ADDRESS. lvii 
Not less wasteful and extravagant is our mode of employing coal for 
domestic purposes. It is computed that the consumption of coal in dwelling- 
houses amounts in this country to a ton per head per annum of the entire 
population; so that upwards of twenty-nine millions of tons are annually 
expended in Great Britain alone for domestic use. If any one will consider 
that one pound of coal applied to a well-constructed steam-engine boiler eva- 
porates 10 Ibs. or one gallon of water, and if he will compare this effect with 
the insignificant quantity of water which can be boiled off in steam by a 
pound of coal consumed in an ordinary kitchen fire, he will be able to appre- 
ciate the enormous waste which takes place by the common method of burn- 
ing coal for culinary purposes. The simplest arrangements to confine the 
heat and concentrate it upon the operation to be performed would suffice to 
obviate this reprehensible waste. So also in warming houses we consume in 
our open fires about five times as much coal as will produce the same heating 
effect when burnt in a close and properly constructed stove. Without sacri- 
ficing the luxury of a visible fire, it would be easy, by attending to the prin- 
ciples of radiation and convection, to render available the greater part of the 
heat which is now so improvidently discharged into the chimney. These are 
homely considerations—too much so, perhaps, for an assembly like this ; but I 
trust that an abuse involving a useless expenditure exceeding in amount our 
income-tax, and capable of being rectified by attention to scientific principles, 
may not be deemed unworthy of the notice of some of those whom I have 
the honour of addressing. 
The introduction of the Davy lamp was a great event in the history of 
coal-mining, not as effecting any great diminution of those disastrous acci- 
dents which still devastate every colliery district, but as a means of enabling 
mines to be worked which, from their greater explosive tendencies, would 
otherwise have been deemed inaccessible. Thus, while the Davy lamp has 
been of great benefit both to the public and the proprietors of coal, it has been 
the means of leading the miners into more perilous workings, and the fre- 
quency of accident by explosion has in consequence not been diminished to 
the extent which was originally expected. The Davy lamp is a beautiful 
application of a scientific principle to effect a practical purpose, and with 
fair treatment its efficiency is indisputable; but where Davy lamps are en- 
trusted to hundreds of men, and amongst them to many careless and reck- 
less persons, it is impossible to guard entirely against gross negligence 
and its disastrous consequences. In coal-mines where the most perfect 
system of ventilation prevails, and where proper regulations are, as far as 
practicable, enforced in regard to the use of Davy lamps, deplorable accidents 
do occasionally occur, and it is impossible at present to point out what addi- 
tional precautions would secure immunity from such calamities. The only 
gleam of amelioration is in the fact that the loss of life in relation to the quan- 
tity of coal worked is on the decrease, from which we may infer that it is also 
on the decrease taken as a percentage on the number of miners employed. 
The increase of the earth’s temperature as we descend below the surface 
is a subject which has been discussed at previous Meetings of the British 
Association. It possesses great scientific interest as affecting the computed 
thickness of the crust which covers the molten mass assumed to constitute 
the interior portions of the earth, and it is also of great practical importance 
as determining the depth at which it would be possible to pursue the work- 
ing of coal and other minerals. The deepest coal-mine in this district is the 
Monkwearmouth Colliery, which reaches a depth of 1800 feet below the 
surface of the ground, and nearly as much below the level of the sea, The 
