368 ODOROGRAPHIA, 
—9° 20! in a column of 100 mm., but the figures are too variable 
to serve as a test. The rotatory powers of turpentines also vary 
according to the source from which they are derived. 
The presence of alcohol may be detected by agitating the oil with 
a few small pieces of calcic chloride; these remain unaltered in a 
pure oil, but dissolve in one containing alcohol, and the resulting 
solution separates, forming a distinct stratum at the bottom of the 
vessel. When only a very little alcohol is present, the pieces 
merely change their form and exhibit the action of the solvent on 
their angles or edges, which become more or less obtuse or 
rounded. 
Santaline, the colouring-matter of Red Sanders wood, is nearly 
insoluble in pure oil of lavender, and exerts no marked influence 
on it, but it is freely soluble in oil adulterated with rectified spirit. 
Auniline-red can be used in the same way; a drop of oil let fall on 
a crystal of “magenta” and gently pressed will not dissolve the 
colour unless alcohol be present. 
By Davy’s molyhdic-acid test for alcohol in fluids generally, 
it is asserted that an admixture of one per cent. of alcohol in 
essential oils can be detected. One part of molybdie acid is 
dissolved with gentle heat in 10 parts by weight of pure con- 
centrated sulphuric acid, and kept in a well-stoppered bottle to 
prevent absorption of moisture. A little of the oil under exami- 
nation is agitated with a small quantity of distilled water in a 
pipette, the small orifice being closed. When the oil and water 
have separated, a few drops of the watery portion is then allowed 
to run out and come in contact with 3 or 4 drops of the molyhdic- 
acid solution placed in a white porcelain capsule. If the oil has 
been adulterated with alcohol, an intense azure-blue coloration 
will develop in a few moments *. 
The revenue of profit per acre depends much on the season and 
age of the plants, but an average yield of 25 lbs. weight of oil per 
acre may be reckoned if worked carefully, and the weather be 
favourable. I have, in fact, gathered 35 lbs. per acre in a good 
year. Much depends on the energy and personal superintendence 
of the grower and care in the distillation. Land cultivated in a 
slovenly manner rarely yields much profit in any kind of farming, 
and if the distillation of this flower be left to the care of imex- 
* Pharm. Journ. [5] vili, p. 201. 
