THE WATER UAM. 107 



that included between D and //,vvith exception of the ascend- 

 ing pipe, I make all the parts, tiiat form this head, of a pro- 

 per strength ; but as the whole requires to be in due propor^ 

 tion, it is necessary to point this out to those who would mak-c 

 use of the ram, and to apprige them of the precautions requi- 

 site to the suc-cess of the machine. 



The dam, as I ha,ve supposed at R, is a very common ■rtroc- 

 ture. Falls of water are applied to some purpose or other, 

 ■almost every-whwe, and ibis arrangment is always requisite. 

 it' a person have not such a dam, and wish to avail himself of 

 a rapid stream to procure a fall, one might be constructed iii 

 the common mode, without any difference on account of the 

 ram, except a place for fixing the tunnel BD in the part 

 i?. 



It is advisable to place a grating QT before the cone leading A tjratitig 

 to the tunnel, to stop the greater part of the filth brought down pia^-ed btilre 

 by the current. This grating should not be very close, as it is the cone, 

 intended to stop only the weeds and bits of wood that would 

 'be liable to prevent the valves from shutting perfectly. Mud 

 and sand could be of little or no injury, because they aa^e con- 

 tinually carried away by the stream O. 



The body of the ram, BCD, should be throughout its whole Bodji^of tie 

 length equal in diameter to the entrance D of the head of the 

 •ram. All irregularities, whether from swelling out or being 

 tiarrowcd in ^ny.part, should be carefully avoided, as they 

 would grea-tly diminish the velocity of the water. The interior 

 surflwe ought to be as smooth as passibh?, to occasion loss 

 friction. 



The tunnel should be n3«.de of iron, copper, or lead, f shall 

 give the me^uis of calculating its thick-ucss below ; but it ought 

 to be capable of sustaining at least twice the pressure of the 

 column of water ascending from the air reservoir. 



The joints of the different pieces which farm the body of 

 the ram, must be made with great care, and strong. The 

 slightest aperture would diminish the effect of the inachijie. 

 There must be neither elbows nor alterations in the slope. 

 With respect to the length of the tunnel, I will give proper 

 directions to any one who wishes to have a water ram con- 

 structed. 



I shall have given every necessary information respcctihg the 

 P 2 fixing 



