousider that if efficient pans be driven at good speed, the pulp being properly heated by, steam, the action of the iron of the pan, in the presence. of the salt, with clean, lively mercury, through circulation ‘of the pulp being ensured, will ‘compete suecssfully ‘with any one.of-thé chemical-receipts. Itis alleged that the heat, and) frictiou, in presence of the iron of the pans, salt, and mercury, give rise to an eléctro-galvanic action, Which has a good deal to do with the decomposition’ of silver minerals.: If so, by fixing'strips of zinc on the wooden sides of the pans, a galvanic battery would be formed, ‘which would much increase this action; ‘whether this is the case'or not, it would cost hut’ little to try it. It is probably on account of this action that many metallurgists consider . zinc-amalgam 10 be very superior to mercury lin its amalgamating powers. The Stanford Mill Process 'Ts far more efficacious thin the one ‘followed at the International Mill (the pansare smaller). Charge, 1,600 to 1,800 Ibs. of pulp, half per cent: of salt, and about a quarter pound of cyauide potassium to the ton. Grind for 4% hours, then add to each pan 200'Ibs. mercury, griud for 1144 hours longer; raise mullers and amalmagate two hours. About one hour before ruuuiug off pan into settler, add some perfectly clean lively mercury, so as to collect together the ‘flonred”’ mercury. Whilst runuing off settler, a stream of cold wateris allowed to flow into it. The coarse .eand, etc, is shovelled out of the settlers and worked over in pans ‘every 48 hours. Now the advantages of this process are, that the cyanide of potassium entirely does away with the use of acid, sulphate of copper, aud oarbonate of soda, whilst the mercury is kept in much _ better condition, and the out-turn of silver is larger. Iu August last, the Stanford Mill. crushed our ore, guaranteed us 85 per cent. of the assay value of the pulp, charged 15 dollars for milling, and made a handsonme profit; onr sheets, so far as they-are reliable (for the figures never agree); showed only 65 per cent. of the assay value of the ore as having been realized in bullion, at the time TI left'the Board. With rich ore, defects of management are not so vital in affecting the interests of a company as when you have to treat ore of a low grade. Then defective management frequently leads to irretrievable rnin. On a comparisonmade hetween the two mills when ruuningon the same quality . of ore, assaying 38 dollars to the ton, the tail. ings at the International mill averaged 13 dol-; lars per ton, whilst the tailings at the Stanford mill ranged between seven and eight. Importance of Careful Mining, Now every dollar per ton that goes away ; with the tailings of our mill represents a loss on the yearly amount of ore crushed of 21. peri cent. on the whole capital of the company, and) therefore is so much lost for distribution as . dividend. That is the way tolook atit. One dollar per ton on 80 tous crushed per day for 830 days, supposing the mill to run so long, taking our capital as 265,0001., is 5,300/, Supposiug this difference to persist throughout the! whole year, that I have shown to exist between) the silver lost in the tailings of our mill, and) that of the Stanford, when 7d on the same grade of ore, that differeuce of 5 dollars be; tween eight and thirteen, represents a differen \{ tial loss of over 26,0002. per annum, or ten per cent. ou the whole capltal.of the company, that would otherwise be available for dividend! a! rather heavy:price to pay per annum for wan of adequate scientific supervision in.our mill. Are shareholders content that this is to g on? It is littlo use paring down wages or economizing trumpery petty expenses, such as, those reported at the last meetiug to have been effected, when from want of proper scientific supervision, your property is subject to such, gigautic drains as . have indicated. Yourmanager goes oumonth after mouth running your) Oasis Mill upou ‘‘tailings.” (Vide last report for January.) It costs atleast five dollars aton! .to work tailings at all, and you ought never to have tailings that pay you to re-work ; you would not have were your amalgamation properly couducted. : The late Board of Management, at my in+ stauce, sent out a competent metallurgist to supply the place of Mr. George Atwood (who possessed the requisite metallurgical skill, hut whose services are now unfortunately lost to us), Mr. R. J. Frecheville, of the Royal School of Mines. Itis to this gentleman thatI am in+ dehted for the only accurate and reliable scientific information respecting our property that has yet reached this side of the water. Mr. Phillpotts has hitherto declined to avail himself of his services, not having been previously con+ sulted iu the appointment. ; ; In Further Discussing the Subject of Milling, ° I wish to observe that there is reason to believe that enough attention is not paid to keeping the, mereury inaclean ative condition, aud the. heavy sand that accnmulates in the eettlers and agitators does not appear to be shovelled out

regularly and worked over in paus, as at the Stanford. This is professed to be attended to at our mill, but I have reason to believe that it is not doneregularly;indeed, some of our pans have beenknown to be running for a long time without grinding, and this was only found out atlast by ‘accident; nor:is it clear that any attempts are made to save the large ‘quautities' of merenry that escape from the mill, ranging from % to 1 ib. per ton. The average charge of our pans is '2,300 bs.; time of treating, 8 hours; thus 3 ‘charges-are worked per day per pan. “Now, lookiug at the high assay value of the tailings, as before ‘shown, it is a question whether the pans are not overloaded, and if a (lesser quantity, say 1,8001bs. per pan were used for 6 hours, four twies a day, probably better results would be dbtaiued thanfrom the larger charges run 8 hours 3 times per day. Thereis, however, in the International Mill scarcely pan ‘power sufficient for the large number of stamps. ‘The excellent practice pursued atthe Stanford \Mill, of adding clean ively mercury to the pans (just before running off, is not followed at the International. There is another point consnected with the question of , : ~The Enormous Loss of Mercury : ‘At our mill, to which I desire to direct attention. The amalgam, after being ‘cleaned and strained, is retorted; the mercury which distils off is led ,through a pipe, kept cold by water circulating round it, into a receiver containing water, and thus condensed to the metalha state, so'as to be again available for use at the mill.: The, crude bullion produced generally amounts to one-fifth or one-sixth of the amalgam operated upon; this erade bullion is theu taken to the assay office and melted into bars. Of course as it always unavoidably contains more or less quicksilver and foreign matters, there is necessarily a discrepancy between the:weight of the crude bullion and the weight of the bars produced from it; but the discrepancy at our millis far larger than it should be, and this is owing to imperfect retorting, . — . -Inone of the largest miuing companies on the Comstock lode, I'find that this loss averaged only 168-100 per cént. for the year ; our loss is frequently 10 per eent., and it has iu an extreme ease even reached 26 per cent. Now, the great bulk of this loss is mercury, and mercury costs 90 cents per pound. The whole figures in detail are before me. Ifthe retorted silver was melted iu pots with alembiec heads, 2 great part of this loss in mercury might be avoided. There are a number of other minor metallurgical details that require careful attentiou in this department. The mines belonging to this company, particularly the North Aurora, appear to have fully borne out all that the experts (employed at the, time of the salé of these mines,) reported of} them. ‘The largest and richest deposits of ore, run close up to the north line of the South. Aurora, which claim ison that portion of the! vein lying between the Eberhardt and North’ Aurora mines. : Whatever may have heen the fault in the Eberhardt Co’s management, indeed if any, it, contrasts very favorably when cdémpared with, that of the South Aurora. Where they have wasted vast sums of money in useloss out-door work, and neglected to develop and follow their, rich ore deposits, thereby bringing discredit on’ the district. By réfereuce to the files of the White Pine News, also to our summary of last week, it will be soen that the developments all the way on! the line of the ‘* Treasure Hill Vein,” from the Hidden Treasure to the Eberhardt, are of the most encouraging and satisfactory character. ' The Emerald Mines of Muzo. The mountains of Muzo, New Grenada, says the Jour. Soc. Arts, like those of the wholo cen, tral Cordillera of the Andes, belong to the lower formation of chalk. In the mines now worked, the emeralds occur in two distinct layers,—the . first, or npper one composed of a bitumen which is hlack and friable; the second, lower down, also of calcareous bitumen, but hard and compact. ,These two layers are generally sep; arated from each other from 17 to 22yards. In the upper layer, the emerald occurs in nests, in . the lower, iu what approaches nearer to veins: Nests df emeralds are seldom found in the latter, hut the gem is more easily extracted. The presence of well crystallized fiuorspar denotes proximity to the emerald, and the occurrence of rock erystal or parisite is also a good sign. ’ The mine of Muzo is worked hoth by galleries aud iu the open air, the latter method, although more expensive, being preferahle on account of the greater ease of finding the emeralds. All the gems now extracted are sent to Pa 2. to be cut, The aunual prodnetion is not made pubke. ’ "There are indications that the mountains of ‘Whizo are'rich in emeralds, and~it is thought that the stores of this precious stone have hardly been touched. But 1 1864, the Columbia Government in return for an annual paytnent of $14,700, granted to a French company Jia lease of the mines at Muzo for ten years, together with a monopoly of all emeralds in_CoTumbia, binding itself to prohibit the working of any other minés in the Uniou, This lease, which expires in 1874, will probably not be renewed. . ‘Evidently the mines of Muzo were known ‘long before the discovery of America, The Spaniards in 1553 found the Indians in possession of a large quantity of the stones. After the arrival of the Lee ee the mines were extensivelv worked, but, for some unknown reason, were abandoned ahout the middle of the 18th century. .After the War of Indepeudonce, the Repuhlic todk possession of the mines an let them out to individuals and to companies. '-with a considerable curvature. Increasing the Vigor of Growth in Plants. A very important announcemeut has lately been made in Frauce as to the effect produced upon the luxuriance of vegetation by the disturbanée of thé natural position of the branches. It has been known for some time that if two branches of a fruit-tree bo selected of about the same size, and the same upward inclination to the horizontal plane, and one of these be bent downward toward this plane, it appears to lose its vigor, while the other gains in a like ratio. Itis now annonuced as the discovery of an iguorant peasant on the Dauuhe, named Hooibreuk, that this law holds good only up to the horizontal position; aud that if tho hranch is depressed still further, and below the horizontal, it becomes characterized by much greater vigor than hefore, and, in fact, will put out leaves and branches to an astonishiug and unheard-of degree. But this depends upon keepiug the hranches as nearly as possible in a straight line, the effect being measurably lost In this case, only the buds which occupy the top of the arc are developed completely, at tho oxpense of the rest, which remain in their original condition, contributing neither to the extension of foliage ‘nor of fruit. Duchesne Toureace, in communicating these facts to Les Mondes attempts to show the causes which seem to determine so great 1 flow of sap to the brauches inclined below the horizontal line, and thinks that the explanation is to be found in the establishment of a siphon arrangement, by means of which the juice is carried over the bend from the main stem in excessive flow. Be this as it may, the fact remains, as illustrated by an experiment prosecuted by this geutleman. In early spring, when the sap was rnuuiugin the vines, he took four plants of about the samosize, and trimmed them so as to leave one stem to each, these beiug arranged vertically, obliquely upward; horiizontally and obliquely downward. He then cut off the stems, and collected aud measured what exuded, and found the amount from the, branch inchned downward was more than three times greater than that from the others. Something About Wool. The San Joaquin Valley Argus complains of the want of discrimination exhibited by purchascrs of wool, and says: ‘‘The great desideratum seems to be quantity—quality being of comparatively little or no importance. An apt illustration of this point was furnished last ‘year in the case ahove referred to. The party in question had 2,300 yearliugs, the fleece from which was considered next to worthless, being short aud oxceediugly foul—the owner estimating at least oue pouud of dirt to every five ponnds of wool. It was baled separately, and with many misgivings as to the result forwarded to market, n fnll statement of the ease being made to the commission merchant to whom it ‘was consigued. It was sold at 2944 cents per pound, while tho fleece from the older sheep, which was long and silky, and almost entirely free from dirt—with which extra care’ had been exercised in shearing, baling, etc.,—brought in tho same market 3144 cents— a difference of only two cents per pound in favor of the finer quality. This heing the case, what encouragement is there for the wool-grower to improve ‘the grade of his sheep, or to exercise . . more than ordinary diligence in the preparation of his wool for market? Cotswolds and Southdowns to the dogs—give us scrubs! The more dirt the more money, seems to be the role; and as the benefits of any system are to be judged by the practical results, we conclude that all efforts to impreve the grade of sheep by crossing stock, etc., must necessarily prove futile, and the time spent therein worst than wasted. Money is what the producer is after—the largest return for a given amouut of labor. Jet him, therefore,. cease his efforts at improvement, and tnru his attention to scruhs aud dirt. The latter will pay—the former won’t—and that’s ‘what wo know about wool.’ ”’ California Butter vs. Eastern Butter. From the tone of the Eastern Press we find that California is in a fair way of securing better prices for butter thau Eastern States do for their own production. A reliable exchange says: ‘The highestcoloris all that is sought for by hoth the local and shipping trade, and prices for such are cousequeutly well sustained, selling at 80@31c., whereas the other grades mentioned are difficult to dispose of at prices varying from 20@26c. There is some increase in the receipts of Ohio, with a slight inprovement in quality, hut the greater portion of it is yet very poor stuff iudeed, and despite the very best offorts of receivers to clear their houses of it, itis too inferior for the market men, and there is no other trade tocarry it off. The reports from New Orleans are not flattering for extreme prices for butter this season, and shippers, except on orders, are buying but . sparingly. The result of this will be 2 gradual weakening of prices, not so much, however, as to deter the Western Reserve from forwarding what is needed’’. , The car load of California butter shipped to the East a few days since, is receiving marked complimeuts from the Atlantic papers; they pronounce Dpou it in Bostou ‘‘as perfectly delicious.”’ If eastern butter isin such disfavor as the ahoye remarks seem to indicate, our shipments will command excellentprioces, for wesend agoodarticle, which is fullyappreciated.