410 On some new Electrochemical Researches 



produced as in all other cases, and that it combined wIiIjl 

 the tellurium, and formed a peculiar alloy ; and this opinion 

 was further confirrned, by the immediate action of potas- 

 sium upon tellurium. > When these metals were gently 

 heated in a retort of green glass, filled with hydrogen gas, 

 they combined with great energy, producing most vivid 

 heat and light, and they composed an alloy of a dark coj:)- 

 per hue, brittle, infusible at a heat below redness, and 

 possessing a crystalline fracture. When the tellurium was 

 in excess in this mixture, or even nearly equal to the po- 

 tassium in quantity, no hydrogen was evolved by the action 

 of the alloy upon water; but the compound of telluretted 

 hydrogen and potash was formed, which remained dis- 

 solved in the fluid, and which was easily decomposed by 

 an acid. 



The very intense affinity of potassium and tellurium for 

 each other, induced me to conceive that the decomposition 

 of potash might be easily effected, by acting on the oxide 

 of tellurium and potash at the same time, by heated char- 

 coal ; and [soon proved that this was the case. About 

 100 grains of oxide of tellurium, and £>0 of potash, were 

 mixed with 12 grains of well burnt charcoal in powder, 

 and heated in a green glass retort ; before the retort be- 

 came red there vvas a violent action, much carbonic acid 

 was given off, a vivid light appeared in the retort, and there 

 was found in it the alloy of tellurium and potassium. 



In attempting to reduce some oxide of tellurium by char- 

 coal, which Mr. Hatcheit had the kindness to give me 

 for the purposes of these experiments, and which must 

 have btien precipitated by potash, or from a solution in 

 potash, I found that a sufficient quantity of alkali adhered 

 to it, even after it had been well washed, to produce an 

 alloy of potassium and tellurium ; but in this alloy the 

 potassium was in very small quantity. It was of a steel 

 gray colour, very brittle, and much more fusible than tel- 

 lurium. 



i shall not arrest the proc:ress of discussion, by entering 

 at present into a minute detail of the properties of the 

 aeriform compound of tellurium and hydrogen; I shall 

 mention merely some of its. most remarkable qualities, 

 and ao-encies, which, as will be shown towards the close 

 of this paper, tend to elucidate many points immediately 

 connected with the subject in question. The compound 

 of tellurium and hydrogen is more analogous to sulphuret- 

 ^J hydrogen, than to any other body. The smell of the 



two 



