400 



NA TURE 



[Feukuaky 3, 1910 



< anton Valais, being- 13S5 metres, and in Canton St. 

 Gall onlv 270 metres. 



Sometimes these pines form distinct and close-grown 

 woods, to the e.xclusion of other conifers, in which 

 each one is similarly developed. Such woods, how- 

 ever, are not common, and are generally restricted to 

 the Orisons and Canton Valais, where the Arve is 

 most abundant. More often, however, even when not 

 mixed with other kinds, individuals grow either in 

 more open order or in small clusters, or even as soli- 

 taries. On the slopes of the northern Alps they not 

 unfrequently form trailing lines, the trees in which, 

 as might be expected, often bear the marks of storm 

 and stress. But the Arve more commonly is asso- 

 ciated with other conifers — the larch, the spruce, the 

 Scotch fir, and sometimes the silver fir. Another, but 

 more lowly companion, is the Legfohre (Pinus mon- 

 taiia), thai: trailing conifer which is more abundant 

 in the eastern than in the western Alps, and altogether 

 absent, so far as Dr. Rikli knows, from the Valais 

 and the Oberland. The Arve also grows in company 



with other trees and bushes, such as the birch, the 

 beech, the Alpine alder, a service {Sorbus aucii- 

 paria), and, of course, with the common rhododendron 

 (R. ferriigiiicuni), the bearberry {Arctostaphylos uva- 

 ttrsi). the bilberry {Vaccinium myrtillus), and another 

 member of that genus ; while in the associated 

 flora a mid-Europe .Alpine, a north-Europe Alpine, 

 and an Arctic-Altaian element may be detected ; the 

 last, as Dr. Rikli remarks, forming a link with the 

 Arve's original home. 



This memoir describes, with illustrations from re- 

 produced photographs, the modes of growth which, 

 according to circumstances, the Arve exhibits. A 

 solitary one, when in its full vigour, is a happy com- 

 bination, as Fig. I proves, of beauty and strength. 

 With the advance of age it is apt to lose its symmetry 

 and compactness, though it is still, as Fig. 2 

 shows, an ornament to the landscape. No 

 more than other trees does it escape being torn by 

 the storm or the avalanche, shattered by the lightning, 

 and nipped, especially when young, by e.Kceptionally 

 NO. 2IOI, VOL. 82] 



severe frosts ; but when overthrown, it sometimes puts 

 out new roots and converts side branches into lead- 

 ing stems. But the Arve has its enemies also among 

 other living things. Man is responsible for reckless- 

 hacking and felling, for forest fires or damage done- 

 in climbing after its cones, the kernels in which 

 have a nut-like flavour. But now that he is re- 

 strained by forest laws, other creatures are the more 

 formidable. Goats, sheep, and cattle (especially the- 

 first, if carelessly tended) do much damage to the 

 young plants ; the roe-deer, the stag, and the chamois- 

 take their share when in search of food. The marten, 

 the squirrel, and even the fox, feed on the nuts, 

 though the last, like the wood and hazel mice, must 

 wait" until they have fallen. Some birds also have 

 similar tastes. Most conspicuous among these is the 

 nutcracker {Niicifraga caryocatactes), which is never 

 so common in the .-Mps as where the Arve is plentiful 

 and its fruit is ripening. The capercaillie {Tetrao- 

 iirogallus) feeds on the young shoots, and the com- 

 mon sparrow, generally to the front in mischief, has- 

 been known to do the same with seedlings. Its insect 

 foes we can only mention. 



In short, Dr. Rikli seems to have touched on every 

 point of interest in the life-history of PitiKS cembra 

 in Switzerland, and has done his work with Teutonic 

 thoroughness. He goes over the country, canton by- 

 canton, and valley by valley, citing statistics of the 

 numbers of the trees, their distribution on either 

 slope, and other distinctive features ; he gives many 

 particulars of the age, size, and rate of growth of the 

 older trees, and refers to the care which, of late years, 

 has been bestowed on their culture. The maps ap- 

 pended to the volume are interesting as showing the 

 relative abundance or scarcity of Pinus cembra in 

 different districts of the -Alps, and the numerous 

 photographs, especially the eighteen separately- 

 printed, some of which are unusuallv good, recall to 

 lovers of that mountain chain pleasant memories of 

 this handsome tree. To such Dr. Rikli 's work will 

 always be attractive ; but to students of forestry it will 

 be indispensable. T. G. B. 



ON HALLEY'S COMET AS SEEN FROM THE 



EARTH. 

 'T'HE following table gives ecliptic coordinates of 

 ' Halley's comet to two decimal places at in- 

 tervals of four days through an arc extending from 

 one end to the other of the latiis rectum of its orbit. 

 The zero of time is very nearly the moment of peri- 

 helion passage, and the figures apply approximately 

 to any return. 



The comet attains unit distance from the sun 

 thirty-nine days before and after perihelion passage. 

 On the former occasion its z coordinate perpendicular 

 to the ecliptic is +o'i5, on the latter —0-07. It is 

 evident, therefore, that the closest possible approach 

 to the earth will occur after perihelion passage. The 



