Oil of chamomile, from Matricaria Chamomilla (common chamomile), which is specially characterized by its magnificent dark-blue color, has a marked narcotic odor and is very high-priced, owing to the small yield of oil by the flowers. The oil from Anthemis nobilis (Roman chamomile) has also a blue color which gradually becomes greenish-yellow.
Camphor (Camphora).
This essential oil differs from the others mainly by being firm and crystalline at ordinary temperatures. Chinese or Japanese camphor melts at 175° C. (347° F.) and boils at 205° C. (401° F.). Camphor is seldom used alone, as its odor is hardly fragrant; but it finds frequent application in the preparation of mouth washes, toilet vinegars, etc. In commerce so-called Borneo camphor is also met with (though rarely), which closely resembles the Chinese in appearance and other qualities, but is more friable and melts at 189° C. (388·4° F.).
Oil of Cascarilla
is not used pure in perfumery, the bark being generally employed instead.
Oil of Cassia (Oleum Cassiæ)
has a yellow color, gradually becoming dark reddish-brown, and an odor resembling that of oil of cinnamon, but the odor is not so fine, nor so strong, as that of the latter. The taste of the oil is of special importance: while that of true oil of cinnamon is burning though sweet, oil of cassia has a sharper taste, and this taste is considered by some a good mark of recognition of the rather common adulteration of true oil of cinnamon which is much more costly.
Oil of Cedar.
This oil, obtained from the wood of the Juniperus virginiana (not from the true cedar, Cedrus Libani), is clear like water, has a pleasant odor, and differs from most essential oils by congealing at a very low temperature (-22° C. or-8° F.) and by its uncommon resinification in contact with air.