18 Mr. J. Morrow. On the Distribution of [Oct. 27, 



Table III contains the results of these experiments. At the centre 

 "two sets of readings were obtained at each load. These, in general, 

 differed but slightly, and the mean values are given. The slight 

 differences were probably due to the limits of accuracy having been 

 reached. * 



Table III. 





Increments of strain at different loads. (Scale readings.) 



Position 













of instrument. 















i to | ton. 



i to 1 ton. 



1 to \\ tons. 



H to 2 tons. 



2 to 2i tons. 



1 



. 4-68 



9-63 



10-12 



10 -30 



5 -73 



2 



3-24 



5 -82 



6 -15 



6-17 ' 



3 -07 



3 



1-20 



1 -92 



2-09 



2-19 



0-84 



4 



o-oo 



0-06 



0-03 



-0-12 



-0-31 



5 



-I -10 



-1 -88 



-2-13 



-2-29 



-1 -69 



6 



-2-95 



- 5-25 



-5-60 



-6 -00 



-3 45 



7 



-4-87 



-9 -40 



-9-00 



-8-55 



-3-96 



The column headed "Position of the Instrument" refers to the 

 number of the mark on the side of the beam in line with which the 

 instrument was attached. 



A minus sign denotes that the lateral strain was a contraction. 



Distribution of Strain. 



At the lower loads the maximum lateral strain per unit of load 

 added is on the tensile side of the beam, slightly greater than that on 

 the compressive side. As the load increases, however, the maximum 

 lateral strain per unit of added load in the tensile fibres decreases, 

 whereas that in the compressive fibres constantly increases. Hence, at 

 fracture, this strain is very much greater on the compressive side than 

 on the tensile. 



The curves in fig. 2 are plotted from the second and sixth columns of 

 Table III, and show the increment of lateral strain at different points 

 in the depth of the beam. The full line refers to loads of \ and J ton, 

 and the broken line 2 to 2 J tons. For the other loads the curves are 

 given in fig. 3. They would be intermediate between the two curves 

 of fig. 2. 



Considering the strain curves for the tensile side of the beam given 

 in figs. 2 and 3, it will be seen that at the lower loads a straight line 

 is obtained, and that as the load is increased the lines become more and 

 more curved in the direction of decreasing strain in the outer layers. 

 This curvature is first noticed in Numbers 3 and 4, but not till the last 

 curve, Number 5, is it very remarkable. On the compression side at the 



