REV. W. THORP, B.A. — AGRICULTURAL GEOLOGY, ETC. 235 
ised, and can be cut off from the remainder of the pit. The ventila- 
tion of the other panels can be continued without detriment, and thus 
practically instead of the air being required to circulate twenty or 
thirty miles, as is frequently the case under the ordinary system of 
working, it is cut off into separate lengths of three or four 
miles each. Mr. Thorp stated that if there had been a separate 
air-course from the downcast pit to the workings south of 
the throw, during the explosion at the Oaks Pit, a great many 
lives would have been saved. Objection was taken to the custom of 
keeping tie air in the goafs or worked out parts of the pit where the 
roof has fallen in, walled up or " dead," as it is termed. They con- 
sidered it was much preferable to keep a circulation of air through 
them, and carry away any slight accumulations of gas rather than 
confine them, with the great risk at some time of their bursting forth 
and setting fire to the pit. Another danger reverted to is due to 
sudden small outbursts of gas called " blowers," which give no notice 
of their approach, but insidiously accumulate, often during the night, 
a very considerable quantity of gas. In board gates it is usual for 
the men to fire the gas, which is accumulated, but in the neighbour- 
hood of goafs, or where the ventilation of the pit is not very perfect, 
this is an extremely dangerous operation. The paper was concluded 
by suggestions calculated to diminish the risk of accident. The 
most important were considered to be the appointment of Government 
Inspectors, who should make an absolute rule that the ventilation in 
every mine should be conducted on the best principles known, and 
- all reasonable means of preventing accidents should be enforced ; 
the size of the furnace should be increased so as to secure proper 
ventilation ; and the coal worked in detached portions of moderate 
size, so that no air-course shall be of greater length than four miles ; 
that the goafs should receive greater attention, and if walled in the 
present manner should be carefully tested at frequent intervals for 
the presence of fire-damp, and no naked lights should be used. 
A communication by the Rev. William Thorp, on the iron-stones 
in the Oolitic district of Yorkshire, was made at Pontefract in 1855, 
in which he compared the iron-stones of North Yorkshire with those 
of the Yorkshire coal-field. In order to show the comparative valu^ 
