DESCRIPTION OF PLATES. xi 



PLATE IX. 



Fig. 111. A weighing machine. The platform supporting the weight rests on 

 the pins A, B, C, D, at equal distances from the fulcra E, F, G, H ; so that 

 wherever the weight may be placed, it presses equally on the lever I K, at L, and is 

 counterpoised by a much smaller weight placed in the scale M. P. 97. 



Fig. 112. A steelyard resembling that of Mr. Paul, in which different weights 

 may be employed. A, a loop to check the vibrations ; B, a scale to be suspended by 

 the hook C. If great delicacy be required in the weights, the fractional parts may 

 be expressed by the turns of a micrometer screw D, furnished with an index. P. 97. 



Fig. 113. A bent lever balance. P. 98. 



Fig. 114. A spring steelyard : half the case being removed, to show the spring. 

 P. 98. 



Fig. 115. AB, the path of the centre of gravity of the human body, such as it 

 would be described in walking, if the legs were inflexible. C D, the path described 

 in running, on the same supposition. P. 100. 



Fig. 116. The actual path of the centre of gravity, as it is usually described. 

 P. 100. 



Fig. 117. An elastic column, compressed by a weight acting at the distance of 

 one third of its depth from the concave surface ; the compression being every where 

 as the distance of the lines A B, A C. P. 107. 



Fig. 118. An elastic column, extended by a weight acting at the distance of one 

 third of its depth from the convex surface, the extension being every where as the 

 distance of A B, A C. P. 107. 



Fig. 119. An elastic column, compressed by a weight acting immediately on the 

 concave surface : the compression extends only to the line AB, the parts beyond this 

 line being extended. P. 107. 



Fig. 120. A column bent, by a weight acting longitudinally, into the form of a 

 harmonic curve : the line A B C D is the limit between the parts which are com- 

 pressed, and those which are extended. P. 107. 



Fig. 121. An elastic plate or rod, considerably bent by a weight acting at its ex- 

 tremity. P. 107. 



Fig. 1 22. An elastic rod fixed at one end, and bent by its own weight. P. 108. 



Fig. 123. An elastic rod supported at each end, and bent by its own weight. 

 P. 108. 



