S84 Dr. Harems Improved Barometer Gage Eudiometer. 



course, in lieu of the five volumes introduced, two volumes of car- 

 bonic acid, and one residual volume of oxygen will remain. 



By means of a forcing air pump, of which a description will be giv- 

 en in the next number of this Journal, the gas may be transferred to a 

 receiver, and washed with ammonia, or milk of lime, and then allowed 

 again to enter the iron bottle. Meanwhile, by due attention to the 

 gage, the quantity which has been absorbed may be ascertained ; and 

 consequently, the proportion of carbonic acid resulting from the oxi- 

 dizement of all the carbon in the gas subjected to analysis. 



Instead of employing the forcing air pump, by substituting a large 

 valve cock for the screw by means of which an aperture in the bot- 

 tle at A is closed, mercury may be introduced through a funnel, and, 

 by its pressure, the residual gas may be easily conveyed, by a flexi- 

 ble leaden tube, to a receiver over the mercurial reservoir, and ana- 

 lyzed in the usual way. For this purpose it is necessary that the 

 valve cocks with which the mercury comes in contact, should be of iron 

 or steel ; and, accordingly, I employ such where mercury is to be used. 



The gases may be supplied, without previous measurement and 

 admixture, by receiving them into the bottle from their respective 

 reservoirs, and measuring them as they enter, by means of the gage.* 



* I subjoin an engraving of the colorimotor, by means of which the ignition of 

 the platina wire, and consequent inflammation of the gaseous mixtures are ac- 

 complished. 



This engraving will convey an idea of the calorimotor suitable to efTect the ig- 

 nition of the platina wire in the galvano ignition apparatus above described. It 



