THE ACTION OF CYLINDRICAL OBJECTS. 



355 



Let A (Fig. 204) be the cylinder, placed horizontally, and B the 

 transverse section of it ; and let the 

 ellipses of elasticity, which in the 

 former are effective in the middle 

 and at the margin, and similarly 

 those of the section (here supposed 

 to lie upon the line C C) be deter- 

 mined by observation. We conse- 

 quently know of each of them, 

 whether it is produced in the 

 direction of the axis or at right 

 angles to it, or whether it acts 

 neutrally and therefore represents 

 a circular section of the ellipsoid. 

 We may also remark that these data 

 for the middle of the horizontal 

 cylinder, where the ellipses of elas- 

 ticity of the side, turned towards and 

 from, intersect, are to be referred to 

 the imaginary ellipse which repre- 

 sents, as above pointed out, the action 

 of the two superposed ones. But 

 since each of these three ellipses 

 may be placed longitudinally or lati- 

 tudinally to the axis of the cylinder, 

 or may even be a circle, which we 

 will denote by Z (longitudinal), q (lati- 

 tudinal), and o, altogether twenty-seven different combinations 

 result, of which, however, only the following thirteen are possible : 



The other fourteen combinations are : 



A A 2 



