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The Age of Oil 297 a wide vogue prevails owing to the lower price of the substitutes as compared with the genuine articles, although they do not possess the imperative character- istics of the latter. After that come the heavier oils, which are used for lubricating purposes and are of varying grades and density. These also enter into the pharmacopoeia, although this factor becomes more pronounced with the heavier products, such as the paraffin wax from which ointments, salves, drugs, and chewing gum are made. The wax gives us the candle which ousted the tallow dip from its eminence as a light; plays a prominent part in the manufacture of perfumes, the preparation of crystallised fruits, certain con- fections, and the making of matches. By blending the petroleum oil products with animal and vegetable oils a wide range of “ compound oils,” which are used for a hundred and one different purposes, are obtained. Lastly, there are the solid products, which are generically described as “ residue.” But, as a matter of fact, it is not a residue in the sense of a waste pro- duct. If the crude oil belongs to what is termed the paraffin group, then this residue takes the form of a coke, not widely dissimilar from that produced by the distillation of coal in the production of gas. This coke is an excellent fuel, but is not used in this direc- tion, because a more valuable use for it was discovered. From this is made the carbons upon which electric arc-lighting depends. If the crude oil belongs to what is called the asphaltic group, then the residue is an asphalt which is now being extensively used in road construction. The asphalt in turn yields bitumen, which is in demand for the manufacture of cables