] 34 > 
CHEMICAL PRINCIPLES. 
Combinations exhalation of the telluric and hydrogen gases. This was dis- ;■ 
oi ieUnn.m. . . . r . , • 1 
covered by Mr. Davy, and I have myself had an opportunity to 4 
verify in another experiment (on a penetrating odour of the 
sulphur and hydrogen gas.) 7'he liquor had deposited tellurium J 
which being. correctly weighed, weighed 0'6 grains. The ■ 
alkaline liquor, neutralised by the muriatic acid, afforded one J 
of oxide of tellurium. I caused it to be evaporated by fire, and 1 
I heated the muriat to clear it of the vvater which adhered. It ] 
weighed 1'3 grains ; dissolved by witer it left a residue of i 
oxide of tellurium, but in too small a quantity to be weighed. 
13 grains of muriat of kali contains 0(5246 grains of kali, in 
which there was 0 1 102 parts of oxigen. The 0 6 grains of 
metallic tellurium requires to be oxidated, according to foregoing 
experiments, 0 147 pans of oxigen. Although this experiment 
cannot be called absolutely precise, it proves, however, that in 
the hydro-tellurium of kali, the tellurium and thekalium require 
the same quantity of oxigen to furm of the first oxide of 
tellurium, and of the last of the kalium. When the mixture of I 
tellurium and kali is dissolved in water, it is necessary that the 
tellurium should be combined with the whole quantity of 
hidrogen, disengaged by the water by the oxidation of the 
kalium ; that is to say, that 100 parts of tellurium .should be 
combined with ^‘I grains of hidrogen, and that the tellurium of 
hidrogen should contain 3 penny we'ghts of hidrogen. 
With another quantity of tellurium of kali I tried to precipi- 
tate some solutions of sulphas cupricus, of sulphas manganesus, 
and of sulphas feriosus. The first gave a precipitate, black aird 
voluminous ; that by the second was brown j and that by the n 
third black. After they were dryed all of them became black. | 
I cannot determine whether they formed hydrotellures or no. li 
On polished steel they did not assume any metallic brilliancy, [I 
and by fire they quickly changed to subtellurates. | 
Tellurium has, therefore, the properly of forming three !♦ 
different classes of saline combinations, that is, (1 .) salts in which 
the oxides of tellurium is the base, (2.) salts in which this oxide > 
acts as an acid,and(3.) salts in which the tellurium and hidrogen » 
act as acids. If in this case the tellurium and the oxigen com- I 
bine il 
