METALS. 



The lead produced by the htcam method \a 

 ft, and, U'M.l.-s a suppression of a 



ration of refining, tho employment 

 i offers many advantages, as the Having 

 cost of previous purification, reduction 

 oxidation of the lead, and consequently of 

 The economy of time and 1 ibor is due 

 rapidity of the operation, tho smaller 

 of hands required, while better work- 

 are necessary in tho old system than iu 



lit, and also more space. 

 When tho lead to bo dealt with contains not 

 lore than one-half per cent, of antimony, it 

 ho operated upon by the new system 

 y, and tho purification becomes reduced 

 of tho rich dross, and tho expense to 

 jut one-tifth of that by the ordinary mode. 

 the case of load which contains a larger 

 lount of antimony, previous purification is 

 lecessary, but this operation need not be car- 

 d so fur as in tho ordinary process; it may 

 arrested when only half per cent, of anti- 

 mony remains in the lead. The arsenic having 

 tho greatest tendency to take the place of the 

 silver, it has been proposed to effect tho purifi- 

 cation by means of soda. 



Assay of Lead. Mr. F. Maxwell Lyte pub- 

 lishes the following in the Chemical News as a 

 convenient method for tho assay of lead-ores, 

 particularly when, as is often the case, the lead 

 to be estimated is mixed as sulphate with the 

 matrix insoluble in acid : u I dissolve the sul- 

 phate or chloride, as the case may be, in ace- 

 tate of ammonium, make the solution as neu- 

 tral as possible, and estimate the lead by a 

 standard solution of bichromate (a half deci- 

 normal solution answers well) with a nitrate- 

 of-silver indicator." This process, according 

 to the author, shortens labor, enables the in- 

 soluble matrix to be weighed direct after dry- 

 ing, and gives accurate results. 



Quicksilver. Ths Scientific and Mining Press 

 describes an improved apparatus for the con- 

 densation of quicksilver- fumes, the invention 

 of Messrs. J. B. Randol and Ferdinand Feidler, 

 of California. Having discovered that the 

 condensation of mercurial fumes is very much 

 facilitated when they are brought in contact 

 with the inside of a glass plate the outside of 

 which is exposed to the external air, they 

 make tho sides of their condensing-chambers 

 largely of glass. Otherwise the surfaces with 

 which the fumes come in contact are of wood, 

 this being much more durable than metal 

 under the action of the fumes, and leaving the 

 quicksilver in a cleaner state. The use of 

 water for cooling is entirely dispensed with, as 

 the glass performs that service in a more satis- 

 factory manner. The above are the distin- 

 guishing features of the invention, which for 

 cheapness, durability, and efficiency of work- 

 ing, is said to be much superior to the appli- 

 ances in common nse. 



The same journal describes a new process for 

 purifying quicksilver from the extraneous mat- 

 ters with which it becomes associated in the con- 



ng-chambers. The blunt or dranght which 

 draws off the mercurial lumen into and through 

 tho condensers from tho furnac.- where the ore 

 is roasted also carries with it a mechanical 

 mixture of fine dirt, particleM of uncon^ 

 carbon, some ash, some undecomponcd cinna- 

 bar, and various other impurities and minute 

 particles of tho metal. This combination of 

 matter is deposited in the condensers in .-. 

 dition resembling lamp-black or paste, it hav- 

 ing become moistened by the steam introduced 

 from tho fuel and ore, and, as a consequence, 

 it becomes intermixed with the quicksilver. 

 The quicksilver, thus contaminated, is placed 

 in an iron tank, to which water heated to 

 the required degree is added, and the Bub- 

 stance intimately mixed. Wood-ashes or other 

 suitable alkalies are added for the purpose of 

 still further cleaning the quicksilver, which 

 is then drawn off into another vessel. When 

 the soot and ashes are put into the tank, the 

 hot water is shut off. A man mixes the 

 soot, ashes, and hot water thoroughly with a 

 shovel, and thus separates the soot from the 

 metal, allowing tho quicksilver to pass off clear 

 and pure. 



Origin of Gold-Nuggets. It having been al- 

 leged, on the basis of experiment, that grains 

 of gold may be made to grow to the size of 

 u pieces" in solutions of auric chloride by the 

 addition of a small quantity of organic matter, 

 the deposition being similar to that which 

 takes place in operations of electro-plating, 

 and that in this we have an explanation of tho 

 formation of gold-nuggets in Nature, Prof. 

 Skey, analyst to the Geological Survey of New 

 Zealand, took up the subject, and in a series of 

 careful experiments has failed to find any con- 

 firmation for the statement. His experiments 

 were briefly as follows : 



1. 0.1315 gramme of gold, hammered thin and 

 bent to a curved disk of such a size as to expose about 

 half a square inch of superficies, was placed in u 

 k'la-s vessel containing two ounces of a solution of 

 auric chloride of a strength equal to half a grain of 

 gold per ounce. For reducing agents small pieces 

 of cork and wood were sunk t>y glass attachments 

 to the bottom of the vessel in close proximity to the 

 disk of gold. 



The vessel was then closed, put in a darkened 

 place, and suffered to remain at rest until all the 

 gold present in solution had been reduced, a process 

 occupying in this case a period of time equal to rather 

 more than two months. 



The gold disk was then carefully examined and 

 weighed. It had a small quantity of very finely 

 granular gold loosely, adherent to it, and apparently 

 equally disposed over its surface. 



With the whole of this loose gold attached, the 

 disk only increased in weight 0.0005 of a gramme, 

 or ili of its weight (a rate of increase that would 

 require about forty-four years to double the size of 

 tho disk), consequently only about the T part of 

 the total amount of gold present in solution had de- 

 posited upon the disk t the remainder having deposited 

 away from it, and this was seen to have indiscrimi- 

 nately attached itself to every surface which had 

 contact with the auriferous solution, whether the 

 bottom or sides of the vessel, -the glass attachments, 

 or even the surface of the liquid having contact only 

 with the atmosphere. 



