June 7, 1373.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
969 
SOME RECENT PROPOSALS RELATING TO 
HEATING AND LIGHTING. 
Whatever may be the position of our country as 
regards the study of the sciences, there can be no 
question as to the activity of the British inventor. 
The philanthropist and the commercial man, the 
amateur and the professional, are all busily working 
their brains to devise new plans, and for the most 
part their*fingers, to make their schemes known to 
the public. We seem, like the Athenians of old, to 
“ spend our time in nothing else but either to tell or 
to hear some new thing.” The inventors proceed in 
very various ways. One will, after much thought and 
many experiments, bring out his method carefully 
elaborated and supported by a strong mass of evi¬ 
dence. Another is fired by an idea, and without 
apparently thinking about it at all, or trying a single 
experiment, snatches up a pen and “ writes to the 
Times ” or other paper, leaving the details to be 
arranged by men of less genius but more practice. 
We propose to examine a few of the plans which 
have recently been suggested as improvements in 
heating and lighting, with especial reference to the 
scientific laws affecting them. 
The first was made known in a letter to the Times 
of October 18th, 1872, under the heading “Supple¬ 
mentary Fuel,” by the Rev. Henry Moule, so well 
known for his labours in the sanitary field. He pro¬ 
poses to cover the bottom of an ordinary grate with 
lumps of chalk to a depth of from two to six inches, 
and light the fire; as usual on the top. Whilst sym¬ 
pathizing with him in his desire to benefit his fellow- 
man, and not doubting for a moment his accuracy in 
reporting the results of his experiments, we are bound 
to say that he appears to have entirely misunderstood 
the real bearing of the question, and that his letter 
exhibits a lamentable want of acquaintance with 
elementary chemical facts. Take the following pas¬ 
sage as an example :—“ With those who have ever 
noticed or read of the great specific heat of chalk, or 
the large amount of carbonic acid contained in it, 
and the convertibility of that acid by means of heat 
into carbonic oxide (a combustible form or substance) 
... or the effect in smelting ore of a few hundred¬ 
weight of limestone or chalk, it has long been a 
matter of strong persuasion that the time must come 
when, at least for domestic purposes, chalk, if not 
limestone, shall be made subservient to the increase 
of warmth and heat and to the diminution of the 
consumption of coal.” Now, passing over the am¬ 
biguous use of the term “ specific heat,” there are in 
these few lines two errors of the first magnitude. 
Taking the latter first; chalk or limestone is not used 
in smelting as supplementary fuel, but merely as a 
flux; that is to say, in order to obtain a readily 
fusible slag. But for its use in this capacity, the 
smelter would gladly dispense with the limestone, 
which, far from serving as fuel, actually appropriates 
a considerable quantity of heat. But the first error 
is perhaps more important. Carbonic acid is not 
convertible into carbonic oxide by means of heat. 
A reducing agent is also necessary, and since ordi¬ 
nary combustion is a process of oxidation, reduction, 
the reverse of this, maybe called unburning. Taking 
carbon as the reducing agent, the change may be re¬ 
presented in chemical symbols, thus,— 
C0 2 + C = 2CO, 
so that every forty-four parts of carbonic acid require 
Third Series. No. 154. 
twelve parts of carbon to reduce them to carbonic 
oxide. Mr. Moule seems to have been misled by 
confining his attention to the bare fact of the com¬ 
bustibility of the carbonic oxide thus obtained, 
neglecting the consideration of the quantities con¬ 
cerned. It is true that the carbonic oxide will bum 
and thus give out a large amount of heat, but this is 
due entirely to the carbon employed in reduction, as 
we have seen above. The combustion of the car¬ 
bonic oxide would be represented by the symbols 
2CO + 0 2 = 2C0 2 . 
Now if these two sets of symbols be put together we 
have,— 
(1) C0 2 + C = 2CO, 
(2) 2CO -f 0 2 = 2C0 2 , 
or combining them,— 
C0 2 + c 4- 0 2 = 2C0 2 , 
from which it is evident that no heat is derived from 
the carbonic acid, or, which is the same thing, from 
the chalk employed. Indeed, heat is actually re¬ 
quired to be expended in tearing asunder the chalk 
into its constituents, carbonic acid and lime, besides 
a considerable quantity employed in volatilizing the 
water always present in chalk. Mr. Moule seems to 
have been aware of this without really apprehending 
its import, for he says in a subsequent part of his 
letter, “ the only thing to be guarded against is that 
of allowing the fire to sink so low that there shall 
not be sufficient heat in the coal to continue to ex¬ 
tract carbonic acid from the chalk, in which case the 
fire becomes dull.” A statement towards the end of 
his letter that chalk thus used “of necessity saves 
fourteen times its bulk of coal,” is to us utterly in¬ 
comprehensible and no explanation is given. 
But although Mr. Moule’s theory appears to be 
erroneous, his observed facts may be accounted for 
in another way, as indeed was indicated by Dr. 
Attfield in the Times of the next day. The heat 
evolved by burning fuel in a common grate passes 
off by three channels, by conduction through the 
walls and surroundings of the grate, by convection 
with the products of combustion, and by radiation. 
The proportion passing by the first of these cannot 
be materially changed except by a radical alteration 
of the principle of construction and fixing of the 
grate, and does not concern us at present. The heat 
taking the second course goes, or should go, wholly 
up the chimney, and is manifestly wasted, except 
that it may warm the walls through which the 
chimney passes, and is serviceable in maintaining 
ventilation. The third portion of the heat, that 
radiated, is principally concerned in warming our 
apartments, and any device which will transfer heat 
from the second to the third channel, will effect a 
corresponding economy. Mr. Moule’s plan does this 
in two ways : by increasing the radiating surface, and 
also by diminishing the draught, and in consequence 
the quantity of heated air passing up the chimney. 
The lessened draught gives us a lower temperature in 
the grate which must be compensated by a larger 
mass of incandescent fuel, but the proportion of heat 
radiated is greatly increased, effecting a saving of fuel 
which may amount to 40 or 50 per cent. Of course 
there is a limit to the reduction which can be made in 
the draught, for, if too much diminished, the products 
of combustion would not be efficiently removed, and 
the fire would not be properly supplied with air. The 
only question we have now to ask, before quitting 
this part of our subject, is whether chalk is the best 
