ON COTTON-SEED OIL. 
227 
Mr. Weatherley’s essay well deserves attention. The author repudiates much 
of the discredit thrown upon the oil on account of its asserted drying qualities, 
and says that it answers well for both burning and lubricating. 
Mr. Weathcrley made some experiments in substituting u winter-bleached 
cotton-seed oil for olive or almond oils, in various pharmaceutical preparations, 
lie states that cold cream, spermaceti ointment, citrine ointment, and some 
liniments were so prepared, and fully equalled the results of the otiicinal for¬ 
mulae. . T 
In England, Dr. Adriani has studied the properties of this oil (Chern. A ews, 
Jan. 7, 1865). He states that the crushed seed is heated to about 180 l ahr., 
and then pressed, when 15 to 18 per cent, of a dark brown-red oil is obtained. 
The specific gravity is *930 or *931, and in this respect, as well as in taste, 
odour, and drying qualities, it has much resemblance to linseed oil, from which, 
however, it differs in its darker colour. Dr. Adriani has shown that the dark 
brown-red colour possessed by the oil does not pre-exist in the seed, but that it 
is the result of the oxidation of a yellowish-green principle that is found in the 
seed, and which may be extracted from it with unchanged colour if precautions 
to exclude the air be adopted. Much attention has been given in some quarters 
to the utilization of this principle as a dyeing agent, but without successful re- 
sults. t . .... , 
The operation of refining the oil consists chiefly in heating it with a weak 
solution of caustic potash or soda (the former by preference). A preliminary 
treatment of the oil by boiling water, to remove mucilaginous matters, much 
facilitates the operation. If the crude oil be well agitated with solution of pot¬ 
ash without the application of heat, the mixture, after repose, will yield a yellow 
layer of u refined oil” floating upon an aqueous solution that is neaily black, 
from the colouring matter abstracted from the oil. A singular purple-coloured 
film may also be produced upon the surface. The loss in refining is stated at 
about 15 per cent. . . , 
I have only to add a few remarks upon the detection of this oil when mixed 
with olive oil. A well-known chemist, whom I regard as the highest autnority 
upon the subject of the adulteration of oils, tells me that lie does not know of a 
test for this purpose. _ t 
The experiments which I have made induce me to regard the nitrate ot mer¬ 
cury test as affording sufficiently clear reactions to enable us to find this oil 
when mixed with olive oil. . 
I have used Pontet’s test as follows :—6 parts of mercury are dissolved m 7% 
parts, by weight, of nitric acid 1*36 without the application of heat, and foim 
the test solution. The tubes for making these experiments are merely stiong 
test-tubes of 7 inches in length, and holding about a fluid ounce. I hey are 
roughly graduated by pouring in 30 minims of water and scratching a line upon 
the glass ; another line is made at the point reached ivhen a total oi G diachms 
of 'water have been poured in. The lower line is marked u test,” the uppei one 
u oil.” Pour in first the test to its mark, and fill up with the suspected oil to 
the other line; shake well and set aside, shaking again about an hour after¬ 
wards. In from three to twelve hours according to the temperature, etc., a 
genuine olive oil will have solidified entirely, the product after the latter interval 
bein 0- quite hard when touched by a glass rod. Cotton-seed oil, when similar y 
treated, will not solidify, but remains fluid. A mixture of 25 parts of cotton¬ 
seed oil with 75 parts of olive oil gives an intermediate condition. Ilie contents 
of the tube become solid, but if a little be taken out with a glass rod, it is found 
to be soft, pasty, and without any friable cnaracter. On the other hand, w len 
pure olive oil is so treated, the product is hard, friable, and not pasty. _ Com¬ 
parative trials should always be made, and caution exercised m accepting the 
apparent conclusions. Where only 12| per cent, of cotton-secd oil is presen , 
