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consumers. But the fact is that the check held by means of the life and efficiency tests made at the bureau, and by the work of inspectors who visit lamp factories with bureau standards and instruments, has had the effect of gradually raising the quality of all lamps made; so that the consumer at large has profited equally with the government in the improvement of the lamp product. The bureau cooperates with the technical staff of the best manufacturers, large and small, and is in this way influential in raising the standard of excellence. Since the lamp trust fixes and maintains prices, the only advantage the government gains by competition is the competition in excellence. A consignment of 50,000 lamps has just been rejected because they fell ten per cent, below the guaranteed life.

The work of other divisions of the bureau, while not appealing perhaps so directly to popular interest, are of no less value to the public weal. For example, the bureau is the legal custodian of the international primary standards of length and mass in the form of the national prototype meter and kilogram, by which the yard and the pound are respectively defined. From these and by methods and instruments of the highest precision our customary commercial and scientific standards are derived. In fact the integrity of our gold and silver coinage can be maintained only by occasional refined checks against the ultimate standard of mass in the vaults of the bureau. The prototype standards are composed of incorrodible metals in alloy; no standard