Volume 26 (1873) (431 pages)

MINING AND SCIENTIFIC PRESS. [January 4, 1873 W, B. EWER...-. nopeoneoDocooaccded SEnIoR EDITOB. DEWEY & CO., Publishers. a. %. DEWEY, GEO. K. BTRONG. W. B, EWER, JNO. L, BOONE. Office, No. 338 Montgomery St., 8. E. Corner of Galifornia St., diagonally acrosa from Wella, Fargo & Co.’a. SuBScRIPTiIons payable in advance—Yor one year, $4: six months, $2.50; three montbs, $1.25. Cluhs of ten names or more, $3 each per annum. $5, in advance, will pay for 1% year. Remittances hy registered letters or P, O. orders at our risk. ApVEBTIsING Rares.—l week. 1 Hite 3 months. 1 year. Per line...+.06 a 25 80 $2.00 35.00 One-half inch. «$1.00 $3.00 7.60 20.00 One inch...seeeeee 2.00 5.00 14.00 38.00 Large advertisements at favorahle rates. Special or reading noti legal advert: tg, notices appearing in extraordinary type or in particular parts of the paper, inserted at special rates. San Francisco: Saturday Morning, Jan. 4, 1873. Legal Tsnder Ratea.—8. F., Thurs., Jan 2.— buying, 89%¢; Selling, 8924. Table of Contents. GENERAL EDITORIALS.—The Coming Expositions; A Monster Casting; A New Volume, 3. California Art Oallery; Smelting on the Pacific Coast; Cheap Cval, 8. ILLOSTRATIONS.—The First Quartz Mill in California, 1. The Tailor-Bird’s Nest, 6. Hoendee’s Patent Gun Lock; The American Bottle Filler, 9. MECHANICAL PROGRESS,—Bessemor’s Steady Ship Saloon; Resistance of Building Stone to Heat, 3. SCIENTIFIC PROGRESS.—Experiments in Neture’s Lahoratory; Nickle as a Gas Uccluder, Heating Water Above the Boiling Point in Open Vessels; Origin of Storms; Gummate of Iron Paper; There is no Ohject Unworthy of Our Notice, 3. USEFUL INFORMATION.— How to Varnish; The Water Telescope; Motion of the Eye; Cultivate Habits of Careful Observation; Power of the Eye in Viewing Minute Ohjects; Bogus Chinese Pearls; How the Diamond Outs Glass; Force of Lightning; Suhstances that Most Resist the Action of Cold; he Pilot Fish, 7. GOOD HEALTH.—The Blood; Poisonous Contec, tionery; Mechanism of the Bones; An Intelligent Drugyist; Nourishment in Food; Power of Man tu Endure Cold; The Art of Walking; Bisulphide of Carhon on the System. 7. MINING SUMMARY from varions counties in California, Lower California, Nevada, Idaho and Utah, 4-5, Market Reports, 12. MINING STOCK MARKET.—Table of Daily Sales and Prices and Comparative Prices for the Week; Notices of Assessments; Meetings and Dividends; Review of Stock Market for the Week, 4. MISCELLANEOUS. —Practical Uses of Geology; Klamath River Mines; Mining for Tin; Another An. cient City; Street Car Tracks; The Reported Chicago Orain traude: [he Lake Superior Tin Discoveries, 2. The Railways and their Mineral Traffic; New Tdria Quicksilver; Cheaper Sewing Machines, Silver and Silver Coinage; I. L. D., 6. Coaiaud Quicksilver, Frozen Up; Delays of Law—Courts of Conciliation; Shell Mounds on the Culifornia Coast; Co-Operation in Great Britain; What is Slate, aud How was it Formed; The Bessemer Saloon Steamhoat The Discovery of Petroleum in Pennsylvania; Nevada Salt and Soda Beds; Virginia Oold Mine, Superior Lake Railroad Iron, 10. New Code Mining Law, 12. New Incorporations, 16. Cautrornta Anr Gautery, — The first number of which is befors ns, is devotsd to musio, drama, art and literature, and is published by Alirsd Chaigneau & Co., 409 Washington street. Terms, $5 per year. It is a very fine spscimen of typography; the ‘‘heading” in particular is worthy of mention, having been made by the zincograph process, by tbe pnblishers themselves. The numbsr contains ‘‘Mrs. Platsdware’s Campaign,’’ ‘* Art in California,’ ‘Free Art Gallsries,’? A skstch of Thomas Nast, a poemby J. F. Bowman and one by Obas. Warren Stoddard. ‘The Art Exhibition and the Gsrome,”’ ‘‘Jottings at a Window," Local Art Notes, The Yosemite Waltz, (Music), ‘Is Joaqnin Miller a Poet?” “ Roman Recollections,’ ‘Unknown Bsnefactors,”’ **Pauline Luecas Debut,'’ Tales from the Grsenroom, eto. The zinco-chromo which accompanies the paper, is made by a nsw and peouliar process, a fact whioh our cotsmporariss seem to havs ovsrlooked, Too much has besn expected from this first attsmpt, and the mannsr in which it is made} has not besn taken in consideration. We will not attempt to criticise the akill of the artist who drsw the picture, bnt think that in this style of printing they have done very well and made a fair bsginning. The work is done by ordinary lettsr prsss printing and not by the slow and expensivs process of lithograpby. Ths procsss is tsn times as rapid and is corrsspondingly cheaper than regular cbromo-lithography. The zincography dons by this process would do credit to any jonrnal in ths United S'ates. Ths manner of making and printing the picture is not generally nndsrstood, but when it is ths excellencs of tbe work will bs appreciated. We look forward in future numbers to an improvemsnt, and think ee will make satipfactory progressin ths new art, Smelting on the Pacific Coast—No. 2. A Few Hints on Making Smelting a Financial Success. In onr last issus we gave a short history of the business of smelting on this coast, its successes and failurss. In this, ws shall try to give a gsneral view of ths operations to be gons through with in smelting ths argentifsrous galsnas and lead ores of this coast, as well asa few hints that may assist those who propose engaging init asa bnsinsss, to avoid tbs errors into which others havs fallen. Of conrss no operation can bs regarded As Successful as a Business Unless it is profitable in a financial point of view, and consequently it often reqnirss soms closs figuring in order to determins whether ths enterpriss will pay, though every facility for smelting may be obtainabls and ths character of the ore may be such as to maks it suscsptible of rednetion by this process. Ws shall first procced to givs the elements necessary for ths success of the operation asa reducing process, and then some of the points to bs observed in figuring ths cost of production and ths chance for profits. Of conrss, the first qnsstion to bs answered before engsging in the erection of furnaces is, whether the Ores to be Worked Ars susceptible of complete and satisfactory reduction by smslting. This may be answered by stating tbat at least inthe ore should be contained 30 per csnt. of metallic Isad, though the preater ths quantity of lead contained, ths easier will bs the operation, other things being eqnal. If ths ores contain as high as forty per cent. or ovsr, further advantags is found in ths possibility of mixing in ths smelt a small proportion of rich silver milling ore, if obtainable, and thus giving ths bnilion a highsr percsntage of silver. In regard to ths pressnes of other base mstsls than lead,in the ore, ws would say that as arule, they ars deleterious not only to ths smelting but toths appearancs and value of ths bullion produced. Antimony in small quantities is not, as a rule, very injurions, as it passes off in great part in the furnace, carryiug with it, howevsr, soms portion of the silver. Copper in small qnantities gives the bullion a hard nature and dark appearancs. Arsenic goes off in fumes, lsaving a very small percentage in the bullion, but has the disadvantage of being very injurious to the workmen. These are the three mstals most generally found in the argentiferous lead ores of this coaat. Self-Fluxing Ores. Tbe next thing to bs determinsd is whether the ore is self-fluxingi.e. whether the matrix is sufficiently fusible at ordinary furnace tempsrature toliquify the whole mass. 2d, whether there is enongh oxides and metallic ironin it to thorongbly reducs the lesd to metalic form, when in contact with the charcoal of the furnace. This can bs most sasily determinsd by asmall blast furnace which should always bs attached to the works, its construction is but a trifling expense, and the convenience of one is very great; asingle twyer is only necessary and the rssults ars alwaya of a practical character, and thongh chsmical analysss of the ores ars sometimes nuscsssary to show what their propsrties are, and what thsy lack, in case the small furnace shows tbem to bs not sel-ffinxing; tbis furnace obviates their use toa great extent. Tu case the ors is not easily fusible, it may be made so by tbe addition of hematite (red oxids of iron) found generally all over the Pacific coast, which being easily melted and holding heat well, gsnerally effects the dssirabls object, besidea being also of valuein another manner to be described hsreaftsr; or sometimes the addition of salt or alkali will effect tbs dssired object. In case the Ore is Not Sel!-Reducing That is, does not contain oxide enough to reduce the lead in the oreto meitallio form in conjunction with the charcoal of. the furnace, it may bs made so either by roasting the galena so as to oxidize the ore, or by partly oxidizing ths ore and then adding the hemitite or mstalic scrap iron to form with the excess of sulphur in the ors, sulphide of iron, which ia carried offin the slag. We will next try and form an idsa as to whsther the opsration will bs successful In a Financial Point of View. Of course this depsnds so much on ths particular circumstancea governing each case that only some general rules to be considered, can bs givsn; ist, other things beiug equal, it is always more economical to run several furnaces, then one ; 2d,a loss of 5 to 10 per cent. must bs expscted on both lead and silver from assay resulta. The more silver and gold in ths bullion the grsater percentage can be obtained the cost of refiniug being no greater for bullion containing 500 ozs. of silver per ton, than bullion containing 100 ozs. per ton. In regard to running expsnses, it takes from 20 to 40 bnshels of ordinary charcoal to smslt one ton of lead ors; on an average 30 bushels might bs caleulated. In making calculations ths following must be regarded as ontlay. Cost of ors extraction; cost of transportation toworks; cost of crushing; cost of fluxes; cost of builion transportation to market; wear and tear of works; cost of “charcoal, 30 bushels per ton; cost of three aets of hands, thres each set for each fifteen ton blast furnacs, 7. ¢., ons feeder, 1 smelter and 1 helper; 2 enginsers, at 12 hour shifts; cost of wood for sngine; ons blacksmith for sharpening bars, ete. Against amount of bullion less ten per cent. on average assay, at from $1 per oz. silvsrto $1.20, according to amount of ozs. per 2,000 ibs., also 414 to 5 cents a pound for lead. This estimats is for 15 ton blast furnaces, ths most economical in our estimation. They ought to havs an inside diametsr of 22 to 24 inches, with 12 to 15 feet fall from feed hold to twyers, a single front, two side and back tweers, ortwo back and two sids twyers, and with blast direct into farnacs. Arched sides to enabls burnt out stones to bs removed; single tap hols and slag spout. This furnace, with 48 incbes hearth, will smelt 15 tons of material a day; that is 12 tons of Isad ore, 3 tons of iron ors (flux,) lead slags and rich silver ore, eto., and properly managed, will do it well. In regard to the actual Working of Sueh a Furnace Ws do not prstsnd to attempt to give any general rules except this adyico. To obtain some one thoroughly and practically sequaintsd with itas superintendant, and msn that know their business to act nnder him, and be assured thst thsy will savs mnch money, anxiety and vexation, even if the salariss paid ars highsr. The following hints may bs nsefnl. In bnilding ths furnacs, tbe spacs betwsen ths furnace and ths lining should bs fillsd with firs sand, to fill any cracks that may bs made in ths lining. Aftsr being built ths furnacs shonld have full tims to dry; water lined tweers ars most economical. In starting ths furnace grsat cars should be taken to heat it vsry thorougbly, but gradually. For a number of days a very light fire should be kept in it, and 24 hours before charging ths firs shonld bs kept at full force, the blast from the tweers being as strong as when the ors is being mslted. A metallic bottom should bs obtained for the farnacs, if possible, by pntting a ton or so of lead or bullion in ths bottom. This keeps the bottom covsred with molten metal and prevents freszing below the twyers. Half charges should bs put into ths furnace for ths first 12 hours, after that, if everytbing is right, full charges may be mads. In charging, care should always be taksn to chargs in the centre of ths furnacs, or otherwise too much work will be given to some particular tweer; nnless,in ordsr to cool aoms particular portion of ths furnacs tbat shows signs of gettiug too hot and burning out, yon chargs ovsr that particular point. Ws consider it a mattsr of little importancs whether one bushe] of charcoal and small charges of ors ars put into ths furnacs, or two bushels of coal and doubls the qnantity of ors is used to each chargs; thongh in largs furnaces we are inclined to think the latter the preferable plan. In Preparing the Ore For furnacs reduction, if it is found necessary to roast it, it can be dons in kilns, cut into tbe sides of a hill and the wood and ore propsrly arranged to carry a draught of air through ths mass; tbs sulphur of the ore will gsnerally furnish a great portion of the fnel needed, thus making tbe oqsration ‘comparativsly inexpensive. Before going into the furnace the ore should be broken into pieces the size of hsns’ eggs, which psrmits the dranght to pass readily throngh and the heat to psnetrate and malt it rapidly. Great care should always bs taken to Keep the Furnace Free So that the blast passse easily through the ore; this is perhaps ths most important point in fnrnace management. As long as the fumes from the furnace are solid and dense and pour out regularly, the elag liquid, and running copionsly, and no impediment offered to the bars that the smelter putsinto tbe furnace from time to time, to bs sure that it is not clogging; everything is as it sbonid be; but if tbe blastis intercepted and the otherthings right, thetrouble is above the twyers and conseqnently not to bs got at so easily, and only to be removed by some change in the charging, which should bs increased in flux and fuel and lessened in ors nntil ths difficulty is removed. In case the slag is not as thin asit ahould be, more flux should be used, and if the fnrnace is cloggsd bslow the twyers it most be barred out by the workmen. As a gsneral rnle the furnace at the feed hole should be kept ‘‘dead,”’ i. ¢., with no visible flams at that point,in order to avoid loss by fumes. Sometimss, however, to burn out obstructiona above the tweers the fireis bronght to such a point and the furnace charged so little as to psrmit the flame to bs seen at the fsed hole, We have not mentioned reverberatory fnrnaces as they have been but little ussd on this coast, ths labor being greatsr to rsdnce ths sams amount of ore by them and the blast consequently having ths preference. Iu_conelusion we wonld say that in our opinion when the people of this coast have obtained the sams expsrience in smelting as they have in amalgamating, and railroads reducs rates so as to reducs tbe price of fuel in remote regions, smelting will bs not only profitable to afew, but will furnish a living to thousands, and many mines now deemed worthlsss will bs made of great value to their owners and to the country gsnerally. At eome future time we may discuss ths propriety of rsfining argsntiferous lead bullion at ths place it is manufactured, A Very Unusual Mineral. Enirors Press:—In prssenting you witha sampls of ths vsry rare minsral—ths ‘‘Molybdate of lead’’—(sent by Captain John Tonkin from ths Tecoma mine, near Bnel City, Nevada, for-stamination,) it may be interesting and valnabls to many of your readers to know its principal characteristics, and general comportment before the blowpipe, etc., soms of which are new, and others not in strict accordancs with book records. It has been found of various cclors, from orangs yellow to aurora red, and from wax yellow to gray and brown; thess samples ars, for the greater part, bright amber yellow, certain portions being changed by oxids of iron, to snnff-color; ths amber parts sre crystallized either into irregular tables, which lis at all angles, or as very flat, four-sided prisms, of strictly lamellar structure, which may bs cloven with tbs greatest ense, parallel to their base, to thin scales, whilst the whole stone is so soft and friabls thatitmay becrumbled between the fingers more liks an artificis] drug than a natural mineral. When heated, it first decrspitates into very nnmerous thin scalss, which on increase of heat becomes of a dark, wax yellow, (returning as befors to pale amber ysllow when cold) on the temperaturs being still furthsr increased it fuses into a light sulphnr yellow mass. Fluxed with carbonate of soda it may bs smelted on charcoal, in ths blowpipe’s yellow flame, when abont half its wsight of lead will bs reduced to ons or more buttons, whilst ths molybdie acid will pass into the coal, this is similar to tungstio acid, with the diffsrence, thst after ths removal of ths lesd, ths molybdenum may be oxydized befors the blue flams, to coat the surface with its copper colored oxids. Whsn fussd with carbonate of soda iu platinnm wirs, it forms a limpid molten glass, which becomes milk white when cold. This bead when fused on charcoal in or befors the blowpipe’s flame, passes into the coal and ths red oxids may bemade torsappear, as best seen by a lens. Fused with borax in platinum wire bsfore ths mount of ths blue flame, ths resnitant glass is ark yellow whsn hot, andof beantiful opalins appearances when cold; but when an excessive qnantity is added, the glsss when hot is dark red, then yellow, and when quite cold, a bluishgray opal. Ths manner in which this opalins appearance closes in from ths wire to ths center of bead, during ths cooling, is very characteristic. Merlet’s moist msthod may also bs resorted to for the detsction of molybdic acid in this mineral, aa follows: Fuse ths powdered sample with nitre in a platinum spoon or crucible, thsn dissolve ths molybdate of potash thus formed, in water boiled over a spirit lamp (or hot stove) filter or pour tbe clear liquor into a porcelain dish (or saucer) then, after placing a small piecs of bright coppsr therein, add to the boiling solution just aufficient hydrochloric acid to dissolve some of the copper, which will form a general light green grolution, and after some time (if molybdic acid is present) just immediately over and aronnd the metallic copper, its characteristic indigo blus. Thisis a very exacting test for a very small qnantity, J. 8. Pairs, M. E. San Francisco, Deo. 31, 1872. Cheap Coal. Notwithstanding the sxtensive deposits of coal in the neighborhood of Coose Bay and elsewhere on onr coast, ths citizens of San Francisco pay pretty high prices for coal. Theonly three mines shipping coal from that district to this city at present are the Eastport, Newport and Hardy. Soms comes from Mount Diablo, and considerable is brought here from Sydney and from England. The reported discovery of coal in the vicinity of Temecula, in San Diego connty, has bsen confirmed, and ssveralolaims have been taken up under the new law. If the coalis minsd aystsmatically and the business carrisd on in a more extensive manner than itis at present, ws have little doubt but that it will be a profitable investment. The coal companies at pressnt at work pay regular monthly dividends and are ysry profitable institntions to the stockholdsrs. In fact the” greatest drawback to our mannfacturing interests in this city is the great scarcity and high prics of fusl, Thers are known to be extensive deposits of coal all over this coast and atill many of the places remain even nnprotected. It seems rather peculiar that while coal mining here has proved so successful, financially, where the mines have been developed, that no more capital has been invested in the businsss. Let us have cheap coal by all means and plenty of it. It will help build up our mannfacturing interests, be of the utmost benofit tomany poor families and bs as important a thing for the welfare of the city as can be dons. MM

MINING AND SCIENTIFIC PRESS. [January 4, 1873 W, B. EWER......-. nopeoneoDocooaccded SEnIoR EDITOB. DEWEY & CO., Publishers. a. %. DEWEY, GEO. K. BTRONG. W. B, EWER, JNO. L, BOONE. Office, No. 338 Montgomery St., 8. E. Corner of Galifornia St., diagonally acrosa from Wella, Fargo & Co.’a. SuBScRIPTiIons payable in advance—Yor one year, $4: six months, $2.50; three montbs, $1.25. Cluhs of ten names or more, $3 each per annum. $5, in advance, will pay for 1% year. Remittances hy registered letters or P, O. orders at our risk. ApVEBTIsING Rares.—l week. 1 Hite 3 months. 1 year. Per line......+.06 a 25 80 $2.00 35.00 One-half inch. «$1.00 $3.00 7.60 20.00 One inch......seeeeee 2.00 5.00 14.00 38.00 Large advertisements at favorahle rates. Special or reading noti legal advert: tg, notices appearing in extraordinary type or in particular parts of the paper, inserted at special rates. San Francisco: Saturday Morning, Jan. 4, 1873. Legal Tsnder Ratea.—8. F., Thurs., Jan 2.— buying, 89%¢; Selling, 8924. Table of Contents. GENERAL EDITORIALS.—The Coming Expositions; A Monster Casting; A New Volume, 3. California Art Oallery; Smelting on the Pacific Coast; Cheap Cval, 8. ILLOSTRATIONS.—The First Quartz Mill in California, 1. The Tailor-Bird’s Nest, 6. Hoendee’s Patent Gun Lock; The American Bottle Filler, 9. MECHANICAL PROGRESS,—Bessemor’s Steady Ship Saloon; Resistance of Building Stone to Heat, 3. SCIENTIFIC PROGRESS.—Experiments in Neture’s Lahoratory; Nickle as a Gas Uccluder, Heating Water Above the Boiling Point in Open Vessels; Origin of Storms; Gummate of Iron Paper; There is no Ohject Unworthy of Our Notice, 3. USEFUL INFORMATION.— How to Varnish; The Water Telescope; Motion of the Eye; Cultivate Habits of Careful Observation; Power of the Eye in Viewing Minute Ohjects; Bogus Chinese Pearls; How the Diamond Outs Glass; Force of Lightning; Suhstances that Most Resist the Action of Cold; he Pilot Fish, 7. GOOD HEALTH.—The Blood; Poisonous Contec, tionery; Mechanism of the Bones; An Intelligent Drugyist; Nourishment in Food; Power of Man tu Endure Cold; The Art of Walking; Bisulphide of Carhon on the System. 7. MINING SUMMARY from varions counties in California, Lower California, Nevada, Idaho and Utah, 4-5, Market Reports, 12. MINING STOCK MARKET.—Table of Daily Sales and Prices and Comparative Prices for the Week; Notices of Assessments; Meetings and Dividends; Review of Stock Market for the Week, 4. MISCELLANEOUS. —Practical Uses of Geology; Klamath River Mines; Mining for Tin; Another An. cient City; Street Car Tracks; The Reported Chicago Orain traude: [he Lake Superior Tin Discoveries, 2. The Railways and their Mineral Traffic; New Tdria Quicksilver; Cheaper Sewing Machines, Silver and Silver Coinage; I. L. D., 6. Coaiaud Quicksilver, Frozen Up; Delays of Law—Courts of Conciliation; Shell Mounds on the Culifornia Coast; Co-Operation in Great Britain; What is Slate, aud How was it Formed; The Bessemer Saloon Steamhoat The Discovery of Petroleum in Pennsylvania; Nevada Salt and Soda Beds; Virginia Oold Mine, Superior Lake Railroad Iron, 10. New Code Mining Law, 12. New Incorporations, 16. Cautrornta Anr Gautery, — The first number of which is befors ns, is devotsd to musio, drama, art and literature, and is published by Alirsd Chaigneau & Co., 409 Washington street. Terms, $5 per year. It is a very fine spscimen of typography; the ‘‘heading” in particular is worthy of mention, having been made by the zincograph process, by tbe pnblishers themselves. The numbsr contains ‘‘Mrs. Platsdware’s Campaign,’’ ‘* Art in California,’ ‘Free Art Gallsries,’? A skstch of Thomas Nast, a poemby J. F. Bowman and one by Obas. Warren Stoddard. ‘The Art Exhibition and the Gsrome,”’ ‘‘Jottings at a Window," Local Art Notes, The Yosemite Waltz, (Music), ‘Is Joaqnin Miller a Poet?” “ Roman Recollections,’ ‘Unknown Bsnefactors,”’ **Pauline Luecas Debut,'’ Tales from the Grsenroom, eto. The zinco-chromo which accompanies the paper, is made by a nsw and peouliar process, a fact whioh our cotsmporariss seem to havs ovsrlooked, Too much has besn expected from this first attsmpt, and the mannsr in which it is made} has not besn taken in consideration. We will not attempt to criticise the akill of the artist who drsw the picture, bnt think that in this style of printing they have done very well and made a fair bsginning. The work is done by ordinary lettsr prsss printing and not by the slow and expensivs process of lithograpby. Ths procsss is tsn times as rapid and is corrsspondingly cheaper than regular cbromo-lithography. The zincography dons by this process would do credit to any jonrnal in ths United S'ates. Ths manner of making and printing the picture is not generally nndsrstood, but when it is ths excellencs of tbe work will bs appreciated. We look forward in future numbers to an improvemsnt, and think ee will make satipfactory progressin ths new art, Smelting on the Pacific Coast—No. 2. A Few Hints on Making Smelting a Financial Success. In onr last issus we gave a short history of the business of smelting on this coast, its successes and failurss. In this, ws shall try to give a gsneral view of ths operations to be gons through with in smelting ths argentifsrous galsnas and lead ores of this coast, as well asa few hints that may assist those who propose engaging init asa bnsinsss, to avoid tbs errors into which others havs fallen. Of conrss no operation can bs regarded As Successful as a Business Unless it is profitable in a financial point of view, and consequently it often reqnirss soms closs figuring in order to determins whether ths enterpriss will pay, though every facility for smelting may be obtainabls and ths character of the ore may be such as to maks it suscsptible of rednetion by this process. Ws shall first procced to givs the elements necessary for ths success of the operation asa reducing process, and then some of the points to bs observed in figuring ths cost of production and ths chance for profits. Of conrss, the first qnsstion to bs answered before engsging in the erection of furnaces is, whether the Ores to be Worked Ars susceptible of complete and satisfactory reduction by smslting. This may be answered by stating tbat at least inthe ore should be contained 30 per csnt. of metallic Isad, though the preater ths quantity of lead contained, ths easier will bs the operation, other things being eqnal. If ths ores contain as high as forty per cent. or ovsr, further advantags is found in ths possibility of mixing in ths smelt a small proportion of rich silver milling ore, if obtainable, and thus giving ths bnilion a highsr percsntage of silver. In regard to ths pressnes of other base mstsls than lead,in the ore, ws would say that as arule, they ars deleterious not only to ths smelting but toths appearancs and value of ths bullion produced. Antimony in small quantities is not, as a rule, very injurions, as it passes off in great part in the furnace, carryiug with it, howevsr, soms portion of the silver. Copper in small qnantities gives the bullion a hard nature and dark appearancs. Arsenic goes off in fumes, lsaving a very small percentage in the bullion, but has the disadvantage of being very injurious to the workmen. These are the three mstals most generally found in the argentiferous lead ores of this coaat. Self-Fluxing Ores. Tbe next thing to bs determinsd is whether the ore is self-fluxingi.e. whether the matrix is sufficiently fusible at ordinary furnace tempsrature toliquify the whole mass. 2d, whether there is enongh oxides and metallic ironin it to thorongbly reducs the lesd to metalic form, when in contact with the charcoal of the furnace. This can bs most sasily determinsd by asmall blast furnace which should always bs attached to the works, its construction is but a trifling expense, and the convenience of one is very great; asingle twyer is only necessary and the rssults ars alwaya of a practical character, and thongh chsmical analysss of the ores ars sometimes nuscsssary to show what their propsrties are, and what thsy lack, in case the small furnace shows tbem to bs not sel-ffinxing; tbis furnace obviates their use toa great extent. Tu case the ors is not easily fusible, it may be made so by tbe addition of hematite (red oxids of iron) found generally all over the Pacific coast, which being easily melted and holding heat well, gsnerally effects the dssirabls object, besidea being also of valuein another manner to be described hsreaftsr; or sometimes the addition of salt or alkali will effect tbs dssired object. In case the Ore is Not Sel!-Reducing That is, does not contain oxide enough to reduce the lead in the oreto meitallio form in conjunction with the charcoal of. the furnace, it may bs made so either by roasting the galena so as to oxidize the ore, or by partly oxidizing ths ore and then adding the hemitite or mstalic scrap iron to form with the excess of sulphur in the ors, sulphide of iron, which ia carried offin the slag. We will next try and form an idsa as to whsther the opsration will bs successful In a Financial Point of View. Of course this depsnds so much on ths particular circumstancea governing each case that only some general rules to be considered, can bs givsn; ist, other things beiug equal, it is always more economical to run several furnaces, then one ; 2d,a loss of 5 to 10 per cent. must bs expscted on both lead and silver from assay resulta. The more silver and gold in ths bullion the grsater percentage can be obtained the cost of refiniug being no greater for bullion containing 500 ozs. of silver per ton, than bullion containing 100 ozs. per ton. In regard to running expsnses, it takes from 20 to 40 bnshels of ordinary charcoal to smslt one ton of lead ors; on an average 30 bushels might bs caleulated. In making calculations ths following must be regarded as ontlay. Cost of ors extraction; cost of transportation toworks; cost of crushing; cost of fluxes; cost of builion transportation to market; wear and tear of works; cost of “charcoal, 30 bushels per ton; cost of three aets of hands, thres each

set for each fifteen ton blast furnacs, 7. ¢., ons feeder, 1 smelter and 1 helper; 2 enginsers, at 12 hour shifts; cost of wood for sngine; ons blacksmith for sharpening bars, ete. Against amount of bullion less ten per cent. on average assay, at from $1 per oz. silvsrto $1.20, according to amount of ozs. per 2,000 ibs., also 414 to 5 cents a pound for lead. This estimats is for 15 ton blast furnaces, ths most economical in our estimation. They ought to havs an inside diametsr of 22 to 24 inches, with 12 to 15 feet fall from feed hold to twyers, a single front, two side and back tweers, ortwo back and two sids twyers, and with blast direct into farnacs. Arched sides to enabls burnt out stones to bs removed; single tap hols and slag spout. This furnace, with 48 incbes hearth, will smelt 15 tons of material a day; that is 12 tons of Isad ore, 3 tons of iron ors (flux,) lead slags and rich silver ore, eto., and properly managed, will do it well. In regard to the actual Working of Sueh a Furnace Ws do not prstsnd to attempt to give any general rules except this adyico. To obtain some one thoroughly and practically sequaintsd with itas superintendant, and msn that know their business to act nnder him, and be assured thst thsy will savs mnch money, anxiety and vexation, even if the salariss paid ars highsr. The following hints may bs nsefnl. In bnilding ths furnacs, tbe spacs betwsen ths furnace and ths lining should bs fillsd with firs sand, to fill any cracks that may bs made in ths lining. Aftsr being built ths furnacs shonld have full tims to dry; water lined tweers ars most economical. In starting ths furnace grsat cars should be taken to heat it vsry thorougbly, but gradually. For a number of days a very light fire should be kept in it, and 24 hours before charging ths firs shonld bs kept at full force, the blast from the tweers being as strong as when the ors is being mslted. A metallic bottom should bs obtained for the farnacs, if possible, by pntting a ton or so of lead or bullion in ths bottom. This keeps the bottom covsred with molten metal and prevents freszing below the twyers. Half charges should bs put into ths furnace for ths first 12 hours, after that, if everytbing is right, full charges may be mads. In charging, care should always be taksn to chargs in the centre of ths furnacs, or otherwise too much work will be given to some particular tweer; nnless,in ordsr to cool aoms particular portion of ths furnacs tbat shows signs of gettiug too hot and burning out, yon chargs ovsr that particular point. Ws consider it a mattsr of little importancs whether one bushe] of charcoal and small charges of ors ars put into ths furnacs, or two bushels of coal and doubls the qnantity of ors is used to each chargs; thongh in largs furnaces we are inclined to think the latter the preferable plan. In Preparing the Ore For furnacs reduction, if it is found necessary to roast it, it can be dons in kilns, cut into tbe sides of a hill and the wood and ore propsrly arranged to carry a draught of air through ths mass; tbs sulphur of the ore will gsnerally furnish a great portion of the fnel needed, thus making tbe oqsration ‘comparativsly inexpensive. Before going into the furnace the ore should be broken into pieces the size of hsns’ eggs, which psrmits the dranght to pass readily throngh and the heat to psnetrate and malt it rapidly. Great care should always bs taken to Keep the Furnace Free So that the blast passse easily through the ore; this is perhaps ths most important point in fnrnace management. As long as the fumes from the furnace are solid and dense and pour out regularly, the elag liquid, and running copionsly, and no impediment offered to the bars that the smelter putsinto tbe furnace from time to time, to bs sure that it is not clogging; everything is as it sbonid be; but if tbe blastis intercepted and the otherthings right, thetrouble is above the twyers and conseqnently not to bs got at so easily, and only to be removed by some change in the charging, which should bs increased in flux and fuel and lessened in ors nntil ths difficulty is removed. In case the slag is not as thin asit ahould be, more flux should be used, and if the fnrnace is cloggsd bslow the twyers it most be barred out by the workmen. As a gsneral rnle the furnace at the feed hole should be kept ‘‘dead,”’ i. ¢., with no visible flams at that point,in order to avoid loss by fumes. Sometimss, however, to burn out obstructiona above the tweers the fireis bronght to such a point and the furnace charged so little as to psrmit the flame to bs seen at the fsed hole, We have not mentioned reverberatory fnrnaces as they have been but little ussd on this coast, ths labor being greatsr to rsdnce ths sams amount of ore by them and the blast consequently having ths preference. Iu_conelusion we wonld say that in our opinion when the people of this coast have obtained the sams expsrience in smelting as they have in amalgamating, and railroads reducs rates so as to reducs tbe price of fuel in remote regions, smelting will bs not only profitable to afew, but will furnish a living to thousands, and many mines now deemed worthlsss will bs made of great value to their owners and to the country gsnerally. At eome future time we may discuss ths propriety of rsfining argsntiferous lead bullion at ths place it is manufactured, A Very Unusual Mineral. Enirors Press:—In prssenting you witha sampls of ths vsry rare minsral—ths ‘‘Molybdate of lead’’—(sent by Captain John Tonkin from ths Tecoma mine, near Bnel City, Nevada, for-stamination,) it may be interesting and valnabls to many of your readers to know its principal characteristics, and general comportment before the blowpipe, etc., soms of which are new, and others not in strict accordancs with book records. It has been found of various cclors, from orangs yellow to aurora red, and from wax yellow to gray and brown; thess samples ars, for the greater part, bright amber yellow, certain portions being changed by oxids of iron, to snnff-color; ths amber parts sre crystallized either into irregular tables, which lis at all angles, or as very flat, four-sided prisms, of strictly lamellar structure, which may bs cloven with tbs greatest ense, parallel to their base, to thin scales, whilst the whole stone is so soft and friabls thatitmay becrumbled between the fingers more liks an artificis] drug than a natural mineral. When heated, it first decrspitates into very nnmerous thin scalss, which on increase of heat becomes of a dark, wax yellow, (returning as befors to pale amber ysllow when cold) on the temperaturs being still furthsr increased it fuses into a light sulphnr yellow mass. Fluxed with carbonate of soda it may bs smelted on charcoal, in ths blowpipe’s yellow flame, when abont half its wsight of lead will bs reduced to ons or more buttons, whilst ths molybdie acid will pass into the coal, this is similar to tungstio acid, with the diffsrence, thst after ths removal of ths lesd, ths molybdenum may be oxydized befors the blue flams, to coat the surface with its copper colored oxids. Whsn fussd with carbonate of soda iu platinnm wirs, it forms a limpid molten glass, which becomes milk white when cold. This bead when fused on charcoal in or befors the blowpipe’s flame, passes into the coal and ths red oxids may bemade torsappear, as best seen by a lens. Fused with borax in platinum wire bsfore ths mount of ths blue flame, ths resnitant glass is ark yellow whsn hot, andof beantiful opalins appearances when cold; but when an excessive qnantity is added, the glsss when hot is dark red, then yellow, and when quite cold, a bluishgray opal. Ths manner in which this opalins appearance closes in from ths wire to ths center of bead, during ths cooling, is very characteristic. Merlet’s moist msthod may also bs resorted to for the detsction of molybdic acid in this mineral, aa follows: Fuse ths powdered sample with nitre in a platinum spoon or crucible, thsn dissolve ths molybdate of potash thus formed, in water boiled over a spirit lamp (or hot stove) filter or pour tbe clear liquor into a porcelain dish (or saucer) then, after placing a small piecs of bright coppsr therein, add to the boiling solution just aufficient hydrochloric acid to dissolve some of the copper, which will form a general light green grolution, and after some time (if molybdic acid is present) just immediately over and aronnd the metallic copper, its characteristic indigo blus. Thisis a very exacting test for a very small qnantity, J. 8. Pairs, M. E. San Francisco, Deo. 31, 1872. Cheap Coal. Notwithstanding the sxtensive deposits of coal in the neighborhood of Coose Bay and elsewhere on onr coast, ths citizens of San Francisco pay pretty high prices for coal. Theonly three mines shipping coal from that district to this city at present are the Eastport, Newport and Hardy. Soms comes from Mount Diablo, and considerable is brought here from Sydney and from England. The reported discovery of coal in the vicinity of Temecula, in San Diego connty, has bsen confirmed, and ssveralolaims have been taken up under the new law. If the coalis minsd aystsmatically and the business carrisd on in a more extensive manner than itis at present, ws have little doubt but that it will be a profitable investment. The coal companies at pressnt at work pay regular monthly dividends and are ysry profitable institntions to the stockholdsrs. In fact the” greatest drawback to our mannfacturing interests in this city is the great scarcity and high prics of fusl, Thers are known to be extensive deposits of coal all over this coast and atill many of the places remain even nnprotected. It seems rather peculiar that while coal mining here has proved so successful, financially, where the mines have been developed, that no more capital has been invested in the businsss. Let us have cheap coal by all means and plenty of it. It will help build up our mannfacturing interests, be of the utmost benofit tomany poor families and bs as important a thing for the welfare of the city as can be dons. MM