Volume 12 (1866) (428 pages)

226 Ghe Blinkngy and Selentific Dress, Sodium Amalgam---Wurtz's Patent, The American Journal of Science for March, contains the following interesting letter addressed to Professor Silliman by Henry Wurtz, of New York, the discoverer and patentee of the nse of eodium amalgam for extracting the precious metals from their ores : In the opinion of yourself and others npon whose judgment I rely, the time has arrived for the promulgation of the discoveries made by me, now mauy years since, of certain new properties of the alkali-metals. readering them of value in tbe amalgamation of ores of the precious metals. You are aware tbat, pending the repeated investigations which I have conducted upon this important subject, I have made communications of my results, both oral and written, from tinie to time to many persons, yourself ainong the number; but that until tbe latter part of the year 1864, no final step was taken to place these discoveries before the public in a tangible forin. On the 27th of December, 1864, a patent of the U. S. Government was granted to me for specified modes of applying the said discoveries; the specification having been at my request retained on file in the Patent Office for six months (as the new patent law permits) ; so that the expiration of the term of this patent did not commence until the 27th of June, 1865, , It appears, however, that my frequent communications had led to wide discussion of the remarkable phenomena iavolved, phenomena which I seldom hesitated to exhibit, even to the most casual acquaintances, taking only the precaution of silence as to the agent employed (the sodiuin) ; and the inevitable consequence has been the occupation of other minds with the subject, both here and abroad. In fact, since the issue of my pateut,I am informed that several applications (necessarily fruitless) have been made at Washington by others for patents covering some or all ol my uses of the alkali-metals ; and an English patent bas heen procured iu the name ol the eminent chemist Win. Crookes, dated August 12,1865 (about eight months subsequent to the filing of my specification at Washington) ; of the specifica. tion of which I have procured a copy, aad fiud it to presenta remarkable similarity to my own, Moreover, 1 frequently find allusions and statements relating to this subject, geaerally more or less iaperlect and obscure, in tbe public prints throughout the world. It has clearly, therefore, become incumbent upon me—if only as a matter of justice to the mining cominunity and others interested—to furuish authentic information as to what has actually beea done, and what it is proposcd to do. I have, therefore, prepared an abstract of my epecibcation, embodying in a condensed form such portions of its substance as appear of preseat importance to miners and metallurgists. Other portions of the subject-matter of the specification will form a sufficiently voluminous, and I hope interesting, topic of a future commuaicatioa ; as, forinstance, my new modes of preparing amalgams of the alkali-metals in large masses with any desired rapidity, safety and economy; and which you, with other cheniical scientists who have witnessed its operation, deem important ina purely ecientifie view ; as involving novel pbenomeaa, aad illustrating molecular laws obscurely seen at present. With a few explanatory ohservations, which secin needed, J shall conclude. I have fouud it necessary, for practical purposes, to prepare three different grades of the sodium amalgams, from each other in their proportions of sodium ahout as the aumnbers 1, 2 and 3; aad which I designate accordingly. a few lines, also, regarding the term * magnetic amalgams,” which aot a Tew will deem fantastic and as snegesting unauthorized analogies. I hope to show, howevcr, at some other time, that iu applying the term I have followed tbe dictates ol reason, and even the direct path of the modern leaders in cosinical dynamies, the apostles of tbe doctrine of correlation of physical forces; and that the analogical element which I find is hetween attractive and repulsive aatagonistic lorce which exerts a chemical, or rather aa elementary discrimination between bodies at insensible distaaces, and the antugonistic force of magnetic attruction and repulsion, which is so emineat an example of a similar elementary discrimination, though at sensible distances also. No oae (to offer am illustration nearly, though not quite perfect) doubts the intimate relation between radiated and convected heat, although the oue propagates itself throughout the universe of space, whilst the other is susceptihlé only of diffusion throughout iasensible distances, from molecule to molecule. More of this, however, hereafter. The term, from its convenience alone, will douhtless come into extensive use, as a technical term, among those who are most concerned in the utilizatioa of the magaetic amalgams. 89 Nassau St., New York, January 15, 1866 SPECIFICATION. My iavention consists: In imparting to quicksilver * * a greatly enhanced adheeiun, attraction, or affinity for other metals and for its own substance; hy adding to it one of tbe highly electro-positive metals * * -sodium, potassium * etc. My invention * * is applicable: Ist. In all arts and operations in which amalgamation by quicksilver can he made available to separate or extract gold, silver or other-precicus metals from tbeir ores. * * * * * 3d. In all operations in which amalgamation by quicksilver, in conjunction with reducing metals, sucb as iron or zine,’can be made available in recovering metals from their soluble or insoluble saliue compounds ; such as silver Irom its sulphate, chlorid or hypo-ulphite; lead from its sulphate or chlorid; gold from its chlorid or other solution. * * * * * x 8th. In the mercurization of metallic surfaces in general , for instance, in the amalgamation of the surfaces of ziuc in voltaic batterica ; of the surfaces of copper plates, pans, etc., used in the saving of gold fromits ores; * * 9th. In the more convenient transportation of quicksilver, hy tbe reduction thereof into solid forms. % * * * * * * Ishall now proceed to the description of those special and peculiar qualities of these amalgams of the alkali-metals which I have discovered, and which have led to my new uses ol them in the chemical and metallurgic arts. A quantity of one of the magnetic anlajgams, dissolved in one hundred timesits weight or mure of quicksilver, commuaicates to the whole a greatly euhanced power of adhering to metals ; and particularly to those which, like gold and silver. lie toward the negative end of the electro-chemical scale. ‘his power of adhesion, in the tase of these two inetals. is so great, that the resistance which I have lound their surfaces, when in the native state, usually oppose to amalgamation (a resistance which is much greater and niore general than has been hitherto recognized, and which is due to causes as yet undiscovered, or at least uninvestigated) is instantly overcome ; whether tbeir particles be coarse, fine, or even impalpable. Even an artificial couting of oil or grease (which is such an enemy to amalgamatiou that the smoke of the miners’ lamps is pronounced highly detrimental in gold and silver mines) lorms no obstacle to immediate amalgamatioa hy this magnetic quicksilver, The atoms of the quicksilver are,as it would seem, put intoa polaric condition by a minute addition of one of tbose metals which range themselves toward the electro-positive end of the scale; so that its affinity for the more electro-negative metals is so greatly exalted that it seizes upon, and is absorbed hy, their surfaces instautaneously ; just as water isabsorbed by a lump of sugar or other porous substance soluble in it. Such quicksilver (unlike ordinary quicksilver) even adheres strongly to surfaces of iron, steel, platinum, aluminum and antimony; an adhesion which, however, as I bave discovered, in the case of these five metals is notof the outure of a true amalgamation, there being no penetration whatever into the substance of the metal ; so that the superficially adherent magnetic quicksilver may he readily wiped off clean, just as water may be from glass. The only metal J have as yet found, which cannot be enfilmed by the usc of the maguetic amalgam, is magnesium. I. Applications of the magnetic amalgams to working the ores of the precious metals. My improvement ia methods cf amalgamating gold and silver ores consists in adding from tine to time to the quicksilver used in amalgamation, about one-hundredth part, or less, ol its weight of one of the magnetic amalgams. The frequeacy with which tbe amalgam is to be added canuot be exactly specified, as it will be found to depend more or less on a multitude ol circumstances ; such, for instance, as the temperature, the purity of the water and the quantity of water used, the ratio borae by the surface of the quicksilver to its mass, the amount and mode of agitation of the quicksilver, the nature of the process and of the apparatus nsed,.the character of the ore, the strength of the amalgam, etc., etc.; so that this importaat point can only be determined hy experience in each case. Some general directions may, however, be derived from the experiments which have heen made. It has been fouud that very much less sodium is requizite in those cases in which much water is einployed, and tbat water frequently renewed ; for instance, in the riffles of a sluice, and ia all forms of amalgamators through which a continual curreat of fresh water is kept ruanine ; mercurial solutions of sodium, as I have discovered, being little affected by water which is free from acid, alkaline, or saline impurities. In those cases, however, in which little water is employed, ard especially when the ore aad quicksilver are ground up together into a . “ elum” or slime, this water soon becomes alkaline, and an oxydation of the sodium sets in, necessitating its frequent renewal. In such cases, therefore, the following manipulation is recommeaded: The whole amount of quicksilver to he used for working up @ batcb of elime, say 40 pounds, is magnetized by dissolving in it one per cent. of amalgam No. 2; or better,.two per cent. of the soft amaleam 2yo. 1, which dissolves more readily; halt of the whole, or 25 pounds, is then tbrown into the mill with the,ore at first, aud, as the incorporatioa proceeds, certaiu fractions of the . other half arc gradually added, at intervals of tine varying according to circumstances, until the whole has been added. II, as is usual, the quicksilver is a portion which has been separated from the slime of a previous operation, it will usually retain some sodium, and therefore will require fresh auialgam in proportiouately smaller quantity. In sluicing operations the soft amalgam No. 1 is most suitable, on account of its ready solubility in mercury ; and in these cases it is practicable to éest the quicksilver in the riffles and ascertain when the magnetic quality requires restoration, by throwing in a few grains of gold-dast. Similar tests are easily applied to slimes, and in amalgamating methods generally, a slip of tarnished sheet copper being a very suitable agent for such teatiuge. It may be remarked in passing, that the amalgam No.1 is at any time easily prepared from No. 2, hy melting it in an iron ladle with about its own weight of quicksilver, or from No. 3, by melting witb twice its weight; considerable time, however, being requisite, in the ease ol No. 3, to produce the additional combination. In copper-plate amalgamation, that is, in those cases iu which auriferous materials are brought into contact with amalgamated metallic surfaces, it is better to substitute altogether lor qnicksilver itsell (both in the first coating of the metallic surfaces, and in any subsequent additions of quicksilver made) the pasty ainaleam No.1. In these modes of amulgamation great economy in wear and tear of apparatus, as well as in first cost, is effected by using, in connection with the magnetic amalgam, plates or surfuces of iron instead of copper. The power of coating or enfilmiug iron renders the amalgams in” fact peculiarly valuable in every form of arastra, drag-mill, or other apparatus for amalgamation which has internal surlaces of iron, these surfaces hecoming couted over with quicksilver, aud tbus immensely extending its cnances of contact with those particles of gold which are so fine as to remaiu suspended in the water. Other important devices arise out of this power of enfilming iron surfaces, such as the keeping of iron surfaces of stamps, and of other apparatus used in crushing ores continually coated with quicksilver. Quicksilver possessed of the magnetic quality may he kept dropping or trickling upon the surfaces of crushingrollers ; or in those crushers in which iron balls are used, the surfaces ol these balls may be kept enfilmed. In like manner as the adhesion of quicksilver to other metals is exalted by the alkali-metals, so, also, as I have discovered, is its cohesion with itsell greatly increased. It is rendered more viscid, more difficult to divide mecbanically, and when thus divided rune together again instantly upoa contact. Hence arise new results of incalculable value. For instance, the so-called “ flouring” or granulation of tbe quicksilver, which in the amalgamation ol ores always occasions so great losses, hoth of the quicksilver itself and of its amalgams with the precious metals, is reduced to a minimum or altogether prevented. The recovery of floured quicksilver and amalgams from slinies and similar mixtures is also greatly fucilitated and accelerated tberehy. For this purpose some stroogly magnetized quicksilver is tbrown into the separator. Such slimes may even be operated npoa with advaatage by the ordinary process of panning by hand; a little magnetic quicksilver bcing thrown into each pan and stirred about at first for a few moments witb the haad, which will collect together and incorporate all the scattered globules of anriferousamalgam. In fact, in all paoniag operations,even upon-the paydirt of placcr diggings, mnch labor, gold, and time may ia this way be saved. It is necessary to specify an important precaution applicuble in some cases in which magnetic amalgams are used, and particularly in those cases in which the ore is ground or agitated with quicksilver in contact with metallic iron. This arises from the liahility of the adhesion of some abraded particles of iron to the amalgam. ‘ihe following plan is therefore recommended in these cases: The amalgam, after separation from tbe excess of quicksilver, and before retorting, is fused in aa earthen dish or iron ladle {with addition of a little quicksilver, ifnecessary, to make it more fluid), and the iron, which will rise and forma scum on the surface, is skimined off. The excess of quicksilver may then, after cooling, he again separated from the amalgam in the usual way. Any amalgam which may adbere to the ironscum is readily detached therefrom by boiling in water to remove the sodiam. Tbie process depends on the simple fact that the adhesion to the iron totally disappears with the extraction of the last traces ol sodium from the quicksilver. In fact, it is possihle to remove all the iron from the amalgam by boiling directly in water, without any previous Tusion ; more particularly if the water be made somewhat acid or alkaline. The presence of iron in a sample of amalgam is readily detected by tbe magnet, which instrument may be sometimes used to advaatage also in separating intermixed iron from anialgam, afterall sodium has been extracted from the latter. ‘There are still other-metals which will usually be found adherent to the amalgam when sodium hag been used ; such ag platinum and osmiridium, These, like iron immediately detach themselves on the removal of tbe sodium by boiling the diluted amalgam in water. A mixture of piatinam or osmiridium, or hoth, with iron, may of course be freed from the latter hy the Magnet. It will generally be found desirable, as in other cases where quicksilver is used and ores containing arsenic or sulphur operated upon, to remove as much as practicable of the arseuic or sulphur by previous roasting or other chemical treatment. * * * * * * IIIl.— Applications to the recovery of metals From their saline compounds. In the common operation of reducing silver to an amalgam’ from its native or artificial” chlorid, or from its sulphate, by the action ofmetallic iron or zine in conjunction with quicksilver, immense advantage arises lrom the use of the magnetic amalgams, especially iu the reduction ol the time occupied toa fraction of that heretofore required. ‘lhis applies as well to ores in which the silver oceurs natnrally as chlurid, bromid or iodid, as to those in which the silver has heen previously converted into chlorid, or sulphate, or both, by roasting with common salt or otherwise; and to clhilorid which has been precipitated from solution. * * When gold has been obtained in solution, either from ores or from other materials, by the action of chloriae, aqua-regia, cyanid of potassium, or any other solvent, also when silver has heen obtained in solution, in hyposulphites or otherwise, the most rapid and thorough mode of saving these metale will be Tound to be their conversion into amalgams, by precipitation with metallic iron in contact with magnetic quicksilver, mole especially when the solutions are dilute. * * ‘The greater rapidity and perfection of the precipitation, in these cases, are obviously due to the absolute contact at once established with the iron surfaces hy the magnetic quick— silver, and the perfect and powerful voltaic circuits thus kept up constantly throughout tbe two metals aud the solution. * * * * * * VIIIl.—Applications to the Mereurializing of Metaliie Surfaces in general. In all cases ia which it is an object to save time and lubor in the coating ol surfaces of other metals with quicksilver, * * * the magnetic amalgams comeinto play. * * * By virtue of the adhesion to iron and other nou-amalgamahle metals imparted by the magnetic amalgams, . am enabled to apply quicksilver, or fluid or pasty amalgams, to any metallic surface, with great-rapidity and facility, with a brush, after the fashioa of a paint; the material of sucb brush being five wire of iron, steel, aluminum, or platinum. Of these the material most geverally suitable is the finest steel wire, tempered to about a spring temper, or somewhat softer; and the most generally nselul lorm for sucb brnsbes, is that of a jlat varnish or white-wash brash. Among the important uses of such hrushes may be instanced ; the amalgaaiativu of copper (or iron) plates used in saving gold from ores ; * * *, Another valuable use is the recovery of quicksilver which has been epilled or scattered in the form of globules; such a flat brush, saturated with magnetic quicksilver, instantly collecting, incorporating, and sucking up the scattered globules, even from the most irregular surface. The same principle of adhesion of magnetic amalgams to a brush of steel wire, is applicable, ia maoy obvious ways, to the sepuration of metals Irom ores, and of granulated or floured quicksilver from ores aud slimes, ete. * * * * * * IX.— Applications to the Transportation of Quicksilver. The ordinary mode of packing and transporting qnicksilver in bulk, is very expensive and troublesome ; and in its ordinary form its transfer from one vessel into another is accompanied by great liability to loss. It will theretore be found very coavenient and useful to possess simple, cheap and practicable modes, such as those described above, of couverting it iato solid forms, susceptible of transportation in vessels of lighter and cheaper material than the ordinary wrought-iron hottles; such, for instance, as glass or earthen ware jars, wooden

226 Ghe Blinkngy and Selentific Dress, Sodium Amalgam---Wurtz's Patent, The American Journal of Science for March, contains the following interesting letter addressed to Professor Silliman by Henry Wurtz, of New York, the discoverer and patentee of the nse of eodium amalgam for extracting the precious metals from their ores : In the opinion of yourself and others npon whose judgment I rely, the time has arrived for the promulgation of the discoveries made by me, now mauy years since, of certain new properties of the alkali-metals. readering them of value in tbe amalgamation of ores of the precious metals. You are aware tbat, pending the repeated investigations which I have conducted upon this important subject, I have made communications of my results, both oral and written, from tinie to time to many persons, yourself ainong the number; but that until tbe latter part of the year 1864, no final step was taken to place these discoveries before the public in a tangible forin. On the 27th of December, 1864, a patent of the U. S. Government was granted to me for specified modes of applying the said discoveries; the specification having been at my request retained on file in the Patent Office for six months (as the new patent law permits) ; so that the expiration of the term of this patent did not commence until the 27th of June, 1865, , It appears, however, that my frequent communications had led to wide discussion of the remarkable phenomena iavolved, phenomena which I seldom hesitated to exhibit, even to the most casual acquaintances, taking only the precaution of silence as to the agent employed (the sodiuin) ; and the inevitable consequence has been the occupation of other minds with the subject, both here and abroad. In fact, since the issue of my pateut,I am informed that several applications (necessarily fruitless) have been made at Washington by others for patents covering some or all ol my uses of the alkali-metals ; and an English patent bas heen procured iu the name ol the eminent chemist Win. Crookes, dated August 12,1865 (about eight months subsequent to the filing of my specification at Washington) ; of the specifica. tion of which I have procured a copy, aad fiud it to presenta remarkable similarity to my own, Moreover, 1 frequently find allusions and statements relating to this subject, geaerally more or less iaperlect and obscure, in tbe public prints throughout the world. It has clearly, therefore, become incumbent upon me—if only as a matter of justice to the mining cominunity and others interested—to furuish authentic information as to what has actually beea done, and what it is proposcd to do. I have, therefore, prepared an abstract of my epecibcation, embodying in a condensed form such portions of its substance as appear of preseat importance to miners and metallurgists. Other portions of the subject-matter of the specification will form a sufficiently voluminous, and I hope interesting, topic of a future commuaicatioa ; as, forinstance, my new modes of preparing amalgams of the alkali-metals in large masses with any desired rapidity, safety and economy; and which you, with other cheniical scientists who have witnessed its operation, deem important ina purely ecientifie view ; as involving novel pbenomeaa, aad illustrating molecular laws obscurely seen at present. With a few explanatory ohservations, which secin needed, J shall conclude. I have fouud it necessary, for practical purposes, to prepare three different grades of the sodium amalgams, from each other in their proportions of sodium ahout as the aumnbers 1, 2 and 3; aad which I designate accordingly. a few lines, also, regarding the term * magnetic amalgams,” which aot a Tew will deem fantastic and as snegesting unauthorized analogies. I hope to show, howevcr, at some other time, that iu applying the term I have followed tbe dictates ol reason, and even the direct path of the modern leaders in cosinical dynamies, the apostles of tbe doctrine of correlation of physical forces; and that the analogical element which I find is hetween attractive and repulsive aatagonistic lorce which exerts a chemical, or rather aa elementary discrimination between bodies at insensible distaaces, and the antugonistic force of magnetic attruction and repulsion, which is so emineat an example of a similar elementary discrimination, though at sensible distances also. No oae (to offer am illustration nearly, though not quite perfect) doubts the intimate relation between radiated and convected heat, although the oue propagates itself throughout the universe of space, whilst the other is susceptihlé only of diffusion throughout iasensible distances, from molecule to molecule. More of this, however, hereafter. The term, from its convenience alone, will douhtless come into extensive use, as a technical term, among those who are most concerned in the utilizatioa of the magaetic amalgams. 89 Nassau St., New York, January 15, 1866 SPECIFICATION. My iavention consists: In imparting to quicksilver * * a greatly enhanced adheeiun, attraction, or affinity for other metals and for its own substance; hy adding to it one of tbe highly electro-positive metals * * -sodium, potassium * etc. My invention * * is applicable: Ist. In all arts and operations in which amalgamation by quicksilver can he made available to separate or extract gold, silver or other-precicus metals from tbeir ores. * * * * * 3d. In all operations in which amalgamation by quicksilver, in conjunction with reducing metals, sucb as iron or zine,’can be made available in recovering metals from their soluble or insoluble saliue compounds ; such as silver Irom its sulphate, chlorid or hypo-ulphite; lead from its sulphate or chlorid; gold from its chlorid or other solution. * * * * * x 8th. In the mercurization of metallic surfaces in general , for instance, in the amalgamation of the surfaces of ziuc in voltaic batterica ; of the surfaces of copper plates, pans, etc., used in the saving of gold fromits ores; * * 9th. In the more convenient transportation of quicksilver, hy tbe reduction thereof into solid forms. % * * * * * * Ishall now proceed to the description of those special and peculiar qualities of these amalgams of the alkali-metals which I have discovered, and which have led to my new uses ol them in the chemical and metallurgic arts. A quantity of one of the magnetic anlajgams, dissolved in one hundred timesits weight or mure of quicksilver, commuaicates to the whole a greatly euhanced power of adhering to metals ; and particularly to those which, like gold and silver. lie toward the negative end of the electro-chemical scale. ‘his power of adhesion, in the tase of these two inetals. is so great, that the resistance which I have lound their surfaces, when in the native state, usually oppose to amalgamation (a resistance which is much greater and niore general than has been hitherto recognized, and which is due to causes as yet undiscovered, or at least uninvestigated) is instantly overcome ; whether tbeir particles be coarse, fine, or even impalpable. Even an artificial couting of oil or grease (which is such an enemy to amalgamatiou that the smoke of the miners’ lamps is pronounced highly detrimental in gold and silver mines) lorms no obstacle to immediate amalgamatioa hy this magnetic quicksilver, The atoms of the quicksilver are,as it would seem, put intoa polaric condition by a minute addition of one of tbose metals which range themselves toward the electro-positive end of the scale; so that its affinity for the more electro-negative metals is so greatly exalted that it seizes upon, and is absorbed hy, their surfaces instautaneously ; just as water isabsorbed by a lump of sugar or other porous substance soluble in it. Such quicksilver (unlike ordinary quicksilver) even adheres strongly to surfaces of iron, steel, platinum, aluminum and antimony; an adhesion which, however, as I bave discovered, in the case of these five metals is notof the outure of a true amalgamation, there being no penetration whatever into the substance of the metal ; so that the superficially adherent magnetic quicksilver may he readily wiped off clean, just as water may be from glass. The only metal J have as yet found, which cannot be enfilmed by the usc of the maguetic amalgam, is magnesium. I. Applications of the magnetic amalgams to working the ores of the precious metals. My improvement ia methods cf amalgamating gold and silver ores consists in adding from tine to time to the quicksilver used in amalgamation, about one-hundredth part, or less, ol its weight of one of the magnetic amalgams. The frequeacy with which tbe amalgam is to be added canuot be exactly specified, as it will be found to depend more or less on a multitude ol circumstances ; such, for instance, as the temperature, the purity of the water and the quantity of water used, the ratio borae by the surface of the quicksilver to its mass, the amount and mode of agitation of the quicksilver, the nature of the process and of the apparatus nsed,.the character of the ore, the strength of the amalgam, etc., etc.; so that this importaat point can only be determined hy experience in each case. Some general directions may, however, be derived from the experiments which have heen made. It has been fouud that very much less sodium is requizite in those cases in which much water is einployed, and tbat water frequently renewed ; for instance, in the riffles of a sluice, and ia all forms of amalgamators through which a continual curreat of fresh water is kept ruanine ; mercurial solutions of sodium, as I have discovered, being little affected by water which is free from acid, alkaline, or saline impurities. In those cases, however, in which little water is employed, ard especially when the ore aad

quicksilver are ground up together into a . “ elum” or slime, this water soon becomes alkaline, and an oxydation of the sodium sets in, necessitating its frequent renewal. In such cases, therefore, the following manipulation is recommeaded: The whole amount of quicksilver to he used for working up @ batcb of elime, say 40 pounds, is magnetized by dissolving in it one per cent. of amalgam No. 2; or better,.two per cent. of the soft amaleam 2yo. 1, which dissolves more readily; halt of the whole, or 25 pounds, is then tbrown into the mill with the,ore at first, aud, as the incorporatioa proceeds, certaiu fractions of the . other half arc gradually added, at intervals of tine varying according to circumstances, until the whole has been added. II, as is usual, the quicksilver is a portion which has been separated from the slime of a previous operation, it will usually retain some sodium, and therefore will require fresh auialgam in proportiouately smaller quantity. In sluicing operations the soft amalgam No. 1 is most suitable, on account of its ready solubility in mercury ; and in these cases it is practicable to éest the quicksilver in the riffles and ascertain when the magnetic quality requires restoration, by throwing in a few grains of gold-dast. Similar tests are easily applied to slimes, and in amalgamating methods generally, a slip of tarnished sheet copper being a very suitable agent for such teatiuge. It may be remarked in passing, that the amalgam No.1 is at any time easily prepared from No. 2, hy melting it in an iron ladle with about its own weight of quicksilver, or from No. 3, by melting witb twice its weight; considerable time, however, being requisite, in the ease ol No. 3, to produce the additional combination. In copper-plate amalgamation, that is, in those cases iu which auriferous materials are brought into contact with amalgamated metallic surfaces, it is better to substitute altogether lor qnicksilver itsell (both in the first coating of the metallic surfaces, and in any subsequent additions of quicksilver made) the pasty ainaleam No.1. In these modes of amulgamation great economy in wear and tear of apparatus, as well as in first cost, is effected by using, in connection with the magnetic amalgam, plates or surfuces of iron instead of copper. The power of coating or enfilmiug iron renders the amalgams in” fact peculiarly valuable in every form of arastra, drag-mill, or other apparatus for amalgamation which has internal surlaces of iron, these surfaces hecoming couted over with quicksilver, aud tbus immensely extending its cnances of contact with those particles of gold which are so fine as to remaiu suspended in the water. Other important devices arise out of this power of enfilming iron surfaces, such as the keeping of iron surfaces of stamps, and of other apparatus used in crushing ores continually coated with quicksilver. Quicksilver possessed of the magnetic quality may he kept dropping or trickling upon the surfaces of crushingrollers ; or in those crushers in which iron balls are used, the surfaces ol these balls may be kept enfilmed. In like manner as the adhesion of quicksilver to other metals is exalted by the alkali-metals, so, also, as I have discovered, is its cohesion with itsell greatly increased. It is rendered more viscid, more difficult to divide mecbanically, and when thus divided rune together again instantly upoa contact. Hence arise new results of incalculable value. For instance, the so-called “ flouring” or granulation of tbe quicksilver, which in the amalgamation ol ores always occasions so great losses, hoth of the quicksilver itself and of its amalgams with the precious metals, is reduced to a minimum or altogether prevented. The recovery of floured quicksilver and amalgams from slinies and similar mixtures is also greatly fucilitated and accelerated tberehy. For this purpose some stroogly magnetized quicksilver is tbrown into the separator. Such slimes may even be operated npoa with advaatage by the ordinary process of panning by hand; a little magnetic quicksilver bcing thrown into each pan and stirred about at first for a few moments witb the haad, which will collect together and incorporate all the scattered globules of anriferousamalgam. In fact, in all paoniag operations,even upon-the paydirt of placcr diggings, mnch labor, gold, and time may ia this way be saved. It is necessary to specify an important precaution applicuble in some cases in which magnetic amalgams are used, and particularly in those cases in which the ore is ground or agitated with quicksilver in contact with metallic iron. This arises from the liahility of the adhesion of some abraded particles of iron to the amalgam. ‘ihe following plan is therefore recommended in these cases: The amalgam, after separation from tbe excess of quicksilver, and before retorting, is fused in aa earthen dish or iron ladle {with addition of a little quicksilver, ifnecessary, to make it more fluid), and the iron, which will rise and forma scum on the surface, is skimined off. The excess of quicksilver may then, after cooling, he again separated from the amalgam in the usual way. Any amalgam which may adbere to the ironscum is readily detached therefrom by boiling in water to remove the sodiam. Tbie process depends on the simple fact that the adhesion to the iron totally disappears with the extraction of the last traces ol sodium from the quicksilver. In fact, it is possihle to remove all the iron from the amalgam by boiling directly in water, without any previous Tusion ; more particularly if the water be made somewhat acid or alkaline. The presence of iron in a sample of amalgam is readily detected by tbe magnet, which instrument may be sometimes used to advaatage also in separating intermixed iron from anialgam, afterall sodium has been extracted from the latter. ‘There are still other-metals which will usually be found adherent to the amalgam when sodium hag been used ; such ag platinum and osmiridium, These, like iron immediately detach themselves on the removal of tbe sodium by boiling the diluted amalgam in water. A mixture of piatinam or osmiridium, or hoth, with iron, may of course be freed from the latter hy the Magnet. It will generally be found desirable, as in other cases where quicksilver is used and ores containing arsenic or sulphur operated upon, to remove as much as practicable of the arseuic or sulphur by previous roasting or other chemical treatment. * * * * * * IIIl.— Applications to the recovery of metals From their saline compounds. In the common operation of reducing silver to an amalgam’ from its native or artificial” chlorid, or from its sulphate, by the action ofmetallic iron or zine in conjunction with quicksilver, immense advantage arises lrom the use of the magnetic amalgams, especially iu the reduction ol the time occupied toa fraction of that heretofore required. ‘lhis applies as well to ores in which the silver oceurs natnrally as chlurid, bromid or iodid, as to those in which the silver has heen previously converted into chlorid, or sulphate, or both, by roasting with common salt or otherwise; and to clhilorid which has been precipitated from solution. * * When gold has been obtained in solution, either from ores or from other materials, by the action of chloriae, aqua-regia, cyanid of potassium, or any other solvent, also when silver has heen obtained in solution, in hyposulphites or otherwise, the most rapid and thorough mode of saving these metale will be Tound to be their conversion into amalgams, by precipitation with metallic iron in contact with magnetic quicksilver, mole especially when the solutions are dilute. * * ‘The greater rapidity and perfection of the precipitation, in these cases, are obviously due to the absolute contact at once established with the iron surfaces hy the magnetic quick— silver, and the perfect and powerful voltaic circuits thus kept up constantly throughout tbe two metals aud the solution. * * * * * * VIIIl.—Applications to the Mereurializing of Metaliie Surfaces in general. In all cases ia which it is an object to save time and lubor in the coating ol surfaces of other metals with quicksilver, * * * the magnetic amalgams comeinto play. * * * By virtue of the adhesion to iron and other nou-amalgamahle metals imparted by the magnetic amalgams, . am enabled to apply quicksilver, or fluid or pasty amalgams, to any metallic surface, with great-rapidity and facility, with a brush, after the fashioa of a paint; the material of sucb brush being five wire of iron, steel, aluminum, or platinum. Of these the material most geverally suitable is the finest steel wire, tempered to about a spring temper, or somewhat softer; and the most generally nselul lorm for sucb brnsbes, is that of a jlat varnish or white-wash brash. Among the important uses of such hrushes may be instanced ; the amalgaaiativu of copper (or iron) plates used in saving gold from ores ; * * *, Another valuable use is the recovery of quicksilver which has been epilled or scattered in the form of globules; such a flat brush, saturated with magnetic quicksilver, instantly collecting, incorporating, and sucking up the scattered globules, even from the most irregular surface. The same principle of adhesion of magnetic amalgams to a brush of steel wire, is applicable, ia maoy obvious ways, to the sepuration of metals Irom ores, and of granulated or floured quicksilver from ores aud slimes, ete. * * * * * * IX.— Applications to the Transportation of Quicksilver. The ordinary mode of packing and transporting qnicksilver in bulk, is very expensive and troublesome ; and in its ordinary form its transfer from one vessel into another is accompanied by great liability to loss. It will theretore be found very coavenient and useful to possess simple, cheap and practicable modes, such as those described above, of couverting it iato solid forms, susceptible of transportation in vessels of lighter and cheaper material than the ordinary wrought-iron hottles; such, for instance, as glass or earthen ware jars, wooden