34 
erties of these gases were determined, which 
are given in the following table : 
q 
el || : q g q 
5 q is) A, ° 
= S) 8D Bb a 
Ct) () A H oO 
tee] A < Md 4 
Refractivities 
(G82) soc oaodoecode 0.1288 | 0.2345 0.968 1.449 2.364 
Densities of gases | 
((Q=39) -sodsadsc000 1.98 9.97 19.96 | 40.88 64 
Boiling points at 86.92 | 121.33° | 163.9° 
VEO WAN ss590s00000 ? i abs. abs. abs, 
Critical tempera- Below | 155.69 | 210.5° | 287.7° 
(HUIS cooncoosononen fe 
Critical pressures.... 43.5. 
meters. 
Vapor-pressure 
HOI) caamsdcoa0s000 ? ? 0.0350} 0.0467 | 0.0675 
Weight of 1 cc. of 1.212 | 2.155 3.52 
liquid. seo se00 2 2 gms. gms. gms. 
Molecular yolume...| ? ? 32.92 37.84 36.40 
In the vacuum tube neon is extremely bril- 
liant and of an orange-pink hue, and is char- 
acterized by multitude of intense orange and 
yellow lines; krypton is pale violet, and xenon 
is sky-blue. 
The five elements clearly form aseries in the 
periodic table, between the seventh and the 
first groups, that is, as a transition from the 
most negative to the most positive group. This 
is of the greatest interest, since in two recently 
published papers Ladenburg has given the 
atomic weight of krypton as about 59, placing 
the element between nickel and copper. It 
could thus find no place in the periodic table, 
as it is now understood. On the other hand, 
as determined by Ramsay and Travers, the 
elements find a natural place in the eighth 
group, as a transition from the negative series 
of the seventh group to the positive series of 
the first group. 
Uo lbp 1ef 
THE RESIGNATION OF PRESIDENT MENDEN- 
HALL. ; 
Men of science everywhere will learn with 
deep regret that Dr. Thomas C. Mendenhall 
has been compelled by ill health to resign the 
presidency of the Worcester Polytechnic In- 
stitute. Fortunately President Mendenhall’s 
health has only been injured by the great 
amount and responsible character of the work 
he has undertaken, and there is every reason to 
believe that after rest in Europe he will return 
prepared to continue work as important as that 
which he has already accomplished at the Ohio 
SCIENCE. 
(N.S. Vou. XIII. No. 314. 
State University, the Imperial University of 
Japan, the U. S. Signal Service, the Rose Poly- 
technic Institute, the U. S. Coast and Geodetic 
Survey and the Worcester Polytechnic Insti- 
tute. It is known to all men of science that, 
while occupying executive positions of great 
responsibility, President Mendenhall has car- 
ried out scientific researches of the utmost im- 
portance, and has taken an active part in all 
movements for the advancement and diffusion 
of science in the United States. He is one of 
the most efficient members of the National 
Academy of Sciences and of the American Asso- 
ciation for the Advancement of Science, of which 
he has been president. He is now president of 
the American Metrological Society, chairman of 
the Massachusetts Highway Commission and a 
leader in many important scientific movements. 
As one of the editors of this journal since its 
reorganization six years ago his services haye 
been invaluable. The grounds of President 
Mendenhall’s resignation, the reluctance with 
which it was accepted and the great value of 
his work at the Worcester Polytechnic Insti- 
tute is shown by the following letters. The 
letter of resignation, dated October 15, 1900, is 
as follows : 
Hon. Stephen Salisbury, 
President, Board of Trustees. 
Worcester Polytechnic Institute : 
Dear Sir: 
I hereby tender my resignation as president of the 
Worcester Polytechnic Institute, to take effect on the 
first of July next. 
I send this communication so long in advance in 
order to afford ample time for the selection of a suit- 
able person to fill my place, and I hope I may be al- 
lowed to add a few words in acknowledgment of the 
continued and unvarying kindress which the board 
of trustees have shown me during my connection with 
the institute. 
As far as I can now remember every suggestion I 
have made relating to the management of the insti- 
tute has been approved by the board and every plan 
for its betterment that I have submitted has received 
its cordial, unanimous and hearty support. My per- 
sonal relations with the members of the board have 
been, without exception, agreeable ; everything that 
they could do to make my administration successful 
and my life in Worcester pleasant has been done, and 
I cannot give measure, however much I might multi- 
ply words, to the feelings of appreciation and grati- 
