358 



MONTHLY JOURNAL OF AGRICULTURE. 



celebrated light-house sometimes appears from 

 this cause like the pipe of a foontain enclosed 

 in a stupendous jet d'eau. The light-room in 

 the old light-house was sixty feet above the sea, 

 and it %vas often buried in the wuves, so im- 

 mense were the volumes of water thro^^Ti 

 over it. 



The hydraulic ram raises water on precisely 

 the same principle : a quantity of the liquid is 

 set in motion through an inclined tube, and its 

 escape from the lo\%-er orifice is made suddenly 

 to cease, when the momentum of the moving: 

 mass drives up, like the waves, a portion of its 

 ovra volume to an elevation much higher than 

 that from which it descended. This may be il- 

 lustrated by an experiment familiar to most 

 people. Suppose the lower orifice of a tube 

 (whose upper one is connected to a reservoir of 

 of ■water) be closed with the finger and a very 

 minute sti'eam be allowed to escape from it Ln 

 an upward direction — the tiny jet would rise 

 nearly to the surface of the reservoir ; it conld 

 not. of course, ascend higher — bat if the finger 

 were then moved to one side so as to allow a 

 free escape till the whole contents of the tube 

 were rapidly moving to the exit, and the orifice 

 then at once contracted or clo.sed as before, the 

 jet would dart far above the reser\-oir ; for in 

 addition to the hydrostatic pressure which drove 

 it up in the first instance, there -would be a new- 

 force acting upon it, derived from the motion 

 of the water. As in the case of a hammer of a 

 few pounds weight, when it rests on the an\-il 

 it exerts a pressure on the latter with a force 

 due to its weight only, but when put in motion 

 by the hand of tlie smith, it descends with a 

 force that is equivalent to the pressure of per- 

 haps a ton. 



Every person accustomed to dra^r water 

 fit)m pipes that are supplied from very elevated 

 sources, must have obsei-ved, when the cocks or 

 discharging orifices are suddenly closed, a jar 

 or tremor communicated to the pipes, and a 

 snapping sound like that from smart blows of a 

 hammer. These effects are produced by blows 

 which the ends of the pipes receive from the 

 ■water: the liquid particles in contact with the 

 plug of a cock, when it is turned to stop the dis- 

 charge, being forcibly driven np against it by 

 those constituting the moving mass behind. — 



The philosophical instrument named a water 

 ham mer illustrates this fact. The effect is much 

 the same as if a solid rod moved with the same 

 velocity as the water through the tube until its 

 progress \\as stopped in the same manner, ex- 

 cept that its momentum would be concentrated 

 ou that point of the pipe against which it struck, 

 whereas with the liquid rod tlie momentum 

 would be communicated equally to, aud might 

 be transmitted from any part of, tlie lower end 

 of the tube ; hence it otten occurs that the ends 

 of such pipes, when made of lead, are swelled 

 greatly beyond their original dimensions. We 

 have seen some j of an inch bore, become en- 

 larged to 1;! inches before they ^vere raptured. 

 At a hospital in Bristol, England, a plumber 

 was employed to convey water through a lead- 

 en pipe from a cistern in one of the upper sto- 

 ries to the kitchen below, and it happened that 

 the lower end of the tube -was burst nearly eve- 

 ry time the cock w-as used. After several at- 

 tempts to remedy tlie evil, it was determined to 

 solder oue end of a smaller pipe immediately 

 behind the cock, and to cany the other end to 

 as high a level as the water in the cistern ; and 

 uo^v it vias found that on shutting the cock the 

 pipe did not burst as before, but a jet of consid- 

 erable hight was forced from the upper end of 

 this new pipe : it therefore became necessary to 

 increa.% its hight to prevent water escaping 

 from it — upon which it was continued to the 

 top of the hospital, being twice the hight of 

 the supplying cisteni, but where, to the great 

 surprise of those who constructed the work, 

 some ^vater still issued : a cistern was therefore 

 placed to receive this water, wliich was found 

 very convenient, since it was thus raised to the 

 highest floors of the building ^vithout any extra 

 labor. Here circumstances led the workmen to 

 the construction of a water-ram without know- 

 ing that such a machine had been previously 

 devised. 



The first person who is known to have raised 

 ^vater by a ram, designed for the purpose was, 

 Mr. \Vliitehui-st, a ^vatchmake^ of Derby, in 

 England. He erected a machine similar to the 

 one represented by the next figure, in 177Q. A 

 description of it was forwarded by him to the 

 Royal Society, and published in vol. Iv. of their 

 Transactions. 



No. 167. Whiteh 



A represents the spring or reservoir, the sur- 

 face of the water in which was of about the 

 same level as the bottom of the c-istem B. The 

 main pipe from A to the cock at the end of C, 

 was nearly six hundred feet in length, and one 

 and a half inches bore. The cock was sixteen 

 feet below A, and furnished water for the kitch- 

 en, offices. &c. When it was opened the liquid 

 1722) 



urst's Water-Ram. 

 column in A C was put in motion, and acquired 

 a velocity due to a fall of sixteen feet ; and as 

 .soon as the cock was shut, the momentum of 

 this lone: column opened the valve, upon which 

 part of the water rushed into the air-ves.sel and 

 up the vertical pipe into B. This effect took 

 place ever\- time the cock was used, and as 

 water was "drawn from it at short intervals for 



