METALS. 



i-.i 



small quantities from tho food, is stored up in 

 8 manner in the system of the ani- 

 mal, tlnis elaborating an element wliirh is or- 

 dinarily regarded as poisonous to the unimul 



U1V. 



Selenium in Commercial Copper. M. Vio- 



i,'ives tho following directions for <1 

 ing the presence of tho metalloid selenium in 

 commercial copper: The metal is to be pre- 

 viou<ly cut up and oxidized by heating it to 

 redness in a muffle. Tho oxide is next to be 

 placed in a combustion tube, and then in a gas 

 or other furnace (as applied for elementary 

 organic analysis), and heated to strong red 

 heat for several hours in a current of dry and 

 pure air freed from aqueous vapor and carbonic 

 acid. If any selenium be present, there will 

 appear, at the cooler portion of the tube, just 

 outside in front of the furnace, a white-colored 

 rin^r, composed of a volatile, crystalline, very 

 hygrometric substance, readily soluble in wa- 

 ter, and not colored blue on addition of ammo- 

 nia, which indicates absence of copper. Tho 

 aqueous solution yields an abundant precipitate 

 with nitrate of silver, which is soluble in 

 excess of nitric acid. Reducing agents turn 

 this white-colored ring into a red-colored 

 substance, which exhibits all the reactions 

 of selenium. The copper operated upon was 

 from Chili. 



Desihering Lead. In some of the Hartz 

 works tho lead in ingots is placed in a large 

 cast-iron pot, similar to that used in the Park- 

 inson process. When the lead is melted and 

 skimmed, about 28 oz. of melted zinc are added 

 for each ounce of silver shown by assay to be 

 in the lead. The alloy is kept melted for two 

 hours, and constantly stirred. On cooling, a 

 scum, which is a mixture of zinc, lead, and sil- 

 ver, is found on the surface. This is removed 

 to a furnace; after the zinc is driven off by a 

 dull-red heat, the remainder is cupelled in the 

 usual way. The lead is further purified by 

 throwing billets of green wood (or steam can 

 be injected) into it. The charges for the fur- 

 naces around Rammelsberg are stated as follows 

 by the Mining Journal : Twenty-one cwt. of 

 ground ore, 11 cwt. of silicious slag, 4 cwt. of 

 lead slag, and 36 cwt. of charcoal. The blast 

 is applied, and tho reduced lead falls into the 

 hollow of the health, while the slag is skimmed 

 off by ladles. The amount of sulphur in these 

 ores is so considerable that, though they are 

 roasted in heaps previous to being brought to 

 the smelting-works, it is yet needful to add so 

 much slag to prevent fusion of the ore until 

 the chief part of the sulphur is driven off. 

 North Germany raises 169,000 tons of lead-ore 

 annually, and manufactures 40,000 tons of 

 metal. Of this the greater part is sold as pig- 

 lead, but about 800 tons of it are sold in the 

 form of sheet-lead. The produce of silver, 

 chiefly from the ores of galena, is 148,689 Ibs. 

 troy in the year. The load-mining employs 

 15,784 hands, and the metallurgic refinement 

 as many more. 



A Cvld Tinning Froceu. 'M., Daubic, of 

 Franco, has made' a remarkable discovery of 

 tinning by a cold process, by which the oxida- 

 tion of iron can be prevented. It is essentially 

 adapted for iron wire used in tin- fabrication 

 of cards and wire cloth. His chief object is to 

 guard against the softening of the iron treated, 

 and this he docs by its successive immer.-ion 

 in baths containing cold solutions of salt of tin 

 with the addition of a certain amount of stun h 

 or other organic matter. The solution pat 

 is composed as follows: To every 20 gallons 

 of water add 6 pounds of rye flour, and let it 

 boil half an hour; filter it, and add 112 Ibs. of 

 pyrophosphate of soda, 34 Ibs. crystallized salt 

 of tin, 134 Ibs. of neutral protochloride of tin, 

 and from 3 to 4 oz. of sulphuric acid. "When 

 the salts are dissolved the solution is distributed 

 in eight or ten wooden vats, a little additional 

 water being added to the first two or three of 

 the vats. The wire is passed successively 

 through the whole of the vats, and, if great 

 brilliancy of surface is required, also through 

 draw-plates at intervals, and the wire, while 

 retaining all its rigidity, becomes covered with 

 a brilliantly-polished coat of tin. Beautiful 

 and inoxidizable cards and wire cloth have 

 been produced by this process, which is ap- 

 plicable to wire for a hundred different pur- 

 poses. M. Daubie, it is said, has also succeeded 

 in silvering iron wire, by using, in place of the 

 salts of tin in tho solution, cyanide of silver 

 and cyanide of potassium. 



Tin in California. Dr. Roessler, mineralo- 

 gist of the Government Land-office at Washing- 

 ton, writes to the Franklin Institute Journal 

 that the tin-ore from California sent to that 

 office for analysis proves to contain 13.87 per 

 cent, of tin. The black mineral in the ore is 

 tormaline; the brownish-red the casiterite. 

 The percentage of the metal found is almost 

 twice as much as that in the several working 

 ores of the Cornwall mines. The property 

 from which the' specimens came is said to con- 

 sist of 50,000 acres of mineral lands, and over 

 twenty openings have been made, from all of 

 which ore was taken. 



Alloys with Manganese. An interesting re- 

 port of attempts to utilize the metal manganese 

 by alloying it with copper, tin, zinc, and lead, 

 was read before the British Association by Mr. 

 J. Fenwick Allen. Mr. Allen did not attempt 

 to produce metallic manganese, on account of 

 the extreme difficulty attendant upon its sepa- 

 ration in a pure state from its ores the metal 

 being practically obtainable only after the 

 oxide mixed with charcoal has been subjected 

 in a plumbago crucible to an intense- heat, for 

 two or three hours. From the first, he also 

 discarded using any of the ores of-manganese, 

 the iron and the silicon in them completely 

 destroying the value of tho product. He 

 says: 



Having obtained a comparatively pure oxide of 

 manganese, recovered from the still-liquor, and hav- 

 ing mixed this with oxide of copper, not metallic 



