Page:Miscellaneous Papers on Mechanical Subjects.djvu/180

 short vertical rods placed under the scales, and adjusts them evenly, before commencing the operation of weighing.

The balance stands on four feet, each adjustable by screws.

The full set of standard weights and measures supplied by the office consists of—

1. A set of standard weights from 1 lb. to 50 lbs. avoirdupois; and 1 lb. troy. 2. From 1 oz. down to $1/10000$ oz. troy. 3. A yard measure. 4. Liquid measures. The gallon and its parts down to half-pint inclusive. 5. A half-bushel measure.

Twenty-one States have been supplied, and other sets are being prepared for the remaining States. There are thirteen workmen employed.

The United States standard yard has been obtained from a 7-feet standard procured from England.

It is made of gun-metal, about 2 inches broad and ⅜ inch thick, and has a thin strip of silver, $1/5$ inch broad, let into it through its entire length. It is divided into small divisions, each being an aliquot part of an inch. The standard was obtained by taking the mean of a great number of measurements made from different points in the 7 feet scale.

A set of standards has been presented to