390 



SCIENCE 



[Vol. LV, No. 1424 



was founded,. and to its development each de- 

 voted his life. 



Born on a farm in the suburbs of Balti- 

 more, March 6, 1873, Waidner received his 

 early training in the public and private schools 

 of that city. He attended Johns Hopkins Uni- 

 versity where he graduated in 1896, and con- 

 tinuing in the graduate school, in which he was 

 a pupil of Eowland, he received the degree 

 of Ph. D. in physics in 1898. The subject of 

 his thesis, "A comparison of mercury and re- 

 sistenee thermometers and an adjustment of 

 Rowland's value of the mechanical equivalent 

 of heat," in collaboration with F. Mallory, is 

 the one to which Waidner devoted practically 

 his entire professional career, namely, the de- 

 termination of fundamental constants and 

 standards relating to heat, and he became the 

 first authority in the country on thermometry 

 and heat measurements. 



He served as instructor in physics at the 

 Hopkins and also at Williams College, going to 

 the Bureau of Standards on August 1, 1901, 

 one month after its establishment. In 1903, 

 he organized the Division of Heat and Thermo- 

 metry, of which he was appointed chief, a posi- 

 tion which he held until his death. It is chai-- 

 aeteristie of him to note that the first books he 

 ordered at the bureau were a set of Regnault's 

 works. 



It is perhaps not without interest to recall 

 the chaotic state existing in 1901 in this coun- 

 try with respect to thermometric data. Clin- 

 ical thermometers were being certified to a 

 scale one-tenth degree in error; manufacturers 

 of thermometric instruments ol" precision each 

 had his own "standards," usually of nebulous 

 or ambiguous origin; for pyrometric data, one 

 had to go to Germany; the temperature scale 

 in the fundamental range 0° to 100°C of the 

 International Bureau vras available with diffi- 

 culty and delay through French-made thermo- 

 meters; there was practically no national or 

 international agreement relating to heat 

 measurements. 



Waidner took up and successfully solved, in 

 collaboration with his associates, each of these 

 problems. Starting with the scale and methods 

 of testing of clinical thermometers, calorimetric 

 thermometry and the substitution of the elec- 



trical resistance method as standard in this 

 range as for a portion of the higher and lower 

 temperature ranges, this work included also 

 exhaustive studies of the limitations of mei'- 

 cury-in-glass thermometers, and the introduc- 

 tion and development of optical and thermo- 

 electric methods in pyrometric measurements. 

 In the course of this work it was necessary to 

 devise many new designs of apparatus and 

 Waidner was exceptionally skillful in this field, 

 and his designs have been used as models by 

 many others. 



He also saw the necessity of improving 

 calorimetric methods to secure greater pre- 

 cision and his work, for example, on methods 

 of measuring heating values of gases is recog- 

 nized as fundamental for gas testing. He was 

 responsible for the establishinent of the dis- 

 tribution of materials of determined calorific 

 value for calorimetric standards on which the 

 testing of fuels depends; and also of pyro- 

 metric material standards of certified melting 

 point, permitting the calibration of pyro- 

 meters by the user. 



The investigations carried out by him or 

 under his supervision on high temperature 

 measurments were started when the subject was 

 comparatively unknown in this country. This 

 work provided pyrometric standards and meth- 

 ods of control for American manufacturers of 

 pyrometers, and was of fundamental import- 

 ance in the development of an industry which 

 now finds application in many branches of 

 manufacture. 



As the bureau expanded, Waidner was able 

 to devote less time to actual experimental work, 

 but to the last was very active in the initia- 

 tion and direction of the problems in heat, and 

 many of the more recent papers from the 

 bureau on such subjects, although they do not 

 bear his name are nevei-theless largely his pro- 

 duct. During the past few years his interest 

 centered mainly about several groups of en- 

 gineering problems, one relating to the deter- 

 mination of constants of importance especially 

 to the refrigerating industry; another con- 

 cerned with the extensive investigations on the 

 fire-resisting properties of structural ma- 

 terials; and a third, dealing with the methods 

 of testing petroleum products. 



