684 L I G II T. 
cjuently nearly filled with water; hut it rifes gradually as 
the gas enters it, and difplaces the water ; the two weights 
LL fufpended over pulleys by chains keep it fteady, and 
prevent its turning round ; otherwife the lower flays M 
of the gazometer would come into contact with the vefiel 
H. There are two fets of thefe flays ; one fliown at M, 
and the other at N. There is alfo an iron pipe O made 
fall in the centre of the gazometer, by means of the flays, 
which Aides over the upright pipe P, by which contrivance 
the gazometer is kept firm and fteady when out of the 
well; it likewife prevents the gas from getting into the 
caft-iron pipe P, and the copper pipe R, any where but 
through fmall holes made in the pipe O at S, at the top 
of the gazometer, where the gas is perfectly tranfparent 
and fit for ufe. The pure gas enters the tube O at the 
fmall holes made in its top at S, and pafles on through 
the tubes P and R to the lamps, where'it is confumed and 
burnt. The feams of the gazometer are luted to make 
them air-tight, and the whole well painted infide and out, 
to preferve it from rult. 
Fig. a Chows an horizontal fefilion of the lower hoop of 
the gazometer K at the part M, with its flays or arms, 
and the manner in which the iron pipe O, before defcribed 
at fig. j, Aiding on the tube P, pafles through the ring in 
the centre of the hoop; an horizontal leition of the re¬ 
ceiver H appears therein. 
Fig. 5 (hows a feftion of one of the gas-lamps; the 
fpace between the outer tube T and the inner tube V, is 
to be filled with gas fttpplied by the pipe R, fhown in fig. 
i, where a flop-cock is inferted for adjufting the flame, 
which gas pafles through a number of fmall holes made in 
the cuter edge of a circular plate, fliown at fig. 6, which 
unites the tubes T and V at their tops. V is the inner tube 
which conveys the atrnofpheric air into the centre of the 
flame; the upper part of this tube is made conical, or wi¬ 
dening outwards, to join a circular plate with holes in it, 
a horizontal view of which is fliown at fig. 6. W is a but¬ 
ton, which can be placed at a fmall diftance above the 
mouth of the lamp; and its ufe is to convey, in an ex¬ 
panded manner, all the air which rifes through this tube 
to the inner furface of the flame, which aflifts the combuf- 
tion very much ; this button may be fet at any convenient 
diftance above the tubes of the lamp, as it Aides in the 
crofs bars XX, by which it is fupported in the inner tube. 
A current of air alfo pafles between the glafs tube or 
chimney and the outer tube T, through holes made in 
the bottom of the glafs-holder, as in Argand’s lamps ; 
this furrounds the flame, and completes its combuftion, 
as explained by the view fig. 3, and fefition, fig. 4,' which 
have a glafs upon each. ZZZZ, figs. 3, 4, 5, and 6, (how 
the tube through which the lamp is fupplied with gas 
from the pipe R, fig. 1. Each lamp confumcs fix cubical 
feet of gas per hour. 
Mr. Clegg’s-communication has the merit of being the 
firft complete defcription of an apparatus of Englifli con- 
flrucfion, for producing coal-gas, which has yet been 
made public, from which one might be made without 
leaving the formation of any part to conjecture, with the 
exception of the mode in which the fcrevv is to be ap¬ 
plied for fattening the lid of the retort: what the fcrew 
turns in through the centre of the lid at B, fig. 1, we 
cannot conjecture; we fliould rather think it mutt be faf- 
tened by a fcrew, or two fcrews, at the fide. Neither are 
the dimenfions of the apparatus mentioned in the defcrip¬ 
tion ; but, a {Turning the length of the inverted vefiel as a 
ftandard, which is the only part vvhofe capacity is noted, 
the proportions of the different parts, as taken from the 
plate, will be thus: The gas-holder fix feet in diameter, 
and 6 1 , feet high ; the retort about five feet long, and 
in diameter ; the firft condenfer two feet in diameter, the 
fecond immerfed vefiel i-g- in diameter; and the inverted 
vefiel, or gas-waftier, two feet long and about one foot 
broad ; the pulley, over which the chains work, which 
jfaife the gas-holder, feet in diameter ; the well 7 feet 
iieep; the flue of the chimney 9 inches acrofs, and the 
fpace between the retort and the brick-work 6 inches, ex¬ 
cept over the fire-place, which is 18 inches long, and 10 
deep. A gazometer, containing feven hundred cubical 
feet of gas, weighs about 20 cwt. and cofts about 2I. 10s. 
the cwt. The whole of an apparatus complete, capable 
of fupportiug forty lamps for four hours, each lamp af¬ 
fording light equal to ten candles of eight in the pound, 
will coft about two hundred and fifty pounds. 
The gazometer or gas-holder alone in this apparatus 
feems objectionable, id being made needlefsly ftrong, as 
it is dated to be formed of wrought-iron plates , and is be- 
fides ftrengthened by two very powerful iron frames in¬ 
fide, when it is not liable to any great preflfure internally 
or externally, or to any friCiion which would require all 
this ftrength. For a common apparatus on a fmall fcale 
a cafk would probably do very well for this part, as the 
water with which it would be always in contact would 
keep it {launch. The filver medal 6f the Society for 
Arts, &c. was prefented to Mr. Clegg for this communi¬ 
cation. 
The next apparatus we fliall notice is by Dr. Stanciifte. 
A vefiel of caft-iron, forming the retort, is fet in brick¬ 
work in any proper furnace; it has a rim caft in the_ fame 
piece, inclofing the top of it, fo as to make a deep groove 
all round in the top of the vefiel. I11 this groove the 
head of the vefiel is received ; and, to make the fitting 
air-tight, a quantity of fufiblealloy k placed in the groove : 
this melts by the heat of fire, and forms a fluid luring, 
which prevents the efcape of the gas. For this ingenious 
invention of luting on the head, Dr. S. has taken out a 
patent. There is a tube leading from the head to the re¬ 
frigeratory ; the joining of this tube with this vefiel is 
formed by a joint, on a fimilar priaciple to the joining of 
the head with the retort ; a tube pafles through the lid of 
the vefiel, and another is fixed concentric to and furround- 
ing the former at a fmall diftance. The fpace between 
thefe is filled with water; and the tube, which connefts 
with the head, is immerfed in the water, which forms the 
joint round the pipe, and by this means the tube and the 
head of the retort can be removed together, to take out 
the coke, and introduce frefti coals. The refrigeratory is 
made in two divifions, one above the other; the tube 
goes down nearly to the bottom of the lowelt divifion, 
and the gas bubbles up from the end of it through the 
water with which the lower partition is partly filled : it 
then pafles out at a pipe to the burners. Thefe mud not 
be of fuch a number as to confume the gas fo fall as the 
retort produces it ; by this means it will be under a con- 
fiderable preflure in the vefiel, which is found conducive 
to the feparation of the tar, &c. 
Fig. 7 is an apparatus by Mr. B. Cooke of Birming¬ 
ham, communicated by him to the Society of Arts, and 
rewarded by them, in May 1810, with a filver medal. A 
is a common fire-place or ftove, built with brick, having 
caft-iron bars to put the fire in at, and a flue that goes 
into a chimney ; above A is the caft-iron pot, (which 
holds from twenty-five to one hundred pounds of coal, 
according to the fize of the premifes to be lighted,) which 
hangs by the bewels or ears on a hook, fufpended by a 
chain in this ftove or furnace, about three inches above 
the bars of the grate, and three inches diftant from tha 
Tides of the ftove; the fire then flames all round this pot, 
and, as it does not reft on the burning fuel, it is the llamo 
only that heats it, fo that it does not fcale, hut will lati 
for years. The fmoke, &c. is carried off into a chimney. 
The cover D of the pot'is made rather conical, to fit into 
the top of the pot clofe, and from the top of the cover 
the elbow-pipe proceeds as far as the mark a. The other 
end of the pipe with the elbow entering the water-joint is 
rivetted to it afterwards ; when the lid or cover of the 
pot is put on, the bewels or ears come over the elbow of 
the pipe that is on the lid, and a wedge is put between 
them and this elbow, to keep down the cover air-tight; 
and a little clay or loam may be luted in the joint, if any 
gas fliould efcape round the cover of the pot. The other 
elbow^ 
