I I. 



Cl 



in an instrument, or * ajflteai of tolU 

 bodir*. for I lie |>urpoee of 



an.itli.T -.{' t:. |j itfli .. 



1 1 



would be eodleeB to deecribe all tbe machine* that here 

 plain, and alao a few cotnbmaUonj of them. 



we shall oooaetnMntliF OOQ&IM owlwi to 



, . .''-tin' u T : >''.,, i*c 



ie Mechanical Powm. TboiTw. aball ex 



ar U an n. 



< called the fmlcrwm. Tbe potties* of tbe 

 tn i are called tbe orai* of 



which tin- fulcrum 



In- arm ara in the MOM attaijcfct liar 

 cd a itnnjkt Imr, and in oilier eeeet a 



> forces act on the lever about tbe fulcrum, called 



>wer and the r*i>Af the power it tbe force applied br 



the hand, or <th<T mean*, to anstain or onreneai the other 



force. ..-i.-iit There are three apecmof leirera: ui tbe 



vreru the powet and tbe weight ; in the 



between tbe fulcrum and tbe |* 



rd the power acte between tbe foknua and tbe 



To fml the comJtfo** if tfirfiViWai of h 

 : in tke 9ame pUu* o* a /-trrr. 



