$792. the iffects of water on machinery. 209 



of the -water must now be lost instead of one eight. 

 Here then the lofs is precisely double what it was 

 before, without any advantage gained to counter-ba- 

 lance that^; — augment that breadth to four feet, you 

 once more double that absolute lofs, (the proportional 

 lofs is much greater,) and so on, the more youencrease 

 the breadth of your wheel, in these circumstances, 

 the greater must the lofs of power be ; so*that, in- 

 stead of an improvement, this innovation is in fact a 

 very considerable deterioration. Indeed it would be 

 _ easy to fhow that in many cases the ivhole of the pow- 

 er of the water, as a dead weight, is thus entirely 

 lost, so that it can act merely by its impetus. 



Observe, what is here said respects wheels con- 

 structed with A A's ; those with buckets, or re- 

 ceivers of any -sort, Avill be considered belo'A^ But 

 in most of these, as far at least as respects that part 

 of the wheel below the axis, the case will not be 

 found to differ much from what is liere stated. 



These observations may be sufficient to fliow that 

 in all cases where a considerable fall of water can be 

 commanded, there must ever be a great waste of that 

 water as a moving power, when it is applied to wheels 

 constructed with float boards or A A's, and to point 

 out in what manner that waste may be augmented 

 or diminiftied. In that mode of construction it is 

 chiefly by its impetus that water acts upon machine- 

 ry. It remains that we now consider the various 

 modes of applying water to machinerj' so as to make 

 it act by its dead weight ; a mode of application that 

 ought in every case to be adopted where the fall is 

 considerable. As this branch of the subject lias «c- 



VOL. xi. D H ;jr 



