§8 ACCOUNT OF A NEW EUDIOMETER. „ 



trials obtained results, the accuracy of which has been more 

 distinctly perceived, the more the science of chemistry has 

 advanced. 



The slow combustion of phosphorus, which unites with 

 Phosphorut the oxigen to form an acid, and the decomposition of the 

 and s 1 .huret flyij sulpnuret of potash, are certain methods of separating 



oi potash cm- ... • . , , 



ployed. combmatioua consisting ot oxigen and azote: but the de- 



composition is effected so slowly, by the action of these sub- 

 stances, that it became a desirable object, to discover some 

 means for accelerating the process. This was supposed to 

 have been effected by Gnyton, who proposed heating the 

 Guyton. sulphuret of potash ; in doing this, sulphuretted hidrogen gas 



however is frequently evolved, which, mixing with the residual 

 gas, increases its quantity, and renders the result fallacious. 

 Davy, The green sulphate of iron impregnated with nitrous gas, 



§, iphate of first discovered by Dr. Priestley, and recently used by Mr. 

 iron impregna Davy for eudiometrical purposes, from its possessing the 

 gas. property of absorbing oxigen gas from the atmosphere, is 



much to be preferred to the method with nitrous gas, as the 

 green sulphate of iron does not combine with the other 

 gassea, with which the nitrous gas is commonly found to be 

 contaminated, and more certain results are obtained. 

 A correct and Having had occasion to repeat many of the experiments 

 com mo bus G f others, and to make some new ones, I soon found what 

 wanting. * every o ie, who has been eugaged on the same subject, must 

 have experienced; that an apparatus more commodious than 

 has yet been proposed, and at the same time capable of 

 giving correct results, with the greatest minuteness, was still 

 a desideratum in eudiometry. To detail the various ideas, 

 that presented themselves on the subject, would be an un- 

 necessary encroachment on the time of this Society : but as 

 I at last succeeded in contriving an instrument, possessing 

 the above properties in a very eminent degree, I flatter my- 

 self I shall not be thought intrusive, in offering a description 

 of it. 

 Description of ^ n * s a PP aratus » which is of easy construction, and cx- 

 med tremely portable, consists of a glass measure M, pi. Ill, fig. 

 by theau.hor. ^ g rac l ua ted into hundred parts; a small gum elastic bottle 

 B, tig, 4, capable of containing about twice the quantity of 

 the measure, and furnished with a perforated glass stopper, 



S, 



