246 Experimental Philosophy. [Lecture 16. 



wheel D will be turned once round. Then, if 

 the circumference of a circle described by the 

 handle of the winch A is equal to the circum- 

 ference of a groove e round the wheel D, the 

 velocity of the handle will be forty-eight times 

 as great as the velocity of any given point in the 

 groove. Consequently, if a line goes round the 

 groove e, and has a weight of forty-eight pounds 

 hung to it below the pedestal EF, a power equal 

 to one pound at the handle will balance and sup- 

 port the weight. To prove this by experiment, 

 let the circumferences of the grooves of the 

 wheels C and D be equal to one another ; and 

 then if a weight of one pound is suspended by a 

 line going round the groove of the wheel C 5 

 it will balance a weight of forty-eight pounds 

 hanging by the line g ; and a small addition to 

 the weight H will cause it to descend, and so 

 raise up the other weight. 



If the line g, instead of going round the 

 groove e of the wheel D, goes round its axle I, 

 the power of the machine will be as much in- 

 creased as the circumference of the groove e 

 exceeds the circumference of the axle: which, 

 supposing it to be six times, then one pound at 

 H will balance six times forty-eight, or two hun- 

 dred and eighty-eight pounds hung to the Jme 

 on the axle ; and hence the power or advantage 

 of this machine will be as two hundred and 

 eighty-eight to one. That is, a man who, by 



