SIR WILLIAM RAMSAY— MOTJREU. 543 
the periodic system the place predicted for a homolog of xenon. 
Eamsay wished to prove this by experiment. And what an experi- 
ment ! The vohime of emanation at his disposal at any one time 
never exceeded five one-thousandths of a cubic millimeter (much 
less than the smallest head of a pin), and to determine the atomic 
weight it was necessary to weigh this infinitesimal volume of gas. 
A modification of the microbalance of Steel and Grant was con- 
structed, whose sensitiveness attained several millionths of a milli- 
gram. The skill shown in preparing, purifying, and weighing the 
minute quantities of emanation was truly wonderful ; and it was this 
work more than all the others which showed Ramsay's marvelous ex- 
perimental talent. The result justified the effort. The mean of five 
determinations gave the number 223 for the atomic weight of radium 
emanation. A full and complete verification of the theoretical pre- 
dictions, which Debierne also confirmed by an entirely different 
method (diffusion) 
The brilliance of his work had brought to Eamsay the highest dis- 
tinctions not only in his own country but all over the world. 
Academies and learned societies hastened to open their ranks to him. 
Our Academy of Sciences, which had elected him a correspondent in 
1895, named him an associate in 1910. He was also an associate mem- 
ber of our Academy of Medicine. In the year 1904, the Academy of 
Stockholm awarded him the Nobel prize in chemistry. 
One of the characteristic traits of Ramsay's personality was his 
enthusiasm, which he communicated to all those who worked under 
his direction, and the impression which he produced on his students, 
even during a very brief contact, remained ineffaceable. Friendly 
and patient with all, to " do well," according to his own expression, 
was all that was necessary to become his friend. 
Ramsay was a remarkable teacher with an elegant and picturesque 
manner of expressing himself, impulsive, clear, concise, and with the 
great charm of simplicity. In his lessons he did not hesitate at times 
to use the most advanced teachings; he was the first in England to 
introduce the works of Raoult, Arrhenius, and Van't Hoff. 
Everything which lives is in a progress of evolution. The real 
life of an experimental science like chemistry is in progress and 
discovery. On this subject, Ramsay was of the opinion that he 
wanted original research to occupy early as great a place as possible 
in the work of a student. He distrusted examinations such as are 
usually held to judge candidates, which were too often dependent 
on chance. He feared especially that they might result in unjust 
and unfortunate eliminations capable of discouraging a student in 
his choice of a vocation. The professor who has followed the 
student during several years in the course and especially in the labor- 
