Chemijiry. _ 85 



It is a common thing with the teachers of chemiflrv to 

 fold up a portion of the dry nitrat of copper in tin foil, and 

 to let it remain for fome time in contaft with the tin, to 

 (liow that it will not aft upon the meial in a dry ftate. The ^ 

 tin foil is then unfolded, and a little water is added to the 

 nitrat of copper, and it is again enclofed in the tin ; when a 

 violent aftlon enfues, accompanied with fparks of fire, and a 

 dilVharge of nitrous air. 



The intention of this experiment is to (liow that bodies do 

 not acl upon each other in a dry ftate — corpora non agunt 

 niji foliita. But from the experiments which have been re- 

 lated, of the non-aftion of the nitric acid on tin, the ex- 

 planation of what takes place muft be fought for in the aclioa 

 of the water on the nitric acid of the nitrat of copper. 



Some writers have taken notice of the production of am- 

 moniac, \vhen nitrous acid is added to copper and tin. As 

 the concentrated acid has no aftion on thefe metals, the 

 ammoniac muft be produced by the hydrogen of the water 

 uniting with the azot of the nitric acid, while its oxygen, 

 and that of the water, unites to the tin and copper, and 

 converts them into oxyds. 



Having related thefe facts, the language of chemifts in 

 future ought to be — The nitric acid has no a6lion on lilver, 

 copper, and tin ; but, if water be added to the acid, folution 

 fpecdily takes place. 



Dr. Hope has taken notice of the non-aftion of the nitric 

 acid on ftrontian earth ; and Mr. Leonhardi tells us, that it 

 quickly dcftroys wool and (ilk, but that linen may remain 

 immerfed in a bottle of the ftrong acid a whole day without 

 injury. 



2. Of the Difference in the Qiiajit'ity of Ammoniac ohtained 

 from Bo/iiS, hy difilling ivlth and without a Lute. 



A quantity of the bones of horfes and cows were placed in 

 a diftilling apparatus, formed of iron, which communicated 

 ■with the worm of a refrigeratory, to which a large glafs 

 receiver was annexed. Upon applying a high degree of heat, 

 three oujices of volatile alkalins fpirit, impregnated with the 



black 



