42 TIMBER AND TIMBER TREES. [CHAP. vn. 



unnecessarily weakening those which remain. There 

 are, undoubtedly, many examples to be found where 

 larger scantlings have been experimented upon, and 

 the results of these are, of course, more reliable and 

 trustworthy. 



The tests for the transverse strength in my experi- 

 ments were conducted, in every case, with pieces 

 2 // X2 / 'x84 // =336 cubic inches. Each piece was placed 

 upon supports exactly 6 feet apart, and then water 

 was poured gently and gradually into a scale suspended 

 from the middle until the piece broke, note being taken 

 of the deflection with 390 Ibs. weight, and also at the 

 crisis of breaking. 



After this a piece 2 feet 6 inches in length was taken, 

 wherever it was found practicable, from one of the two 

 pieces broken by the transverse strain, and tested for 

 the tensile strain by means of a powerful hydraulic 

 machine, the direct cohesion of the fibres being thus 

 obtained with great exactness. Further, for the purpose 

 of determining the proportions of size to length best 

 adapted for supporting heavy weights, a great many 

 cube blocks were prepared, of various sizes, as also a 

 number of other pieces of different form and dimensions, 

 which were then, by the aid of the same machine, 

 subjected to gradually increasing vertical pressure in 

 the direction of their fibres, until a force sufficient to 

 crush them was obtained. 



