Excerpt from British Engineering Standards Association: Formed in 1901 as the Engineering Standards Committer The revision of this Specification was commenced July, 1915, and the Panel appointed for the purpose submitted a recommendation to the sub-committee on Electrical Accessories that in carrying out this revision the Specification should be extended to deal with wattmeters, power factor and frequency meters, and to include both indicating and graphically recording instruments. This proposal was agreed to and the Panel found it necessary to draft two Specifications, one dealing with indicating and the other with recording instruments. The Specifications, therefore, are much more than a revision of the Report No. 49. The question Of the degree of accuracy which should be called for in the Specification involved long discussion during the preparation of the first report, and the same question has again been discussed at considerable length. It is argued on the one hand that the object of a Standard Specification is to secure generally the highest possible quality in the manufacture Of the apparatus dealt with, and this school Of thought considers questions Of cost as secondary matters. The opposing party urges that the Object of a Specification is to define the minimum standard of quality which must be attained if the apparatus is to perform satisfactorily the functions for which it is intended, and that nothing higher than this minimum should be required by the Specifications, if industry is not to be hampered by unnecessary cost of production. The Clause dealing with limits of accuracy in this Specification is the result of a compromise between these two points of view. While intended to secure a degree of accuracy adequate for the purposes indicating instruments are usually required to serve, it must not be interpreted as signifying that, in the Opinion of the Panel, indicating instruments cannot be 'made to read within closer limits than those laid down. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.