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THE POPULAR SCIENCE MONTHLY 



The Engineering Building. 



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 inter- 

 national 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 coin- 

 age 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 



