60 Dr David Christison on the [sess. li. 



every year, and although the tree grov^rs at the rate of above 

 an inch yearly, its characteristics can hardly be taken as 

 typical of the species. 



African Cedar. — Girth, 42 inches. Vigorous, healthy, and 

 reliable. 



Yeios. — Girths, 27, 34, 41, 72 inches. This is the only 

 species in which scaling of the bark seems to be a formidable 

 obstacle to accuracy of measurement, yet the uniformity of 

 results during five years does not appear to have been seriously 

 disturbed from this cause, and the averages taken for so long 

 a period in four specimens may be accepted as sufficiently 

 reliable. 



Deodars. — Girths, 24, 26, 34, 70 inches. The two older 

 trees are not easily measured, but the results do not differ 

 materially from those obtained in the two younger trees, and 

 the average of the whole is satisfactory. 



The following general conclusions may be drawn from the 

 Tables : — 



1. July was decidedly the best growing month in the 

 deciduous class, its proportion being double that of any other 

 month. It was also the best in nine of the eleven species. 

 But in the evergreens no month predominated decidedly over 

 the others, June being but a trifle above July, while May 

 and August lagged not far behind. This arises partly from 

 growth in each species being more evenly distributed over 

 the months among evergreen than deciduous trees, partly 

 from the maximum occurring in a greater variety of months 

 among the former. Thus, May was the maximum month in 

 Abies Lowiana and Pinus austriaca, June in Araucaria 

 imbricata and Sequoia girjantea, July in Taxus haccata, August 

 in Cedrus Deodara, while in Cupressus Laivsoniana the maxi- 

 mum was distributed nearly equally over June and July, 

 and in Cedrus atlantica over July and August. 



2. In several species the rate of increase, month by month, 

 to the maximum was not progressive. This occurred chiefly 

 in the deciduous group, and was most marked in the group of 

 oaks. Thus, in the Hungary oak the rates for April and 

 May were almost the same ; while in the Turkish, American, 

 and English oaks the rate for June was actually less than for 

 May, in some of them most remarkably so. It would be 

 rash, however, to hold that these results are generally applic- 



