Notes on Glycerine. 585 
- The following plan is adopted in manufacturing glycerine 
from palm oil. Steam, at a temperature of 550° to 600° 
Fahrenheit, is introduced into a distillatory apparatus, con- 
taining a quantity of palm oil. The fatty acids take up 
their equivalents of water, as does also the glycerine, and 
they are then distilled together into a receiver, where the 
condensed glycerine, being of a greater specific gravity than 
the fatty acids, sinks below them, and is gradually removed. 
If not of the proper density, it is concentrated; if dis- 
coloured, it is re-distilled. The best glycerine has a specific 
eravity of 1:26, and contains 98 per cent. of anhydrous 
glycerine. Its chemical formula is Cg Hg Og. 
It is unnecessary to dwell upon the superiority of glyce- 
rine prepared in this manner over that manufactured by 
the common processes, in which the glycerine produced is 
always more or less contaminated by the lime, oxide of 
lead, chlorine, and other reagents employed for the pur- 
pose of separating it from the fatty acids. 
Amongst a very large number of specimens of glycerine 
which I have examined, I have found none completely free 
from impurities except Price’s, and all authors are unani- 
mous upon this point.* In writing of the properties of this 
substance, I wish it, therefore, to be understood that pure 
glycerine is referred to, as I have known considerable dis- 
appointment, annoyance, and occasional injury to result 
from the employment of common impure glycerine. 
When pure, it is a colourless inodorous liquid, of the 
consistence of a thick syrup, and of a fresh, sweet taste. It 
is soluble, in any proportions, in alcohol and in water. It 
is not crystallisable, and possesses no influence upon pola- 
rised light. It does not absorb oxygen from the air, and, 
consequently, is not liable to rancidity, but, as it has a 
ereat affinity for moisture, it should be kept in closely 
stoppered bottles. It has no effect upon vegetable colours. 
Its selvent power has a more extensive range than even 
alcohol, as it is capable of dissolving some substances upon 
which the latter has no action. 
When acted upon by the weaker acids, no change of 
composition is effected, but when it is mixed with strong 
* In illustration of the care which is exercised in the distillation of 
glycerine at Price’s Works, it may be mentioned that, in the last part 
of the process, the glycerine is distilled through pipes lined with silver, 
in order to avoid its contact with any metal which might contaminate 
the glycerine. It is also frequently submitted to test in the laboratory, 
so as to guard against the accidental presence of any impurity. 
