CIRCULAR CYLINDERS UNDER CERTAIN PRACTICAL SYSTEMS OF LOAD. 209 
inside the cylinder. I have chosen the stress ZZ in preference to the others, as, 
except in the neighbourhood of the centres of the plane ends, it is everywhere the 
Diagram 12.—Distribution of Principal Stress ZZ inside the Cylinder (case of compression between 
Rough Rigid Planes). 
\90'65m570 
The lines are drawn at intervals of "05 Q, of the stress. The critical line corresponds to ZZ UOl Q nearly 
greatest of the three principal stresses, and therefore ZZ will be the iinporta)it 
quantity when we come to discuss the maximum stress. 
The diagram has been constructed by carefid interpolation from the values 
tabulated above, and from it we see that the surfaces of equal principal stress in the 
VOL. CXCVIII.—A. 2 E 
■2C 
