806 
NEW ELEMENTS FOUND IN AIR. 
In the last few years it has been found 
that ordinary air contains some elements, 
the existence of which had not even been 
suspected. For nearly three-quarters of a 
century it was supposed that we knew all 
about the composition of the air, but in 
1892 Lord Rayleigh found that a globe 
filled with atmospheric nitrogen weighed 
more than the same globe filled with nitro- 
gen made from chemical compounds con- 
taining nitrogen, and this observation fol- 
lowed up led to the discovery of argon, an 
inert gas, present to the extent of about 
one per cent. in the air. Then efforts were 
made to find argon in mineral substances ; 
certain minerals that were supposed to give 
off nitrogen on heating were heated in 
vacuous vessels and thus helium was dis- 
covered. Recently Professor Ramsey has 
found two other inert gases in air besides 
argon; he obtains them by the fractional 
evaporation of liquid air, and he has named 
them neon and kripton. Quite recently 
it has been claimed that the mineral pitch 
blende contains the elements radium, 
polonium and actinium, and that these 
elements emit rays that are capable of pro- 
ducing skiagraphic images on sensitive 
plates, and of discharging electrified bodies. 
PROGRESS IN INDUSTRIAL CHEMISTRY. 
Hand in hand with the development of 
scientific chemistry and the discovery of 
new compounds has gone the improvement 
of manufacturing processes and the methods 
of industrial chemistry. At the beginning 
of the last century potash was the chief 
alkali, and this was obtained from wood 
ashes. Leblanc invented a method of 
obtaining soda from salt, and for many 
years this was the only way of getting 
alkali on the large scale. Now this method 
has been almost entirely replaced by the 
Solvay or ammonia-soda process, and it is 
very probable that before many years this 
SCIENCE. 
[N. S. Von. XIII. No. 334: 
in turn will be replaced by the electrolytic 
process of obtaining alkali from salt solu- 
tions. There is a constant evolution of 
new methods in chemical industry, the 
older processes have to give way to more 
economic and perfect methods. For more 
than one hundred years, all the sulphuric 
acid that is used has been made in lead 
chambers, and one improvement after the 
other was added to this process until it was 
brought to a high state of perfection; but 
now, with the opening of the new century, 
the sulphuric acid manufacturers are pull- 
ing down their lead chambers. A new and 
better method of making the acid has been 
devised. Sulphur dioxide and air are led 
over finely divided platinum and the result- 
ing sulphur trioxide is conducted into 
water. It has long been known that sul- 
phuric acid can be made in this way on the 
small scale in the laboratory, but it is only 
recently that the principle has been adapted 
to the commercial preparation of the acid. 
Heretofore the difficulty has been that the 
contact substance, the finely divided plati- 
num, soon lost its activity. Now it has 
been found that this can be overcome by 
carefully purifying the gases before they 
come in contact with the platinum, and 
that, by keeping the temperature of the 
interacting gases below the point of decom- 
position of the sulphur trioxide, the action 
can be carried on indefinitely and on the 
commercial scale. The resulting sulphur 
trioxide is led into water and sulphuric acid 
of any degree of concentration obtained. 
Other important changes in industrial 
chemistry have been brought about by the 
application of electricity to the preparation 
of chemical elements and compounds. 
Places like Niagara Falls that have abun- 
dant water power for the production of elec- 
tric currents are rapidly becoming the seats 
of important chemical industries. The 
electric current is at present used chiefly 
in two ways in inorganic chemistry. First 
, 
