By Mr. John Hay. 



223 



Some walls in high and exposed situations have been fur- 

 nished with screens. For this purpose, wrought iron forked 

 bats, as in the adjoining sketch, are fixed in the 

 front of the wall, at 2£ inches beneath the coping, 

 and 35 inches distant, to receive the upper ends 

 of moveable rafters, the tops of which are furnished with 

 small pulleys or rollers. A screen of thin osnaburgh or 

 canvas, all in one piece, is provided for each division of the 

 wall, bound round the edge with small rope or cord. A small 

 rope for each rafter is fixed to the screen ; these being passed 

 through the pulleys, a man placed at each end of the screen, 

 having the ends of half the ropes in his hand, easily brings it 

 up to the top of the wall, where it is fixed for the night, and 

 in the morning let down nearly to the ground. Two ropes for 

 each rafter attached at the top of the screen, crossing one 

 another on the outside, bind it close to the rafters. This kind 

 of covering has been successfully used upon hot and other 

 walls, for protecting the trees when necessary in spring or 

 autumn. 



