793 
MECHANICS. 
to the bottom. It will be proper to have a cock on this 
funnel. There thould alfo be another pipe in the top of 
the boiler, having a valve on the top. If this be loaded 
with a pound on every fquare inch, and the fire fo regu¬ 
lated that fteam may be obferved to puff fometimes from 
this valve, we may be certain that it is palling through our 
difhes with fufficient rapidity ; and if we fhut the cock 
on the funnel, and load the valve a little more, we fhall 
caufe the fteam to blow at the covers of the ftew-pans. If 
one of thefe be made very tight, and have a hole alfo fur- 
nifhed with a loaded valve, this pan becomes a digefter, 
and will diflolve bones, and do many things which are im¬ 
practicable in the ordinary mode of cookery. For the 
whole of this fedtion we are indebted to the Encyclopaedia 
Britannica. 
IV. Heating Rooms by Steam .—Steam has been fuccefs- 
fully applied as a fubftitute for open fires in heating ma¬ 
nufactories; and promifes to be highly beneficial, not only 
in point of economy in faving fuel, but alfo in leflening 
the danger of accidental fire. Mr. Niel Snodgrafs, of John- 
ftone, Renfrevvftiire, Scotland, received, in May 1806, the 
reward of forty guineas, which had been propofed by the 
Society of Arts, for this objedt, in the preceding year. 
This mode of heating rooms will, perhaps, be mod dif- 
tindtly explained by a brief hiftory of the firft ideas of 
Mr. S. on the fubject ; of his attempts to put them into 
practice; and of the fucceflive improvements which have 
been fuggefted to him by experience. 
In April 1798 he was engaged by Meflrs. Mackintofh 
and Dale, to manage a cotton-mill near Dornoch, in the 
county of Sutherland. He remained in Glafgow for fix 
months after this, fuperintending the conftruCtion of ma¬ 
chinery for the mill. During this period he was led to 
confider of a cheap method ot heating the mill, as he had 
learnt that fuel was extremely fcarce and dear in the coun¬ 
try in which the mill was fituated. It was evident that 
none of the methods which he had feen praCtifed could be 
applied, but at an enormous expenfe ; and his experience 
had pointed out to him important defeCts and inconveni¬ 
ences in them all. Having obferved a mode of drying 
muflins by wrapping them round hollow metal cylinders 
filled with fteam, praCtifed at the bleach-fields near Glaf¬ 
gow, it occurred to him, that, by means of a proper appa¬ 
ratus, fteam might be applied to heat a cotton-mill, or any 
other large manufactory. It was evident that this not 
only would be an economical mode of producing heat in 
large works, fo far as fuel w'as concerned, but that it would 
prevent the danger of fire, to which fuch works, when 
heated in the ufual manner, are muchexpofed. He com¬ 
municated his notions to a number of cotton-fpinners and 
others, from whofe fuggeftions he expected aftiftance. 
But he met with nothing but difeouragement, the projeCt 
being every-where treated lightly,or pronounced to be im¬ 
practicable. Strongly imprefled, however, with the ad¬ 
vantages of the plan, he perfevered in his refolution to 
make trial of it, and ordered tin pipes to be made for the 
purpofe. Thefe he ereCted in the mill in May 1799. 
When filled with fteam, they at once produced the necefi- 
fary degree of heat; but the pipes, having been damaged 
in the carriage, proved not fufficiently ftrong. Indeed 
Mr. S. was immediately fenfiftle, that their pofition was 
unfavourable. With a view to fotne conveniences in 
point of room, they had been carried up diagonally in one 
end of the mill, whence the upper fides ot the pipes be¬ 
came fooner heated than the lower, which caufed an un¬ 
equal expanfion. The water arifing from the fteam con- 
denfed in the pipes in its return to the boiler, and alfo ob- 
ftruCted the fteam in its afeent. In order to remedy thefe 
defeCts, the pipes w'ere altered, and ereCted in a perpendi¬ 
cular pofition ; and certain tubes were connected with them, 
to carry off the water arifing from condenfation. The 
.whole apparatus,- as it ftood after this alteration, is repre¬ 
fen ted on Plate XXXII. 
Fig. 133. prefents a view of an inner gable, which is at 
one extremity of the working-rooms of the mill. On the 
Vol, XIV, No. 1014- 
other fide of this gable there is a fpace of feventeen feet 
enclofed by an outer gable, and containing the water- 
wheel, the ftaircafe, and fmall rooms for the accommoda¬ 
tion of the work. In this fpace the furnace and boiler are 
placed on .the ground. The boiler cannot be fnown here, 
as it lies behind the gable exhibited ; nor is it of any con- 
fequence, as there is nothing peculiar in it. A circular 
copper boiler, two feet diameter, by two feet deep, con¬ 
taining thirty gallons of water, with a large copper head, 
as a refervoir for the fteam, was found to anfwer in the 
prefent inftance. The feeding-apparatus, &c. are in every 
refpedl the fame as in the boiler of a common fteam-engine. 
The (team is conveyed from the boiler through the gable, 
by the copper pipe B, into the tin pipe C C. From G it 
paffes into the centres of the perpendicular pipes E, E, E, 
by the fmall bent copper tubes D, D, D. The pipes E, E, E, 
are connected under the garret-floor by the tubes F, F, for 
the more eafy circulation of the fteam. The middle pipe E 
is carried through the garret-floor, and communicates with 
a lying-pipe thirty-fix feet in length, (the end of which is 
feen at G,) for heating the garret. At the farther extre¬ 
mity of the pipe G, there is a valve falling inwards to pre¬ 
vent a vacuum being formed on the cooling of the appa¬ 
ratus ; the confequence of which would be the crufhing 
of the pipes by the prelTure of the atmofphere. Similar 
valves, K, K, are placed near the top of the perpendicular 
pipes E, E; and from the middle one E, the fmall pipe 
paffes through the roof, and is furniflied with a valve at I, 
opening outwards, to fuft’er the air to efcape while the 
pipes are filling with fteam, or the fteam itfelf to efcape 
when the charge is too high. The water condenfed in the 
perpendicular pipes E, E, E, trickles down their fides into 
the three funnels L, L, L, the necks of which may either 
pafs through, or round, the pipe C, into the copper 
tube M M, which alfo receives the water condenfed in C C, 
by means of the fiiort tubes N, N. The pipe C C is it¬ 
felf fo much inclined as to caufe the water to run along 
it to the tubes N, N; and the pipe G in the garret has an 
inclination of eighteen inches in its length, to bring the 
water condenfed in it back to the middle pipe E. The 
tube M M carries back the water through the gable to the 
boiler, which ftands five feet lower than this tube. It is 
material to return the water to the boiler, as, being nearly 
at a boiling heat, a confiderable expenle of fuel is thereby 
faved. The large pipes are ten inches in diameter, and 
are made of the fecond kind of tinned iron plates. The 
dinrenfions of tire (mailer tubes are feen by their compa¬ 
rative fize in the figure ; and perhaps they might be varied 
without inconvenience. 
The apparatus eredted as here deferibed, was found 
fufficiently ftrong, and had required no material repairs 
up to the year 1805, when the prefent communication was 
made to the Society. The leading objedt being to fave 
fuel, in order to derive as much heat as pofiible from a- 
given quantity of fuel, the flue from the furnace, which 
heats the boiler, is conveyed into common ftone pipes 
placed in the gabie. Thefe are eredted fo as to prevent 
any danger of fire, in the manner fhown at fig. 134. The 
fteam with this auxiliary communicates a heat of about 70 0 
to the mill, the rooms of which are 50 feet long, 32^ feet 
wide, and 8^ feet high, except the lower ltory and garret; 
the former of which is 11, and the latter 7, feet high. 
The rooms warmed in this manner are much more whole- 
fome and agreeable than thole heated try the beft-con- 
Itrudled ftoves, being perfedtly free from vapour or con¬ 
taminated air. 
By various experiments it appears, that the expenfe of 
fuel is fcarcely one half of what is neceflary to produce 
the fame degree of heat with the beft-conftructed ftoves. 
Mr. S. was the better able to make the companion, lince 
he had previoufly had five years experience of cotton- 
mills on what was, at that time, reckoned the molt ap¬ 
proved plan. 
There are obvious defects in the application of the 
principle, as pradtifed in the inftance delcribed above. Of 
9 Q fom e 
