38 
POPULAR SCIENCE REVIEW. 
bodies of water in London which contribute moisture. These 
may be noticed as constituting a local cause of fog. Indepen- 
dently of the local cause of fog, which, no doubt, may always 
be mitigated to some degree, there remains the permanent cause, 
which arises from the geographical position of England — a com- 
paratively small island surrounded by the sea — and that is a 
cause over which we can have no control.’ Whereas another 
authority’s confession of faith ‘ consists in stating that London 
fogs are due to London smoke — are, in fact, frequently made 
up of smoke, and nothing else ; and that if we could get rid of 
smoke we should probably be rid of fogs at the same time.’ 
Probably the truth lies somewhere between these two 
extremes ; the correlative remedies being better drainage, and 
more perfect and economical combustion of our bituminous fuel. 
The former reform must be left in great measure to public 
bodies — such as the Metropolitan Board of Works. The latter 
is to a great extent in our own hands, and will amply repay 
closer attention than it now obtains. The mere use of coke 
instead of coal for domestic fires, if sedulously and perseveringly 
insisted on in opposition to the prejudice and obstinacy of ser- 
vants, will achieve much. In time Dr. Siemens’s apparent para- 
dox that it is better and more economical to divide our raw coal 
preliminarily into two manufactured products, gas and coke, 
before recombining them in a properly constructed hearth, may 
prove a truth of practical application, and may be made to save 
for use many costly by-products now lost and allowed to do 
injury. Captain Galton makes a good suggestion, — 
‘ Open spaces should be created. Of course, if we could cut 
London in two from north to south by a broad open space, as 
it is cut in two from east to west by its river, it would do 
something to break up the cloud of smoke. In the year 1 852 
Sir Joseph Paxton proposed to carry a broad boulevard round 
London. It was a very feasible scheme in those days ; it is a 
pity it was not carried into effect. Open spaces carefully under- 
drained, and so situated as to favour the circulation of air 
through the centre of London, would form a most important 
feature in promoting the health of London, if such things were 
possible.’ 
It remains to be seen how far his proposed object will be 
furthered by the great arterial streets from Holbom to the 
Strand now in contemplation. 
As regards the decarbonization of domestic smoke the ques- 
tion is more arduous. In our household fire-places the tempera- 
ture is never very intense, the supply of air ample ; the smoke 
is evolved only because the temperature is not high enough to 
cause ignition and combustion of the gas and suspended car- 
bon. It is not practicable in any open fire to get a sufficiently 
