166

EXPERIMENTS WITH

TRACT 36.

rally chose, when the body p was removed, to fix in its steada thin piece of lead of the same weight, placed horizontally;so that the weight, which was to turn round the arm ghwithout the body p, did also carry round this piece of lead.This I did, lest it should be objected that the body p retard-ed the weight m by its quantity of matter, as well as by itsresistance. But mathematicians will easily allow, that thereis no necessity for this precaution.

6. “ The measures of the parts of this machine, were as

follow:

“ The diameter of the barrel bcde, and of the silk

“ The length of the arm gh, measured from theaxis to the surface of the globe p, was ----- 49‘5

“ The body p, the globe made use of, was of paste-board, its surface very neatly coated with marble pa-per, and was not much distant from the size of a 12lbshot, being in diameter - -- -- -- -- 4 - , 1 ?

“ So that the radius of the circle described by thecentre of the globe, was - -- -- -- -- 5T7.5

7. “ When this globe was fixed at the end of the arm, anda weight of half a pound was hung at the end of the stringat M ; it was examined, how soon the motion of the descend-ing weight m, and of the revolving globe p, would becomeequable as to sense. And with this view 3 revolutions being-suffered to elapse, it was found, that

The next 10 were performed in - 27''£

So that the first 10 were performed in 27£

2nd 10 in - - - - - 27£

3rd 10 in - - - - - 27-t

t{ These experiments sufficiently evince, that even withhalf a pound, the smallest weight hereafter used, the motionof the machine was sufficiently equable after the first 3 revo-lutions.

Inches.

string wound round it, was

2-06

20 in less than30 in - - •