February 28, 1901] 



NA TV RE 



427 



RECENT WORK OF THE INDIAN MARINE 

 SURVEY.^ 



'T'HE importance of the work intrusted to the Indian Marine 

 -*■ Survey, alike from the point of view of the hydrographer, 

 of the geologist, and of the zoologist, is so well known to all 

 men of science that it would be mere waste of time to attempt to 

 emphasise it on the present occasion. All the Reports that have 

 from time to time been published by this Survey bear witness 

 to the zeal and energy with which the work is carried on — 

 frequently under circumstances of great difficulty — and to the 

 capacity and accomplishments of the officers to whom it is 

 entrusted. But it will be no reflection on previous documents of 

 the same nature if we call attention to the special interest 

 attaching to the one now before us, on account of the varied 

 nature of the subjects on which it touches, the philosophical 

 manner in which these are treated, and the problems presented 

 by many of them. 



The first section of the Report is by Commander T. H. 

 Heming, R.N., who has entire charge of the Survey; and 

 geologists will read with great interest his account of the rapid 

 silting-up of the Gulf of Martaban that is now in progress. It 

 appears that an enormous quantity of sediment is being carried 

 into the Gulf by the Salween River ; a sample of water taken at 

 spring tide during the dry season yielding no less than i/300th 

 of dry mud by weight. The deposit has mainly taken place 

 outside the lo-fathom line, and so heavy is it that in spots where 

 there were formerly from 40 to 50 fathoms, the depth is now 

 rediiced to from 15 to 20 ; the area affected being approximately 

 2000 square miles. " Putting the amount of water discharged 

 by the river flowing into the Gulf at a low estimate," says the 

 Report, " and supposing it capable of supporting on the average 

 one-quarter of tne proportion of sediment held in solution 

 [? suspension] by the specimen examined, there would be 

 more than enough solid matter carried into the Gulf in forty 

 years to cause the silting-up which has actually taken place." 



Another point of interest in this section is the longitude of the 

 Andanians, which, as deduced by running a meridian distance to 

 Sugar-loaf Island, was found to difi"er by i' 70" from that given 

 by the Great Trigonometrical Survey. In consequence of this 

 discrepancy it is now proposed to run a meridian distance be- 

 tween Port Blair and Diamond Island both ways, in order to 

 obtain the best possible results with the means at disposal. 



Passing on to the section o*" the Report written by the 

 Surgeon-Naturalist, Cnptain A. R. S. Anderson, we may call 

 attention to the remark as to the rapid change in the coloration 

 and appearance of the animals of Ford Bay, Great Cocos Island, 

 when the coral bottom of the open channel is left for the 

 sandy bottom of the bay. While quarantined off" Colombo a 

 lucky haul brought up no less than forty-one examples of the 

 rare crustacean Lupocydus orienlalis, of which only three speci- 

 mens were previously known to science. In another haul, which 

 brought up a miscellaneous collection of dead corals, sharks' 

 teeth, fish-bones and bones of turtles, the interesting fact was 

 discovered that while some of these were in practically the same 

 condition as at the time of their deposition, others had been 

 highly impregnated with mineral matter. No embedding in 

 sediment had, however, preceded the fossilisation (if the term is 

 permissible in this connection), which had evidently taken place 

 as the bones lay loose on the sea-bottom. 



In a haul taken some distance east of the Maldives, Captain 

 Anderson was fortunate enough to procure over 200 specimens 

 of an echinoderm nearly related to the West Indian Palaeo- 

 pneustes kystrix, but apparently specifically distinct. When 

 placed in spirit these urchins turned it a magnificent rich purple, 

 although their own colour was a dull madder-brown. Many 

 other rare and interesting invertebrates were obtained at other 

 dredging stations, but we must omit mention of any of these to 

 refer to a totally different subject. 



Between Colombo and Rangoon an excellent opportunity was 

 afforded of carefully observing the flight of the common flying- 

 fish {Exocoelus evolans). " When they first rise from the 

 water," writes the narrator, " they do so with a very rapid 

 fluttering of their wings lasting for two to three seconds ; they 

 then soar along till their speed is so reduced that they descend 

 and touch the water, into which they either fall with a splash or 

 dip the elongated tip of the caudal fin, and, I think, the ventral 

 fins on which they seem to poise themselves, again rapidly 



1 Administration Report of the Marine Survey of India for the Official 

 YeariSgS-gg. Pp. 17. (Bombay : Government Central Press, 1900.) 



NO. 1635. VOL. 63] 



vibrate their wings, and get up sufficient speed to renew their 

 flight ; this process I have seen them repeat as often as seven 

 times in the course of one long flight. Very occasionally, how- 

 ever, I have observed these fish fluttering their wings without 

 touching the water with their caudal and ventral fins." 



After mentioning that in order to observe these motions calm 

 weather and a binocular are necessary. Captain Anderson pro- 

 ceeds to say that he fails to understand how Moseley, as n irrated 

 in his "Naturalist on the Challenger^ as well as several other 

 observers, have denied the fluttering of the wings in flying-fish. 

 Apparently he is unaware that it has been stated in the " R )val 

 Natural History " by the editor, as the result of personal 

 observation, that these fish do possess the power in question, as 

 indeed had been attested in Land and Water by a much earlier 

 observer. Captain Anderson's observations also corroborate 

 the statement made by the writer last referred to, that flying-fish 

 are capable of altering the direction of their flight : an attribute 

 that was denied to them by Dr. Mobius in his well-known 

 account. 



In a later paragraph Captain Anderson draws attention to the 

 circumstance that in flying-fish the lower surface of the body is 

 flattened in order to enable them the more easily to rise from 

 and hover over the water, and that in the allied genus, Hemi- 

 rhamphus,! the members of which rush at full speed along the 

 top of the water with only the hinder portion of the body 

 immersed, a similar flattening is observable. 



While lying in Burmese waters off Moulmein, the surveying 

 vessel encountered a large quantity of drift-wood brought down 

 by the Moulmein river. Some of this became entangled in the 

 paddle-wheels, and on three mornings snakes were found on the 

 floats. A female leopard, probably carried down by the strong 

 tide, took refuge one morning on a cargo boat moored somewhat 

 higher up, and eventually swam ashore, where she was shot. 

 These instances are of much interest in connection with the 

 dispersal of species. , 



Much of the latter portion of this section of the Report is 

 occupied by an account of the author's experiences in the 

 Andaman Islands, where he has much to say concerning both 

 the natives and the fauna. In one passage he mentions that, 

 while walking through the forest, a native announced the 

 presence of a large mass of wild honey in the immediate neigh- 

 bourhood, which he detected by its smell, although this was 

 quite imperceptible to the European members of the party. 



In conclusion. Captain Anderson refers to the remarkable 

 circumstance that in the neighbourhood of the Andamans there 

 occur masses of sandstone at a depth of between 39 and 226 

 fathoms which are quite bare of coral, although there is an 

 abundant growth of the same in the immediate neighbourhood. 

 It is inferred that the bare area, and probably also the larger 

 portion of the bank, has never been within the zone of massive 

 reef-building corals. " Had it ever been so, it is most improb- 

 able that there should be bare rock exposed at 39 fathoms. 

 For that the bank is eminently suitable for the growth of coral, 

 both the dredgings and the soundings, by bringing up live coral, 

 showed ; at no part of the bank was there any turbidity of the 

 water sufficient to check coral-growth. . . . Were the theory 

 correct that, given a bank rising within a comparatively short 

 distance of the surface, deposit will accumulate on that bank 

 and so form a basis for a coral island^ there is no reason why, 

 in the case of this bank, bare rock without any such deposit 

 on it should be found." 



Many other equally interesting and suggestive extracts might 

 be culled from this valuable report did limitations of space 

 permit. R- L. 



THE TEACHING OF PHYSIOLOGY. 



IT is scarcely too much to say that the only real scientific 

 knowledge is that obtained through personal experience. 

 Lectures and text-books have their places in a scheme of instruc- 

 tion in science, but they only convey information at second- 

 hand, whereas original experimental work creates and fosters 

 the inquiring spirit characteristic of a progressive mind. What 

 students need to be taught is that they must be not so much 

 receptive as constructive ; and the way to give force to this view 

 is to insist upon their taking an active share in investigation at 



1 A mis-spelling of this and several other names is noticeable in the Report, 

 but, as the writer of this notice is well aware, much allowance must be made 

 for an author whose copy is set up by native Indian printers. 



