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Classification of the Sci
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or knowledge of the worker. Thus we have Bone-setters, Bouncers, Watchmakers, Humorists, Chirpodists, Dermataxists, Slate cutters, who live by some sort of superiority, generally native, over the average man. But it will be found that it is only single arts or small groups of arts that are so bound together. The unity of a practical science, each of which, for the most part, governs a number of different arts, and still more that of a group of related practical sciences,—such, for example, as the sciences of Transportation and the sciences connected with the growth of Plants,—lies in a common purpose, although this purpose does not per se gratify any particular instinct. A man engaged in transportation, for example, or in inquiry into the principles upon which different kinds of transportation ought to be conducted, must take cognizance to a certain extent of what it is that is to be carried, whether iron,