477
on ^ 1S ^ er (P^ ace d on the lid of the cask), furnished with two perforated shelves,e at e and another at d; which divide the interior of the filter into three com-394 partments. Into the lower space immediately over the shelf <?,
the tube b } furnished with a stopcok, enters, to esiablish acommunication with the cask ; the middle cavity e is filled withcoarsely ground charcoal or other filtering materials; and theupper one has an eduction pipe, V. When the stopcocks of thetubes a and 6’are opened, the water passes from the cistern intothe oil cask, occupies from its density always the lowest place,and presses the oil upwards, without mixing the two liquids;whereby first the upper and purer portion of the oil is forcedthrough the tube b into the filter, and thence out through thepipe Z. When the fouler oil follows, it deposites its impuritiesin the space under the partition c, which may from time to timebe drawn off through the stopcock k, while the purer oil ispressed upwards through the filter. In this way the differentstrata of oil in the cask may be filtered off in succession, andkept separate, if found necessary, for sale or use, without run-}j e -^ an 7 risk of mixing up the muddy matter with what is clear. According to theof the water cistern n, will be the pressure, and, of course, the filtering force,v en the filter gels choked with dirt, it may be easily recharged with freslt materials.f re n ^ te ring caustic alkaline leys through linen or quartz, it is proper to exclude thecom C0n ^ act °f a > r i which is done by enclosing the upper vessel, and attaching a pipe of] e „ s mu uication between its cover and the shoulder of the lower vessel or recipient of theit jJjj te Proportion as these flow down, they will displace their bulk of air, and drivethe top of the upper vessel above the foul leys,bm c any te°fiifications of the above described apparatus are now on sale in this country;of a ei ' la tnly the neatest, most economical, and effective means of transforming the waterlatent i? nant pool into that of a crystalline fountain, is afforded by the Royal
jijn filters of George Robins.
met a i|- ARMS, Manufacture of. This art is divided into two branches, that of theing a as * c an, i °f the wooden work. The first includes the barrel, the lock, and the mount-ain] i n 0 .tee bayonet and ramrod, with military arms. The second comprises the stock,] ° w ling pieces, likewise the ramrod.
end' t . ae Rnrreh ft s interior is called the bore ; its diameter, the calibre; the backpin’of .oeeech; the front end, the muzzle ; and the closing of the back end, the breechprj Ce( j f teg- The barrel is generally made of iron. Most military muskets and low-tettnd ® UI } S are f as fiioned out of a long slip of sheet-iron, folded together edgewise' T fiite if Saewer into a cylinder, are then lapped over at the seam, and welded at asel eciet j j. The most ductile and tenacious soft iron, free from all blemishes, must befitenace *° r s bp- R is frequently welded at the- common forge, but a proper air-° r nind e ansWers better, not being so apt to burn it. It should be covered with asheshtandri] ^ shape of the bore is given by hammering the cylinder upon a steel
for f 0 In a groove of the anvil. Six inches of the barrel at either end are left open% Put f 1 ? t * le fi re ech and the muzzle by a subsequent welding operation; the extrem-?°fever ) tbe ® re filing stopped with clay, to prevent the introduction of cinders,■ttto altern -® 1 * 1 ?f two inches there are from two to three welding operations, dividedtee f°rmer atll r an( l ^ ow ** eats > tee l atte r being intended to correct the defects ofh°rn 0 f ' The breech and muzzle are not welded upon the mandril, but upon thetn a<I e SQ e atu 'il; the breech being thicker in the metal, is more highly heated, and istee groove V 'fV' V * l * er to save l a b° r t0 tee borer. The barrel is finally hammered inav ery llvn . tee anvil without the mandril, during which process it receives a heat
for
r y two
touske
minutes. In welding, the barrel extends about one third in length; and
but for cavalry pistols, only 9
teche s ls eventl| ally left from 3 to 3J feet long;
ho^\ best iron plates for gun-barrels are those made of stub iron, that is, of old
lrOIl platfiS for guii-ucmcia ait U1U3C uiauc «-M oittv Liictt »o, uut
H -1 0n e tim e !/ We ^ e d together, and forged into thin bars,.or rather narrow ribands.Scribed f r amascus barrels were much in vogue; they were fashioned either as above^ riband 1 mat * e °f bars of iron and steel laid parallel, and welded together.
^ e lded togeth 8 0 * same damascus stuff coiled into a cylinder at a red heat, and then
r ticted of stnh a V^ e s ? ams * The best modern barrels for fowling pieces are con-r s °metitnes le nai * lr ? n manne1 '. The slip or fillet is only half an inch broad,
v end whifd? ,,an< * * S ^ dicker at the end which is to form the breech, and thinnermoderated J S form the-muzzle, than in the intermediate portion. This fillet.
Jhral direction t0 * ncrease its pliancy, is then lapped round the mandril in a
^rlap a little in a P r °per length of cylinder is formed; the edges being made toorder to give them a better hold in the welding process. The coij