LXIV. 



W. H. WARREN AND S. H. BARRACLOUGH. 





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into contact with the compression plate of the vertical testing 

 machine. The columns were thus placed in the machine without 

 injury. The compressions produced by the loads applied were 

 measured for each two tons increment by means of dial extenso- 

 meters arranged on opposite sides of the column as shown in Fig. 3. 

 These dials record the compressions between two fixed points in the 

 column, and are independent of the movement of the machine. 

 The readings were observed to 01 mm., and a sample 1 of the 

 results obtained is shown in Table I. The curves in figs. 5 and 6 

 show the relation between the loads and the compressions produced. 

 A short column of brickwork 12 inches long and 9 inches by 9 

 inches in section was tested with a double set of Marten's mirror 

 apparatus arranged on two opposite sides, the reflected images of 

 the four scales being observed with four telescopes in the customary 

 manner (see Fig. 4 and Table II.). It was also retested immedi- 



1 It was not considered necessary to reproduce the whole of the obser- 

 vations taken, as this would have greatly increased the bulk of the paper 

 without any corresponding advantage. The plotted curves show the 

 kind of result obtained with sufficient accuracy. 



