272 



NATURE 



{July 18, 1889 



considerable share of his attention in the long interval between 

 the publication of the first and second editions of his book. As 

 to acquaintance with the objects of his writings, he had none, I 

 presume, with that horrid creature with the swim-bladder from 

 which he believed we are all descended ; nor with most of the 

 animals which have formed the connecting links between that 

 distinguished progenitor and man ; but, nevertheless, his great 

 collection of facts and evidences have been of sufficient weight 

 to revolutionize the history of creation, and to pervert hundreds 

 of thousands from their faith in the poetical narrative of Moses. 



However, Dr. Guppy is correct in saying that there are certain 

 upraised ancient reefs in the Lau group of Fiji. Lieut. Malan 

 was no doubt alluding to the islands of Tavutha, Naiau, and 

 Kambara, which have every appearance of atolls lifted out of 

 the sea, for they are coral islands of considerable height, with 

 an exterior rim and depression in the centre, between 150 and 

 200 feet deep. It does not follow that they may not form now 

 part of a descending area ; nor that the Bukatatanoa and Reid 

 Reefs may not be participating in the movement. It is remark- 

 able that only one reef has yet been discovered which connects 

 the atoll awash with the i.-laud many hundreds of feet high which 

 has been, to all appearance, an atoll in past ages. As far as I 

 am aware, there is no island known, except Aldabra (which has 

 a lagoon dry at low water, and is, therefore, an abnormal 

 instance), of coral formation, with a lake in the centre and 

 openings on the lee side ; in such a stage as an atoll would 

 be if it was elevated, say, 20 or 30 feet ; nor do I believe 

 that anyone has yet seen an upraised island barrier reef. The 

 sight would be so phenomenal, that the news of its existence 

 would speedily become public property. It must be remem- 

 bered that, while proofs of upheaval are easily detected, direct 

 evidence even, of subsidence, is most difficult to obtain. All 

 searching under water is groping in the dark. 



I may here remark, as it is our common object to arrive at 

 the truth, and surveyors are not special pleaders, that there is 

 an error in Mr. Dana's examples of subsidence (p. 310, " Coral 

 Reefs," Darwin, third edition). Nanuku Islets are cays on a 

 spur from a barrier reef, and Bacon Islets are formed of coral. 

 It is unfortunate that these should have been inadvertently 

 taken as types so late as 1885, three years after the charts were 

 published, though it is easy to understand how Mr. Dana was 

 mistaken in his first book when he had to rely simply on the 

 excellent sketch made by the officers of Wilkes's expedition, to 

 which he was attached ; but these mistakes do not necessarily 

 invalidate the conclusions of the experienced naturalist, who, 

 had he thought of it, could have selected other and better 

 examples from the same group. 



It would be premature to discuss the cases of the Tizard and 

 Macclesfield banks before Dr. Bassett-Smith records the results 

 of his examination of the specimens collected, in pursuance of 

 Captain Wharton's directions, chiefly by himself and Lieut, 

 Parry, of the Rambler ; but this much may be said — the existence 

 of a submarine cliff is established in the former, and the sectional 

 slopes have a great resemblance to those of mountains. The 

 condition of the Itu Aba and its surrounding reef appears to 

 favour Mr. Murray's views ; but the general state of the reef does 

 not, as far as I can see, disprove the theory of subsidence. The 

 one Macclesfield bank section is not at all like that of a sinking 

 mountain ; and the condition of the coral on the top might 

 indicate either a downward or upward movement, or neither. If 

 we hnd, as in both these cases, a mixture of dead and live coral 

 on the rim of an atoll, the inference seems more in favour of 

 subsidence than elevation. It implies that a sudden descent to a 

 depth beyond that in which the less hardy individuals of the 

 species can flourish, has killed the growing insect ; and that a 

 new effort is being made to regain the surface. Specimens of 

 reef-building corals were brought up from depths below even 30 

 fathoms ; but, as far as the imperfect appliances which we have 

 at present could help us, there was no evidence that masses of 

 coral were at all common below 13 fathoms. The condition of 

 the slopes could be safely compared to the banks of a river 

 stream with the blades of grass growing thinner and thinner as 

 the distance from the water was increased (Darwin, p. iii). 



In the case of the Bukatatanoa, and other large reefs of a 

 similar character, my difficulty with respect to Mr. Murray's 

 theory is this : if corals commenced to grow on sediment which 

 had lodged on a submarine inequality, why should nearly all 

 parts have kept pace so evenly in their growth? The highest 

 portion of the bank on which the Bukatatanoa Reef — according 

 to the theory of Mr. Murray — rests, would surely not be around 



the sides, but somewhere in the centre. There would be a 

 summit of some kind, to which the sediment would be first at- 

 tracted. Is it not most improbable that first the pelagic organ- 

 isms which are dead, and then the coral polyps which are alive, 

 should maintain an even contour around three sides of a bank 

 and many miles away from the highest part of it, and arrive at 

 the surface of the ocean much about the same time ? If it is 

 said. How do you know it arrived at the surface at the same 

 time ? I point to the connected form of the barrier. According 

 to Mr. Murray, had it not done so, it would have formed in- 

 numerable rings instead of being connected, without a break, 

 for so many miles. 



Reid Reef, to the north of Bukatatanoa, is a still more remark- 

 able instance. Here, there is a feature, which Mr. Murray men- 

 tions, quite apparent, viz. the paucity of coral heads in a lagoon 

 where the barrier is uninterrupted ; but the difficulties which I 

 have ventured to place before him are greater than ever: (i) 

 Why should wave-action distribute a bank on the weather as 

 well as the lee side of the land? (2) Why should the insect 

 reach the surface simultaneously on all sides, as shown by the 

 continuous reef and the uniformity of its breadth ? To the best 

 of my recollection, the islets within this barrier are of volcanic 

 origin, but the point is not material. 



With reference to Mr. Murray's explanation of the deficiency 

 of reef under Mbuke Levu (Mount Washington), may I point 

 out that it is of great assistance in showing why, when discussing 

 subsidence, it is not necessary to hesitate for examples at those 

 islands which have a barrier on one side and a fringe on the 

 other. On a cliffy, steep side, the sinking fringe would, of 

 course, remain very close to the new coast-line, and, if it assumed 

 the barrier form at all, would rapidly become filled with pieces 

 from the land. 



The fragmentary character of the Great Barrier Reef of Aus- 

 tralia does not seem to have excited the attention it deserves in 

 this controversy. I believe that there are innumerable passages 

 through it, and that, instead of being termed a "barrier," it 

 might better be described as a collection of large patches. 



W. UsBORNE Moore. 



8 Western Parade, Southsea, July 9. 



The Hailstorm in Liverpool. 



Sunday, yune 2. — A very sultry afternoon, with heavy 

 thunder- clouds in the south-west and west, and continual rumb- 

 lings from the same direction, the storm evidently passing over 

 the Dingle and Toxteth Park. Soon after 3.30 p.m. lightning 

 became visible and the storm broke. 



At first a few large drops of rain fell, making patches of l\ to 

 2 inches in diameter on the cement. In a minute or two, large 

 lumps of ice came slowly down, rebounding to an astonishing 

 height. As the stones became more numerous they decreased 

 considerably in size and fell with greater force. This lasted for 

 ten or twelve minutes. The rain had nearly ceased during the 

 height of the storm, but began again towards the end for a short 

 time. I immediately collected some stones off the grass, and 

 placed them in a dish on some blotting-paper. 



They were evidently of two classes ; the one having clear ice 

 kernels, the other white misty ice. If the stone was large the 

 kernel was surrounded with another coating of the opposite kind 

 of ice, a dark line intervening between the two, and here and 

 there I noticed a third or fourth layer. 



Many in themselves spherical had a pear-shaped appendage, 

 which, however, soon melted away. One or two (Fig. 4) had 

 the second layer thinner than the others, making a hollow be- 

 tween the centre and exterior layer, both above and below. 



I found one of a most curious construction (Fig. 3). The 

 stone was all composed of white ice except at one end. The 

 white ice seemed to terminate like the petals of a flower, closing 

 in round a centre of clear ice. This construction was entirely 

 formed below the surface, the stone being otherwise smooth. I 

 could not take accurate measurements owing to the absence of a 

 correct scale, but approximately the stones I drew measured as 

 follows : — 



Breadth. Width. Thickness. 



(1) II" _ ... I" ... tV 



(2) spherical, about \%" 



i'-,\ 15" I a " 14" 



Ko) ITT ••• '■TS •■• 115 - 



(4) U" - l^V 



(5) ir - itV - n" 



The stones had all a metallic taste and also* a flavour of ozone. 



