236 ANNUAL OF SCIENTIFIC DISCOVERY. 



he boils an excess of dry hydrous alumina in hydrochloric acid for one 

 hour ; then, pouring off the clear liquid, adds one-sixth its volume of 

 water. In this mixture was set an earthen porous vessel, containing 

 sulphuric acid, diluted with twelve parts of water, and with a piece of 

 amalgamated zinc plate in it. In. the chloride of aluminum, solution was 

 immersed a plate of copper, of the same amount of immersed metallic sur- 

 face as that of the zinc, and connected with the zinc by a copper wire. 

 The whole was then set aside for some hours, and, when examined, the 

 copper was found coated with a lead -colored deposit of aluminum, which, 

 when burnished, possessed the same degree of whiteness as platinum, and 

 did not readily tarnish, either by immersion in cold water or by the action 

 of the atmosphere, but was acted on by sulphuric and nitric acids, whether 

 concentrated or dilute. If the apparatus is kept quite warm, and a copper 

 plate much smaller than the zinc plate is employed, the deposit appears in 

 a very short time sometimes in half -a minute ; if the chloride solution is 

 not diluted with water, the deposit is equally, if not more, rapid. 



The author has also succeeded in obtaining a quick deposit of aluminum, 

 in a less pure state, by dissolving common pipe-clay in boiling hydro- 

 chloric acid, and using the clear liquor undiluted in place of the above- 

 mentioned chloride. Similar deposits were obtained from a strong aqueous 

 solution of acetate of alumina, and from common alum, but more slowly. 

 "With each of the solutions named, the deposit was hastened by putting 

 from one to three small. Smee's batteries in the circuit. 



To obtain the deposit of silicium, monosilicate of potash (prepared by 

 melting together one part silica with two and one-fourth parts carbonate of 

 potash) was dissolved in water, in the proportion of forty grains to one 

 ounce measure, proceeding as with aluminum, the process being hastened 

 by interposing a Smee's battery in the circuit. With a very slow and 

 feeble action of the battery, the color of the deposited metal closely resem- 

 bled that of silver. 



ON THE FORMATION OF VESSELS OF GOLD BY TRE AID OF PHOS- 

 PHORUS. 



The property of phosphorus, of precipitating certain metals from their 

 solution, has long been known ; and gold is among the number. M. Levol 

 has used this process in forming gold vessels, so useful in chemical 

 research. He takes the perchloride of gold, and places in it, at the ordi- 

 nary temperature, some phosphorus, moulded of a form convenient to serve 

 as a nucleus for the vessel of gold. To give the phosphorus the desired 

 shape, it is melted in a water-bath near CO C. in temperature, within a 

 vessel of glass having the form required. After cooling it, the phosphorus 

 is taken out solid from its envelope, breaking it if it be necessary. The 

 precipitation of the gold or the construction of the vessel is then begun ; 

 and it finally remains only to remove the phosphorus by remelting it and 



