522 
PROFESSOR A. H. CHURCH ON TURACIN. 
Dumas’ method. A fourth determination by the same process had given me 
7'01 per cent., a figure which I rejected at the time as not being in accord with the 
three other analyses, which agreed well with one another. Subsequently I made a 
large number of other “absolute” nitrogen determinations, with more discrepant 
results, some yielding figures a good deal higher, and others, again, a good deal lower 
than those previously obtained. Many of these analyses were performed with the 
same sample of turacin ; in one instance only did the percentage obtained, 6'75, show 
a fair agreement with the earlier numbers. I then secured the aid of two expert 
analysts, accustomed to the use of all the modern refinements in apparatus and 
processes for the determination of nitrogen by the absolute method, and constantly 
performing analyses of the most varied and complex niti’ogenous bodies. But their 
results, six in number, though all obtained with the same sample of turacin, agreed 
neither with one another nor with any of my own previous determinations, the 
highest figure in the whole set being only 6 *15 per cent. I had previously tried 
once more the soda-lime combustion method, making two analyses, in a current of dry 
hydrogen, with the following results :— 
i. 
ii. 
grm. 
grm. 
Turacin taken, corrected for ash ..... 
■2448 
•478 
(NH 4 )oPtCl 6 obtained ......... 
•2713 
•5265 
Platinum obtained from above salt .... 
1222 
•233 
Nitrogen percentage, calculated front platinum f 
found (Pt — 194*8)./ 
7-17 
7 01 
These results, it will be observed, tended to confirm the higher figures obtained in 
some of the Dumas’ analyses. I therefore made two more determinations by the 
soda-lime method, conducting the combustion, as before, in a current of hydrogen, 
but receiving the evolved ammonia in a standard sulphuric acid. On subsequent 
titration of the contents of the bulbs, the percentages of nitrogen obtained were 
7'23 and 7'38. This volumetric estimation was difficult to complete, owing to the 
hue of the indicator being interefered with by that of some coloured distillation- 
products in the bulbs, and I do not attach much importance to these very high 
figures, the mean of which is no less than 7'3. It seemed, however, worth while 
to make further experiments with the modified soda-lime method, and Dr. F. E. 
Matthews, of Cooper’s Hill College, very kindly undertook to determine the 
nitrogen by this process, which he had brought to great perfection, and had practised, 
with undoubted success, in the case of substances very difficult to analyse satis¬ 
factorily. Dr. Matthews purposely employed very small quantities of turacin, and 
he used the Nessler method of estimating the evolved ammonia, but I have every 
reason to believe that his results are the most exact obtainable under the conditions 
named. He used part of the same sample of turacin (the whole weighed 4 grms.) 
