University of Michigan - Michiganensian Yearbook (Ann Arbor, MI)

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accurate and reliable standand of electro-motive force known, and is now used in all the important physical laboratories in the United States. On accepting the appointment to the Professorship of Physics in the University of Michigan in 1886, Professor Carhart entered actively upon the reorganization of the department. The small outfit of antiquated apparatus and the narrow accommodations afforded upon the fourth floor of the main building, were soon replaced by commodious quarters in a new laboratory and modern instruments of accuracy and precision. Laboratory work in Physics became a reality and the subject acquired an added interest from actual contact with the phenomena described. The departmentof electrical engi- neering, organized to meet the increasing demand for work in this branch of Science, has risen so rapidly in rank and importance that today the crowded laboratories and lecture room render increased accommodations an imperative necessity. Professor Carhart has made numerous valuable contributions to current Scientific literature. Not to mention in detail his various articles appearing from time to time in the fl7llL'l'Z'L'!Zll fourmz! ey' Sciwzcc, The Pkz'!os0j20z'ca! Magasz'1zc, The Physica! Rczfiew, and the English and American electrical journals, the following are a 'few of the subjects to which he 'has given special study: Relation between the Electro-motive Force of a Daniell Cell and the Strength of the Zinc Sulphate Solutiong Relation between Direct and Counter Electro-motive Forces represented by an Hyperbolag On Surface Transmis- sion of Electrical Dischargesg An Improved Standard Clark Cell with Low Temperature-Coefficient, A One Volt Standard Cellg Theory and Design of the Closed Coil,iConstant Current Dynamog The Electrical Conductivity of Copper as Affected by the Surrounding Medium. In more general lines he has also written valuable papers. His address as Vice President of Section B. Of the American Association for the Advancement of Science, delivered before the Section of Physics in 1889, is a noteworthy review of the existing know- ledge touching electrical phenomena, and contrasts sharply the present methods of scientific investigation with the vague speculations and theories So prevalent in the past. As the natural outgrowth of his extended researches on the standard cell, he published in 1891, a work on Primary Batteries, presenting in a concise and lucid form not only the valuable results of personal investigation, but the Widely scattered literature of the subject. Some idea of the importance of

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attractions of scientific study and research, the powerful infiuence of Professor Whitney, with whom he studied German, the nearness of the Sheffield Scien- tific School, and his uniform success in teaching, all served to turn his mind toward teaching as a profession, and the choice of his life work was made. , In 1872, Mr. Carhart was called to the Northwestern University at Evanston, the first year as instructor, the following year as Professor of Physics. Here he remained for fourteen years. During this time the equip- ment for teaching the Physical sciences at Northwestern, rose rapidly from a meagre collection of useless apparatus, to the completion of a magnificent laboratory carefully planned and liberally furnished throughout. This was a period of remarkable development i11 the scientific world at large, electricity advanced with giant strides, the telephone, the microphone, the dynamo and the electric light followed each other in quick succession, like the glittering pageantry of a dream, and the public were eager to hear and know of the last new thing. Professor Carhart was one of the most enthusiastic explorers in this new domain of science, and in response to urgent appeals, delivered popular scientific lectures i11 many cities, including Minneapolis, Milwaukee, Evanston, Chicago and New York. In I876 he was married to Miss Ellen M. Soule, at that time Dean of the Woman's College of the Northwestern University, and Professor of the French Language and Literature. To the enthusiasm, inspiration, and sympathetic encouragement of this gifted and cultured woman he owes much of his best work. In 1881 he was granted leave of absence for a year's study abroad. After attending the Paris Exposition of Electricity as one of the International jury of Awards for the United States, he spent the greater part of his time in study and research in the University of Berlin. Here he came under the personal instruction of Professor von Helmholtz, at whose suggestion he undertook the investigation of the relation between the electro-motive force of a Daniell cell and the density of the included zinc sulphate solution, The investigation was so thorough and the results so important as to command notice in all the leading scientific publications of Europe, and the values are found in tables of physical constants today. An immediate result of this year's work was the development of the Carhart-Clark Standard Cell. to the perfection of which he has given years of patient study. This cell, which is a modification of the form originally proposed by Latimer Clark, is in many respects the most Q

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the work may be gained from the fact that it is the acknowledged authority on the subject both in America and England, and that it has recently been trans- lated into German. He has also published Elements of Physics, QCarhart and Chutej 1893, University Physics, Part I, 1894, and has now in press a work on Electrical Measurements which will appear during the present year. The new edition of Johnsons Encyclopedia will contain articles from Professor Carhart on Electric Lamps, Electric Potential, Thermal Electricity, Units, and WVattmeters. As a writer he has the happy faculty of stating scientific facts clearly, brieliy and accurately. His books are concise and teachable. Professor Carhart has been repeatedly honored hy learned bodies both at hon1e and abroad. In ISQZ, while in attendance at the meeting of the British Association in Edinburgh, he was invited, together with von Helmholtz and Guillaume, to sit as visiting member with the famous connnittee on units. In june, ISQ3, he received the honorary degree of LL. D. from his Alma Mater, Wesleyan University. He was one of the five official delegates repre- senting the United States, appointed by Secretary Gresham to the Interna- tional Electrical Congress held at Chicago in 1893. From this body of international delegates, a committee of three, consisting of Professor von Helmholtz of iBerlin, Professor Ayrton of London, and Professor Carhart, was appointed to prepare specifications for the Standard Clark Cell, their report to be adopted as the legal usage in the scientific and commercial world. He was chosen President of the Committee of judges for the Department of Electricity at the World's Columbian Exposition, a position of peculiar importance and responsibility, and to the performance of the delicate and arduous duties appertaining thereto he showed himself remarkably well adapted. He delivered the principal address at the opening of the new scien- tific building in the University of Colorado on the seventh of March, 1895. As a teacher in his favorite science Professor Carhart is characterized by clearness, accuracy and intense earnestness of purpose. As a lecturer and experimenter he has few equals. His experiments succeed g-a statement best appreciated, perhaps, by those who know how easy it is to arrange experiments that shall fail. In every experiment there are, besides the underlying princi- ple, the nameless minutiae whose thorough comprehension is vital to success. His experiments succeed because he does not rest until these minute details are not only known, but under control, and success, like genius, comes at last to mean, an immense capacity for taking pains, JOHN O. REED,