PRECIPITATION OF OXIDES BY THEIR ©WN METALS. 



47 



little eminences of scales of lead a third of a line long; 

 and at the same time crystals were deposited, which were 

 in part attached to the slip of lead, and in about twelve 

 hours had covered the ^lip, and formed a fine groupe inter- 

 spersed with scales of lead. It was only near the point of 

 0, where the solution was weakened by the supernatant li- 

 quor, that no crystals were deposited with the scales of 

 lead. The upper part of the slip of lead was covered vfitk 

 gray oxide. 



The result of this experiment showed I had not conjee- The specific 



tured without reason, that no lead was separated in experi- ^'^^7'*^ "^ ^'^® 



- ' .^ . p / ,. ,.„. ■ fluidsshould 



ment 11 because the specihc gravity of the liquors dinered differ. 



too little, which occasioned the electric fluid to be badly 

 conducted, and the liquors to mix too soon and destroy the 

 chain. 



13. A solution of an ounce of acetate of lead in three Exp, withaoet- 

 ounces of distilled water, forming a chain with five ounces ^^^^' °^ ^^^^' 

 of water and a slip of lead, had experienced scarcely any 

 change at the end of 24 hours, except that the lead appear- 

 ed a little duller toward the bottom, and a little brighter 

 toward the top. 



' 14. I evaporated the superfluous water from the solution Acetateoflead 

 of lead, and employed as the upper liquor distilled vinegar. ^'."^ distilled 

 'a few minutes after the chain was completed the ppint of 

 was perceptible, above which the slip of lead became of a 

 whitish gray, and below it several points of a blackish gray 

 were formed. The latter, after the expiration of 36 hours, 

 had increased so as to cover almost the whole of the lead 

 immersed in the liquor. These points, examined with 

 more care, exhibited the form of little knobs. They were 

 friable, which led me at first to take them for oxidule of 

 lead ; but having rubbed them with a hard substance they 

 acquired the metallic brilliancy, which showed, that they 

 jrere metal. 



Erperiments with muriate of zinc, water, acidulated water,- 

 and zinc. 



15. I formed a chain with half an ounce of zinc dissolved Muriate of 

 in muriatic acid and diluted so as to form four ounces of^'"*^' 

 solution, five ounces of water, and a slip of zinc. Soon 



after 



