Dec. 1897.] BOTANICAL SOCIETY OF EDINBURGH 87 



Again, it may be that the whole experiment was too late 

 in the season, or it may be that the soil was otherwise 

 unsuitable, or it may be that the nitragin had lost its 

 vitality, or it may be that it does not possess some or any 

 of the virtues ascribed to it. I hope, during the coming 

 season, to be able to say which of the many hypothesis 

 that may be started are of any importance, for I hope to l^e 

 able to anticipate every possible objection that a believer in 

 the value of nitragin might be expected to raise. 



Measurement of the Girth of Coniferous Trees at 

 Bkaemar in 1894. By E. Turnbull, B.Sc, and 

 Percival C. Waite. (With Plate.) 



(Read 9th December 1897.) 



During April 1894 we spent a fortnight at Braemar, 

 and had many opportunities of observing the destruction 

 caused by the great November gale of 1893. 



Every wood and forest in the neighbourhood had 

 suffered, and the foresters had been busy during the 

 winter sawing the blown trees into logs. We determined 

 to measure the radii and annual increment of diameter of 

 specimens of Scots pine, Norway spruce, and common 

 larch, so as to be able to calculate the annual increment 

 of girth. 



Those trees had all, with one exception, grown on the 

 slopes of steep hills, and it was found that the side of the 

 tree which was most obscured by the hill or other trees 

 presented the smallest radius, while the longest radius 

 was turned towards the greatest light. 



Thus we found the greatest radii on the N., E. and S. 

 sides respectively, in trees with an open aspect in those 

 directions. In none of our specimens did we find the 

 greatest radius to the W., but this may be merely an 

 accidental occurrence, and one to which at present we can 

 attach no importance. 



It is a law in plant-growth that leaves and the young 

 aerial parts of plants turn towards the light. This pbeno- 



