180 ANNUAL OF SCIENTIFIC DISCOVERY. 



TO COAT IRON WITH COPPER. 



IT is well known that if a plate of iron be immersed in a solution of 

 sulphate of copper, it speedily becomes coated with the copper in solu- 

 tion ; but the copper thus deposited on the surface does not adhere 

 firmly, and may be readily removed by friction. By means of the fol- 

 lowing process of M. Reinsch, the iron may be covered with a coating 

 of copper as firm and as durable as in electrotype deposit. The process 

 is as follows : Polish the iron by rubbing it well with cream of tar- 

 tar, and afterwards with charcoal powder, and place the metal thus 

 polished in hydrochloric acid diluted with three times its volume of 

 water, in Avhich a few drops of solution of sulphate of copper have been 

 poured ; after a few minutes have expired, withdraw the iron and rub 

 it with a piece of cloth, then replace it in the solution, to which add 

 another portion of sulphate of copper. By following on this plan, and 

 adding at each immersion a new supply of sulphate of copper, the layer 

 of copper may be increased at pleasure. Lastly, introduce the iron, 

 thus coated with copper, into a solution of soda, then wipe clean and 

 polish with chalk. The coating thus obtained will be as firm and dura- 

 ble as that deposited by the electrotype process. Chern. Gazette, 

 Jan. 9. 



MALLEABLE BRASS. 



IT is known that common brass containing from 27.4 to 31.1 per 

 cent, of zinc, and from 71.9 to 65.8 per cent, of copper, is not 

 malleable, but that articles of it must be made by casting. M. 

 Machts, of Germany, has recently found that by melting together 33 

 parts of copper and 25 of zinc, or 60 parts copper and 40 parts zinc, 

 alloys can be formed which possess malleability in a high degree. The 

 alloy formed from the last-named proportions is harder than copper, 

 very tough, and is, in a properly managed fire, quite malleable ; so much 

 so that a key was forged out of a cast rod. London Chemist. 



ZINC COMPOUNDS NOT INJURIOUS TO HEALTH. 



AT a late meeting of the Academy of Sciences, at Paris, M. Sorel, 

 replying to some authors who, at preceding sessions of the Academy, 

 had made observations tending to show that zinc was not innocuous, 

 stated that for fifteen years he had employed in his establishments for 

 the galvanization of iron several hundred workmen, a large number of 

 whom were occupied with pulverizing and sifting the gray or subox- 

 ide of zinc, for galvanic painting, and in no instance had any of the 

 workmen of the establishment, although in the midst of an atmosphere 

 containing much of the oxide, suffered at all from it. The white oxide 

 of zinc had aiso been fabricated for some months, without any ill 

 effects, although the men breathe considerable quantities of the oxide. 



NEW METHOD OF ASSAYING COPPER ORES. 



MR. H. PARKES, of the Burry Copper Works, Wales, communicates to 

 the London Mining Journal a new method of assaying copper ores, 



