The last enters into the composition of some of the solid lubricating greases, and is also used as an adulterant of other oils.

The viscosity test, although of considerable importance in the examination of lubricating oils, has been shown to have very little discriminative value as a general test.

This was soon put into operation in Scotland, first with the Boghead coal or Torbanehill mineral, and later with bituminous shales, and though he had to face much litigation Young successfully employed it in the manufacture of naphtha and lubricating oils, and subsequently of illuminating oils and paraffin wax, until in 1866, after the patent had expired, he transferred his works to a limited company.

Even if the slide itself is mechanically perfect, the irregularity in the thickness of the lubricating oil between the bearing surfaces of the slide is apt to produce a variable error.

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.