Constituents of Russian petroleum to the extent of almost 80 per cent. They are hydrocarbons of the general formula C,.II2

, is a yellowish liquid of sp gr. i,i986 and boilingpoint about 2ii degrees C., prepared from benzene by the action of a mixture of sulphuric and nitric acids, and can also be produced by the action of strong nitric acid on turpentine. It has an intense odoui of oil of bitter almonds, is soluble in alcohol and ether, and is much used in perfumery and as a flavouring principle, also in the dye industry. There are several dinitrobenzenes and trinitrobenzenes 3 respectively.

The use of symbols and formulae to denote the constitution of chemical substances.

A reddishyellow essential oil distilled from orange flowers, of which there are several varieties. Sp. gr. about C87 to o88, soluble in alcohol, ether, etc. Its constituents include linalyl acetate, linalool, geraniol, and limonene.

An oily, colourless, alkaloidal liquid of sp. gr. 1009, constituting the acrid basic principle of tobacco, in which it is found present in amount varying from 2 to 8 per cent. Nicotine is not present in the seed of the plants but appears in the young plant immediately the chlorophyll begins to function, and originates in the leaf. It is soluble in water, alcohol, and ether. Preparations of it are extensively used for horticultural purposes as an insecticide, also as a dip for the destruction of ticks and other pests on the wool of sheep.

2HCl A complicated organic substance used as a local anaesthetic in place of cocaine, being less toxic.

or SWEET SPIRIT OF NITREA drug, used as a diuretic and stimulant, prepared by the action of nitric acid upon alcohol. It is a yellowish, aromatic, volatile, and inflammable liquid of sp. gr ogoo, boiling at C., soluble in alcohol and ether,

Atomic weight, 2224. A rare inert element of recent discovery, being a radium emanation soluble >n water, prepared by heating a radium compound or by dissolving it in water and pumping off the gases slowly generated from it, and from which it is obtained by first of all removing any associated oxygen, hydrogen, carbon dioxide, and nitrogen, thus leaving the niton from which in turn the generated helium may be pumped off. It can be condensed to the solid state, and both it and the liquid forms are phosphorescent. It is said to spontaneously decompose into helium and other substances.

An aromatic alcohol of sp. gr. o88i isomcric witH geraniol, occurring in the finer extracts of rose and neroli.

is a white, lustrous substance, soluble in benzol, alcohol, ether, and chloroform, and slightly soluble in water, made by fusing betanaphthalone sulphonate with caustic soda and subsequent distillation. It is used in making dyestuffs and as an antiseptic.