tive surface in 

 water, 



S3i EXPERIMENTS ON THE METALS FROM THE FIXED ALKALIS. 



litmus; but, after being washed in a small quantity of 

 water, it loses this property ; but in this case likewise it 

 is partially desom posed by the air in the water ; so that 

 it is not easy to say, whether the power is inherent in it, 

 or depends upon the diffusion of a small quantity of mu- 

 riatic acid through it. In other respects, it resembles a 

 weak acid, combining with water, and with the alkalis. 

 It precipitates most metallic solutions. It is instantly de- 

 composed by oximuriatic acid, depositing a film, at first 

 metallic; but which is soon converted into muriate of tel- 

 lurium*. 



^Arsenic -^ s arsenic nas an affinity fov hidrogen, it occurred 



to me as probable, that it would present some phenomena 

 analogous to those offered by tellurium, in its actioa 

 upon potassium, and in its operation upon water, when 

 electrified. 



made the nega- Arsenic made the negative surface in water, by means 

 of a part of the new battery containing 600 double plates, 

 became dark coloured, and threw down a brown powder ; 

 but it likewise gave off a considerable quantity of inflamma- 

 ble gas. 



in a solution of Arsenic negatively electrified in a solution of potash like- 



P otas t wise afforded elastic matter ; but in this case the whole solu- 



tion took a deep tint of brown, and was pellucid ; but it 

 became turbid, and slowly deposited a brown powder, by 



and in contact, the action of an acid. When arsenic was made the negative 



potash° l surface, in contact with solid potash, an alloy of arsenic 



and potassium was formed of a dark gray colour, and 

 perfectly metallic ; it gave off arseniuretted hidrogen by the 

 action of water with inflammation, and deposited a brown 

 powder. 



Potassium and When potassium and arsenic f were heated together in hi- 

 drogen 



* From the results of one experiment, which I tried, it seems that 

 tellurium, merely by being heated strongly in dry hidrogen, enters 

 into combination with it. An accident prevented me from ascer- 

 taining, whether the compound so formed is exactly the same as 

 that described in the text. 

 Volatile pyro- "\ In reasoning upon the curious experiment of Cadet, of the pro- 

 phorus from duction of a volatile pyrophorus by the distillation of acetite of 



potasi 



