207 
If I had to travel much by railway through that district, 
I should like to wear magnetic railway spectacles, and a 
magnetic respirator in dry weather. 
Mr. Charles Bailey, as bearing upon the subject intro- 
duced by Mr. Sidebotham, drew attention to some experi- 
ments which Mr. Charles Stodder, of Boston, U.S., had been 
making on the microscopic contents of the atmosphere of 
that city. Amongst other investigations he was led to 
examine a fine black dust from a beam in the polishing 
shop of the United States Armoury, at Springfield. He 
found it to contain a few vegetable fibres, some apparently 
organic fragments, and some broken crystals ; but the great 
mass of it was made up of amorphous fragments of iron, of 
the 1-100 m.m. and upwards in size, as well as curved and 
irregular fibres and masses of iron with sharp jagged edges, 
from 5 to 15 m.m. in size; there were also some very minute 
perfect spheres, probably iron. In trying the effect of a 
magnet upon this dust, he found it removed it from a sheet 
of paper as completely as if it had been swept off with a 
brush, and he concluded that the non-metallic portions 
adhered to the iron particles by the thin layer of oil with 
which all the particles of dust were coated. 
To prevent this dust passing into the atmosphere of 
cities, Mr. Stodder recommended a plan which had been put 
in practice many years ago in this country, but abandoned 
from the indifference of the workpeople, viz., the fixing of 
magnets in the immediate neighbourhood of grindstones 
and polishing wheels. 
In the same report, Mr. Stodder alludes to the labours of 
two members of this Society — Dr. Angus Smith and Mr. 
J. B. Dancer — in examining the contents of the air, and 
points out an important matter considerably affecting the 
results of such investigations, viz., the method employed for 
filtering the air through water. The usual method has been 
