250 Dr Christison on the [sess. lii. 



On the whole, we may conckide that, imrler the given con- 

 ditions of soil and climate, beeches of so considerable a girth 

 as 7 feet, maij continue to grow at the rate of 1 inch a year, 

 and even when 12 feet in girth, at the rate of 0*80, and that 

 the average of healthy beeches of mature age should be at 

 least 0"60. The average of the seven measured in the favour- 

 able season of 1878 was 0"80. 



The ranr/c of the annual increment varied much in the 

 different trees, the lowest, 1'20 to 0'80, being in No. 7, and 

 the highest, 0"60 to -OlS, in No. 38. The aggregate range 

 was also considerable. In the seven trees measured for ten 

 years, it lay between 5'70 in 1878 and 3"40 in 1880. Includ- 

 ing the three trees which were measured only in the last 

 seven years, it was between 7"oO in 1882 and 4-90 in 1887. 



None of the measured beeches suffered lasting injury 

 either in appearance or growth from the three consecu- 

 tive bad seasons ; but the effect at the time was distinct 

 enough on growth, the girth-increase of the seven trees then 

 under observation having dropped from 5"70 in 1878 to 4-25 

 in 1879, and 3-40 in 1880, rallying, however, to 4-30 in the 

 third severe season, 1881, and further in 1882 almost to the 

 standard of 1878. It is worthy of remark that all seven, 

 without exception, fell off in 1879, but only four of them 

 continued to fall off' in 1880, the fall in some, however, being 

 very great, while in 1881 every one either improved, or at 

 least suffered no further loss. This general improvement in 

 the third of three trying seasons seems very remarkable, but 

 was common to the deciduous class in general. It is not 

 easy to account for the escape of three in 1880, unless situa- 

 tion had something to do with it ; two of the three were on 

 the island at Craigiehall, and actiially improved substantially 

 in their increase in that year. The species a])parently did 

 not entirely escape from the depression of 1883 ; and the 

 increase was low in 1885, 1886, and 1887, but particularly 

 in tlio latter year. 



Quercus Rolmr. 



The ]>ritish oak, in the neigldjouiliood of Edinburgh, as 

 in most parts of Scotland, rarely takes very kindly to the 

 soil. The st(!m, indeed, often attains a considerable size, and 

 is well shaped, but tlicre is generally a marked scantiness in 



