316 « Ae B. Quinbycon Crank Motion. 
see that the study of statistics is indispensable to arrive at 
any degree of perfection, and.the knowledge it procures is 
an essential part of the science of the engineer in tracing 
canals; a truth which appears to have gone unheeded until 
now, but which cannot be too loudly proclaimed since 
public attention seems. specially directed to that important 
‘3 . : 
o . 3 
Paris, 17th June, 1821. 
Ward has written on the subject of this important pro- 
blem ; but I take the liberty to assert, that the principle 
ladrant, are as the perpendiculars repectively from those 
pulls WEE Tie BF Herein te BPR RAO 
the above quoted sentence is false; and that to obtain 4- 
satisfactory result, in the case in uestion, we must attend 
he matters which Mr. Ward’s demonstration does not em- 
ace. 
That the eff--cts produced at the several points of _divi- 
sion of the uadrant are not as the perpendiculars. respeet- 
ively from, those points to the line of force, may, be proved 
in the fo OWing. manner, | 
