BAIR,D&.TATLOCK(LOM)ON)LTD. 



jarefully noted. The difference between the first and second volume is the amount of carbonic acid absorbed. 

 Before, however, the gas is drawn back from the gas laboratory vessel, the minute amount of gai which remains 

 in the capillary tube on the right which escapes measurement is expelled. Oxygen gas is now connected to the 

 nd of this tube, which may be contained in an apparatus similar to that in which the sample of gas was taken, 

 ind a sufficient quantity of it drawn into the measuring tube. In order to thoroughly mix the two gases, they 

 ire forced into the potash chamber and again drawn into the measuring tube, and the exact volume carefully 

 noted. An electric spark is now passed through the mixture, and the contracted volume after cooling is noted. 

 The resulting carbonic acid is absorbed by again transferring the ignited gases into the potash chamber, and after 

 inally obtaining it in the measuring tube, the remaining volume is carefully noted. As the gases remain through- 

 out saturated with aqueous vapour, it is not necessary to make any correction for its tension. 



The calculations are simple and readily made. 



Let a = corrected volume of gas taken. 

 Let 6 = corrected volume of gas after absorbing CO,. 

 Let c = contraction after explosion with oxygen. 

 Let d = volume of CO, produced by the explosion. 

 a- b= CO,. 



. 



a-(CO, + CO+H) = N. 



i his form of apparatus is specially adapted for the analysis of blast-furnace gases ; but by introducing an 



mpruved method of connecting the capillary tubes together it can be very readily adapted to make analyses of any 



ft of gases. Instead of having only one chamber containing potash, we can increase the number to any 



A tube containing mercury and a ball of peroxide of manganese saturated with glacial phosphoric acid can 



I to remove sulphuretted hydrogen ; for absorbing oxygen, a solution of pyrogallate of potash ; to remove 



url'onic oxide, an acid solution of subchloride of copper ; and heavy hydrocarbon can be absorbed by strong 



fuming sulphuric acid. By connecting tubes containing these various reagents to the measuring tube, the gas 



nay be subjected to the action, if required, of all of them. 



The calibration of the measuring tube or eudiometer is readily effected in the following manner, viz. : 

 .'ommencing with the tube full of mercury, pure distilled water is drawn into it until it is full. A small glass 

 lask, contracted at the neck, into which a small piece of sponge is placed, is carefully weighed. The water is now 

 ittle by little forced out of the tube and received into the flask, which is weighed after each addition of water, 

 the height of the mercury in the tube being observed at the same time. It is best to remove about 5 millimetres 

 >f water at a time, making careful weighings and observations after each removal. After having removed all the 

 .vater, a table is constructed which should show the value in corrected volume of the whole scale for each i 

 -Millimetre. 



4715 



4715 Gas Analysis Apparatus, Orsat's, new form designed by L. M. Dennis. Esq., Cornell 



University, Ithaca, U.S.A. 



See Journal of Industrial and Engineering Chemistry (U.S.A.), Vol. iv., No. u Dec., 1912. 



Descriptive pamphlet on application. 



550 



(CHEMICAL AND SCIENTIFIC APPARATUS AND PURE CHEMICALS. 



855 



