346 



SCIENCE 



[Vol. XVIII. No. 463 



Autumn Colorations. 

 In investigating this subject the first question is, What causes 

 the variation in coloration ? This may be answered by saying that 

 it is a natural ripening of the leaf, a change in the coloring matter 

 of ihe leaf called chlorophyl. One botanist has said: " The green 

 matter in the tissue of a leaf is composed of two colors, red and 

 blue. When the sap ceases to flow iu the fall, and the natural 

 growth of the tree ceases, oxidation of the tissue takes place. 

 Under certain conditions, the green of the leaf changes to red; 

 under different conditions, it takes on a yellow or brown tint. 

 This difference in color is due to the difference in combination of 

 the original constituents of the green tissue, and to the varying 

 conditions of climate, exposure, and soil. A dry, cold climate 

 produces more brilliant foliage than one that is damp and warm." 



It is said by some who have visited England that in many places 

 the ivy, so much cherished by the English people, is being replaced 

 by our American ivy, Ampelopsis quinquefolia. although in that 

 climate it does not take on as beautiful tints as it does in this 

 country, but yet is far ahead of the English ivy. Anot. er botanist, 

 who has visited southern Germany and Switzerland, says that our 

 American ivy is used very extensively in that country for deco- 

 rating all sorts of buildings, and that the leaves take on more 

 beautiful tints than he ever saw in this country. This may be 

 partially due, however, to the contrast between the vine and the 

 -almost universally white color of the buildings in those river 

 valleys. 



AVe may conclude, then, that climate has much, but not all, to 

 do with the variation in coloration for different plants of the 

 same species in the same locality; in fact, different parts of the 

 same plant vary in coloration. Just what makes this difference 

 is an open question. It will be noticed that in many places where 

 one leaf overlaps another that the under leaf is variable in color 

 and that some are variable where they have not been thus imme- 

 diately overlapped. So we see that in some respects it resembles 

 the cokring of the skin of the apple. For, if an apple naturally 

 red at maturity, is partially covered, the covered portion remains 

 green. So far is tliis true that if a paper band is put around the 

 apple before it begins to turn the skin will not color under the 

 band. In this way a person can put his initials or his full 

 nnnie upon an apple. This might also be done with the leaf, but 

 the coi ered portion would not remain green, and might be of the 

 same shades as the exposed portion. This shows that the coloring 

 of Ihe leaf resembles, but is not identical with, that of I be apple. 

 The same may be said with reference to the grape. It has been 

 proven time and again that the grape colors fully as well partially 

 or completely covered as when exposed and, too, to just the same 

 color. This is probably due to the fact that the grape skin itself 

 is nearly transparent and the coloring matter is in the pulp imme- 

 diately nest it. Tl e coloring of the leaf resembles these sorts of 

 coloring more than it does the coloring of flowers. For. if a rose 

 be naturally red, it is thought, I believe, that it will be brighter red 

 when fully exposed. 



Just here we might suggest that, by propagating from individual 

 plants that bear very bright, highly-colored leaves, in a few gen- 

 erations it might be possible to get a tree he leaves of which 

 would be much bi-ightcr than the one with which we started. 



The general brightness of the coloring of the leaves probably 

 depends largely upon the weather during the time of the ripening 

 of the leaves. This present autumn of 1891 is a poor season for 

 bright colorations in the vicinity of Columbus, Ohio, at least. 

 This may be partially due to the dry weather late in September 

 and early in October. 



It would require careful observation on particular plants for a 

 number of years to prove that the weather has the greatest influ- 

 ence. Two plants in particular may be noticed. One i.^i a Japanese 

 species of Ampelopsis on the west side of a brick building. Last 

 autumn the leaves showed great variation in color, making the 

 vine attractive, but this autumn the leaves turn brown and dry 

 xip on the vine, and are rather unsightly. The otht r is a small 

 "tree, generally known as '-sweet gum," or "American liquid- 

 amber" (L. styraciflua), standing in an exposed position. Last 

 autumn the tree showed great variation in coloration, but this 

 autumn nearly all the leaves turn a dull yellow or brown. 



By referring to my diary, I Hnd that in 1890, from Sept. 15 to 

 Oct. 31, there are fifteen days where the weather is recorded as 

 more or less rainy, namely, Sept. 26, 27, Oct. 4, 5, 11, 14, 15, 16, 

 35, 26, 28, 29, 30, 31; while for the same time in 1891 only seven 

 days are recorded as more or less rainy, namely, Sept. 30, Oct. 4, 

 6, 14, 18, 19, 20. We may infer from this that wet weather makes 

 bright colored leaves. Jack Frost probably plays his role, and 

 the food of the plant in all probability is an agent in the matter. 

 However, even this fall our trees and shrubs are affording us many 

 specimens of Nature's handiwork worthy of the highest admira- 

 tion. Dame Nature does not venture to denude all her trees and 

 shrubs without making some to please the eye of man. 



This leads us to the question. Is this all mere chance, or is it 

 done for a purpose ? In the case of the coloring of the fruits and 

 flowers, it is evident that it is for the reproduction and distribu- 

 tion of the species. But in this case it can scarcely be for either 

 of these purposes. If it is for the protection of birds or insects by 

 resemblance, it serves its purpose very poorly indeed. However, 

 let the cause be what it may, let the purpose be what it may, we 

 always enjoy them, and thus they serve a purpose. 



It is surprising how little attention our authors have given to 

 this subject. They have found " sermons in stones and books In 

 running brooks." Is there not enough of beauty in it to give a 

 poet the inspiration, if that is what is wanting? One poet has 

 said, — 



" Heaped in the hollows of the grove, 



The withered leaves lie dead ; 

 They rustle to the eddying gust. 

 And to the rabbit's tread." 



Longfellow's words are familiar to all: — 



' ' The day is cold and dark and dreary ; 



It rains, and the wind is never weary. 



The vine still clings to the mouldering wall, 



And at every gust the dead leaves fall, 



And the day is dark and dreary." 

 We do not find even an allusion to the beautiful coloring of the 

 leaves no more than if they were always brown and sear. 

 Lastly, we might ask, — 



How might not the trees have been made ? 



Intransplantable by shovel or spade. 



Not one twig on a leafy bower, 



Blooming in beauty or bearing a flower ; 



Not one leaf changing its hue 



To blend so beautifully with heaven's own blue, 



Not one form to please the eye 



While towering upward toward the sky. 



E. E. BOGUE. 

 Ohl^ State Uuiveraity, Colambus, O., N.5V. 11. 



Beech-Tree Struck by Lightning. 



I SEND you an additional note on the beech-tree struck by 

 lightning in July (Science, Aug. 11). The tree in question was 

 one of a group of four beech trees and one ash tree, it was an 

 old tree and only in half leaf at the lime. It has since withered 

 almost entirely. That it really was struck there can be no doubt, as 

 I was sitting at a window within fifty yards of it, and I knew by 

 the sound that something had been struck, as the report was 

 sharp and sudden, not reverberating, and was simultaneous with 

 the flash, and, upon going out immediately afterwards, I found 

 the upper part of the trunk and branches freshly bared and the 

 bark strewed at the foot of the tree. T. D. 



York, England. 



The Crescent Moon with a Star within its Rim. 



There is one passage in the poem of the "Ancient Mariner" 

 which had always been a puzzle to me until a few years ago, when 

 I observed a phenomenon which I think supplies a satisfactory 

 explanation of the meaning of the author. The lines referred to 

 are those in which the crescent moon is described as having a star 

 within its rim. I was in the south of England at the time, and 

 the phenomenon which I saw was as follows : One clear evening, 



