338 Kirkwoop AND GiEsS: CHEMICAL STUDIES 
The following facts regarding cocoa-oil have been compiled 
from various sources. They may be compared with similar data 
for other fats and oils given in the standard works of Konig, 
Staedeler, Lewkowitsch and others : 
A. The heat of combustion of cocoa-oil is 9,066 small calories 
per gram.* It is as low as that of any other fat; slightly lower 
than butter. This is due to the fact that it contains a large pro-’ 
portion of fatty acids of low molecular weight. 
B. Melting point is at 24° C. Congealing temperature is 22- 
23° C. Fatty acids from it melt at 24.6° C. They congeal at 
cee Oe 
C. Saponification value = 257.3-268.4t 
D. Iodine number = 9.0-9.5 ; same for its fatty acids = 8.5- 
9.0.§ 
E. Specific gravity = 0.9115 at 40° C.|| - 
F. Acid value = 9.95-35.21. 
G. Reichert-Meissl figure = 7.4; Hehner = 88.6—90.5. 
H. Barium figure (Konig-Hart) = 117-120. 
I. Molecular weight of the mixed fatty acids = 196-211. 
The use of cocoa-fat and other cheap vegetable oils aS 4 
substitute for butter among the poorer classes has been in- 
creasing. Cocoa-fat is better adapted for cooking than for table 
use. It is frequently employed as an adulterant of ordinary 
butter. Prepared cocoa-fat makes a fairly good substitute for com- 
mon butter. The fresh material becomes rancid after a time, 
because of its accumulating content of free fatty acid resulting from 
bacterial agency. Volatile acids are formed. Its tendency 
rancidity is not as great, however, as that of animal fats. The 
fatty acid present in the fat to begin with can easily be removed 
with insoluble basic compounds, such as magnesia. By this means 
ae 
* Merrill, Quoted by Sherman and Snell : Journal of the American Chemical 
Society, 23: 166. Igo1. 
+ Kénig : Menschlichen Nahrungs- und Genussmittel, etc., 2: 322. 1893. 
t Konig : /bid. 
4 Benedikt. Quoted by Vaubel: Physikalischen und chemischen Methoden 
eevee Bestimmung organischer Verbindungen, 2: 235. 1902. 4 
|| Values given after E-I inclusive are quoted by Hopkins : Oil-Chemists’ Han : 
book, 38, table iv. 1900. See also Lane: Journal of the Society of Chem 
Industry, 20: 1083. 1901, 
