The Romance of Modern Chemistry

x— -J up This means that the use of '* a result which, in view of —3 °n metals, is highly un- No objection of this sort can be urged are [ro- Hence fats and oils but^hA °®Cial,,eye’ m'Sht be cIassed as a lubricant, but the naturally occurring variety, which, by the way is a solid, not a hquid, finds only a limited applies, tion in this direction. been11^! X lubricating P^poses has greatly restneted m recent times by the intro- wells U 7T > ° ’ °btained fr0m P^oleum Ils. It must be borne in mind that the fatty oils are compounds of glycerine and an acid, and that under of t'‘:°nS~When eXP°sed’ for to the action of high-pressure steam-they may be split into these constituents. U1 fiJUbnTing «fatt °’.1 may kad to the fo™ation of free acid on the bearings, a the corrosive action of acids desirable. j” against the petroleum or mineral oils, for "w simply hydrocarbons, compounds of carbon and bvdi gen, and as such are unaffected by air or steam. Hence it comes that for lubricating purposes fatty oik have been largely displaced by mineral oils. As a matter of fact, most of the lubricating oils used at the present tune are mixtures of the two varieties. The discovery of petroleum has' very notably re- st, icted the use of fatty oil., in another direction, namely, m their application as illuminants. It is not so very long ago since paraffin oil was a novelty, and up to that time vegetable oils, such as olive and rape oils, were largely employed as sources of light Nowadays we may say with confidence, the private individual uses nothing except paraffin as a burning oil. It is the railways which famish the most conspicuous example Of adherence to the old custom, the lamps used on 243