57 
determine whether or not such an effect is produced, and 
thus settle this point by direct experiment. 
Another source of accidents at this time of the year has 
to be taken into consideration. Before Christmas and in cold 
weather there is often a brisk demand for coal, and both 
managers and men are in a hurry to increase the output, 
and under such circumstances probably there may be 
sometimes not so much care and caution exercised as are 
necessary for them to use in the dangerous work in which 
they are engaged. 
In the management of a fiery mine, in my opinion, 
1. There ought not to be any unventilated wastes. 
2. The mixed use of Davy lamps and naked lights should 
not be permitted where the former are commonly employed. 
3. Blasting of coal by gunpowder should not be sanc- 
tioned where Davy lamps are in common use. 
4. An anemometer under the care of a competent man 
should be in constant use in order to see that a sufficient 
current of air is passing through the workings to insure 
perfect ventilation of the mine.. 
5. When there are marked indications of fire damp in a 
mine, shown by a cap on the flame of a lamp, the men en- 
gaged in hewing and drawing coal should be removed from 
the pit until by ventilation the place is cleared of gas and 
rendered safe for a working collier. 
The above precautions may probably cause an increased 
cost in the getting of coal, but they are necessary for the 
preservation of human life if such catastrophes as now fre- 
quently occur are to be prevented. It is now pretty gene- 
rally admitted that all explosions of fire damp are caused 
by there being too little pure air and too much of that gas 
in a mine. 
“ Chemical Notes/ 5 by M. M. Pattison Muir, F.R.S.E., 
Assistant Lecturer on Chemistry, Owens College. 
I. On the Solubility of Potassium Perchlorate in Water. 
