82 



THE HYDRAULIC HAM. 



we think, be hailed as a real blessing to 

 the Horticulturist. Such a desideratum, 

 for many localities, is the Hydraulic Earn. 

 Wherever a small constant stream of water, 

 or even a spring with a very moderate re- 

 gular overflow, can be found, within any 

 moderate distance of the grounds to be irri- 

 gated, a plentiful supply of water may be 

 furnished without any farther cost or ex- 

 penditure of power than what is involved 

 in the purchase and erection of the machine 

 itself. A stream or spring in a deep val- 

 ley, or a brook at two or three hundred feet 

 distant, may thus be made to force itself 

 up-hill to any desired point, where a pond, 

 cistern or reservoir maybe found most con- 

 venient. 



From such reservoir the water may be 

 led to any lower part of the grounds — a 

 complete irrigation maintained wherever it 

 is needful. Thus, lawns may be kept as 

 fresh as emerald, and beds of vegetables 

 and flowering plants grown with a luxuri- 

 ance and perfection rarely seen in our cli- 

 mate. 



Where the source affords an abundant 

 supply of water, fountains may be kept pla}^- 

 ing by the same means, and it is surprising 

 how much beauty and value may be con- 

 ferred on pleasure grounds by the addition 

 of as much water as will be supplied by a 

 good Hydraulic Earn fed by a small but un- 

 failing rivulet of water. 



The construction of the Hydraulic Eam 

 is at once simple and ingenious. We ex- 

 tract the following highly interesting de- 

 tailed account of the invention, from Eio- 

 bank's Hydraulics : 



Every person accustomed to draw water 

 from pipes that are supplied from very ele- 

 vated sources, must have observed, when 

 the cocks or discharging orifices are sud- 

 denly 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 up against it 

 by those constituting the moving mass be- 

 hind. The philosophical instrument named 

 a v;ater hammer 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 was 

 stopped in the same manner, except that 

 its momentum would be concentrated on 

 that point of the pipe against which it 

 struck, whereas with the liquid rod the mo- 

 mentum Avould be communicated equally 

 to, and might be transmitted from any part 

 of, the lower end of the tube ; hence it of- 

 ten occurs that the ends of such pipes, when 

 made of lead, are swelled greatly beyond 

 their original dimensions. We have seen 

 some 3-4 of an inch bore, become enlarged 

 to 1 1-4 inches before they were ruptured. 

 At a hospital in Bristol, England, a plumb- 

 er was employed to convey \vater through 

 a leaden pipe from a cistern in one of the 

 upper stories to the kitchen below, and it 

 happened that the lower end of the tube 

 was burst nearly every time the cock was 

 used. After several attempts to remedy 

 the evil, it was determined to solder one 

 end of a smaller pipe immediately behind 

 the cock, and to coxxy the other end to as 

 high a level as the water in the cistern ; 

 and now it was found that on shutting the 

 cock the pipe did not burst as before, but a 

 jet of considerable height was forced from 

 the upper end of this new pipe : it there- 

 fore became necessary to increase its height 

 to prevent the water escaping from it — up- 

 on which it was continued to the top of the 

 hospital, being twice the height of the sup- 

 plying cistern, but where to the great sur- 

 prise of those who constructed the work, 

 some water still issued : a cistern Avas 

 therefore placed to receive this water, 

 which was found very convenient, since it 

 was thus raised to the highest floors of the 

 building without any extra labor. Here 

 circumstances led the workmen to the con- 

 struction of a water-ram without knowing 

 that such a machine had been previously 

 devised. 



