C. M. Warren on Organic Elementary Analysis, 391 
with soda-lime and chlorid of calcium, as recommended by 
Mulder,‘ to take up any traces of carbonie acid which may es- 
cape absorption in the bulbs, and the trace of moisture which is 
invariably carried forward from the latter. Special care should 
taken to select both sets of bulbs with the view to have the 
Openings in the one as nearly as may be of the same size as 
those of the other, so that the bubbles of oxygen, considered as 
representing volumes, entering the sulphuric acid bulbs, may be 
Teadily compared with the bubbles or volumes of carbonic acid 
entering the potash bulbs; these bubbles may then serve as a 
valuable index by which to regulate the supply of oxygen. 
Especially is this true in cases where the composition of the body 
analyzed is pretty nearly known, as then the number of 
bubbles of oxygen required for every bubble of carbonic acid 
produced may be readily calculated. 
But as it is, in any case, advisable to conduct the experiment 
80 that there shall always be an excess of oxygen passing unab- 
Sorbed through the potash bulbs, and as this excess would sel- 
dom be large even if a sufficiency of oxygen were admitted to 
burn the most richly hydrogenized body known, it may gene- 
Tally be well to admit enough for such a case. _ : 
volume of oxygen actually consumed in burning the 
lightest liquid known—probably of the formula C, H, ,—which 
Thave separated from petroleum, and which contains a larger 
Percentage of hydrogen than any other non-gaseous body, as 
compared with the volume of carbonic acid formed, is as 1:62:1; 
the fraction representing the oxygen which is taken up by the 
hydrogen of the body, and which of course becomes condensed 
and disappears from the volume of carbonic acid. In burning 
this body with just the equivalent quantity of oxygen,—as- 
suming that the combustion would be complete under such cir- 
