360 
sivable to keep the: smoke confined toa 
passage as nearly horizontal, as; was con- 
sistent with.. that, principle 5, for, in. a 
former experiment; it had been found that, 
from the want of this caution, and in con- 
sequence of some descent, in the flue, the 
hydrogen accumulated. in it so as to burn 
like gas on the application of,a light, and 
on one occasion to cause a violent ex- 
plosion. 
In the first experiment. with the new 
flues a ton of copper was placed in the 
furnace, when at a proper heat, and the 
process of calcining commenced : the fol- 
lowing account is extracted from the letter 
of the gentleman who reports upon it :— 
*‘ The smoke issuing from the vent was 
perceptible only to a good eye looking 
against. a wood behind it; two persons 
ascended to the top of the perpendicular 
stack, whilst a workman stirred the ore in 
the farnace: whilst this was doing, two 
observers sat on the edge of the stack on 
the lee side, so that all the smoke which 
issued must pass over their faces; and 
they state that they. found no kind of in- 
conveniencies when seated on the mouth 
of the chimney.” The reporter says, 
“ Whilst I ‘stood by the furnace I could 
perceive a small issue of smoke, which 
appeared to hover for an instant at the 
mouth of the stack, but was dissipated very 
soon after it had entered the atmosphere. 
I went up to the stack and into it by 
the door, there I found a mixture of smoke 
and hydrogen gas, smelling like common 
smoke, but I inhaled it repeatedly with- 
oul experiencing any of those distressing 
sensations which always affect me when I 
inhale copper smoke, and to which you 
were once witness, as we walked by the 
crown works on a day when, the smoke 
being remarkably low, it wasimpossible to 
avoid it. I immediately went into the 
garden and procured a common plant in a 
pot in full vegetation ; this I had placed on 
the summit of the stack, and the superin- 
tendant tells me this evening, that it does 
not yet appear at all affected ; indeed, he 
declares it impossible tliat it should be ; he 
says he has no doubt remaining on the 
subject, ‘ the thing is accomplished, and 
nearly all the smoke which does escape is 
combustible ;’ he adds, ‘ it is evident that 
950 feet of such flues are sufficient to 
destroy all the noxious properties of the 
copper works.’” 
‘This experiment was made on the 23d of 
March, 1822, On the’@5th, the reporter 
proceeds as follows—‘* On opening the 
flues this morning the first and second were 
found charged with soot and a white crust, 
probably arsenic, and sulphur over the 
bottom and lower part of the sides. - Nas, 
3, 4, and 5, presented soot, with a super- 
statum of sulphur, in considerable quan- 
tities. Mr. Young thinks that the three 
flues contained from 4 cwt. to 1 cwt, of 
Report of Chemisiry and Experimental Philosophy. 
{May I, 
deposit, the 6th.and? th soot, and a smaller 
quantity..of sulphur ; the 8th coal-tar, 
which; continued to form on to, the 14th, 
gradually diminishing, accompanied by’ 
very. little, sulphur... From the 16th to 
the end, there was no.deposit worth notice, 
and \the. bricks and mortar of the 24th 
were not even discoloured. On lighting 
the furnace to-day. the smoke was. ten 
minntes in reaching the mouth of the stack. 
After the fire was well up, we threw in a 
bundle of wet straw, and observed that the 
smoke arising from its combustion appear- 
ed at the mouth of the stack in three 
minutes.” The reporter proceeds, to ob- 
serve, ‘¢ It uow appears, in the undeniable 
shape of experimental fact, that the noxi- 
ous parts of copper-smoke may _be effec- 
tually controlled and compelled to,stay, in- 
dvors without any chemistry besides. that 
which natures furnishes. Bricks and mor- 
tar, and a tolerable mason, are all the array 
of power and science which need be called 
into action. The draft in your fines. is so 
perfect, that Mr, amanager of 
copper-works, who furnished the...ore, 
cautioned the man against.allowing..the 
fire to become too intense for the process.of 
calcination; and there is no. doubt that 
several hundred feet of flue might be added 
without impeding the draft, .M.———, 
however, thinks that all which now escapes 
may be consumed by combustion;..we 
have no doubt on the subject.” ..~ ».. 
The writer of the foregoing. letters, 
having been warned against trusting;too 
implicitly to first impressions, ona single 
attempt to reduce principle into practice, 
writes on the 28th March as follows :— 
“ In the detail which I sent you,-L believe 
I did not observe, as I should hayedone, 
that the ore was as well calcined im as short 
atime, and without mere fuel, as,is used 
in the ordinary flues;—this by way of sup- 
plying an apprehended omission, Now 
for the objections which have presented 
themselves, either in the shape-of my own 
ideas or the sayings of others. It did 
occur to me that the newness of the flues 
night operate favourably in expediting the 
process of condensation and precipitation. 
It was also said, that the fresh. mortar 
would have a chemical action on the acid 
particles of the smoke, and thus neutralize 
one part of the mischief. A question has 
also been started, whether there can be 
sufficient draught obtained through such a 
length of flue to melt the ore after calcina- 
tion. On this last point I have.feit doubts, 
but the superintendant says he feels no 
doubt on the subject, and states; that, if 
any such difficulty should arise; he would 
shorten the passage without apprehension, 
becanse in the process of melting there is 
far less offensive matter -disengaged,-and 
of course léss to precipitate, than tn caleina- 
tion. It is fair also’ to take mito Consi- 
deration that our stack or chimney is not 
the 
. 
