60 THE BOOK OF THE LANTERN. 



emergency. In some of my experimental lectures, where 

 I require a lime-light for occasional use on the plat- 



FIG. 26. 



form, I carry with me a small bag holding only three feet 

 of gas, and a special form of pressure board which I have 

 designed for the purpose. It consists simply of two pieces 

 of inch board, each pierced on one edge with corresponding 

 centre-bit holes three-quarters of an inch in diameter- 

 Into these holes fit half a dozen round rods of pine. A 

 couple of pieces of wood screwed to the under edge of one 

 of these pieces of board serve as a support to the twenty- 

 eight-pound weight employed. The lower part of this 

 skeleton pressure board is furnished with a couple of bolts 

 which shoot out, and into two screw eyes, fastened to the 

 floor. The whole arrangement will be rendered clear by 

 the annexed sketch (fig. 26). I merely describe it here in 

 the hope that it may be as useful to others as it has been 

 to myself. 



