Vernier

(vur'ne-ur.) (Math.) An instrument which forms a nece ary part of all instruments where lengths or aug les have to be estimated with precision; it derives its name from its inventor, a French mathematician, who died in 1637; and consists e entially of a short graduated scale, ab, which is made to slide along a fixed scale, AB, so that the graduations of both may be compared with each other. The fixed scale, AB,being divided into equal parts, the whole length of the V., ab, maybe taken equal to nine of those parts, and itself divided into ten equal parts. Each of the parts of the V., ab, will then be le than a part of the scale by one tenth of the latter. This granted, in order to measure the length of any object, mn, let us suppose that the latter, when placed as in the figure, has a length greater than four but le than five parts of the fixed scale. In order to determine by what fraction of a part mn ex. ce eds four, one of the ends, a, of the V., ab, is placed in contact with one extremity of the object, mn, and the division on the V. is sought which coincides with adi vision on the scale, AB. In the figure this coincidence occurs at the eighth division of the V., counting from the extremity, n, and indicates that the fraction to be measured is equal to ffof a part of the scale, AB. Consequently, if the scale AB were divided into inches, the length of mn would be 4 = 4 inches. Ver'non, in Mi ouri, a W. co., near Indian Ter.; C. Nevada. Pop. 11,247.-In Wisconsin, a S.W. county, drained by the Mi i ippi; C. Virogua. Pop. 18,645. [s. 935]