318 Chemical Society. 
into practice with great apparent success by MM. Will and Var- 
rentrapp of Giessen. ‘ 
After drawing a favourable contrast between the new m ‘hod 
and those previously in use when the proportion of nitrogen to be 
determined is small, the author proceeds to inquire into the validity 
of the objections before alluded to. It is stated by M. Reiset that 
when sugar is burned with the usual mixture of hydrate of soda and 
lime in fine powder, and the gases evolved conducted into hydro- 
chloric acid, an addition of pure chloride of platinum and evapora- 
tion to dryness gives rise to a quantity of the double chloride of 
platinum and ammonium, indicating in some experiments | to 1°5 
per cent. of nitrogen in the body analysed ; and as this was considered 
too great to be attributed to accidental impurity, it was ascribed to 
the absorption of the nitrogen of the air contained in the tube by 
the mixture of carbonaceous matter and alkali, and the subsequent 
conversion of the cyanide so formed into ammonia; and this idea 
was strengthened by repeating the experiment with the tube filled 
with hydrogen instead of air, when the production of ammonia was 
found to be lessened. It became important to know how this very 
serious objection could be disposed of. 
On repeating the experiment, it was found that when the finest 
white sugar-candy was thus burned, a certain quantity of the yellow 
platinum salt always remained upon the filter after washing with the 
mixture of alcohol and ether, but this quantity, instead of indicating 
1 per cent. or more of nitrogen in the sugar, gave in three expe- 
riments only ‘06 per cent., a quantity attributable to impurity. 
Tartaric acid and charcoal made from white sugar gave similar 
results, the ammonia amounting to a mere trace, doubtless due to 
foreign admixture. 
It is difficult from such experiments to avoid drawing the con- 
clusion that the appearance of the nitrogen is in all such cases due 
to accidental impurity in the body burned, and not to any direct or 
indirect formation of ammonia from the nitrogen of the air. 
To those practising the new method under discussion the fol- 
lowing observation may be useful :—in mixing the organic matter 
with the alkali in a smooth porcelain mortar some inconvenience is 
experienced in the obstinate adhesion of some of the mixture to the 
bottom of the mortar and also to the pestle, and which is often with 
difficulty removed by triturating two or three small successive por- 
tions of dry soda-mixture ; the powder is too soft to cleanse perfectly 
the mortar, and a little left behind would necessarily occasion loss 
in the ultimate result. By the use of a few grains of finely powdered 
glass this inconvenience is obviated; the glass is rubbed for a few 
seconds in the mortar, which it cleanses in the most complete man- 
ner, and can then be transferred to the rest of the mixture in the 
tube, where its presence can occasion no injury whatever. 
As additional testimony to the value of the new method, Dr. 
Fownes subjoins the results of a set of experiments made by himself 
with a view of testing the process before venturing to employ it 
upon bodies of yet unknown composition :— 
