¥idter, 
—_—— 
S46 
The Society of Arts have published a 
description of 
a filter by Mr Moult, which consists of a vessel in whi 
Mc Mowlt’s the foul water is contained, and a bason of 
ats 
ering 
Mr Hem- 
pel’s. 
Harman 
& Dearn’s 
gravel 
filters, 
stone bei in it, the water will percolate 
the stone into its cavity, from whence it can be taken 
up clear and fit for use ; or the filtered water may be 
drawn off, by means of a curved leaden pipe, to reach 
over the edge of the bason and act as a , with a 
cock at the lower end. By this plan of filtering the water 
into the bason, the d it is not left on the stoné, and 
will therefore be less liable to clog ‘up a . The 
same principle was proposed by Mr Collier; his ma- 
chine Laer nd ofa pes or rh A vessel to contain the 
foul water. Within this vessel cylindrical tubes of earth- 
en ware are fixed ; these tubes are closed with a hemi- 
spherical end, but the other end, which is open, is ap- 
plied to the sides of the vessel, and closely Imted there- 
to, so thet no water can gain entrance into the vessel, 
without first penetrating through the substance of the 
tube. A was provided in the side of the vessel, 
opening within the tube to draw off the pure water. Mr 
Collier proposed also to fill up the vessel with pieces of 
broken ery, which, by presenting a great surface, 
would allow every facility to the deposition of the gross 
impurities of the water, and thus avoid the clogging up 
of the filter, and also render the process more expedi- 
trous. a 
A patent was granted in 1790, to Mr Hempel for a 
method of making filtering vessels or basons, from a spe- 
cies of pottery; the composition of which was four parts 
of tobacco pipe clay, mixed up with five of coarse sea, ri- 
ver, or drift sand. For large vessels, this composition 
is found liable to crack in the burning, equal parts of 
the clay and sand were therefore recommended ; and if 
this was found insufficient to prevent the tendency to 
cracking, one-ninth part of Stourbridge clay, or of old 
crucibles broken down and pounded, was to be added: 
the basons were turned in a potter's lathe, in the usual 
manner. 
The filtering stones most commonly used are not the’ 
best kind, as they are too expensive, hable to be broken; 
and will not produce so great a quantity of filtered wa- 
ter as others, which, in imitation of the great natural 
filters, have beds of gravel and sand for the water to 
pass through. A very ane apparatus for domestic 
use, consists of a cylindrical vessel of pottery, provided 
with a cock to draw off the clear water ; upon this is 
fitted another cylindrical vessel, having a globular bot- 
tom, which is pierced with small wales a stratum of 
coarse gravel is first spread in the vessel, over this a 
stratum of fine gravel, and above this fine sand. If the 
bottom of the vessel is covered with a coarse cloth, to keep 
the sand from running through the holes in the bottom, 
the gradations of gravel and sand will be rendered less 
necessary, A plate of earthenware, or a board, is laid 
upon the sand, and being perforated with holes, allows the 
water to pass, but prevents the disturbance of the sand 
when the foul water is poured in upon it, and in per- 
colating through the sand it is filtered. The fineness of 
the sand and the thickness of the bed will be regulated 
yy experment ; and it is one of the greatest advan 
this construction for a filter, that it can be so 
adapted to the of filtration which the water re- 
ires, the bed being made thick if the water is very 
i, and diminished in proportion to its purity, by 
which means tek ee can be pas- 
sed “ym i my ter. cane ae changed 
every 1 or three w to keep apparatus 
perfectly sweet and clean, 
FILTER. 
The late ingenious Mr Bramah, had a patent for va 
rious modes of conveying and ing off beer and 
other liquors, in he describes a filtering appara~ 
ed to ‘in the pipes to conduct 
was a cyl vessel, made of cop~ 
troduced to the vessel near the lower part to i 
the liquor, and from near the u end a si 
proceeded to convey it away. Between these 
fixed the filtering floor, consisting of flannel, 
bags, sponges, or porecagisar man se ich 
sp u a horizontal plate pierced full of 
holes, end ited .in-the oplinnleh dade abe ering : 
stance ; another similar plate was fixed and 
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lower pipe by means of a pump or otherwise, and as~ 
cending through the inecing Same passed off in a clari« 
fied state: the impurities which ¢ collect in 
the conical bottom of the. cylindri ssel, whence 
; 
a 
vessel, 
they can be drawn off by a cock. This contrivance 
adapted to give a slight filtration to a great quantity of 
patent for a method 
liquor, such as beer. 
n 1791, Mr Peacock took out a 
the filtering bed. Mr Peacock tor 
sandy gravel, sand, broken and pulverised glass or 
tery, &c. These were to be C +o 
ings, and then sorted by sieves into a number of differ- 
ent sizes ; these are to be spread in different layers, be- 
ginning with the largest and spreading the smaller par- 
ticles over these, in a regular gradation, until the finest 
is at the top. This arrangement is better than that 
have before spoken of, when the water 
through the finest, being less liable to choke 
Professor Parrot of Paris, invented a filter v 
acting both by the ascent and descent. It is 
in the Philosophical Journal to consist of a 
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filters through the sand, and passes off. At the top 
the lowest leg, it is recommended to have three inches 
of difference een the level of the two surfaces of 
the water, and eighteen inches of pure sand for the 
water to h. When the section of the tube was 
four inches by two, that is eight square inches, it would 
pass six Paris pints of pure water every hour, 
Mr John Isaac Hawkins has contrived a filtering 
apparatus, which we consider as better adapted for do- 
mestic } 
; ' 4 is to be 
compel of Shrconl, pounded tesa Cnre sad 
as 
and above this, other ‘increasing in size, 
which are as ease; the wh 
vered with a board wtb haked to: edenit 
~~ 
Mr Pea- 
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