394 'AST IRON. 



tested, ami liroke at 6'95 tons and 7 - 29 tons per square 

 iiH-h respectively, or with a mean tensile strength oi' 

 7-12 tons ]>! sqii.-nv inch. 



Now. using Lame's i'onnula (given above) to calculate 

 the maximum tensile stress in the model cylinder at the 

 bursting load, the following are the data required : 



External radius of cylinder = R = (V515in. 

 Internal radius of cylinder = r = 0'2G5in. 

 Diameter of ram = 0445m. 



Sectional area of ram = 0-155 sq. in. 



The bursting pressure in tons per square inch will be 



0*65 . , 



P = fKlT^ == *'*9 tons per square inch. 



The maximum stress, as calculated from the bursting 

 pressure, is 



R 2 + r 



4 . 193 (0-515)'-' + (0-265) 



(0-515)-' - (0-265)' 



-4-193'^ 

 0-195 



= 7-203 tons per square inch. 



This result lies between the two results of the tensile 

 tests given above, so that it may be assumed that 

 in this instance the actual results accord very well with 

 the theoretical values deduced from Lame's formula. 



Proceeding on similar lines for the original cylinders, 

 it was found that the maximum stress in the metal, due 

 to the greatest static pressure (5,4001bs. per square inch), 

 would be only about four tons per square inch, whereas 

 the tensile strength of the metal was found to be over 

 seven tons per square inch ; so that it must be supposed 

 that the increased pressure was due to inertia effects of 

 the water. 



The static head was derived from a tank placed in the 

 college tower. 



