lupton: safety lamps. 
277 
By the test all these lamps are safe, as a matter of fact, they 
are all exceedingly dangerous. It is an elementary proposition that 
an experiment with a negative result proves nothing until ifhas been 
repeated a great number of times. One experiment is enough to 
prove beyond the possibility of doubt that a lamp will explode the 
gas ; it takes a hundred experiments to establish an even prima facie 
case, or a probability that it will not fire the gas. There is only one 
mode in which we can make reasonably sure that all the lamps in 
the mine are safe; and it is this, to adopt a lamp which has 
successfully passed the heaviest test a thousand times ; to make 
every lamp an exact and perfect copy of this tested lamp ; to discard 
every lamp that is damaged ; and every time after a lamp has been 
used, it must be examined by a competent person to see that it has 
not been damaged, and every time that the separated parts of a 
lamp are put together it must be done by a competent person, and 
the operation must be watched by two other persons, one of whom 
should be the collier who is going to use it, and the other an ex- 
perienced deputy or fireman. This involves some loss of time and 
some expense, on which I remark that the time is only a minute 
spent by the collier to preserve his own life ; that the expense is an 
insurance by the owner of the safety of his mine. But I submit to 
all reasonable men, that when in our anxious search after the perfect 
lamp, we discard those lamps that for two generations have served us 
fairly well, we must not blindly rush into far gi-eater and more con- 
stant danger than these from which we seek to escape ; yet this is 
what there is likely to happen under cover of a permanently fixed 
shield, imperfect lamps may be given out and returned undetected, 
until some day there is an accident of which the cause will remain a 
mystery. 
I now describe a few of the lamps. The Marsaut (see figs. 7 and 8), 
here we notice there is no ring below the glass, the glass is fixed by 
the oil-pot, this is the same in the Belgian-made Mueseler and in the 
Wolf lamp. This is in some respects a disadvantage, because it 
involves re-fixing the glass every time the lamp is cleaned — but in 
other respects it is a very great advantage, because it secures the 
glass in its position; whereas in those lamps where the glass is fixed 
