The National Bureau of standards

Early in the history of our Government an office of weights and measures was established in connection with the Coast & Geodetic Survey for the purpose of providing suitable standards of length in connection with its work. At about the same time it became necessary for the Secretary of the Treasury to adopt standards of mass and capacity, and to provide copies of the same for use at the various custom-houses, thus increasing its functions to include mass and capacity. Later he was directed by the Congress to provide copies of these standards of length, mass, and capacity to the various states. This work was necessarily delegated to the office of weights and measures. Precision measurements of length necessitated the adoption and comparison of thermometic standards through the ordinary range of temperature. During the last years of the office of weights and measures it had begun in a very small way the testing of standards of electrical resistance and electromotive force, but owing to the limited facilities of the office its work was practically confined to the bare necessities arising in connection with the work of the Treasury Department. In urgent and important cases comparisons were made for other departments of the Government and for the public, although no provision was made directly for that purpose. In the meantime the scientific, manufacturing, and commercial interests of the country had assumed gigantic proportions. Accurate measurements were employed where before guesswork and rules of thumb were considered quite sufficient. Scientific work, and the introduction of scientific methods of manufacturing necessitated accurate methods of measurement. The dissemination of scientific knowledge and the adoption of the interchangeable method in manufacturing made the use of uniform working standards imperative, a result to be obtained only through primary standards of the highest type, and a central institution provided with the facilities for their compar- son with secondary or working standards.