May 1891.] BOTANICAL SOCIETY OF EDINBURGH. 107 



Among other points that come out is the notable one that the 

 fortnightly minimum (400), after growth was fairly established 

 in Spring, and before its final decline in Autumn, fell in June- 

 July, or the height of summer, and the maximum (775) as 

 late as the first half of September. 



The same general results appear when the numbers are 

 arranged in periods of four weeks : — 390, 1350, 1210, 750, 

 1400, 1325, 550. Here the minimum (750) appears in the 

 very middle of the season, with on either side two periods, 

 each of which has not far from double its amount. 



But it is also evident that the depression does not occur 

 in the trees simultaneously. Hence, in the mass, the results 

 tend somewhat to neutralise each other ; and if we take the 

 trees individually, the contrasts come out more strongly, at 

 least in Ahics Lowiana and A. grandis, the most vigorous in 

 look, and the quickest growers of them all. The fortnightly 

 figures are as follows : — 



Abies Lowiana, 45, 50, 185, 235, 245, 195, 95, 75, 150, 175, 175, 225, 100, 50. 

 „ grandis, 20, 145, 150, 110, 0, 90, 85, 100, 200, 250, 175, 250, 150, 75, 



In Ahies Loiviana there is a rise from 45 to a maximum 

 of 245, followed by a great and prolonged fall to a minimum 

 of 75, and a rise to a second maximum of 225 late in autumn. 

 Similarly, in Abies grandis, there is a spring rise from 20 to 150, 

 a summer fall to zero, and an autumn rise to 250. But the 

 fall takes place much earlier in A. grandis than in A. Loiviana, 

 the minimum of the former falling on 24th May-7th June, 

 and of the latter on 5th-19th July. The same phenomena 

 are nearly as well marked in Abies Douglasii, but its fort- 

 nightly minimum falls on 14th-28th June. In Finns 

 excelsa the phenomena are less marked and regular. There 

 is a tolerably well-marked retardation all through July, but 

 the subsequent rally is much less than in the others. In 

 Pinus Pinaster the same tendency can be traced, although 

 still more feebly, but it is a lanky, less vigorous tree, and 

 fell oft' much in its girth-increase in 1890. 



1888 and 1889. — It may be asked. Are the apparent 

 anomalies of 1890 not accidental, — due to some special cause 

 in the season ? iortunately, we have the means of testing 

 this by observations on three of the same trees in 1888 and 

 1889, and in two other pines which were under observation 

 in 1888 only. The intervals of observation were both longer 



