some new Objects in Chemical Philosophy. 31- 
but it soon becomes brown, and deposits tellurium, by expo- 
sure to air. When disengaged from an alkaline solution by 
muriatic acid, it reddens moistened litmus ; but after being 
washed in a small quantity of water, it loses this property ; 
but in this case likewise it is partially decomposed 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 muriatic acid through it. In other respects, it re- 
sembles a weak acid, combining with water, and with the 
alkalies. It precipitates most metallic solutions. It is in- 
stantly decomposed by oxy muriatic acid, depositing a film, 
at first metallic ; but which is soon converted into muriate of 
\ 
tellurium.* 
As arsenic has an affinity for hydrogene, it occurred to me 
as probable, that it would present some phenomena analogous 
to those offered by tellurium, in its action upon potassium, 
and in its operation upon water, when electrified. 
Arsenic made the negative surface, in water, by means 
of a part of the new battery, containing 6go double plates, 
became dark coloured, and threw down a brown powder ; but 
it likewise g'ave off a considerable quantity of inflammable gas. 
Arsenic negatively electrified in a solution of potash, like- 
wise afforded elastic matter ; but in this case the whole solution 
took a deep tint of brown, and was pellucid ; but it became 
turbid, and slowly deposited a brown powder, by the action 
of an acid. When arsenic was made the negative surface, in 
* From the results of one experiment which I tried, it seems that tellurium, merely 
by being heated strongly s in dry hydrogene, enters into combination with it. An acci- 
dent prevented me from ascertaining whether the compound so formed, is exactly the 
«ame as that described in the text. 
