Lubricating

(lu'-brik-a-ting). Making smooth or slippery. L. Oils, oil products obtained chiefly from petroleum and u lubricating purposes. Some crude an ural lubricating oils, requiring little or no treatment t fit them for use. The other petroleum lubricatinj are obtained in one of two ways either by driving the light hydrocarbons from the crude oil, yield in what is called a "reduced oil," or they are th obtained by distilling the petroleum residuum it stills. The lightest of the lubricating oils, gravity from 320 B. to 380 B., are frequently " neutral oils." They are largely used forthepurpo mixing with animal or vegetable oils, and it is therefore nece ary that they should be thoroughly deodorized, decolorized, and deprived of the blue fluorescence, or "bloom," characteristic of petroleum distillates that contain paraffin. Heavier lubricating oils are called '♦spindle " oils and " cylinder" oils. The most important characters to be po e ed by these oils are high tire-test, low cold-test, and a high degree of viscosity, ubrication (lu-brik-a'-shuri). The proce of making smooth or slippery by the application of a lubricant.