[SHUTT & CHARLTON] MELTING POINT OF FATS 25 
a spatula. The surface of the fat should be left even with that of the 
mould, which is then removed. 
After placing the cone with its adhering disc of fat on the surface 
of the mercury (b), the temperature of the water-bath is uniformly and 
slowly raised. We have obtained the best results from using a rising 
temperature practically equivalent to 1 degree per minute. 
After the melting point has been noted (which is indicated by the 
ringing of the bell), the melted fat is wiped from the surface of the mer- 
cury by a piece of filter paper. In making a number of determina- 
tions, the mercury will be found, after a time, to become sluggish. It 
should then be shaken with gasoline, together with a few drops of 
nitric acid, if necessary. 
The following data include the highest and lowest melting point 
determinations in the series under investigation. Two other results 
(C and D) taken without any selection from our records have been 
added, in order to show the extent to which duplicate determinations 
may vary: 
MELTING POINTS OF PORK FAT, 
A.—Highest: Shoulder, 39°8°C. B.—Lowest: Shoulder, 27:0°C. 
os ae 39°6°C. ce 27-200; 
as af 40-0°C. as a 2702: 
- Los. warts? C; us Tomes. 22687 a: 
rf : 41°8°C, ff . yap Vl Os 
€ (fs 41°8°C. cc (a4 26°7°C. 
ie Shoulder, 35:5°C. D. Shoulder, 30°1°C. 
“< 35°4°C. si 30-1°C. 
Hein os: 348°C) hoi... 2067 €: 
. 35°1°C. . 30:5°C. 
The use of this apparatus seems to present the following advan- 
tages : (1) There is no necessity to re-melt the fat, as when drawn-out 
glass tubes are used, and thus one source of error is avoided ; (2) The 
factor of pressure is practically eliminated; (3) Rapidity ; The 
method appears to allow of about twice as many determinations being 
made per hour as by that of Christomanos. In conclusion we may say 
that the variations due to a too rapid -rise of temperature do not appear 
to be any greater than those of other electrical methods. 
