970 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[June 7, 1873. 
material for this purpose. The result of calcining 
chalk is lime, and this seems to he a very objection¬ 
able substance to form in a domestic grate, as it 
readily breaks up into a light powder which would 
be rapidly distributed about the room, and by its 
corrosive action do much mischief. Ordinary ashes 
are sufficiently unpleasant in that way, and lime 
would probably be much worse. On the other hand 
the same result may be attained by other means. 
The draught may be effectually and without trouble 
controlled by means of an iron plate at the bottom of 
the grate in place of, or upon, the usual grating, and 
radiating surface may be supplied by fireclay balls, 
etc., or by adjusting the draught so that the mass of 
fuel may itself be sufficiently large, without an 
unnecessary consumption. 
The next scheme which we would consider is, like 
the preceding, a proposal to employ something which 
has already been burnt—an ash—as a source of heat, 
ignoring the real fuel employed. In a letter to a 
Manchester newspaper, a gentleman propounds a 
method “ by which heat may be obtained at probably 
a cheap rate, and certainly, to an inexhaustible 
extent,” namely, by the electrolysis of water, and 
subsequent combustion of the resulting oxygen and 
hydrogen. He is extremely candid, and says that he 
is “ aware that the method has been in use for some 
time in chemical laboratories,” and that his “project 
is purely a theoretical one, requiring, no doubt, 
alterations before it can become of practical value.” 
The plan is described in considerable detail; the 
collection of the gases in separate receivers, their 
conveyance by pipes to the place to be heated, the 
arrangement of the jets at an acute angle, and the com¬ 
bination of the gases “ producing a most intense heat, 
with a blue flame and an impalpable” (! !) “amount 
of steam.” The flame is to heat a fireclay ball in 
order to facilitate radiation, and the whole is to be 
protected by a perforated earthenware cover. The 
author says that the advantages of this method over 
our present system of fires, “besides its cheapness,” (!) 
are twofold—firstly, that no oxygen is removed from, 
or carbonic acid added to, the atmosphere ; and 
secondly, that that desperately expensive luxury— 
an English fireplace and chimney—may be dispensed 
with. The last sentence contains a somewhat 
mysterious statement, namely, “that the two gases 
in question never explode so long as they are present 
in proper proportions.” 
Now, the author of this scheme apparently does 
not see that the real source of his heat is not the 
water decomposed and again formed, but the fuel 
employed in obtaining the zinc or other material 
used in the battery ; and that the question does not 
turn, as he thinks, on “ whether the intense heat of 
the oxy-hydrogen flame can be so placed as to render 
incandescent the whole surface of the fire-balls,” but 
on whether his circuitous method of applying the fuel 
above mentioned admits of less waste of energy than 
other modes. 
The third proposal which we will consider is pri¬ 
marily directed to lighting, although it is said to be 
also available for heating. We refer to the air gas 
introduced by the “Air Gas Light Company, Limited.” 
Several schemes have at various times been brought 
forward for charging ordinary atmospheric air with 
some volatile hydrocarbon, so as to produce an in¬ 
flammable mixture which shall serve as a substitute 
for. coal gas. In the plan we are now considering, 
air is driven through a light hydrocarbon spirit, which 
has been subjected to a process (not made public) by 
which its proportion of carbon has been increased, as 
the light petroleum oil alone would hardly give suffi¬ 
cient illuminating power. There are four questions 
which at once suggest themselves in regard to this 
process. Can these light petroleum oils be always 
obtained at their present low price ? The directors 
of the Air Gas Light Company seem to expect to 
obtain them at a still cheaper rate ; but if their pro¬ 
cess were to come into general use it is very likely 
that the price would rise considerably, for its present 
lowness is probably due only to the absence of de¬ 
mand. Once find a use for large quantities of the 
material and the price must rise, just as did that of 
coal-tar and gas-liquor. 
Next, is the “gasogen” a substance which can be 
safely stored in quantity ? This may not be a matter 
of much difficulty if large public gasworks only are 
considered, where it would be kept and used under 
proper skilled superintendence ; but the Company 
proposes to light private residences, churches, hos¬ 
pitals, etc.; and considering the class of persons in 
whose care it would probably be placed for such 
purposes, we can hardly think its use other than 
dangerous. We may mention that the Company 
apparently recommends the “generator” to be placed 
outside the building. 
Further, can the illuminating power always be 
kept to the same standard ? It must be remembered 
that the quantity of hydrocarbon taken up by the 
air depends on the temperature and on the time 
during which the air is in contact with the liquid. 
If it is allowed to stand for some time over the 
hydrocarbon, or is passed very slowly through it, it 
would become saturated, and the quantity of hydro¬ 
carbon volatilized would depend solely on the tem¬ 
perature ; but if the current is too rapid the satu¬ 
ration would not be complete, and the amount 
volatilized would depend both on the temperature 
and on the rate of passage of the air. Therefore, to 
ensure a gas of constant illuminating power, the tem¬ 
perature and velocity must be uniform, or must vary 
proportionately. 
Our fourth question is, can the gas be distributed 
through long services of pipes without deterioration, 
that is, without depositing the hydrocarbon with 
which it has been charged ? The answer to this will 
depend on whether in its course it will at any point 
be reduced to a temperature below that at which the 
hydrocarbon which it contains would be sufficient to 
saturate the air. If this be the case, the excess of 
hydrocarbon must of course be deposited at that 
point, and the practical result would be a more or 
less rapid transfer of the “gasogen” from the “gene¬ 
rator” to the cold region by a process of distillation. 
This is precisely the way in which it happens that 
we are so often troubled with “jumping” gas-lights, 
due to “water in the pipesand we need hardly, 
point out that “‘petroleum in the pipes” W'ould be far 
more objectionable, and, indeed, dangerous. This 
can be prevented, either by giving the air a charge 
of hydrocarbon so small that it would not be suffi¬ 
cient to saturate it at the lowest temperature to which 
it will be subjected, or by keeping the temperature 
of the generator below such a point. In fact, this 
latter would probably happen in any case, for the 
volatilization of the hydrocarbon renders latent a 
large amount of heat; and we are informed that the 
temperature of the generator is so reduced, that its 
exterior becomes covered with ice from the conden- 
