WATER. 



thefe being united together, will caufe them to fhut both 

 together. The aperture for this valve is of a rcftangular 

 form. 



A valve in two leaves, fuch as is called a butterfly-valve, 

 may alfo be hinged in the middle of the opening, but would 

 too much obftruA the water-way. When the main pipe is 

 of a large diameter, (for inftancc, two feet or upwards,) 

 the ftop-valve may be made in three, four, or more leaves 

 connefted together by mechanifm, fimilar to Venetian win- 

 dow-blinds. 



Another kind of valve is poifed upon an axis, like a com- 

 mon fire-ftove chimney damper; the axis does not pafs 

 through its centre, but divides it into two unequal fegments. 

 The valve is not opened fo far as to ftand in the line of the 

 current of water, but, when opened, ftands inclined to that 

 current ; fo that the larger fegment being placed towards 

 the dream, the latter may by its aftion fliut it at the proper 

 time. It is opened by mechanifm fimilar to the former. 

 Another kind of valve is a fpherical ball of porcelain, which 

 is fitted into a feat. • • u 



When the machine is made ufe of in an open river, which 

 does not admit of having its water penned up by a weir or 

 dam-head, the main pipe ought to be laid fo as to be covered 

 by the low waters of the river ; and it ought to be parallel 

 to the furface of the river, fo as to have the greateil poflible 

 declivity that can be obtained in the length of the main 

 pipe : its mouth or receiving end (hould be Ihaped hke that 

 of a trumpet or bell. In all cafes whatfoever, the valves 

 ought to be conipletely under the furface of the water, in 

 the lower refervoir. 



Performance of the hydraulic Pam, (fee Ram) — M. Mont- 

 golfier, in his publication, fays, that a belier hydraulique, exe- 

 cuted with care, is capable of rendering three-fourths of the 

 force which is employed to move it, that is, the produdt of the 

 weight of water raifed, multiplied by the height to which it 

 is raifed, will be equal to three-fourths of the produft of the 

 weight of water which works the machine, multiplied by 

 the height of the fall. Commonly it yields fix-tenths, but 

 he would only engage to furnifli half. Thus, if the water was 

 to be raifed lOO feet by a fall of 5 feet, he would engage 

 to make a machine which (hould deliver at 100 feet a 

 fortieth part of the whole quantity which fell. He recom- 

 mends particularly that the machine (hould be fixed in the 

 mod folid manner, by mafonry or timber, fo that the (hock 

 of the water can produce no motion of the machine, be- 

 caufe all fuch motion will dedudl confiderably from the 

 quantity of water raifed. It is Hated that the machine will 

 make from 20 to 120 llrokes/x-r minute. 



The dimenfions of an hydrauUc ram at the bleaching 

 ■works of M. Turquet, near Senhs, in France, when re- 

 duced to Enghlh meafure, are as follow : diameter of the 

 body of the ram 8 inches, fall of the water 3 feet 4 inches, 

 height to which the water is raifed 15 feet i inch. In three 

 minutes this machine made 100 ftrokes, which expended 

 67 cubic feet of water, and raifed 9-4: cubic feet : hence, 

 67 cubic feet x 3i feet — 223, and 9:! cubic feet x I5tV 



feet = 140. Now 



223 



is equal to -rVsths, fo that the 



effeft produced is above fix-tenths of the power applied. In 

 another experiment it was found to be 64-hundredths. This 

 machine raifed a quantity of water equal to 6.2 inches of water 

 (pouces de fontanier), for 269 litres which are nearly equal 

 to 280 pints, in three minutes ; and the pouce de fontanier 

 is a meafure of running water equal to 14 pints (French) 

 per minute, or 796.37 cubic inches, Engli(h. This ma- 



chine working 24 hours willraife 134400 pints (French), or 

 4512 cubic feet Englifh, of water to a height of 15 feet 

 I inch. The water raifed by this machine is equal to f the 

 power of a man, according to our ftandard. 



M. Montgolficr recommends the pipe or body of the ram 

 to be of an equal diameter through the whole length ; and 

 all internal irregularities are to be avoided, becaufe they 

 diminifh the velocity of the water : the ftrength of the pipe 

 (hould be at lealt equal to fuftain a column of twice the 

 height to which it is intended to raife the water. 



He fays, that he executed one with a fall of 10 feet, 

 which comprelTed the air in an air-ve(rel to an equal degree 

 with 40 atmofpheres, which, taking the prelTure of the at- 

 mofphere equal to 33 feet of water, makes the preffure 

 equal a column of water 1320 feet in height. 



Improved hydraulic Ram. — M. Montgolfier, the fon of 

 the inventor, has recently obtained a patent in England for 

 an improved hydraulic ram, in which, by attention to fome 

 minute particulars in the conltruftion, he is enabled to make 

 the length of the tube much lefs than in the former ma- 

 chines ; and he has even obtained a refult equal to 84 per 

 cent, of the power employed. 



One of thefe improvements is the addition of a fmall 

 fnifting-valve, which, at each movement, ferves to introduce a 

 fmall quantity of air into the head of the ram, from whence 

 it is driven by the next movement into the air-veflel, which 

 would otlierwife become filled with water, if the air, ab- 

 forbed by the contaft of the water under a ftrong preffure, 

 were not continually replaced by fome fuch means. 



Alfo, in the interior of the head of the ram is an annular 

 fpace, furrounding the frame of the (lop-valve : this con- 

 tains a fmall volume of air, which cannot be forced into the 

 air-veffel, but which, at each movement, is conipreffed by 

 and receives the firft effort of the moving water. This he 

 calls the air-matrafs, and by means of it, the (hutting of 

 the ftop-valve makes lefs noife, the pipe is not ftrained, and 

 all the operations take place with fo much eafe, that the 

 machine is lefs fhakcn, and lefs frequently out of repair. 

 The following is a defcription of the new machine. 



That end of the pipe or body of the ram which receives 

 the water of the refervoir is formed like a trumpet -mouth, 

 that the water may flow more readily into the pipe ; and the 

 length of the pipe muft be regulated according to the height 

 of the fall of water, which is to produce the current through 

 it. The pipe is compofed of feveral pieces or lengths 

 fcrewed together by flanches, or other fimilar means ; but 

 it is in the end piece, which is called the head of the ram, 

 that the moving parts of the machine are placed. 



The extremity of the pipe or head of the ram is a hollow 

 fphere, the diameter of which is nearly twice as great as the 

 bore of this pipe : the upper part of the fpherical end is flat- 

 tened, fo as to reduce it to a fegment of a fphere, with a flat 

 circular furface on the top or upper fide, in the centre of which 

 furface is a large circular opening to receive and hold the 

 feat of the ftop-valves, at which the water i{rues ; but when 

 the valve is clofed, it prevents the water from iffuing. 



When the valve opens, it defcends perpendicularly into 

 the hollow fphere, and leaves a free paffage through the 

 opening. Its motion is guided between three or four per- 

 pendicular ftems, which have hooks formed at the lower 

 ends to retain or fupport the valve when opened ; and thefe 

 ftems are fixed by fcrews, fo that they can be regulated to 

 allow the valve to defcend more or lefs, and open a greater 

 or lefs paffage for the water. The valve is made of metal, 

 and hollow, for it has a flat circular plate of metal, with a 

 hollow cup or difh of metal attached to its lower furface : 



this 



