544 On the Dlff'erettee tfBffeli in Over/hoi and Breajl Wheels. 



roborate ftUl further, the demonftration we have given of the formation of the regular hexae?* 

 dral prifm in this fubftance. 



(To be concluded in our next.) 



IV. 



On Water-iuheets. 

 To Mr. NICHOLSON. 



SIR, 



OUR attention to the Inquiries fent laft month, Induces me to tranfmit the annexed 

 japer for your conCderation. 



Your opinion that a float-board-wheel is preferable to a bucket, agrees with that of an ex« 

 perienced mill-wright. 



I hope, through the medium of your valuable Journal, the fubjedl will receive further dlf-< 

 cuflion ; as the ground on which the preference is given is not obvious. 



It will, no doubt, be agreeable to you to learn, that the fphere of your Journal's ufeful com* 

 munication is extended to the northern verge of Ireland ; and that, amidft the tumult of po* 

 litical ftrife, the arts of peace, and the interefts of fcience, are not yet forgotten. 



I am, your obliged reader, 

 Fthfuary l-j^Z, DeKRIENSI*. 



On Water-wheels. 



THE effe£l of water-wheels, arlfing from the gravitating power of the water ; to retain 

 die water, feems the point neceflary to be attended to, in the conftru£lion of the wheel. 



The form of the bucket-wheel feems bed adapted to this end ; yet in ftreams, where the 

 fall is not confiderable, a preference is given to float-board-wheels. 



Why is this preference given to float-board-wheels ? Suppofe a ftream which has a fall of 

 £x feet, and a fupply which renders it equal to the power of fix horfes: 



Allow this power to be adequate to raife a given weight, one foot high, thirty times in a 

 minute. 



It is convenient to have a water-wheel of ten feet diameter. A bucket-wheel is made of a 

 width adequate to the fupply of water. Will this wheel be lefs competent to the work than 

 a large float-board-wheel ? If fo, to what is the lofs of power in the fmall, or the gain of power 

 in the large, wheel owing ? 



WITHOUT entering minutely at prefent into the fubjeft here ofl^ered for confideration, 

 which I leave to my other correfpondents, I fliall only remark, that the preference feems to 

 have been given to the clofe breaft-wheel, for ftreams afibrding confiderable quantities of 



water 



