No. 8. 



Hydraulic Ram. 



247 



top soil to the depth of two inches; this 

 prevents all grass or weeds from growing, 

 and the plants will require no cultivation 

 after they are set out. After the top was 

 removed, I harrowed the ground smooth 

 and marked it out in drills, eighteen inch- 

 es apart, and set in the plants four inches 

 apart. Some I set out on sods fourteen 

 inches square, placed in holes a little below 

 the surface. They all flourished far beyond 

 my expectation: the first year they put forth 

 runners three feet long, and every vine was 

 loaded with fruit. The plants can be set out 

 from September to December, and from April 

 to the last of June." 



Yours, &c. B. G. Boswell, 



For ihe Farmers' Cabinet. 

 Hydraulic Ram. 



In the last number of the Cabinet is an 

 article recommending the application of a 

 syphon to the supply pipe of a hydraulic 

 ram. It seems to me that the principles 

 upon which such a modification depends, 

 should be carefully examined, before any 

 person incurs unnecessary expense in intro- 

 ducing iL 



It is a settled principle in hydraulics, that 

 the total efficacy of a water power is found 

 by multiplying the quantity of water by the 

 height of the fall. Now as no mechanical 

 contrivance can increase power, it is evident 

 that were there no loss from friction and im- 

 perfect application of the water to machine- 

 ry, the whole effect would be of easy calcu- 

 lation. The only diflerence tlien, that results 

 from the use of different kinds of machinery, 

 arises from the more or less perfect manner 

 in which they use the power of the water. 

 Now I think it will be apparent from the 

 following remarks, that the use of a syphon 

 is a less perfect mode than a straight pipe, 

 and of course should be discouraged. If it 

 is a fact that a larger quantity of water was 

 raised by H. H. Straw bridge when he used 

 his bent pipe, it would no doubt be interest- 

 ing to the "readers of the Cabinet to have 

 the discrepancies between practice and theo- 

 ry explained. 



First — We shall endeavour to explain the 

 principle on which the syphon acts; for it is 

 plain the whole argument must be based on 

 this, H. II. S. appears to suppose that the 

 fall of water is increased by the employment 

 of the syphon. He says, "The fall of water 

 requisite to work it being very small, I con- 

 tinued to increase it by the improvement I 

 am about to describe." And again, "In this 

 manner, by employing a syphon instead of a 

 straight pipe, conducting from the pond or 

 spring to the ram, a fall of six or twelve 

 inches, which would not afford sufficient 



power to work the ram, may be increased 

 in power so as to equal that of a natural fall 

 of many feet." Again, — "The power will 

 of course be in proportion to the perpendicu- 

 lar height of the syphon; which cannot, 

 however, be made to act if its elevation ex- 

 ceed 32 feet. This will give a power of 14 

 lbs. to the square inch, if merely the dead 

 pressure be taken into consideration, but a 

 much greater power, if the momentum of 

 the descending column of water be calcu- 

 lated." 



I now propose to show that the theory de- 

 veloped in these remarks is not sound. 



The whole moving power in the syphon 

 depends upon the difference in the perpendic- 

 ular height of the columns of water in the two 

 legs. Let A B C be a syphon, the longer 



leg being B C. The whole moving force, 

 I and of course the only force applicable to 

 working machinery of any kind, is the col- 

 umn D C, A and D being on a level. The 

 water in B D can exercise no effect on the 

 machine— except from its momentum ; a 

 point to be considered hereafter — its whole 

 force being expended in supporting the wa- 

 ter in A B. This must be evident; for were 

 the leg B C to terminate at D and be slight- 

 ly turned up as at C, to prevent the water 

 from dripping out, no water would be dis- 

 charged by the syphon. This being the 

 case, and the law, that every effect is in pro- 

 portion to the force which produces it, being 

 of universal application ; the addition of the 

 column D C cannot cause an action by the 

 machine equal to that which would be pro- 

 duced by the whole water in B C. 



I am aware that there is a popular notion, 

 that the water in the shorter leg being raised 

 by atmospheric pressure, the whole of that 

 in the longer may be applied to the moving 

 of machinery. This, however, is fallacious. 

 It is true that the water is forced up by at- 

 mospheric pressurp, and it is also true that 

 the water in the longer leg is supported by 

 atmospheric pressure to precisely the same 

 amount. The two columns being thus kept 

 in contact by the pressure of the air acting 

 at the two extremities of the tube, the ac- 

 tion of the water is, so far as its dead pres- 

 sure is concerned, perfectly analogous to a 



