200 



. KNOV/LEDG2 



pollen with him ; anil as he rifles the nectaries in the 

 second blossom, he loth deposits pollen from the last plant 

 upon the sensitive surface of the carpels in this, and also 

 collects a freslx lot of jwUon to fertilize whatover other 

 tlower he niav next favour with a call. The increased 

 i-ertainty of fertilisation thus obtained enables the plant to 

 dispense with some of the extra carpels which its buttercup 

 ancestors once possessed ; and by lessening the number to 

 three, it nianajLces to get the whole set impregnated at a 

 single visit But, as three seeds would be a small number 

 to depend upon in a world of overstocked markets and 

 adverse chances, it makes up for the diminution of its 

 carpels by largely increasing the stock of seeds in each. 



Thus the whole shape and arrangement of the monks- 

 hood liear distinct reference to the habits and tastes of the 

 fertilising bees. It is a mountain plant by origin, 

 lielonging to a tribe which took its rise among the great 

 central chains of Europe and Asia, and these Alpine races 

 are usually highly developed in adaptation to insect ferti- 

 lisation, because they depend more absolutely upon a few 

 upland species than do the eclectic (lowers of the plains, 

 which may be impregnated hap-hazard by a dozen ditterent 

 flies, or motlis, or beetles. We can still dimly trace 

 many of the links which connect it with very simple 

 and primitive buttercups, if not directly, at least 

 by the analogy of other plants. For all the 

 buttercup tribe show us regular gradations in the same 

 direction. Tlie simplest kinds are round, yellow, and 

 many-carpelled, like the buttercups. Then those species 

 which display their sepals largely have dwarfed petals, like 

 liellebore and glol>e-flower, or have lost tliem altogether, 

 like marsh-marigold, which trusts entirely for colour dis- 

 play to its big golden calyx. The still higher anemones 

 have the sepals white, red, or blue ; and the very advanced 

 columbine has all the petals spurred, and developed into 

 nectaries, like those of monkshood. l!ut columbine 

 still keeps to single terminal flowers, so that here the 

 live petals remain regular and circularly symmetrical, 

 though the carpels are reduced to five. Fancy a number 

 of such columbine flowers crowded together on a spike, 

 however, and you can readily picture to yourself by rough 

 analogy the origin of monkshood. The sepals would now 

 liecome the most conspicuous part ; the two upper petals 

 would alone be useful in insuring fertilisation, and the 

 lower ones would soon shrivel away from pure disuse. 

 The development of the hood, and the lengthening of the 

 upp<,T petals, would ea.sily follow by insect selection. It 

 is a significant fact that our only other spiked buttercuji, 

 the larkspur, has equally irregular and bilateral flowers, 

 though its honey is concealed in a long spur formed by the 

 petals, and accessible to but one English insect, the 

 humble Ikc. 



VENDS NEARING TRA>'SIT. 



By the Editor. 



(Conlinutd from pwje 275.) 



IN the firfct part of this article, I liave given an account 

 of the various changes of appearance presented by the 

 l«autiful star which sometimes shines as Hesperus, the star 

 of evening, and sometimes as Lucifer, the morning star. 

 I>.t U8 now consider what this star really is, so far, at least, 

 as we can learn by using tijh^copes and other instruments. 

 Venus has, in the first place, been measured, and we 

 find that she is a globe nearly as large as the earth. Like 

 the earth, she travels round and round thi- sun continually, 

 but not in the same time as the eaKli. The earth goes 



round the sun once in twelve months, while Venus goes 

 round once in about seven-and a-half months ; so that her 

 year, the time in which the seasons run through their 

 changes, is four-and-a-half months less than ours. If 

 Venus has four seasons like ours, — spring, summer, 

 autumn, and winter, — each of these seasons lasts eight 

 weeks. Venus also, like our earth, turns on her axis, and 

 so has night and day as wo have. Her day is not quite so 

 long as ours, but the dillerenco — about twenty-five minutes 

 — is not very important 



So far there is nothing in what we liave learned about 

 Venus which does not agree well with the idea that the 

 planet is a world like our earth, where people like ourselves 

 might live very comfortably. For it would not matter 

 much to us, probably, if the year were shortened by four 

 or five months, and the day by half-an-liour — supposing 

 always that trees and vegetables were so made that they 

 could thrive under the change. In fact, if anyone leaves 

 the temperate regions to visit the tropics, ho has to under- 

 go a greater change. For in England, and throughout the 

 United States, the seasons change from the heat of summer 

 to the cold of winter, and back again to the heat of summer, 

 in twelve months ; but at the equator, the greatest heat 

 occurs in spring and autumn, or at intervals of only six 

 months. So far as the length of the year is concerned, an 

 American or an Englishman could very well bear the 

 change to the temperate zone of Venus, where the interval 

 between the successive seasons of greatest heat amounts to 

 seven-and-a-half months. 



But when we consider some other points, we see that 

 Venu.s, beautiful though she looks, would not bo a com- 

 fortable home for us. Venus is much nearer to the sun — 

 the great (ire of the solar system — than our earth is. She 

 receives, then, much more heat from him. In fact, it is 

 easily calculated that if our earth were S(^t travelling on 

 the path of Venus, we should receive almost exactly tfwico 

 as much heat from the sun as we do at present. This 

 would be unbearable, except, perhaps, in the Polar regions ; 

 and even there the summer, with that tremendous sun 

 above the horizon all through the twenty-four hours, would 

 be scarcely bearable. Besides, wliat a contrast between 

 the hot Polar summer and the cold Polar winter, wlien for 

 weeks together the sun would not be seen at all. Altogether, 

 this earth would be a miserable home for us if her path 

 were as close to the sun as that of Venus. 



We see, then, that either there must be some peculiarities 

 about Venus which prevent the sun from heating people 

 there as he would certainly heat us if our home were there, 

 or else the creatures which live on Venus must be difierent 

 from ourselves and the other animal inhabitants of our 

 earth. Unfortunately, we cannot make telescopes largo 

 enough to show us what is going on upon that planet, and 

 there is no reason for hoping that such telescopes can ever 

 be made. What wo know, however, about the planet's 

 condition does not seem to show that creatures living there 

 would be more comfortable than we should be if the earth 

 were put wliere Venus is. Just the contrary, so far as we 

 can judge. The seasons on our earth are caused by the 

 fact that she turns on a slanted axis. If her axis were 

 ujiriglit, there would be no seasons; if it were more slanted, 

 the contrast between summer and winter would be greater. 

 Now Venus has her axis much more slanted than the 

 earth's, so that her seasons must be very marked ind(^'d. 

 Thus the heat of her summer weather must be even more 

 terrible than if her globe were inclined like the earth's. 



But there is yet anoth(;r point to be noticed. On the 

 upper slopes of lofty mountains, there is snow all the year 

 round, even in the torrid zone. That is because the air up 

 there is so rare that t does not act like the denser air 



