Sir Robert Christison, the great Scotch chemist, has made some
curious observations on the effects of a cold, wet season in diminishing the normal growth of trees. He makes out, on careful measurements, that comparing 1879 with 1878, eleven deciduous trees—not oaks—made on an average 41 per cent. less growth in last year than in the year before. Of 17 pine trees, the average deficiency was 20 per cent. ; and of seven oaks, the deficiency was 10 per cent.; so that heat appears to have more to do with the making even of wood than moisture has, It is strange that the growth of the oak, which drops its leaves, seems less dependent on heat than that of the pine, which we usually associate with very cold regions ; but, perhaps, it need not be the tree which is most stunted by cold, which is most easily killed by it. The arrest of growth may sometimes be a safeguvd against vital injury-
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