AO 



NA TURE 



J^March 1 1, 19C9 



body by forced breathing, and inhalation of oxygen just 

 before holding the breath so as to prevent the system suffer- 

 ing from oxygen want. Neither of these two conditions 

 would be influenced by doubling the atmospheric pressure, 

 as a few deep breaths of nearly pure oxygen at normal 

 pressure afford one much more oxygen than is needed by 

 the body even during eight minutes. 



If air is inhaled instead of oxygen, the duration of the 

 apnoea is naturally increased with increase of the atmo- 

 spheric pressure up to a certain point, as the total amount 

 of oxygen thereby taken into the lungs, and rendered avail- 

 able for vital processes, rises proportionately to the 

 pressure. H. M. Vernon. 



22 Norham Road, Oxford. 



Moral Superiority among Birds. 



Two letters have recently appeared in Xatlre upon this 

 subject, but they have mainly referred to the relative moral 

 sense of difjeyeni groups of birds. 



It may be of interest to note the relationships existing 

 between allied species. Amongst Corvidje, the rook is 

 gregarious, and breeds in rookeries. It always allows the 

 starling (Sturnida') and the jackdaw to associate with it, 

 and even to breed in the midst of the same social com- 

 munity as itself. Thus these birds are regarded as on an 

 equality, or at worst as inoffensive satellites. A feasible 

 ixplanation is found in the fact that all three are social 

 species, and frequent human habitations. 



On the contrary, the carrion crow lives at most in pairs, 

 never collecting in a body to feed or to nest. It is a 

 scavenger, a feeder on offal, in a word, an outcast. Com- 

 pared with the work of the rook or that of the two 

 birds just mentioned, so beneficial to the farmer, the 

 carrion crow's role is mean and degraded — though neces- 

 sary. It is sly and cunning, and also addicted to 

 purloining. Thus, compared with the rook, which is 

 industrious and useful, and not usually sly, it exhibits n 

 kind of moral inferiority. Very rarely does the rook suck 

 the eggs of game or kill chicks, &c. (on which see Sbool- 

 iiig Times and British Sportsman, July 18, igo8). Indeed, 

 the moral inferiority of the carrion crow is proved by the 

 rook's own attitude towards it. The latter will not allow 

 the crow to invade its domains or to feed \vith it, and if 

 any one of its own species turns to the evil habits of -the 

 crow it is ousted by general consent of the community. 



The same demeanour is maintained in the relations 

 between the rook and the magpie and jay. 



Since psychic as well as morphic characters constitute 

 the sum total of " specific " characters, the study of the 

 moral sense in birds is important. ■ In the animal world 

 its very existence is perhaps best proved by experiment 

 rind comparison. Its neglect in biological work is a matter 

 for regret. In the near future it must plav an important 

 part. \. R. HoRWOOD. 



Leicester Corporation Museum, February 24. 



The Dryness of Winter (1908-9). 

 Thure has been a good deal of surprised comment on 

 the very dry chanacter of this winter, but the season is 

 apparently quite normal in this respect ; that is, a very dry 

 autumn tends to be followed by a dry winter. Here is a 

 table showing the ten driest autumns at Greenwich from 

 1S41 to 1907, and the rain-character of the winter follow- 

 ing in each case : — 



Rainfall 



2 'So 

 3"32 

 3'33 



4-12 

 4-i8 

 4-25 

 4-54 

 4'62 

 47> 

 473 



3-36 



2-38 



6 29 



5-00 



3-98 

 3-27 

 4-46 

 3-91 

 3 97 



Average ... 4^06 ... 4"! 7 

 NO. 2054, '^"OL- ^O] 



Thus in only one case (1884-5) was the winter rainfall 

 in e.xcess. 



The autumn rainfall of 1908 (3-94 inches) would come 

 between (j) and (4) of the above list. 



The opposite tendency (with a very wet autumn) is also, 

 I think, perceptible, though less pronounced. 



Alex. B. MacDow.all. 



Is there a Vertical Magnetic Force in a Cyclone .' 



The discovery of a powerful magnetic force along tlie 

 axis of a solar vortex will have suggested, no douljt, to 

 others besides myself the possibility of a vertical magnetic 

 force in a terrestrial cyclone. If such should exist, and 

 the electrification of the air be positive, there would be a 

 reduction in the magnitude of the vertical component of 

 the earth's field in the northern hemisphere when the centre 

 of the cyclone passes over the place of observation. ,As 

 to the magnitude of the effect, an elementary calculation 

 shows that the intensity of the force in C.G.S. units at 

 the centre of a mass of air 100 miles in radius, revolving 

 with a velocity of fifty miles per hour at that radial 

 distance, would be less than 10^" p, where p is the volume 

 density of electrification in coulombs per cubic cm. Under 

 ordinary atmospheric conditions p has been estimated as 

 of the order io-'°, although much larger values have been 

 sometimes obtained, and the magnetic force consequently 

 would be of the order 10-'. 



Unless the density of electrification is very large in 

 cyclones, it is not likely that a magnetic effect would be 

 observed. Perhaps a tropical cyclone of great velocity, in 

 an exceptionally highly charged atmosphere, might leave 

 a small trace of its passage on the vertical force record. 



Rochdale. March 8. J. R. .^SH worth. 



THE COAST OF THE C.WCASIS.' 



MM.ARTEl.'S description of his journey ,ind ob- 

 • servations in the Caucasus forms one of those 

 tall octavo- volumes, handsomely printed and super- 

 abundantly illustrated, which are published in- Paris 

 at about one-third of the price that would be thought 

 necessary in London. It is the outcome of .-1 voyage 

 for geographical study undertaken in ■ 1903 at the re- 

 quest of IVi. A. .S. Yermoloff, Minister of .\griculture 

 to the Russian (iovernment. The war in the Far East 

 has hitherto delayed the pubhcation of the results, 

 which now takes place in this agreeable form rather 

 than in an official pa'r.phlet. 



Among- the towns that are rising on the eastern 

 shore of the Black Sea, with a view to the attraction 

 of visitors to a new and romantic Riviera, are Sotchi, 

 the favourite of .M. Yermoloff, and Gagri, the haunt 

 of wealthy worldlings. Travellers in Russia will 

 know how eager the rich are to get out of it in their 

 weeks of leisure, and at tiagri since 1903 a pleasure 

 station has been devised which may in time, within 

 the limits of the empire, rival Biarritz or Monte Carlo. 

 .At present its richly oriental bazaar remains; in the 

 fields behind the town the tombs of Mohammedan 

 occupiers stand amid the lands they loved and tended ; 

 and even at the back of a sea-front of luxurious hotels 

 there must always rise the castle wall built bv Mithri- 

 dates, the dark zone of forests, and the limestone 

 plateau of ArabiUa, 8000 feet above the sea. 



M. Martel's passage of the densely wooded ridges 

 on the two flanks of the Arabika (pp. 172-S7) sup- 

 plied more adventure than is usual in a specially con- 

 ducted tour, and this may have made him tolerant 

 of civilised Gagri, then but a year old. But he is 

 far more attracted towards Sotchi, farther up the 

 coast (p. qo), where isolated villas are to rise on the 

 margins of wooded parks, and where even the Grand 



I " La C5te d'A^ur Riisse (Ri- 

 Pp. 358. (Paris : Ch. Ddagrave, 1 



du Caurasel." Py E. .A. Martel. 

 -actually 1908). Price lo frinci. 



