committee, which elected Mr T. Bell, H.M. Inspector of
Mines, as its chairman, with Professor P.P. Bedson and Drs Drummond and
Hume as professional advisers. The problem considered was whether the
fumes produced by the combustion of certain explosives, one of which was
roburite, were injurious to health. The trial comprised the chemical
analysis of the air at the "intake," and of the vitiated air during the
firing of the shots at the "return," and also of the smoky air in the
vicinity of the shot-holes. Five pounds and a half of roburite were used
in twenty-three shots. It had been asserted that the fumes from this
explosive contained carbon-monoxide, CO, but no trace of this gas could be
discovered after the explosion. On another occasion, however, when 4.7
lbs. of roburite were exploded in twenty-three shots, the air at the
"return" showed traces of CO gas to the extent of .042 to .019 per cent.
The medical report which Drs Hume and Drummond presented to the committee
shows that they investigated every case of suspected illness produced by
exposure to fumes, and they could find no evidence of acute illness being
caused. They say, "No case of acute illness has, throughout the inquiry,
been brought to our knowledge, and we are led to the conclusion that such
cases have not occurred."

~Manufacture.~--As now made, roburite is a mixture of ammonium nitrate and
chlorinated di-nitro-benzol. The nitrate of ammonia is first dried and
ground, and then heated in a closed steam-jacketed vessel to a temperature
of 80 deg. C., and the melted organic compound is added, and the whole stirred
until an intimate mixture is obtained. On cooling, the yellow powder is
ready for use, and is stored in straight canisters or made up into
cartridges. Owing to the deliquescent nature of the nitrate of ammonia,
the finished explosive must be kept out of contact with the air, and for
this reason the cartridges are waterproofed by dipping them in melted wax.
Roburite is made in Germany, at Witten, Westphalia; and also at the
English Company's extensive works at Gathurst, near Wigan, which have been
at work now for some eighteen years, having started in 1888. These works
are of considerable extent, covering 30 acres of ground, and are equal to
an output of 10 tons a day. A canal runs through the centre, separating
the chemical from the explosive portions of the works, and the Lancashire
and Yorkshire Railway runs up to the doors. Besides sending lar