Am. Jour. Sci., Vol. XXIX, 1910. 



Plate 



Wrought iron tube enclosing marble column after compression (see below). 



b 



Column of marble before and after compression under a load of 296,725 pounds per 

 square inch (20,875 kilos, per square cent.). The finer lines of the scale are one millimeter 

 apart. 



i 



