IXPERIMENTt ON THE METALI PROM THE FIXED ALKALIS. 33 J 



that it has a stronger attraction for hidrogen, than that 

 alkali* 



These circumstances of the action of tellurium upon Thisdoesnot 

 water are so different from those presented by the action s i um to be a 

 of other metals, that they can hardly fail to arrest the compound, 

 attention of chemical inquirers. I have made some expe, 

 periments on the subject, and on the action of tellurium 

 on potassium, and I find, that, instead of proving that 

 potassium is a compound of potash and hidrogen, they 

 confirm theidea of its being as yet, like other metals, unde- 

 composed. 



When tellurium is made the positive surface in water, Experiments oa 

 oxigen is given off. When it is made the negative surface, bein^nositivT 

 the voltaic power being from a battery composed of a and negatively 

 number of plates exceeding 300, a purple fluid is seen to e ectri " ed - 

 separate from it, and diffuse itself through the water ; the 

 water gradually becomes opaque and turbid, and at last 

 deposits a brown powder. The purple fluid is, I find, a 

 solution of a compound of tellurium and hidrogen in water; A compound of 

 which, in being diffused, is acted upon by the oxigen of the hidden" T^ 

 common air, dissolved in the water, and gradually loses duced. 

 a part of its hidrogen, and becomes a solid hydruret of 

 tellurium. The compound of hidrogen and tellurium pro- , 

 duced at the negative pole, when uncombined, is gaseous at 

 common temparatures ; and when muriatic acid, or sulphuric 

 acid, is present in the water, it is not dissolved, but is given 

 off, and may be collected and examined. 



I acted upon potash by means of a surface of tellurium, Experiment 

 negatively electrified, by a part of the large voltaic appa- wuh * ellurinm 

 ratus lately constructed on a new plan in the laboratory of trified. 

 the Royal Institution, an account of which, with figures, 

 will be found at the beginning of this paper. 1000 double 

 plates were used. The potash was in the common state, as 

 to dryness. There was a most violent action, and a solution 

 of the tellurium, with much heat, and a metallic mass, not 

 unlike nickel in colour, was formed ; which, when touched 

 by water, did not inflame or effervesce, but rendered the * 



water of a beautiful purple colour, and when thrown into 



* Journal, vol. xxiv, p. 318. 



water 



