8 INTRODUCTORY 



the usual form of the Reeser and Mackenzie machine 

 is nof adapted. 



In the Reeser and Mackenzie machine, the fibre 

 is held in a vertical position with its ends secured in 

 clamps, one of which is fixed and the other attached 

 to the arm of a balance. The other balance arm is 

 then loaded until the fibre breaks ; the loading is 

 effected, not by adding weights, but by a screw device 

 which pushes a movable bar along the beam until 

 breaking occurs. A scale allows the strain at the 

 moment of breaking to be read off. The increase in 

 length is ascertained by means of a scale situated 

 at the end of the beam where the fibre is held. 



