OBSERVATIONS on THe Turory, &c. 319 
A deaf perfon not perfectly fkilled in reading words 
from the lips, or who ihould afk any thing in the dark 
would be able to procure common information by putting 
various queftions, and by telling the perfon that, as he is 
deaf, he requefts anfwers by figns, which. he will direct 
him tochange according to circumftances.—If he had loft 
his way, if he enquired for any one, if he wanted to pur- 
chafe any thing, and in all the common occurrences of life, 
his {peech would be fo ufeful, that it would certainly more 
than repay the trouble of obtaining it; efpecially <as it. 
would be.amode of facilitating every other acquirement. 
WILLIAM 'THORNTON. 
a 
N*. XXXIV. 
Obfervations on the Theory of Water-Muills, - (continued : 
from page 193.) by. W. Warina.. 
Read, April (4 INCE the Philofophical Society were pleafed 
hit ag to favour my crude obfervations on the theory - 
of mills with a publication in their tranfactions, I am ap- 
prehenfive fome part thereof may probably be mifapplied. 
It being therein demonftrated, that, ** the force of an. 
invariable ftream impinging again{t a mill-wheel in mo- 
tion is in the fimple dire& ratio of the relative velocity,” 
fome may fuppofe, that the effet produced, fhould be in 
the fame proportion, and either fall into an error, or, find 
ing by experiment, the effect to be as the fquare of the 
velocity, conclude ithe new theory, to be not well founded; 
therefore, I with there had been a little added to prevent 
fuch a mifapplication, before the fociety had been troubled 
with the reading of my paper on that fubje€t; perhaps, 
fomething like the foliowing. 
The 
