TIMBER FOR AEROPLANE AND PIT-PROP PURPOSES. 



71 



Noble Silver Fir. District grown : Murthly. 

 Material received, 25th November 1918. Material tested, November 1919. 



Black Italian Poplar. District grown : PoUok. 

 Material received, 25th November 1918. Material tested, November 1919. 



Bent and cracked 14 ins. from small end. 

 Cracked and bent in two places (1)4! ins. 



from small end, (2) 11 ins. from small end. 



Bent considerably under maximum load but 



not crushed. 

 Bent considerably under maximum load but 



not cracked (tested Novemlter 1918). 

 Slightly Vjent in two places before test. Under 



maximum load crack developed in centre of 



one of original bends (tested November 1918). 

 Bent considerably before test : i "3 in. out of 



straight. Under maximum load bent but 



not crushed (tested November 1918). 

 Slightly bent before test. Bent considerably 



under maximum load and was crushed on 



compression side (tested November 1918). 



In December 19 19 I was supplied with ten pit-props of 

 average Finnish red and white wood, the overall diameters 

 varying from 3 inches to 6 inches, the average crushing strength 

 was 3996 lb. per sq. inch. It will be observed that good, well- 

 grown Scottish timber is quite as strong as the imported timber, 

 and there seems no reason why a large amount of the timber 

 required for coal pit purposes should not be grown in Scotland. 



During the tests of a certain quality of Scots pine, it was 

 found that the timber had been attacked by the fungus 

 {Ceratostoma piliferum), which produced the well-known blueing 



