64 
tioned above, except the linen materials 
were new, and particularly strong. On 
the other hand, a smaller quantity of 
woollen would, in a less degree, produce 
the effect of preventing the paper hanging 
fire; while, from containing more linen, 
it would possess greater strength; but I 
consider the above proportion most eligi- 
ble, and combining (if the paper is pro~ 
perly manutactured) a sufficient degree of 
strength, with the property of not retain- 
ing fire. The paper should be “ engine 
sized ” with alum only, in the proporuon 
of about ten pounds to one hundred and 
twelve pounds of staff, and no oil or spi- 
rits of vitriol, or any other ingredients, 
should be put into the engine. The pa- 
per should not be picked. This paper 1s 
adapted to be cured in the usual manner 
previous to being made use of.” 
{{R. ARCHIBALD JONES (STEPNEY), for a Me- 
thod of discharging Colours from dyed 
Silks. 
This invention consists in taking one 
pint of aqua fortis, (mtric-acid, we pre- 
sume,) and diluting it with an equal quan- 
tity of water, thickened with flour, or 
any other substance, to such consistency 
as may be proper tor the blocks, with 
which the patterns are printed. After 
they are printed, they are to be put into 
a steaming box, where they are to be con- 
tinued till the discharge is brought out: 
they are then rinsed and dryed. 
Remark.—We should very much doubt, 
if the specification given by Mr. J. be 
sufficient to secure to him the exclusive 
privilege, if it be contested by any one. 
CHARLES VISCOUNT DE VAUXS (CHETSEA), 
for a Machine which will shew the Latitude 
and Longitude at Sea: it will also serve as 
a weighing and measuring Machine, &c. | 
The chief part of this machine is a hy- 
droscope, which is a double box sus- 
pended one in the other, and supported 
by an axis or horizontal pivot, hollowed 
jn the inside, which keeps the two boxes 
perpendicular in all the motions of the 
ship. The inside box contains a sort of 
clepsydra, or double sand-glass, furnished 
with one or two perpendicular scales; by 
means of these scales, which cover two 
sand-glasses, the weight of the sand, fall- 
ing in due proportion on the bottom one, 
acts upon a spiral ring fixed perpendicu- 
larly in the top of the largest box, to which 
it is joined by some wires, and a hook, 
placed in the centre of each scale: by 
these means the weight of the sand falling 
New Patents lately Enrolled. 
[ Feb. T. 
in a certain time, expresses upon a dial 
in front of the top box, and divided into 
sixty parts, or minutes of a degree, the 
quantity of miles run by a ship accord- 
ing to its velocity. But the continual va- 
riation of that velocity is expressed upon 
another dial placed upon the side of the 
frame, which supports the double box. 
A globe of an equal specific gravity with 
the water is plunged in the sea, about the 
middle of the ship, which has a commu+ 
nication with the inside of a room in the 
ship, where the hydfoscope stands, by a 
cord or cham through a cylinder, A 
cord or chain passing over a pulley or 
crank enters the tube or pivot of the 
boxes. In this tube the chain joins a 
band or rod of brass, which passes through 
a brass collar, in which the sand descends 
from one glass to the other. The band of 
brass has a longitudinal opening equal to 
the extent of the attraction of the globe 
upon another spiral spring, placed hori- 
zontally in the same tube on the other 
side of the brass collar; so that the greatest 
velocity of a ship being supposed to be 
twelve miles in an hour, the ship going at 
that rate, a globe of six inches in diame- 
ter cannot receive in the water a greater 
resistance than i@ib., or ilb. per mile, 
as the spiral spring shews upon its rod. 
The rod of the spiral spring expressing 
12\lb. or twelve miles, not coming out of 
the spring more than four-tenths of an 
inch for that weight, or for that resistance 
of the water upon the globe than the lon- 
gitudinal opening made in the band or 
rod, which passes through the communi- 
cation between the two glasses, permits 
the sand to fall accordmg to the ve- 
locity of the ship, and stops it entirely 
it the ship is at rest. If this hydroscope 
is used on land instead of the sea, or in 
a ship merely for a time-keeper, then the 
sand will always run at the same rate, 
and express regularly the time upon the 
interior circle of the dial divided in twen- 
ty-four parts, and it will be suffered to 
wind, that is, to turn the box or clepsy- 
dra every twenty-four hours. 
By the same principles of the weighing 
clock, the same dial which serves on the 
side of the hydroscope for weighing the 
resistance of the fluid, or the run of a 
ship, if this dial is taken separately, with 
its spiral spring, is a convenient machin 
to use instead of scales for weighing any 
commodities: it requires no weights, nor 
any other scales ; it never entangles like 
scales, and is said tu be as sure and con- 
yenient as it is ornamental. This ma- 
chine will likewise become an excellent 
perpetual 
