H. KAMERLINGH ONNES, 1853-1926! 
By F. A. FREETH 
Prof. Heike Kamerlingh Onnes, whose death on February 21 will 
be widely regretted, was born on September 21, 1853, in Groningen. 
As a youth he attended a school in that town, of which J. M. Van 
Bemmelen, who later became professor at Leyden, and whose name 
will always be remembered in connection with colloid chemistry, was 
principal. 
In 1870 Onnes became a student at the University of Groningen, 
and from 1871 until 1873 he worked under Bunsen and Kirchhoff at 
Heidelberg. He remained in Groningen until 1878. His doctoral 
dissertation was entitled ““ New Considerations on the Axial Changes 
of the Earth,” and was marked by the combination of theory and 
accurate experiment which is characteristic of all his later works. 
In 1881 he became influenced by the theories of Van der Waals and 
wrote an important paper in which he deduced the law of corre- 
sponding states from considerations of statistical mechanics. 
In the following year Onnes became professor at Leyden. In his 
inaugural address he insisted that the laws of physics could be de- 
termined by accurate experiment alone. His motto “From meas- 
urement to knowledge” was then stated for the first time, and his 
remarks upon the necessity of the then recently designed pumps of 
Cailletet and Pictet for the attainment of low temperatures were 
almost prophetic. It was about this time that Onnes planned his 
cryogenic program, which has since made his name famous through- 
out the world. In 1894 he published his first paper on the design and 
equipment of the Leyden laboratories, and in his inaugural address 
in 1894 he laid down the importance of accurate measurements at 
very low temperatures. 
The formation of the cryogenic laboratory at Leyden was only 
made possible by the extraordinary energy and tenacity, combined 
with organizing talents of a very high degree, which Onnes brought 
to bear on this subject. Asa preliminary it was necessary for him to 
train mechanics and glass blowers, and as a result of many years 
of patient work he obtained an organization which is still unique. 
In 1904 Onnes was able to control large supplies of liquid air. By 
+ Reprinted by permission from Nature, vol. 117, No. 2940, Mar. 6, 1926. 
20837—27——_35 533 
