Determination of Nitrogen in Organic Compounds. 255 
hydrochloric acid of the ordinary strength, and this part of the 
operation is done by applying the mouth to the extremity d, and 
drawing the acid through the extremity g. 
‘As means of decomposing the organic substance containing 
nitrogen, that is to say, of oxydizing its carbon and hydrogen, we 
make use of the hydrate of potash, or soda mixed with caustic 
lime, in such proportions, that the mixture when exposed to a 
strong heat will not melt, but only slightly run together. This 
mixture has the advantage of being easily pulverized, and of not 
attracting moisture very rapidly, and generally it is managed with 
the same facility as the bioxide of copper or the chromate of Jead. 
We have preferred latterly the mixture containing soda, in prefer- 
ence to that with potash; because the hydrate of soda, on account 
of its smaller atomic weight, contains more water, and conse- 
quently more oxydizing material than the same weight of the 
hydrate of potash. Also the mixture of the hydrate of soda and 
lime attracts moisture less 1 me Lily cis of potash and lime ; 
and moreover, the hydra’ of soda requires but twice its weight 
of anhydrous lime to form a ‘eahesatte: aa will not melt at a red 
heat. For one part of. potash three of lime are necessary. The 
easiest method of preparing it, 1 3 the lime in a solution 
of known concentration, of eitherof the above alkalies; heat the 
mixture to redness in acrucible, and rub it to a fine peter. Or 
we may rub up quickly one of the alkalies (first melted and then 
cooled) in a warm mortar, and then mix intimately with it anhy- 
drous lime in the proper proportion. In this latter case, the lime 
must be first slaked and then heated to redness as a fine powder 
before being used. The mixture prepared in either of the above 
as “* ~, Ways is once more heated to redness to drive away all mixture 
and then preserved in a well stopped phial.” 
In performing an analysis, the process is as follows: 
“The burning tube, clean and dry, is half filled with the alka- 
line mixture, and that is the measured quantity to be mixed with 
the su ieiucied about to be analyzed, which is first dried and 
Weighed in the ordinary method. The quantity of the substance 
employed should vary according as it contains more or less nitro- 
gen. When rich in this element about three grains, but when 
its quantity i is quite small about six grains should be used.” 
“'The mixture of the weighed substance with the m 
quantity of the alkaline powder, is done in a porcelain mortar 
