102 



THE POPULAR SCIENCE MONTHLY 



PROFESSOR ONNES AND TEE 



LEIDEN LABORATORY OF 



PHYSICS 



The Franklin Institute has made the 

 first awards of its Franklin medal, es- 

 tablished last year by a gift from Mr. 

 Samuel Insul, to Mr. Thomas Alva 

 Edison and to Professor Heike Kamer- 

 lingh Onnes. Mr. Edison 's great con- 

 tributions to the applications of science 

 are known to us all. It may be of in- 

 terest to give some statement of the 

 work of Professor Onnes and the 

 Leiden Laboratory, taken from the re- 

 port of the institute. At the present 

 time it is well to remember the im- 

 portant contributions made to science 

 by the smaller nations. It is certainly 

 a remarkable fact that Holland should 

 have more physicists of high distinc- 

 tion than the United States. 



Heike Kamerlingh Onnes was born 

 on September 21, 1853, at Groningen, 

 Holland, where his father was engaged 

 in manufacture. He was educated in 

 the schools of his native town, and 

 there also he began his university stud- 

 ies in 1870. Two years later he re- 

 moved to Heidelberg, where he spent 

 three semesters, working under the di- 

 rection of Bunsen and Kirchoff. He 

 then returned to Groningen, and a few 

 years after he became assistant to Pro- 

 fessor Bosscha at Delft, where he com- 

 menced work upon his thesis for the doc- 

 torate. In 1882 he and H. A. Lorentz 

 were appointed professors of physics in 

 the University of Leiden, then a little 

 known and quite unpretentious seat of 

 learning (so far as physical science was 

 concerned), but which, as a result of 

 the collaboration of these two highly- 

 gifted young physicists, has become one 

 of the world's great centers of physical 

 research. 



While Lorentz confined his energies 

 mostly to the fields of theoretical and 

 mathematical physics, Onnes directed 

 his energies to the creation of a labora- 

 tory for experimental research. In 

 spite of great obstacles, particularly of 

 very inadequate appropriations for 

 equipment and maintenance, the inde- 



fatigable director found ways and 

 means of furnishing his laboratory with 

 the special machinery and precision in- 

 struments required for the researches 

 of the professors and their students. A 

 very important — in fact, an essential — 

 factor in this development was the es- 



1 tablishment by Onnes of a training 

 school for mechanicians, and it was in 

 the shops of this school that many of 

 the special instruments for the labora- 

 tory weie constructed. At the same 

 time the young men engaged there were 

 trained to assist the director in carry- 

 ing out the often difficult and intricate 

 operations in his experimental work. 

 On various occasions Professor Onnes 

 was thus enabled to command a force 

 of some thirty assistants, to each of 

 whom a special duty was assigned. 



The work of this great laboratory at 

 Leiden is recorded in the Leiden Com- 

 iii mi iea lions, published since 1891, and 

 includes a vast number of most impor- 

 tant contributions to physical science. 

 Among them are investigations on 

 magneto-electric effects, as well as a 

 series of most important papers upon 

 magneto-optical phenomena, such as the 

 classical one by Zeeman, describing the 

 discovery of what is now known as the 

 Zeeman-effect. But, while these early 

 investigations were all carried out under 

 Onnes's direction, they were in many 

 cases inspired or suggested by his dis- 

 tinguished colleague, H. A. Lorentz. 

 The really representative work of the 



| laboratory has been in the field of mo- 



t lecular physics, and particularly in re- 

 search at low temperature. The great 



| bulk of the Leiden Communications is 

 devoted to the records of those remark- 



I able series of researches which were 

 conceived by Onnes himself and carried 



! out under his direction. 



The history of these researches began 

 with the creation of the cryogenic lab- 



i oratory, and it may be divided into sev- 

 eral distinct stages or periods. The 



| first of these was occupied with the pro- 



| duction of liquid oxygen on a large 

 scale, and with the use of this material 

 in a three-cycle process of obtaining 



