WATER. 



flower, for inflance 20 turns per minute, tlien tlie load may 

 be increafed in proportion ; 111%. to 25^ lbs., and this will be 

 lefs fatiguing. 



The Force of Horfa tu raife Water.— 'VlAi we find 

 varioufly ftated by different authors as the force of men. 



In this, as in the former inftance, we feel inclined to give 

 the preference to Mr. Smeaton's eftimate, both from his 

 fuperior experience and accuracy, and alfo becaufe by his 

 MS. papers, we are informed of the particulars of his ex- 

 periments. He found, from examining the accounts of a 

 colliery, that each horfe drew 27720 pounds one foot per 

 minute ; but as tlicy could only continue to work at that 

 rate for 4^ liours per day, Mr. Smeaton fixed his ftandard 

 at 250 hogfheads per hour raifed ten feet, which is equal to 

 22,916 pounds, raifed one foot high. Still we find in two 

 of his machines, of which we have already given the parti- 

 culars, the performance fell rather (hurt : vie have, there- 

 fore, chofen to recommend 352 cubic feet of water, or 

 22,000 pounds per minute raifed one foot high, as a ftandard 

 for a horf^'s force, when lie works 8 hours per day, and 

 moves with a velocity of z\ miles per hour. This is fettled 

 by univerfal confent as the molt proper pace for a horfe to 

 walk ; and he will in that cafe draw juft ICO pounds, which 

 is an eafy number to remember. 



The eftimate of Defaguliers we confider as the maximum 

 of a horfe's power ; for the horfe-power of MefTrs. Boulton 

 and Watt is only ufed as a meafure of the ferce of their 

 Ream-engines. See that article. 



In applying horfes to work machines, the circular traft 

 in which they walk fhould be as large as poffible, 

 that the horfes may turn round in the circle with little 

 inconvenience. Few cafes will admit of a walk of more 

 than 30 feet diameter ; and in proportion as this is di- 

 minifhed, the horfe lofes fome of his power. No horfe-walk 

 fhould be made of lefs than 20 feet diameter, if he is re- 

 quired to aft with any confiderable force. When this fizt? 

 cannot be obtained, we are of opinion that the horfe would 

 ■«rork to a greater advantage by walking within a larg? per- 

 pendicular wheel, like thofe wheels ufed for eranes. 



It muft be remembered, that the horfe fhould always 

 move with a velocity of 2\ rm\es per hour, or 220 feet per 

 minute ; and, therefore, the number of turns which he will 

 make in a minute muft be proportioned to the fize of the 

 track in which he works. 



The machine which is to raife the water fhould be fo 

 connefted with the principal wheel which the horfe turns, 

 that it will move with the proper velocity, when the horfe- 

 wheel turns at the rate above fpecified. The velocity 

 proper for moft machines is mentioned in the defcription 

 of each. 



Water-Wheels applied to raife IVater The circumference 



of a water-wheel wall work to the greateft adTautage, when 

 it moTes with a velocity of from 3 to 4 feet per fecond, or 

 from 180 to 240 feet per minute. A very proper velocity 

 for a water-wheel is to make it the fame as the liorfeg, by 

 the above table ; and we have, therefore, adtled the velocities 

 for fmaller diameters. 



H 



Diameter 



