i879-1 
Its Present and its Future . 
63 
thousands of examinations of the air in all parts of the 
country, and directs Government interference where persons 
and property are too much imperilled by atmospheric con- 
tamination. In Glasgow a city analyst has been recently 
appointed with this special duty. New York is already 
showing the effeCt of the sulphurous and nitrous vapours 
sent out from its myriad chimneys. Recently the U. S. 
Signal Officer, in his room at the Equitable Insurance 
Building, took out from a carefully wrapped package an 
instrument which he desired to show me, and it was hope- 
lessly corroded by the acid vapours sent out from the tall 
chimney of the United States Assay Office near by. In 
Philadelphia there is scarcely a house-front which is not 
disfigured by some stain of magnesia and lime-salts, a result 
in part due to the acid vapours in the atmosphere. And 
when rains sweep down and carry with them in solution 
such agents, they are more powerful to corrode metal, and 
even stone surfaces, than would at first appear credible. 
When one of the normal constituents of the atmosphere is 
wanting — the ozone — it has largely lost its sweetening and 
disinfecting powers, and there is much reason for believing 
that the prevalence or severity of certain diseases is inti- 
mately connected with the varying amounts of ozone in the 
atmosphere. Unfortunately there is much difficulty in esti- 
mating the percentage of this constituent of the air, and in 
guarding against the disturbing influences upon our deter- 
minations of other bodies possibly present. To overcome 
these difficulties experiments have been on foot in the labor- 
atory of the Stevens Institute of Technology for many 
months. Numerous analyses of the atmosphere, collected 
in various parts of the United States, have been made and 
recorded. They will serve as contributions towards a begin- 
ning of a chemical climatology of this country, and might, 
with great profit to the physician, the agriculturist, and 
meteorologist, be vastly extended by Government aid in 
connection with the Signal Service and the Department of 
Agriculture. We cannot do unaided as much in researches 
of this character as can be done in the laboratories of the 
Old World by Government assistance, but we can at least 
labour in the hope that the time is not distant when the 
importance of research of this kind, even if it does not end 
in a profitable invention, will be generally understood and 
generally encouraged. 
