310 TRANSACTIONS AND PROCEEDINGS OF [Sess. lvi. 



The range is greatest iu the two earlier months, due no 

 doubt to the great variety in the meteorological conditions 

 of different springs, by which the early efforts at growth are 

 apt to be much retarded, or even entirely stopped. But the 

 variations in a particular month are, no doubt, not always 

 entirely ruled by the meteorological conditions of the month 

 itself. Previous unfavourable months may influence a 

 month favourable in itself ; and in an unusually late season 

 the main growth may be pushed on, as it were, towards the 

 end of the season. Thus the very high proportion (28'5) of 

 August 1891 must apparently be due to this cause, as the 

 spring growth was very deficient, while August itself was a 

 cold and wet month. These disturbing influences make the 

 study of the connection between weather and monthly growth 

 very intricate. 



c. Monthly Proportion of Girth-increase in Deciduous Trees, 

 individually. 



In Table VI. I have given the monthly p.c. of girth- 

 increase, not only of the thirty-four young trees under 

 observation from 1887 to 1891, but also of twenty-four of 

 the older set observed between 1883 and 1887, making 

 fifty-eight in all, belonging to twenty-two species. The 

 Table gives the half-season p.c, as well as the monthly p.c, 

 the trees being arranged in the order of greatest growth in 

 the first half-season. The averages of the younger trees are 

 almost all founded on five, and of the older ones on four 

 years' observations. 



It would take too much space to give all the results that 

 might be derived from Table VI. I must limit myself to a 

 few of the most obvious and striking ones. 



Species which show the largest prajwrtional Increase 

 in the different Months. 



April. The most reliable instance of a comparatively 

 large proportion is in the quickest-growing species of all, 

 Quercus conferta, the three trees of which attained 9, 9, and 

 8 p.c. of their total growth in this month. Larger results 

 come out in No. 44, Quercus palnstris (10 p.c); No. 14, 

 Farjus (11 p.c); and in No. 33, Carpinus (17 p.c), but these 

 trees grew .slowly and irregularly, and are ncjt so reliable. 



