Some writers, even of good reputation, have held that the blue is the true body colour of the air, or of some ingredient in it such as ozone.
Galbanum, myrrh, stacte, frankincense, calamus, cassia and cinnamon, were all of them used in perfumes, even the myrrh being probably the kind distinguished at the present time in the Bombay market as perfumed myrrh or bissabol, which still forms an ingredient of the joss sticks used as incense in the temples in China.
Throughout the southern portion sand is a large ingredient, and to the northward there is more or less lime.
Its viscid character, and its non-liability to dry and harden by exposure to air, also fit it for various other uses, such as lubrication, &c., whilst its peculiar physical characters, enabling it to blend with either aqueous or oily matters under certain circumstances, render it a useful ingredient in a large number of products of varied kinds.
Thus its non-liability to freeze (when not absolutely anhydrous, which it practically never is when freely exposed to the air) and its nonvolatility at ordinary temperatures, combined with its power of always keeping fluid and not drying up and hardening, render it valuable as a lubricating agent for clockwork, watches, &c., as a substitute for water in wet gas-meters, and as an ingredient in cataplasms, plasters, modelling clay, pasty colouring matters, dyeing materials, moist colours for artists, and numerous other analogous substances which are required to be kept in a permanently soft condition.