OCTOBER 22, 1897.] 
presence of any second gas in purified ar- 
gon; from what has been known as ‘pure 
helium,’ however, this process finally iso- 
lated a heavier gas which showed the spec- 
troscopie characteristics of argon. No ex- 
perimental evidence has so far been ob- 
tained for a gas with a density of 10. 
The address concludes with a discussion 
of the probable position of argon in the 
Periodic System, the argument being along 
the same lines as that previously put for- 
ward by the author in his work, ‘ The Gases 
of the Atmosphere.’ Attention is called to 
the fact that the differences of the atomic 
weights of elements following one another 
in any one Series are quite irregular, vary- 
ing in the Lithium Series from 1.0 to 3.0, in 
the Sodium Series from 1.0 to 3.5, fete. 
Again, in the Silver Series iodine undoubt- 
edly follows tellurium, and yet all the re- 
cent determinations of the atomic weight 
of the latter element unite upon a figure 
almost a unit above that of iodine ; just as 
density-determinations indicate an atomic 
weight for argon nearly one unit higher 
than that of potassium which follows it in 
the System. The author concludes that the 
relative weights of the atoms of elements, 
while indicating roughly their position in 
a perfect Periodic System, are not to be 
taken as the absolute criterion of their 
relative sequence. As itis not possible in 
this short review adequately to discuss this 
matter, the reader is referred to the author’s 
own statement of the argument.* 
In the course of the Meeting Professor 
Ramsay presented (1) a paper dealing with 
the process employed in the separation of 
gases of different densities by fractional 
diffusion, and (2)—for Mr. Morris Travers 
—a proof of the fact that the hydrogen 
evolved on heating minerals in a vacuum 
is due to the decomposition of water me- 
chanically held and is not present in the 
form of any other compound. In a paper 
* SCIENCE, Oct. Ist, pp. 493-502. 
SCIENCE. 
615 
before the Physical Section he called atten- 
tion to the great delicacy of refractivity- 
determinations as a means of deciding upon 
the purity of light gases. 
The superiority of the oxalate method 
for the separation of thorium from the 
other elements with which it is usually 
associated was demonstrated by Professor 
Brauner, who also presented the results ob- 
tained in a redetermination of the atomic 
weight of the metal. Professor T. W. 
Richards reviewed his recent very impor- 
tant work upon the atomic weights of 
cobalt and nickel, explaining the methods 
of purification of the salts employed and 
the apparatus in which they were got ready 
for weighing. Professor Meslans gave an 
interesting exhibition of the properties of 
free fluorine prepared according to the 
method of Moissan, but in a vessel of 
copper, instead of platinum, and sur- 
rounded by a freezing-mixture of ice and 
solid carbon dioxide. A very brief paper 
by Professors Moissan and Dewar on some 
of the physical constants of liquid fluor- 
ine was read by Professor Meldola. 
Other papers on inorganic chemistry were 
those of Mr. E. C.C. Baly, on the formation 
of a compound when mercury falls in a 
finely divided state through an atmosphere 
of oxygen, and which appears to contain 
the oxygen in the form of ozone ; of Dr.C. 
A. Kohn, on the electrolytic determination 
of copper and iron in oysters, reminiscent 
of the recent ‘oyster scare’ in Great 
Britain ; of Professor W. W. Andrews, on 
the great increase in the rapidity and ac- 
curacy of blowpipe determinations through 
the use of tablets of plaster of Paris instead 
of charcoal ; of Professor Dunnington, on 
the occurrence of titanic oxide in soils; 
and of F. T. Shutt, on analyses of Canadian 
virgin soils. 
In the field of organic chemisty the most 
interesting paper—perhaps the most striking 
communication presented at this meeting of 
