The practical application of electric motors to printing press machinery
Journal of the Franklin Institute
Oct., I899. ] Apphcatzbtz ~ Electric 2VZotors. 259 very accurate measurement of pressure, and errors of ~¢ of I per cent. are of importance. Recent studies of the errors of aneroid mechanisms have indicated directions in which still further improvement is possible. The hair hygrometer is about the only type of hygrometer that seems practically available in the construction of a kite meteorograph, but it is, nevertheless, not as sensitive and reliable as we desire. Ten minutes or more are
... or more are required for the hairs to show a change of io per cent. in the humidity. Aside from this sluggishness, the indications of the instrument are not wholly reliable and should be frequently checked and verified by comparison with readings of the wet and dry-bulb thermometers. The greatest need in kites for future work is a more perfeet means of automatic adjustment to extremes of wind velocity and considerable reduction in weight of the structure so that better ascensions can be made in light winds. The remarks already made in respect to the errors of the recording instruments indicate the nature of improvements required therein.