386 Progress in Science. (July, 
and that the miner will thus eventually be relieved of one of the most 
fatiguing and dangerous branches of his work. 
An improved form of safety-lamp, which appears to offer considerable 
advantages, has been constructed by Mr. H. D. Plimsoll. At the base of the 
lamp is an air-chamber in form of a truncated cone, the upper rim of which 
closely surrounds the wick of the lamp. The bulk of this cone is occupied by 
the oil-reservoir, and the space between the outside of this vessel and the 
inner wall of the conical cavity is reduced to a width of about one-eighth of 
aninch. Air is admitted to this chamber through very minute orifices in a 
metal plate, and passes through the narrow space to the wick. The brilliant 
light thus obtained is not dimmed by any cage of wire-gauze, for the flame is 
merely surrounded by a cylinder of thick glass. Should any fire-damp enter 
the lamp, the quantity is said to be too small to break the glass by its explo- 
sion. The flame cannot be communicated to the exterior, as it is cooled 
down by the metal walls of the narrow air-chamber, while the explosion inside 
the lamp at once extinguishes the flame, and thus prevents the lamp becoming 
red-hot. If the air be very dangerous, Mr. Plimsoll cuts off all communication 
with the outside, and connects the air-chamber of his lamp with a reservoir of 
pure air, and as soon as this supply is exhausted the lamp is necessarily 
extinguished. As the light is brilliant there is not much temptation for the 
miner to unscrew the top; but should he do so, a self-extinguishing arrange- 
ment comes into play and effeually thwarts his obje@. 
Air-compressing machinery has of late been very successfully applied to 
underground haulage and ventilation at the Ryhope Colliery, in Durham; and 
a valuable description of the machinery, by Mr. W. N. Taylor, has been pub- 
lished, with ample illustrations, in a recent number of the ‘* Transactions of 
the North of England Institute of Mining Engineers.” The moving power is 
a 150 horse-power steam-engine, with two horizontal cylinders, each 32 inches 
in diameter, and having a 5-foot stroke. This engine is placed at the surface, 
and works two air-compressing cylinders, each 33 inches in diameter, with a 
stroke of 5 feet, dire@ly connected with the piston-rods of the steam-cylinders. 
The air, after passing through four receivers, is finally conveyed to a double 
hauling engine with two cylinders, 14 inches in diameter, and working with a 
stroke of 18 inches. This engine is placed underground, and effects the 
haulage by means of a rope-drum with spur-gear. A large and economical 
power is thus available underground, and can be readily direéted to any part 
of the workings; manual labour in hewing and putting the coals may in this 
way be readily superseded. The compressed air is also a valuable ventilating 
agent, freeing any working-place from gas, and lowering the temperature of 
the workings so that our deep mines may be wrought with much more conve- 
nience to the men and profit to the owners. 
It has long been held by Mr. Godwin-Austen, Mr. Prestwich, and some 
other distinguished geologists—although staunchly opposed by the late Sir 
R. I. Murchison—that coal-bearing rocks may exist at comparatively moderate 
depths beneath the newer rocks in the south-east of England. To decide 
this point an experimental boring is about to be undertaken in the Wealden 
area. The spot selected for the experiment is at Archer’s Wood, near Battle, 
the property of Lord Ashburnham, who has nobly given the site, and has 
further aided the undertaking by a liberal subscription. This boring will prove 
by actual experiment what are the charaéters and thickness of the strata imme- 
diately beneath the Ashburnham beds, or the lowest series of the Wealden 
formation, in Kent and Sussex. At the same time it will decide whether 
palzozoic rocks can be reached, at this locality, within a depth of 2000 feet ; 
and, finally, whether the carboniferous strata of Belgium and North-Eastern 
France extend across the Channel, as has been suggested, and are continuous 
with some of our western coal-fields. The care of this scientific undertaking, 
which is one of great national importance, is entrusted to a committee of some 
of our most eminent geologists, and the work will be commenced at once, so 
that something may be done before the British Association visits Brighton. 
A subscription-list has been opened, and large sums have already been 
