72 TRANSACTIONS OF ROYAL SCO'lTISH ARBORICULTURAL SOCIETY. 



result (cf. p. 82). I tested, however, two samples of attacked 

 Scots pine — one lot from Ballater and one lot from Strathdon — 

 but only made transverse tests, as I received instructions before 

 the compression specimens could be prepared, to destroy the 

 whole stock of timber which showed traces of the attack of this 

 fungus, as it was feared it might spread to the large stock of 

 timber I had in the building at the time. 



The most interesting point in connection with this blueing is 

 that it seemed to have a tendency both to lower the limit of 

 elasticity and to reduce considerably the numerical value of the 

 modulus of elasticity. 



The four specimens from Ballater showed a limit of elasticity 

 of 2832 lbs. per sq. inch, and a modulus of elasticity of 

 1,250,000 lbs. per sq. inch; and the four specimens from 

 Strathdon had a limit of elasticity of 3,042 lbs. per sq. inch, 

 and a modulus of elasticity of 1,051,000. 



There was apparently no great effect upon the ultimate 

 strength of the wood. 



The results of the pit-prop tests in 191 9 and 1920, and the 

 general conclusions resulting from the whole of the tests, will be 

 dealt with in a further communication. 



7. Forest Protection. 



In the scheme of nature the struggle for existence brings 

 certain opposing influences into conflict. Left to themselves an 

 apparent condition of equilibrium is established which neverthe- 

 less undergoes gradual change in the course of time. In the 

 plant kingdom it is those forms which can adapt themselves to 

 the prevailing environmental conditions that succeed best in the 

 struggle for existence. Thus the unfit become eliminated, while 

 the survivors which may be classified into the fit, more fit and 

 fittest, continue the process, gradually tending towards the sur- 

 vival and predominance of the fittest. When man interferes 

 with any natural process, whether it is by the cutting down or 

 the planting of forests, he must do so with due regard to natural 

 laws if he wishes his labour to result in ultimate benefit to 

 himself. 



For the successful cultivation of field or forest crops a sound 



