615 
Lamp " appears sufficient to satisfy all our scruples at once, 
it is relied upon with implicit confidence, and generally- 
believed to be what its name implies. A Safety Lamp is 
wanted, it is bought, sold, used, and believed to be such, 
no one taking the trouble to test whether it is or is not what 
it professes to be. If an explosion does unfortunately occur, 
it is indeed rarely that the cause can be traced to its source 
satisfactorily, but the lamp is never once thought about, if 
the miner has his lamp all in perfect order he is said to be 
quite safe ; let us see if such is really the case. 
During the last few months I have, in conjunction with 
Mr. "Wilson, under- viewer of the Darfield Main Colliery, and 
Mr. Minto, of the Mount Osborne Colliery, conducted a series 
of experiments upon the different kinds of Safety Lamps in 
use, with a view to show their comparative merits, care 
being taken that each lamp of its kind was perfect and in 
good working order. 
These experiments were witnessed by a number of gentle- 
men connected with the various collieries in the neighbour- 
hood. A rectangular box, constructed of deal boards 12 feet 
long, and measuring 11 by 4 inches inside, was inserted into a 
flue in connection with a chimney shaft to produce a current. 
A current of pure air is sent through this box, the quantity 
and velocity of which was regulated by a small sliding door 
near the inner end. In the top of the box, about the centre, 
is a small sliding door, which on being removed discloses an 
opening of sufficient size to admit a safety lamp. Through 
this opening a lamp can be dropped into the centre of the 
"level," and can be seen through a small square of glass 
fixed in the side thereof. A service pipe of coal gas is con- 
nected by means of an India rubber pipe, which is termin- 
ated by a small, metal pipe and tap, and the gas allowed to 
play into the end of the box ; by means of this pipe it will be 
seen that the current of pure air passing through the 
