694 THE POPULAR SCIENCE MONTHLY. 



the earth's figure are likely to be presented at an early day. As 

 Superintendent of Weights and Measures, Prof. Mendenhall enters 

 upon another field of duty for which his work in the past has 

 been a preparation. He has long borne a prominent part among 

 the teachers who have pressed and still continue to press the met- 

 ric system upon the American public. He is an active member of 

 the American Metrological Society, and has repeatedly, on the 

 platform and through the press, taken occasion to impeach the 

 current irrational medley of pounds avoirdupois and troy ; of 

 grains, gallons, feet, and bushels. 



Prof. Mendenhall has uncommon gifts as a lecturer ; his mas- 

 terly expositions of physical themes continue to be given despite 

 the pressure of official duties. At the Cooper Institute in New 

 York, the Lowell Institute in Boston, the Peabody Institute in 

 Baltimore, the Mechanics' Institute in Cincinnati, the Brooklyn 

 Institute, and in other of the chief popular lyceums of the 

 country, he has been greeted by large audiences. The honorary 

 degree of Ph. D. was conferred on him by the Ohio State University 

 in 1878, and that of LL. D. by the University of Michigan in 1887. 

 In the latter year he was chosen a member of the National Acad- 

 emy of Sciences. He was elected a member of the American As- 

 sociation for the Advancement of Science at the Indianapolis 

 meeting in 1871, and was advanced to the grade of Fellow in 1874. 

 In 1882, at the Montreal meeting, he presided over the Section of 

 Physics. His address on that occasion was a forcible plea for 

 physics in education, presenting a judicious view of the value of 

 guidance when students attempt original research. In 1888 he 

 was chosen President of the Association, and in that capacity at 

 last year's meeting, in Toronto, won golden opinions on all hands. 

 At the approaching meeting in Indianapolis he will, it is under- 

 stood, take for the theme of his address, as retiring president, 

 The Relation of Science and Scientific Men to the General 

 Public. 



In 1887 he contributed the first volume to The Riverside 

 Science Series, A Century of Electricity. A revised and enlarged 

 edition of this capital popular treatise has been issued this year. 

 From among his numerous contributions to scientific publications 

 we select : On the time required to communicate impressions to 

 the sensorium and the reverse, American Journal of Science, 1871 ; 

 On the heaping of liquids, American Journal of Science, 1873; 

 An improvement on Bunsen's method for specific gravity of 

 gases, Proceedings of the American Association for the Advance- 

 ment of Science, 1878; Temperature and index of refraction, 

 American Journal of Science, 1876 ; Co-efficient of expansion of 

 a diffraction grating, American Journal of Science, 1881 ; Mem- 

 oirs of the. Scientific Department of the University of Tokio, Ja- 



