FOKMS OF BEAM AND PULLEY. 



15 



honest scientific endeavor can always or nearly al- 

 ways be avoided. 



It would not be a very difficult matter, usually, 

 to rig a large pulley at the edge of the cliff, through 

 which the rope may run securely. One could be 

 constructed for the purpose, surmounting an iron pin 

 to be driven into the soil, or wedged in a crevice, 



Fig. . 



at the summit of the cliff. Another plan would be 

 to insert the pulley into the end of a strong beam, 

 which should be allowed to project a few inches 

 beyond the brow of the cliff, its opposite end be- 

 ing firmly anchored by some simple means. Of 

 course, the utmost care must be taken to secure 



