12 NATURAL SCIENCE [July 



certain species of Coscinodiscus which are abundant at one season, 

 disappear later in the year. 



Plants and the Weather 



We have received an interesting little pamphlet on the effects of 

 weather upon vegetation, the subject of a recent lecture to the 

 Bradford Naturalists' Society. 



The lecturer, Mr John Clayton, has made some simple but none 

 the less instructive experiments, the results of which he put before 

 his audience. The effects of sunshine are, as we should expect, very 

 striking. Of twelve bean-plants, as like as possible in size and 

 health, six were placed in the ground where they would catch all 

 the sunshine of the day ; the other six were sheltered by a boarding 

 which effectually prevented any rays from falling upon them. When 

 freshly gathered in October the weight of beans and pods grown in 

 sunshine was more than three times as great as in the case of those 

 grown in the shade (99:29), while the weight of the dry beans was 

 in a similar proportion (16 : 5). The experiment was continued in 

 succeeding years. Thus in 1892 the fresh weight of beans and pods 

 grown from the sunshine-grown seed of 1891 was half as much again, 

 as in the case of plants from shade-grown seeds — all being grown in 

 sunshine and under precisely similar conditions in the second year. 

 In the fourth year plants with an exclusively shady ancestry produced 

 flowers, but failed to mature fruit. 



A series of measurements illustrating the contraction of trees in 

 frost was made in the winter of 1894-5. A comparison of the 

 girth of tree-trunks in October, when growth had ceased but before 

 the frost set in, with the girth at 9 a.m. on February 8th, at a 

 temperature of 3° F., showed an appreciable contraction under frost. 

 In the sycamore it was from two to three sixteenths of an inch, in 

 the elm from three to five sixteenths, in the oak from five to six 

 sixteenths. On March 2, at a temperature of 39° F., the trunks had 

 expanded to their original measurements. To this contraction under 

 frost is due the frequent splitting of our forest trees. 



An interesting review is also given of the distribution of sunshine, 

 rain, &c, in the different months of the year ; and various improve- 

 ments are suggested for individual months, which we recommend to 

 the consideration of the clerk of the weather. 



Plant Chemistry 



The chemistry of some common plants is discussed by Dr P. Q. 

 Keegan in a recent number of The Naturalist. The buttercup owes 



