Dr. David Christison, at the April 14th meeting of the Edinburgh Botanical Society, gave the results of monthly measurements of different species of deciduous and evergreen trees in the Edinburgh Botanic Garden from 1883 to 1886. It was ascertained:

1. That some trees begin to increase in girth in April, but only a very little, and that some continue to grow to a still more trifling extent in September; that the growth of evergreens in May is considerable, but that the main increase of deciduous trees is confined to June, July, and August.

2. The maximum month of growth in most of the deciduous trees examined was July, and in most evergreens June.

3. That the increase in deciduous and evergreen trees in April was about equal, but the latter then went rapidly ahead, so as to accomplish the greater part of their annual increase in the first half of the growing season, while that of deciduous trees took place in the last half. In both classes, however, there were exceptions, and notably the Deodar, which increased in energy up to August, and accomplished 65 per cent. of its increase in the latter half season.

4. The annual increment in evergreens is spread more equally over the months than that of deciduous trees. Several species of the latter grew more than 50 per cent. in a single month. Some of the results are shown in the table, which gives only those species in which the results are fully reliable. Experiments on many other species have been commenced with the view of ascertaining their characteristics, and whether a general law of distinction between deciduous and evergreen trees can be made out.

Monthly Percentage of Increase of Girth in different Species of Trees, in Edinburgh Botanic Garden or Craigiehall, based on Three Years' Measurements: