SHORT NOTES ON PROFESSIONAL SUBJECTS. 
91 
The sheers and gyn were made as nearly upright as possible, the gun or other 
weight to be taken across the ditch was placed on the top of the superior slope, 
and the double blocks of both tackles were hooked to the gun-sling. Both tackles 
were then hauled in alternately, the gun moved along the slope, fell off it, and 
became suspended under the sheers. 
The capstan was then manned, working both tackles at the same time and 
moving the ropes as shewn by the arrows in Big. 1. The gun travelled across the 
ditch along the dotted line (theoretically part of an ellipse of which the foci were 
the heads of sheers and gyn). 
Fig. l. 
o 
The time taken by one gun in travelling from the outer side of the exterior* 
slope to the opposite side of the ditch (87 feet) was an hour. The time might 
have been much less had there been more men, but there was only one small 
relief to work the capstan. 
This method admits of considerable modification. In some circumstances (with 
a narrow ditch or with a light weight) one sheers only would be necessary. On 
the other hand if the weight were very great it would be necessary to allow the 
weight to descend lower into the ditch than in the particular case described, but 
of course this proceeding involves more time and labour. 
From top of scarp to top of counterscarp 50 ft. From feet of gyn to feet of sheers 80 ft. 
