1811.) 
Mr S. proceeds with the fine linen and 
worsted cloth, which answers for the 
- Back or grotind of the auleum}; this 
fixed in the frame or otherwise suspend- 
ed in length and breadth, either perpen- 
dicular, leaning, or horizontal, it then 
receives a considerable quantity of glue, 
together with a Sinall portion of water 
colour; these two ingredients warmed 
into a proper consistency of heat, and 
laid on with a brush, at once form a 
flexible parchment: | the operation ~ of 
the brush gives lassitude to every thread ; 
the cloth will) then expand nearly an 
inch in every foot; the frames must be 
then extended in all directions to the 
utinost extent that the worsted or linen 
will admit of. When thoroughly bard 
or dry, another process commences, the 
parchment undergves some considerable 
friction from pumice-stones, all promi- 
nent threads and superfluous glue 
is cleansed off, and then what follows, 
is a thin coat of colour, as nearly as 
possible to the colour of the flock in- 
tended for the face of the auleum: the 
whole piece of parchment being thinly 
covered, the flock is put into a sieve 
and dispersed over it, which still con- 
tinues strained to a very high pitch, the 
aulzum is then dressed on the under 
side, and the fluck diffuses and regularly 
adheres to the composition until finish- 
ed, The aulawum is then dried, by a 
very strong fire which takes off the effluvia, 
Se 
MR. JOHN ISAAC HAWKINS’, (GREAT 
TIVCHEIELD-STREET,) for a certain 
instrument applicable in Mechanics us 
a Balance or Equipoise. 
_ The nature of this invention, and the 
manner in wlich the same is performed, 
are best described by the drawings 
attached to the specifications; but per- 
haps the following account may give the 
reader some insight-into the subject: 
Tnstead of a weight commonly used to 
counter-balance or equipoise a lamp, 
chandelier, lustre, window-sash, shutter, 
&c. a steel spring is employed, such as in 
a. spring-clock, is called a main-spring, 
one end of which is attached to a fixed 
axis, and after coiling this spring around 
the axis, it is fastened by the other end 
to a barrel, which has rotation on the 
axis, as is done in a spring clock, It is 
nown that if a small weight be sus. 
pended by a line or chain, to the cir- 
cumference of the barrel, the barrel 
will be turned a small distance, but to 
wake it turn farther, a larger weight is 
essary. This spring and barrel is 
Garetore not an equipoise or balance, 
Monturxy Mac, No, 212. 
‘ 
Patents lately Enrolled. 
865 
but requires an addition to constitute 
it such, for which reason a fusee is fast~ 
ened to one end of the barrel: this 
fusee is so formed, that when the spring 
is slack, or nearly so, and consequently 
very weak, the line or chain, which 
Supports the weight, shall hang near the 
axis; but as hy the rotation of the 
barrel, the spring is wound up and be- 
comes stronger, the said line or chain 
shali recede upon the fusee from the 
axis, and thereby~ procure a greater 
power of purchase upon the spring, and 
this in. such ‘proportion as) that the 
spring shall support any given weight 
when hung to the line or chain in all 
situations. The same effect may be 
produced by fixing the barrel instead of 
the axis, and letting the fusee with the 
axis be turned, instead of the barrel being 
turned. This machine may be made of 
iron, brass, steel, or any kind of hard 
metal, or other hard substance; and in 
order to bring it into action it must of 
course be fixed in Some situation Capa- 
ble of supporting its own weight, and 
the weight of the thing to he balanced, 
and the whole machine may be conceal. 
ed by any covering or ornament, which 
fancy may suggest. In some cases two 
Or more machines are placed on one 
fixed axis, for the purpose of counter 
balancing two or more window-blinds, 
or weights of any description. For some 
purposes it will be requisite to have two 
or more lines or chains, and consequent. 
ly to make the rusee with double or 
multiple grooves; or to have two or more 
fusees. For other purposes it may be 
convenient to put the spring and barrel 
on oné axis, and the fusee on another, 
and to employ a line or chain to connect 
them together, as well as one going 
round a cylinder fixed to the fusee, to 
Support the weight to be counter-ba- 
lanced. The shape of the fusee must, 
in all cases, be determined by the va- 
rying power of the spring; and the 
thickness of the line or chain. A sim- 
ple rule to find this shape is’ to take 
account of the actual weight which the 
spring will support at every half or 
quarter turn of the barrel, the weight being 
suspended from the circumference of the 
barrel, Multiply this weight by the 
tadius of the barrel, and divide the sum 
by the weight designed to be suspended 
from the fusee, the quotient will shew the 
distance at which the line or chain ought 
to hang from the axis, and consequent 
ly will determine the shape of the fusee, 
In the case of lamps, in which the weight 
is perpetually varying, a small spring 
3A is 
