October 31, 19 12] 



NATURE 



The existence of the stratosphere has taught us, how- 

 ever, that this is not the case. 



Though it seems rational to presume that the high 

 westerly winds are an extension of those at higher 

 latitudes {±15°), and also that the Krakatoa wind 

 comes from still higher latitudes, being deflected by 

 the rotation of the earth in an easterly direction, more 

 observational data from other stations are urgently 

 wanting for a thorough explanation of the facts. 



Batavia, September 24. W. van Bemmelen. 



The Blind Prawn of Galilee. 



In describing the eyeless prawn from Galilee that 

 he named Typhlocaris galilca, Dr. Caiman stated 

 that, according to the information at his disposal, it 

 was found in a small pool near the town of Tiberias 

 communicating with the lake and fed by a mineral 

 spring (see Trans. Linn. Soc, London, 2nd ser., 

 zool. xi., p. 93, 1909). As Typhlocaris is one of the 

 most peculiar crustacean genera described of recent 

 years, further particulars as to its proi enance may be 

 of interest to naturalists. The pool in which alone, 

 so far as is known, it occurs is situated some two 

 hundred yards from the Lake of Tiberias, an hour 

 and a half's sail north of the town of that name. 

 Originally this pool was one of the chambers in a 

 Roman bath at some forgotten city, perhaps 

 Capernaum or Bethsaida. It is still completely en- 

 closed by stout masonry which gives it a symmetrically 

 octagonal outline, but its surface is choked with 

 gigantic floating grasses. There is now no visible out- 

 flow or inflow of water, which apparently percolates 

 through the bottom at several places and decreases in 

 volume by desiccation. .As its temperature is dis- 

 tinctlv lower than that of the water in the aqueduct 

 that works a corn-mill between it and the lake, it 

 seems improbable that there is any great outward per- 

 colation. It is evident, however, that the water, which 

 even now is nowhere less than about 4 ft. deep, was 

 in ancient times much deeper, and that the overflow 

 was conducted away by means of apertures in the wall 

 high above the present surface, while there are traces 

 of an aperture through which it may have entered the 

 pool in volume in a masonry platform that juts out 

 into the pool from one of its eight sides. The water 

 is slightly saline, but not so markedly so as that of 

 some springs in the vicinity. 



The first Typhlocaris that I saw on a recent visit 

 to the pool was crawling on the side of tlie platform 

 about three feet below the surface, making its way 

 slowly in and out of the crevices. .Apparently the 

 claws as well as the antennje were used in testing the 

 surface along which it moved. A piece of bird's flesh 

 weighted with a small stone was lowered on a string 

 to attract it away from the stones and render its 

 capture more easy. It seized the string" in both its 

 claws and gave it a vigorous tug. It then made its 

 way to the flesh, but when the latter was forthwith 

 attacked by a number of small fish (Discoanalhus 

 lanila), the prawn moved away. .Although the fish 

 made no attempt to injure it, it invariably avoided 

 theni. When touched with a net it darted violently 

 backwards, straightening its claws in front of it as it 

 did so, but no great difficulty was experienced in cap- 

 turing it. .At the time of our visit (about 5 p.m.) the 

 pool was in shade, but the prawn did not seem to 

 avoid such light as reached it. .A second individual 

 was seen crawling on the bottom at dusk, but none 

 ivere seen in the early morning. 



There was no trace of colour on the living prawn, 

 ■except that the internal organs of the thoracic region 

 produced a dusky blotch externally. The whole body 

 was otherwise of a semi-opaque white like that of 

 paraffin-wax. 



The appearance of Typhlocaris in the pool is most 

 NO. 2244, VOL. 90] 



erratic. Herr Grossmann, who sent the first specimens 

 to the British Museum and assisted me greatly in my 

 search for more, tells me that he has often visited the 

 pool without seeing any, and one of the German 

 fathers who have a hospice in the neighbourhood 

 stated that while on one occasion a Bedouin caught 

 five individuals in a single day, on another none were 

 seen for six months. On the whole, I agree with 

 Dr. Caiman in thinking that the real habitat of 

 Typhlocaris is subterranean, but I have little doubt 

 that having once made their way through some crevice 

 into the pool, individuals are able to flourish there, 

 hiding in crevices in the walls or under the vegetation 

 that floats on the surface. N. Annandale. 



Tiberias, Palestine, October 8, 1912. 

 Is the Earth Shrinking? 



In a recent popular work I find the statement, 

 "The earth is still slowly shrinking. ..." I am 

 aware that this statement fits in with our preconcep- 

 tions and may even appear trite and commonplace, 

 but it is sometimes just such statements that best 

 repay investigation. I would, therefore, inquire 

 whether there is any unequivocal evidence that the 

 volume of the earth as a whole either is now suffer- 

 ing, or has in the past suffered, progressive diminu- 

 tion. 



If there were direct evidence of progressive cooling 

 on the part of the earth, diminution of volume would 

 b? almost a necessary inference, but on this point I 

 understand that geological evidence is by no means 

 favourable. As regards the presence in various regions 

 of folding, overthrusting, reversed faulting, &c., such 

 phenomena are evidence of surface compression in 

 regions where they are found; and in a precisely 

 similar manner the presence of rifts, fissures, ordinary 

 faulting, &c., is evidence of local surface expansion, 

 although the latter result is seldom emphasised. In 

 a given region it is easy to picture such a combination 

 of' folding" with fissures cutting across the folds as 

 would cause the region to sufl'er distortion without 

 either diminution or increase of superficial area._ If 

 such be conceivable within the limits of a local region, 

 it is evident that the mere presence of folding and 

 the like, unsupported by an intricate quantitative 

 examination, will not warrant the conclusion that the 

 earth as a whole is shrinking. On the other hand, 

 if due regard be paid to the physical properties of the 

 materials composing the earth's crust, is it not re- 

 markable that extensive regions exist which do not 

 appear— at least in geologically recent times— to have 

 suffered compression? 



October 13'. H. Birrell. 



For a quantitative discussion of the effects of secular 

 cooling on the earth's crust, Mr. Birrell may be 

 referred to a couple of papers by Dr. C. Davison and 

 Sir George Darwin in the Philosophical Transactions 

 of the Roval Society for 1887. He will find that 

 though the' speculative nature of the assumption is 

 frankly confessed, yet the observed phenomena are 

 shown to be consistent with the theory of contraction 

 and secular cooling. On the whole, students of cosmo- 

 gony (as opposed to geology), arguing to sorne extent 

 frorn the analogy of other celestial bodies, are in 

 agreement in accepting the hypothesis of secular cool- 

 ing. -A notable exception is Prof. F. R. Moulton, of 

 Chicago. In conjunction with Prof. T. C. Chamberlin, 

 he has developed a "planetcsimal hypothesis," accord- ■ 

 ing to which the earth was built up by a series of solid 

 accretions. The hypotheses of secular cooling and 

 initial hich velocity of rotation for the earth have 

 no place in his theory. For details Mr. Birrell may 

 be referred to "The Tidal and other Problems" 

 (Carnegie Institution of Washington, 1909)- 



F. J. M. Stratton. 



