NEEDLE. 
mode drawn Into the lungs, producing many diforders, 
and in very few years prove fatal to the operators. In 
grinding the needles, the points muftbe laid on the grind- 
Itone, as nearly under that part of the tube which goes 
over the top of the done as convenient, for which purpofe 
the tube is made to move backwards or forwards, fo as to 
fuit the molt convenient part of the grindftone employed 
by the workman. There is a great advantage arifingfrom 
r blowing the air out of the room, as any ftagnation of air is 
thus prevented ; and, the whole quantity being blown out 
in a very few minutes, there will always be a renewal of 
frelh air, which will be very falutary to the workmen, par¬ 
ticularly if confined in a Imall apartment. 
This contrivance confilts of a conical box or cafe, iri- 
clofing nearly one-half of the grindftone, to receive the 
dull of fteel and (tone, made in the operation of grinding, 
which is caufed to enter the box by a current of air pro¬ 
duced by a pair of bellows. The needle-grinding mills 
are generally very extenfive buildings, with numerous 
apartments, each containing many grindftones for point¬ 
ing needles, all which are driven by one powerful water¬ 
wheel, or other firft mover. And the bellows, which are 
employed in Mr. Prior’s plan to carry oft' the duft, might 
be made large enough to fupply all the grindftones con¬ 
tained in one room, or even one wing of the mill. A A, 
fig. 2, reprefents a large wheel, giving motion to the 
grindftone by a band apaffing round a pulley B, fixed on 
the axis orfpindle of the grindftone C, (which is fupported 
in'the ufual manner, though not here fhown.) The great 
wheei is reprefented in the drawing as if mounted in a 
frame D D, to be turned by. a handle, on the oppofiteend 
of thefpindle, in the fame manner as the wheels ufed for 
turning lathes or cutlers’ grindftones; but, in the needle- 
mills, this large wheel is part of the mill, and is generally 
fituated beneath the floor of the room in which the 
grindftones are placed, being fixed on a long horizontal 
Fiaft, which carries feveral fuch wheels, each giving mo¬ 
tion to one grindftone. Upon the end or any other con¬ 
venient part of this (haft a crank E is fixed, which, by 
means of a rod F, gives motion to a pair of double bellow's 
G, conftruCted and aCting in the fame manner as thofe 
ufed for organs, being contrived to keep up a conftant 
and regular fupply of air. They confift of two diftinCt 
parts, G and H. The lower one is the feeder, and throws the 
air into the upper one H, which is the regulator, to equa¬ 
lize the current of air, and make it conftant. The feeder 
G confifts of two boards ; the upper one, ff, fixed, and 
the lower one, ee, moveable on hinges at its joint, by 
means of the rod F, as before defcribed. It is conne&ed 
with the upper board by leather, furrounding all its fides, 
and neatly folded. In the lower board c e is an aperture, 
covered by a valve (called by the organ-builders a pallet), 
opening inwards to permit the entrance of the air, but to 
prevent its return : through the upper board ffis another 
opening, with a valve Ihutting downwards ; through this 
the air paflhs into the regulator H, which is alfo made 
with two boards connected by hinges and leather, in the 
fame manner as the feeder; from the regulator the air 
paffes off to the grindftones by a trunk K, extending 
along the whole length of the mill immediately beneath 
the floor. When the lower board re of the feeder is de- 
prefled by the motion of the crank E and the rod F, the 
chamber of the feeder is enlarged, and the external air 
opening the valve in the board ee, fills the cavity. When 
the board is lifted up, this valve clofes, and the contained 
air is forced through the valve in the board/ - into the re¬ 
gulator, the repetition of which motion keeps a conftant 
fupply of air in the regulator. The top board del of this 
is loaded with weights, which, refting upon the included 
air, forces it out from the regulator, in an equable 
ftream, through the trunk K, and from that to every 
grindftone in the mill. N O O P is an afiemblage of tin 
pipes, which fnrround the grindftone, and have openings 
in the fronts of them, through which the air iltues, to 
carry off the duft. This is Ihown fepqrately at fig. 3, 
Voh, XVI. No. 1145. 
677 
where M reprefents a brafs focket, which is fuppofed to be 
fixed to the floor, and by means of a fmall pipe communi¬ 
cates with the wind-trunk K; into this the end of the pipe 
N is fitted, and, the other end of it being fupported by the 
point of a ferew Q, it turns on this as a centre ; the two 
pipes O O are foldered into this at right angles, and are 
united at the top by the fliort pipe P : in thele pipes fmall 
flits or crevices are made, as Ihown by the dark lines, 
through which the air iflues, and, blowing towards the 
grindftone, carries off the particles of duft into the trunk 
R, fig. 2, which may.be continued forward at S, through 
the wall of the building, into the open air; or, if it is 
turned fideways, as at T, all the trunks R of the other 
grindftones may be carried into it, which will fucceed 
better, becaufe the whole body of air, being thus carried 
through one common trunk, and being thrown out into 
the open air in one place, will have the greater force to 
carry the duft with it. I is a fafety-valve, covering an 
opening in the top of the upper board dd of the regu¬ 
lator : it is kept fnut by a wire fpring, and has a wooden 
handle or tail L, by which it may be lifted up. When 
the board of the regulator rifes as high as is intended, 
this tail comes in contact with a piece of wood, and thus 
opens the valve, permitting the air toefcape; by which 
means there is no danger of the bellows being burft, for 
this valve is always opened when the regulator becomes 
full, fo as to be in any. danger of a rupture. The pipes 
O O P, as before mentioned, turning on a centre, can be 
moved nearer to the grindftone at pleafure, as it becomes 
reduced in diameter by w'earing away. 
3. Mr. Thomas Roberts, of Dumfries, propofes to ob¬ 
viate this inconvenience by removing the noxious dull: 
by means of a fly-w'heel, or ventilator. His invention was 
rewarded by a prefent of ten guineas in the feflion of 
1815. The model which was fent to the fociety is de¬ 
fcribed as having its fans, each four inches long, in a di¬ 
rection parallel to the axes, and one inch and a quarter 
broad. Though the cylinder where the fans move is four 
inches in diameter, a cylinder in the middle is left open 
for a continual fupply of air. When the wheel is .turned 
eighty times in a minute, fixteen and a half cubic feet of 
air would be difeharged, admitting that part of the cylin¬ 
der containing the fans to be ventilated each turn¬ 
ing. A machine, having the fan-box fixteen-inches cube, 
would ventilate at the rate of nearly 1100 cubit feet in 
one hour. 
Fig. 4 reprefents the machine in perfpeCtive: a, the great 
wheel giving motion to the whole, which, on being made 
to revolve, (by means of the connecting bands,) turns 
the fmaller wheels, b and c; b is a fmall wheel attached to 
the arbor or axle, d; upon this arbor is the grindftone, e; 
c, is a fmall wheel upon the axle of a fan wheel, fliut up 
within the box,/ - . Figs. 5 and 6 are leCtions of the fame, 
fhowing the interior of the fan-box, with the paffages for 
conducing and difeharging the duft. The grindftone- 
being in aftion, as reprefented by fig. 4, fmall particles of 
fteel or duft will pafs down the funnel, g, in which the 
grindftone hangs, and thence through the circular aper¬ 
ture into the fan-box, (part of the funnel being removed 
in fig. 6, to fhovv this,) which aperture may be contracted 
by the Aiding Flutters, h, h. Fig. 7, the fan-wheel, 
marked i, i, i, i, in figs. 5 and 6, which, being turned with 
confiderable velocity, by the wheel and band (feen at c, 
fig. 4), impels the wind and duft out through the open¬ 
ing, h, at the back of the fan-box. Fig. 6 likewife exhi¬ 
bits a method of tightening the bands by ftiifting the 
centre of the great wheel which hangs in the Aider, /; 
this Aider, moving tipon the pivot, m, can be. raifed or 
lowered, and with it the great wheel by the wedge, n, be¬ 
ing drawn backward or forward. 
June 2, 1812, a patent was granted to Mr. John Scam- 
bler of Sheffield, for gilding of needles. It loon appear¬ 
ed, however, that a gilt needle w r ou!d not work fo well 
as a well-poliffied fteel needle not gilt. The patentee thep 
confined his gilding to the head and eye, which he pre- 
8 K tended 
