2(H) Mr. J. E. H. Gordon on Dr. Kerr's Experiments 



it, 3 inches from the bottom, the glass was set on one of its 

 long edges on them, in the centre of the box. Two holes 1J 

 inch in diameter were made opposite to each other in the ends. 

 Into these pings of mahogany, whose inside ends were padded 

 with leather, were inserted, so that the leather ends pressed on 

 the centres of the end edges of the glass. Holes being made in 

 the outside ends of these plugs, long brass stair-rods were put 

 through them, so that the middles of the rods were in the 

 plugs and the ends projected horizontally in both directions. 

 The ends being tightly drawn together with string, the elas- 

 ticity of the rods pressed the plugs tightly upon the glass. 

 The plugs and leather were slightly oiled. 



SI CTIONAI 



PIAI. 



&.JI urass 



Two pieces of tinfoil 15 inches by 5, were pasted on thin 

 slips of soft wood, and placed symmetrically on the sides of the 

 glass. Each was kept in position by two stout pointed wires 

 (kitchen skewers), which were passed through holes in the 

 mahogany, and whose points stuck into the soft wood carrying 

 the tinfoil, and pressed it against the glass. Each skewer 

 was fixed by a nail driven alongside it into the mahogany. 

 At the centre of each side, and at right angles to it, was fixed 



