18 PHENOMENA OF PLANT-LIFE. 



ing its growing force consisted of a frame, or bed, of seven 

 inch boards, one foot long. These were arranged in a radial 

 manner, like the spokes of the lower half of a wheel, their 

 inner edges being turned toward the central axis. These 

 pieces were held firmly in place by two end-boards, twelve 

 inches square, to the lower half of which they were secured 

 by nails and iron rods. A heini-ellipsoidal cavity, about five 

 inches deep in the centre and eight inches long, was cut from 

 the inner edges of the seven boards, and in this the squash 

 was carefully deposited, the stem and vine being carefully 

 protected by blocks of wood from injury by compression. 

 Over the squash was placed a semi-cylindrical harness, or 

 basket of strap-iron, firmly rivetted together. The meshes 

 between the bands, which crossed each other at right-angles, 

 were about one inch and a half square. The harness was 

 twelve inches long and the same in width, so that when placed 

 over the squash, it just filled the space between the end- 

 boards. Upon the top of the harness, and parallel with the 

 axis of the cylinder and the squash, was fastened a bar of 

 iron with a knife-edge to serve as the fulcrum of a lever to 

 support the weights by which the expansive force was to be 

 measured. At first, an iron bar, one inch square, was used 

 for a lever, then a larger bar of steel, then a lever of chest- 

 nut plank, then one of seasoned white oak plank, and, finally, 

 one of chestnut, five by six inches square, and nine feet long ; 

 but even this required to be strengthened by a plate of iron 

 four inches wide by half an inch thick and five feet in length. 

 The fulcrum for the lever was also renewed from time to time 

 as the weight was increased. 



The following 'table shows the weight of iron lifted by the 

 squash in the course of its development : 



August 21, . . . . . . 60 pounds. 



" 22, ... >. 69 



" 23, . . . 91 " 



44 24, . . . . . .162 



" 25, . . ... . 225 



" 26, . . . ., . 277 



" 27, ' 356 



" 31, 500 



