[cokkr] apparatus FOR APPLYING BENDING MOMENTS 



61 



be carried on to the breaking point, and the fixing of the axis effectu- 

 ally stilled the vibrations, which were produced in the original arrange- 

 ment. 



Figures 2 and 3 show the arrangement used in a small machine, 

 which was built through the kindly aid of Professor Bovey, F.R.S., and 

 which has been in regular use in the testing laboratory of McGill 



fwS 



University during the past winter session. Figure 2 is a face view of 

 the torsion head consisting of a casing A pivoted in bearings B and 

 fitted with a worm wheel operated by a worm C on the shaft D, pro- 

 vided with a hand wheel. The axles E, E rest on roller bearings to 

 eliminate friction, and one side carries an arm F and locking pin to 

 fix the easing in the vertical plane when torsional moment only -s 

 applied. If both kinds of stress are applied, the casing turns with the 

 bar, so that the twisting moment is always applied in a plane at right 



