This, of course, is indispensable for measuring. It is made in a variety of patterns, and any but the very cheapest and commonest may be used. The latter are often unsatisfactory in the hinge or joint. A two-foot is as useful as any; it may be either twofold or fourfold, that is, with one or three joints. Both in regard to length and folds the choice depends entirely on the worker, some preferring one kind and some another. Indeed, a similar remark applies to all tools.