Jan. 1898.] BOTANICAL SOCIETY OF EDINBURGH 95 



largest radius was found to be on tlie side exposed to the 

 greatest light. 



The present paper is an attempt to find a relationship 

 between the annual diameter-increment and the climatic 

 or meteorological conditions. A better plan would have 

 been to compare the annual area-increment with those 

 conditions, but the additional labour of calculating the 

 areas for each year would have extended the work over 

 another month ; by this latter method, however, the 

 average height of the curves would have been maintained : 

 whereas, by using the diameters only, the average heights 

 of their curves naturally decrease with time, because, as 

 the girth of the tree expands, the average increment of the 

 diameter decreases. 



There is very little lost in the method adopted, since 

 girth and area are continuous functions of the diameter. 

 The rise and fall seen in the diameter curves would be 

 seen at the same places in the girth and area curves, only 

 they would be more pronounced in the last two. 



Of the specimens mentioned in the first paper, only five 

 could be used for the purpose of drawing out continuous 

 curves of the annual diameter-increment, because in these 

 cases the measurement of each annual ring had been 

 taken, while in the three omitted from the present paper 

 measurements had often to be taken of 5 or more years 

 collectively, owing to the smallness of the rings. 



Meteorological observations have been made at Braemar 

 since 1856 — the greater part of the time by Mr. James 

 Aitken, the present observer — at the Observatory founded 

 by H.Pi.H. the late Priuce Consort in 1855; and the 

 observations from 1856 to 1893 were reduced, by Mr. 

 E. C. Mossman, F.Pi.S.E., and recorded in the "Journal" of 

 the Scot. Met. Society (Vol. x.. Third Series, No. x., 1894). 



From Mr. Mossman's tables I have calculated means for 

 periods of three and six months respectively, while the 

 tables supplied the yearly means ; and curves have been 

 drawn for temperature and rainfall, showing the three- 

 monthly periods, beginning with January of each year. 



By uniting the second and third periods and taking the 

 averages, the curves for the growing season — April to 

 September inclusive — have been obtained. My object in 



