359 



BOOK-NOTES, NEWS, dc. 



At the meeting of the Liunean Society held on June 16th, Mr. 

 Miller Christy read a paper entitled "Observations on the seasonal 

 variations of elevation in a branch of Horse- Chestnut." Mr. 

 Christy detailed the results of a series of observations, extending 

 over three years, which he had made on the branch of a certain 

 horse-chestnut tree growing in his garden. Having noticed for 

 some years that the elevation of this branch above the ground was 

 very noticeably greater during winter, when devoid of leaves, than 

 during summer, when the foliage was on the tree, he made a series 

 of careful observations on its various changes in elevation, due to 

 the difference in the weight of the branch at different seasons of the 

 year. The tree in question was a small one, some 40 ft. in height. 

 The branch on which the observations were made was the lowest on 

 the tree, and about 29 ft. in length. Having driven a nail into the 

 side of this branch at a point 16 ft. 3 in. from the bole of the tree, 

 Mr. Christy measured from time to time the distance between this 

 nail and a brick which he had buried in the ground immediately 

 below. This he did on forty-two occasions between April 21st, 

 1895, and April 25th, 1898, namely, twelve times in 1895, nine 

 times in 1896, fourteen times in 1897, and seven times in 1898, or, 

 on an average, about once monthly during the three years : and the 

 rise and fall of the branch as thus observed was shown diagrammati- 

 cally by means of a chart.- From the results it appeared that during 

 winter little or no change in the elevation of the branch took place. 

 From about the middle of April to the middle of May a rapid 

 descent — the "vernal descent" — took place, coincident with the 

 growth of the leaves. After this ensued a short period of quiescence 

 — the " midsummer rest." Early in August, coincident with the 

 development of the fruit, another and more rapid descent began, 

 which continued during September. Finally, the fall of both leaves 

 and fruit during October was followed by a very rapid rise, the 

 branch almost recovering, during about four weeks, the elevation 

 which it had been gradually losing during the preceding six months 

 or more. In the year 1897 the results were noticeably affected in 

 consequence of the injury caused to the foliage of the tree by the 

 extremely severe hailstorm of June 24th. The extreme range of 

 variation in elevation observed during the three years was about 

 12^ in. (from 81 to 68|- in.). In addition to this periodic seasonal 

 rise and fall, the branch appeared to be undergoing permanent 

 descent, the maximum and minimum elevation in each succeeding 

 year being less than in the year before. These results were, as Mr. 

 Christy pointed out, exactly what anyone might in advance have 

 expected to have occurred ; but he thought that it might be a 

 matter of some interest to show, as a result of precise observation, 

 that these movements actually did occur, and to what extent. 



Dr. Morris has resigned the assistant-directorship of Kew 

 Gardens for the new post of " Imperial Commissioner of Agri- 

 culture for the West Indies." Mr. Chamberlain, when announcing 



