LeMon XII.] 



MECHANICS. 



how the change of direction is effected ' i adopted for subdividing the 



SeveJ.ed wheels placed at various angles ; 

 and F/V. 45 exhibits another method of 

 changing the direction by means of a 



friction, by making the axle to revolve OK 



fif. 44. 



A heel, which works into an ordinary 

 . whose axis is at right angles to its 

 own. 



i< meant by a cog wheel ? 



i wheel with projecting teeth; 



the term cog being used for all large teeth. 



s a shaft? 



P. A long and large axle, attached to 

 some part of a machine, which enables us 

 a great <1 



til shafts are call- 

 ed spindles. 



H7. T. What is 

 a pivot or gudgeon ? 

 1 'ie end of a 

 shaft, axle, orspindle, 

 upon which it turns 

 and rests. 



148. r What is 

 a crown wheel ? 

 r.,.4*. 



teeth placed at right angles to its < 

 ference (see Fig. 45.) 



7*. In not the motion of mat 

 sometimes irregular ? 



P. Yr* ; and it m*y proceed either from 

 pal mover. 

 -Mire or the load, I 

 or def proper transmis 



force, .v 



i cause the 

 irregularity of motion ; and how may fric- 



two or more wheels, which are therefore 

 termed friction wheels, as in Fig. 46. 



l-'il. T. How may the irregularities of 

 machinery be generally reme,. 



P. By li a rvoir of power to 



each machine, which will enable the prime 

 mover to give a more equal motion. This 

 is accomplished by the fly-wheel, which 

 seen attached to mangles, turning- 

 lathes, &c. 



1. VJ. T. Then it appears the power is 

 capable of being accumulated and concen- 

 trated. Is this the case? 



P. Yes. We see this in the grocer's 

 handmill, which has a fly-wheel attache? 



i bo prevented ? 



\ Kr 



MI; the proper acUpt.r 



ng away, KM in the 

 of a whr-l. whu-h revolves with great 

 ; and, in order to din. 



The coining-press (Fig. 47) said to have 



example of the effect of 



. A man causing the ncrew to 

 i ken a good 



imjirrisinn nf the die upon tli. 



by whirling the balls at : ml uf 



i tur. 



153. T. Can the force of machinery bt 

 Yes; by employing a cog-wheel, 



