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dwindling and ultimate loss of the organ. I would, however, Probably your readers will be as much astonished as I * venture to supplement what he has said by the following : viz., when they read the extracts I have above given from the "Origiu given the state of panmixia, it is apparent that variations in the of Species " by the side of Mr. Romanes's letter. direction of excessive size will be injurious—both as taxing After dismissing Mr. Darwin, Mr. Romanes proceesls to say: the nutriment of the organism, and often as mechanical en " In this connection, however, it requires to be stated that the cumbrance. On the other hand, variations in the direction idea first of all occurred to myself, unfortunately just after the of greatly diminished size will be advantageous, as causing appearance of his last edition of the Origin of Species." a diminished tax on the resources of the organism. Now Now, inasmuch as the idea in question is (as I have showe it is a demonstrable fact that excessive variations in both direc-above) formulated in the last edition of the "Origin of Species." tions do naturally though rarely occur-probably more often than I confess that I do not think it requires to be stated that the is supposed, since we do not see all the young born. If the varia- | idea occurred to Mr. Romanes shortly after the publication tions in the direction of excessive diminution of a useless organ that work. What more natural? The idea occurred to me (as, for instance, tailless cats or hornless sheep) survive as being also shortly after the passages above quoted from Mr. Darwin less taxed-whilst the complementary variations in the direction were published. It certainly never appeared to me *anfor of excessive size tend in the struggle to die without reproducing, tunate" that this was the case, and I cannot see where the mis. owing to their awkwardness and their relatively greater burden i fortune comes in in regard to Mr. Romanes. As soon as the in life-then it is clear that panmixia may lead rapidly to the matter had taken root in his mind, Mr. Romanes published in dwindling and eventual extinction of a disused organ without NATURE, March 12, April 7, and July 2, 1874, an exposition d any transmission of acquired parental character. The fact that the importance of the principle of cessation of selection » » there is no use for an organ-or, in other words, the "effect of commentary upon a letter by Mr. Darwin himself (NATUEL, disuse"-is that the congenitally small varieties of the organ vol. viii. pp. 432, 505) in which Mr. Darwin had suggested that survive, and are even favoured in the struggle for existence. with organisms subjected to unfavourable conditions, all the

Whilst Weismann has the merit of having insisted on a form of parts would tend towards reduction. Mr. Darwin, with his usual his doctrine as the effective reply to those who argue in favour of kindly manner towards the suggestions of a young writer, givesa Lamarck's theory of the transmission of acquired qualities from p. 309 of vol. ii. of " Animals and Plants under Domestication instances of " disuse,” it is yet the fact that Mr. Darwin him-second edition), Mr. Romanes's view, "as far as it can be given self recognized and formulated the doctrine of panmixia in the in a few words. The view, as it there appears in Mr. Darwin's last (sixth) edition of the "Origin of Species," published in 1872 ; words, is certainly not the same as that which Mr. Ramses la and he even went further than Weismann, for he associated the expounded in NATURE of March 13, 1890 (p. 437), and soci principle of the economy of material with the principle of the represents what Mr. Darwin had been able to gaiber frous Nr cessation of selection. It is therefore, it seems to me, not at all Romanes's letters to NATURE of 1874, it is not at all surprising improbable that when Darwin refers, here and there throughout that Mr. Darwin did not recognize any resemblance betwees. his works, to a reduced or rudimentary condition of an organ as and his own statement, viz. that "the materials forming sy “due to disuse,” or “explained by the effects of disuse," he does part, if not useful to the possessor, are saved as far as posible, not necessarily mean such effects as the Lamarckian second law thus "rendering a useless part rudimentary." Whether the asserted and assumed (though often he does appear to mean such); is, or was, Mr. Romanes's view or not, it is Darwin's, and is ik but he may mean, and probably had in his mind, the effects essence of the anti-Lamarckian view of the effects of disas of disuse as worked out through panmixia and economy of March 15.

E. RAY LANKESTER, growth.

The passages in Darwin which seem to me to have been missed or neglected by those who think panmixia altogether a

Exact Thermometry. new idea are as follows :

SHORTLY after the publication of my second letter on the (1) "If under changed conditions of life a structure before subject (NATURE, January 23, p. 271) I received a letter from useful, becomes less useful, its diminution will be favoured M. Guillaume, who very kindly called my attention to a jupe for it will profit the individual not to have its nutriment by Prof. J. M. Crafts (Comptes rendus, xci. p. 370), in which wasted in building up a useless structure.” After an example the "plastic theory” is discussed. Prof. Crasts states that he in point from the group of the Cirripedia, Darwin con- has subjected thermometers to prolonged heating at 353* C. ttinues : "Thus, as I believe, natural selection will tend in the under various conditions as regards pressure, the internal pres long run to reduce any part of the organization as soon as it sure being in many cases considerably greater than the external

, becomes, through changed habits, superfluous, without by any but that there was invariably a rise of the zero-point. The e means causing some other part to be largely developed in a periments were carried out in very much the same manners corresponding degree" ("Origin of Species," sixth edition, that described in my first letter (NATURE, December 19, 88 P. 118).

p. 152), and had I known at the time of the earlier work of (2) "Organs, originally formed by the aid of natural selection, Prof. Crafts, I should of course have referred to it. Prof. Crafts when rendered useless, may well be variable, for their variations also describes and quotes experiments with air-thermometers can no longer be checked by natural selection. . . . It is the temperature in one determination by Regnault being s high scarcely possible that disuse can go on producing any further as 511° C., and the internal greater than the external pressure : effect after the organ has once been rendered functionless. in every case the bulb diminished in volume. From these te Some additional explanation is here requisite, which I cannot sults, Prof. Crafts concludes that it is not proved that pressure give. If, for instance, it could be proved that every part of the plays any part in the contraction of the glass. organization tends to vary in a greater degree towards diminu My experiments can therefore be regarded as little more than tion than towards augmentation of size, then we should be able confirmatory of the earlier work of Prof. Crafts and others, bar to understand how an organ which has become useless would as such it may be worth while to give the results. The method be rendered, independently of the effects of disuse, rudimentary, adopted was fully described in my first letter, and it is therefore and would at last be wholly suppressed; for the variations only necessary to repeat that in thermometer A the externa towards diminished size would no longer be checked by natural pressure exceeded the internal, while in thermometer C there selection. The principle of the economy of growth explained in was considerable internal pressure, but no external. Asarding a former chapter [cited in quotation No. 1], by which the to the plastic theory, therefore, the zero-point of A should have materials forming any part, if not useful to the possessor, are risen, while that of C should have fallen. The results previously saved as far as possible, will perhaps come into play in rendering described were regarded as insufficient by Prof. Mills, and a useless part rudimentary" "Origin of Species," sixth edition, have therefore continued the beating for a much longer time. PP. 401-402).

I have also made similar experiments with two other therrno 'I had written thus far, and intended to finish this letter by meters belonging to the same batch, at a temperature of abant asking if the anti-Lamarckians are not really carrying out the 356°, the thermometers being heated in the vapout of boiling spirit of Darwin's doctrines, although not the absolute letter, mercury. During the first three hours, the two thermometers when I received your issue of March 13, containing a long lettera and 6 were treated in precisely the same manner, es regarde from Mr. George Romanes, headed "Panmixia.” In that letter pressure, as A and C, and it will be seen that the zero-point Mr. Romanes, whilst amending (as I have done above) Prof. b showed a slightly greater rise than that of a. Afterwards, air Weismann's statement of the principle of panmixia, makes the was admitted into thermometer a, so that there was an excess of definite assertion that “it is remarkably strange that this prin internal over external pressure in both thermometers, but the ciple should have been overlooked by Mr. Darwin."

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The results obtained are given in the following table :

I may also mention that M. Guillaume has informed me that

M. Tonnelot has heated several thermometers to 450°, and that, Temperature 280°.

notwithstanding a considerable internal pressure, a rise of the Total Duration Zero Rise

Zero Rise

Mean

zero-point was observed in every case.
time
of point

point of rise of
each of A.
zero. of C.

All these results seem to lead unmistakably to the conclusion

zero per hours. heating

hour. that pressure has little or no effect on the rise of the zero-point.

Three questions remain to be discussed0'15

(I) Would the total rise of the zero-point be different if two 05 0'35 ... +03 04

0.187

similar thermometers were subjected to sufficiently prolonged 7'5 - 5'5 ... 13 0:8 II

08

0'145 heating at different temperatures? At first sight, it would cer. 12 4'5 ... 20

07
1.8

07 0'156 tainly appear that at 356° the total rise with my thermometers 17 5 23

0'3 2'05 0'25 0'055 must be greater than at 280°, but I do not feel satisfied that the 22'5 5'5 ... 26

0*3
2015

O'I 0'036 proof is sufficient. If we map the observations of zero-point 29

6.5 ... 295 0°35 2'5 0'35 0'054 against the time of heating, curves are obtained which appear 35 6 3'15 02

28
0'3

0'042 as if they might become horizontal after a few weeks or, pos86

51 4'1 o'95 395 I'15 o'02 sibly, months; but if, instead of the actual times, we take their 133 48 07 49 0'95

logarithms—as in the diagram-as abscissæ, there is no appear. 201 68 5'25 0-45 5.5

06
O'008

ance of an approach to the final state at either temperature. 369... 168 6.5 1'25

68
13 ... O'008

But while at 356° the curve has become almost a straight line,
Temperature 356°

at 280° there appears to be an increasing tendency towards the

vertical direction. I do not for a moment argue that the curves 6

indicate that the maximum rise would be the same at both tem0:4 o'05

peratures if the experiments were carried on for a sufficiently 3 56

long time; but, at the same time, I do not think that they 61 6'05 1'942 3 .80

afford any convincing proof that the total rise would be different. 2'0

81 2'o 0*667 125 6'5 ... 10-3

The results merely tend to increase my scepticism as to the 23 10'35 2'25 0*350

value of the determination of the maximum rise at o' obtained 15

25 ... 10-95 0.65 III 0-75 0'280 66

by extrapolation of the curve constructed from observations at 51 ...16-1 5'15 16'1

5'0 O'100 113 47...18-45 2-35

183

that temperature. It does not appear to me that it would be

2'2 0'048 181 68 1.65

justifiable to extrapolate these curves at all, and I am afraid that

20'0 17 0'025 305'5... 245...2075 ... 065 206

they do not throw much light on the total rise of zero-point at

06 0'025 22145... 16 ... 2009

either temperature. Very much more prolonged heating would 0915 207 292 ... 705...21:8 ... 09

be necessary before arriving at a definite conclusion.
217
I'O 0'013

(2) With regard to the causes of the contraction of the bulb, The last result at 356° is a little uncertain, owing to a breakage I have no hesitation in admitting that—as shown by M. Guil. of the apparatus.

laume—the removal of the condition of strain caused by the

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3.000

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2.000 LOGARITHM OF TIME (IN HOURS)

more rapid cooling of the outer parts of the glass, is insufficient (3) Lastly, there is the question raised by Mr. Tomlinson, as to account for the results. No doubt we must also take into to whether repeated heating and cooling between wide limits of account the toy rapid cooling of the glass as a whole, which temperature is more effective in raising the zero-point than proprevents the molecules from assuming the position of greatest longed heating at the higher temperature. The points represtability, perhaps in the same sort of way that the assumption by senting the individual observations fall very fairly on the curves sulphur of the monoclinic or the more stable rhombic form de constructed from them, and do not seem to indicate any noticepends on the rate at which solidification takes place. That able difference in the effect of long or short heating. The results ihere are other causes besides these two does not at present can hardly, however, be regarded as decisive. appear to me to be proved.

University College, Bristol, March 1. SYDNEY YOUNG.

Foreign Substances attached to Crabs.

group to which he gives the very convenient name "alloSINCE Hyas is one of the most abundant Crustaceans found

cryptic." Animals which trust rather to the offensive than la off the east coast of Scotland, Mr. Holt must adduce consider the inconspicuous character of the foreign bodies with whit. ably more than two instances before it can be admitted that the they associate themselves he terms "allosematic" (ous, , attachment of Simple Ascidians to this crab is at all a usual sign). occurrence. If it is, I should still be anxious to inquire whether

It is obvious that the allosematic method of protection is 23 the crab does not-in spite of the apparent difficulty of the but perfect, since it is largely free from the loss due to cape operation-place the Ascidians upon its back with its own nip

mental tasting attendant upon the method of a purely waiting pers. I may cite Gosse's well-known experiment with Pagurus

appearance ("autosematic").

WALTER GARSTAYO. prideauxii and Adamsia palliata, described in his "Year at Plymouth, March 21. the Shore," for the purpose of analogy. But Mr. Holt will find a case, probably quite similar to that which he mentions, in Bell's “Stalk-eyed Crustacea," Two specimens of Hyas ara

Sea-bird Shooting. neus were found with oysters attached to their backs, that on the Is it not time that something more was done to stop the larger crab being three inches in length, and five or six years wholesale slaughter of our sea-birds? During the past wider old, probably a much more "serious incubus” than Mr. Holt's the havoc has been terrible, and unless some restraint is in Tunicates. The crab's carapace was but two and a quarter we may expect before long to find our shores depaded of the inches in length. Hence, despite the "world of weight upon white wings. When the birds had no value, there was a its shoulders," Mr. Thompson concluded that "the presence of though a wide one, to their destruction, because of the ca this oyster affords interesting evidence that the Hyas lived killing them; but recently a large demand has sprung up is several years after attaining its full growth.” Probably the their skins, and an organized traffic is now carried on in the larvæ of the oysters, and of the Ascidians also, happened carcases. to alight upon the crabs at the end of their free-swimming The shooter gets from threepence to sixpence per bird from the existence, although six or seven years seems to me to be a amateur dealer, and for the sake of this paltry sum (surely llor remarkably long age for a Hyas.

birds are worth more to us alive than this!) there is not a Barnacles upon the backs of Maia, Carcinus, &c., are also sporting lounger on the coast who can possess himself of a gun due to the same, as it were, accidental cause.

who does not kill every bird which can be reached either from But, whatever the explanation, these exceptional cases do not the shore or from a boat. The gulls are pursuad, I am tas alter the fact that the foreign bodies found upon Hyas are usually even as far as the Dogger Bank. fixed there by the crab itself. The specimens I have seen have The beautiful kittiwake is the greatest sufferer. One of tk been covered with fragments-not living colonies--of Algæ, dealers boasted to me the other day that he had passed "ease Hydroids and Polyzoa, which are fastened by the hairs of the ten than nine thousand dead birds through his hands les crab's carapace and legs exactly as in Stenorhynchus, and in season, chiefly kittiwakes.” He added that he had got so this crab the process of attachment has been frequently observed carcases in one batch from one sportsman. here and accurately recorded.

From inquiries, I judge that this person's trade represents At the same time I by no means hold that the two groups about one-third of the dead birds which have been sent away from which were defined in my previous letter are absolutely marked our little town this season. I know the traffic is carried on 2 off from one another. The hermit crabs make use of both other points, and no doubt this is but an example of what u methods of protection. Bits of Sponges may frequently be seen going on all round our coast. When we consider that the upon the carapace of Maia, Stenorhynchus, and Inachus, and I cases which can be secured represent only a fraction of the birds have occasionally found colonies of Leptoclinum and Didemnum killed or injured, we gain some idea of the extent of the me upon both Maia and Inachus. In these cases the inconspicuous chief. Indeed, during the past month it has been possible by appearance is not lost, but the attachment of small Sponges and take a long walk along our shore without seeing a single w Didemnids is probably an additional protection against the gull. Who wishes to see a blank seascape ? numerous night-feeding fishes, which hunt their prey by the Now, surely, we all have equal rights in these graceful birds, senses of smell and touch.

and the numerous class who love to see them alive deserve As to the inedibility of Tunicata, I did not-as Mr. Holt as much consideration as the mischievous minority whose plesstates-"assume" it. I have experimentally found it to be a sure it is to destroy them! It is not as though these buter fact (as I stated in my letter) that the odour and taste of “ Tuni: were worthy persons, compelled to a cruel employment for cata, and especially Compound Tunicata," are almost invariably their daily bread: they are, on the contrary, nearly all of a sufficient to prevent fishes from eating them. Exceptions do class who deserve no sympathy-of a comfortable class wie, ) not disprove the rule, and it is quite possible that Pelonaia is verily believe, would shoot their next-door neighbours if they not distastesul. But this is not established by a few specimens could do so with impunity, and could dispose of the carcases having been taken on one or two occasions from the stomachs of Just imagine the new variety of "sport" which one of the Cod, Haddock, and Dab; and although Mr. Holt quotes Prof. described to me not long ago! He said you could catch : McIntosh as speaking of the "abundant” occurrence of Molgula gulls at sea by baiting a floating fishing-line with liver, and arenosa in the stomachs of Cod and Haddock, he will find upon this way, though you did not get quite

so many as with a gun, reading Prof. McIntosh's words again, that they are open io a you had far better fun, especially from the kittiwakes, as they different interpretation.

are wonderfully game," and, when they feel the hook. In my previous letter I omitted to mention that a species of flacker about and scream like a child"! hermit crab also, Eupagurus lucasii, takes advantage (regu Is it too much to ask that our Legislature, which has spent larly?) of the distastefulness of Compound Ascidians. Mr. much time in the past on laws in the interests of the so-calles Harmer has, with much kindness, examined for me a specimen preservers" of game, will do something, and that

speedily, in te in the Cambridge Museum. The crab inhabits a univalve which interests of those who would fain be truly preservers of these is covered with Distaplia magnilarra.

birds ? At least they should extend the protection afforded to Mr. Holt's statenient that “ Actinin mesemoryanthemum is "game” to these noble birds, and order that those wbo skait certainly a favourite food of the Cod” is so astonishing that I them shall pay a heavy license for their despicable sport amet hope he will adduce the evidence for his assertion. Mr. Brook those who deal in the dead carcases a still heavier. had not found this to be so when he reported upon the food of And nothing in this matter must be left to local authoritiek this fish for the Scottish Fishery Board, and indeed only the In seaside places self-interest vitiates the sentiment on this ques youngest Cod ever frequent the tidal waters to which A. mesem. tion. The fisherman finds it easier to earn money by letting his bryanthenum is confined. Further, although Pagurus bern boat to the sportsman" than by his legitimate productive is hardus, when not associated with an Anemone, is very frequently dustry; the tradesman fears to lose these men's custom; and the found in the stomachs of Cod and Haddock, I do not know a gentry, mostly supporters of "sport," are perhaps not sorry to single instance of its having been found in the stomachs of the have such an excellent safety-valve for guns which might other same fish when associated with one.

wise poach on their preserves ; and besides, there is in Yorkshire I am informed by Mr. Poulton that, in a work which is shortly a semi-political aspect to the matter. Thus it has happened that to appear, he has included such animals as Stenorhynchus and of late years the clause in the (so far as it goes) excellent Sex Caddis worms, which disguise their appearance with foreign birds Preservation Act " of 1869, which permits a lengthening bodies simply in order to escape identification by enemies, in a of the close time under certain conditions, has been rendered

tugatory through the action of our county magistrates, who have taining scrolls of photographic paper. These cylinders refused to present the requisite petition to the Home Office. were made to revolve slowly by a very simple connection They must have been aware that their action doomed innumer with a clock, so as to give the paper a progressive moveable young birds to death by starvation, since the cliff-climbers ment behind the index of the instrument, the place of collect the eggs until July (a perfectly legitimate industry, by which was registered by the representation of its own the way, carried on by hard-working men, and producing image. valuable food), and thus render it impossible for the majority of the birds to get their young reared by the Ist of August.

In 1846, Mr. Charles Brooke and Sir Francis Ronalds And, in consequence, whenever during August i go on the each brought forward a method for the registration of shore under the great cliffs where the birds breed, my ears are

magnetic and meteorological instruments by means of filled with the melancholy "piping" of the starving helpless photography. The methods are those now in use, the young, dying slowly on the ledges, whose parents have been former at the Royal Observatory, Greenwich, and the shot--for sport, or threepence. G, W. LAMPLUGH. latter at the Observatories of the Meteorological Office. Brillington Quay.

Although these instruments were not shown, they

were fully illustrated by photographs and drawings. A Locusts.

number of the barograms and thermograms were ex

hibited by the Astronomer-Royal and the Meteorological With reference to the flight of locusts which passed over the Council, showing the passage of storm centres, and sudden steam-ships Golconda and Clyde in the Red Sea about November changes of temperature and humidity. A set of baro 35 last, it would be interesting to ascertain to what species grams from various parts of the world was exhibited by bey belong. The past year, 1889-90, has been marked in the Meteorological Council, showing the barometric peregrinum, which, starting, it is believed, about the end of the oscillation due to the Krakatað eruption, August 1883. bot weather (May or June), from the sand-hills of Western The thermogram at Kew on May 8, 1871, showed a fali Rajputana, have, during the past six months, spread in vast of about 20° of temperature during a thunderstorm numbers over the whole of Sind, Rajputana, the Punjab, North. at 4 p.m. West Provinces, and Oudh, besides penetrating sporadically into Mr. Symons exhibited a photographic scale showing Guzerat, Ahmedabad, Baroda, Khandesh, and parts of Central the intensity of sunlight during the solar eclipse of July India, a stray flight even appearing in the Kistna district of the 18, 1860 ; and the Kew Committee showed the chemical Madras Presidency

photometer devised by Sir H. Roscoe in 1863. Mr. This insect, which is supposed to be the locust of the Bible, J. B. Jordan exhibited his experimental instrument for and which is undoubtedly the one that periodically invades Algeria from the Sahara, though it is altogether distinct from recording the intensity of daylight, and also the three the locust Stauronotus maroccanus, of which so much has been patterns of his sunshine recorder. 'Similar instruments heard in Algeria during the past two years, is likely to be the designed by Dr. Maurer, of Zürich, and Prof. McLeod, species which was observed in the Red Sea. To ascertain the were also shown. Prof. Pickering sent a photograph of point

, however, with certainty, it is essential that specimens, his Pole-star recorder, in use at the Harvard College which I am told fell upon the deck of the ship Clyde in con Observatory, U.S.A., for registering the cloudiness during suderable numbers, should be examined and determined entomo- the night." This instrument consists of a telescopic logically, and my object therefore in addressing you is to objective attached to a photographic camera and directed endeavour to obtain some of the specimens for comparison with to the Pole-star; the camera is provided with very those which have invaded India.

sensitive plates which are inserted in the evening, and a It is worthy of notice that in 1869 when Rajputana suffered shutter, worked by an alarm clock, is closed before dawn. msiderably from locusts, vast swarms were also observed by If the sky be clear during the night, the plate, after skups passing through the Red Sea, and it would therefore be development, shows a semicircle traced by the revolution interesting to learn to what extent 1869 and 1889 were years of of the star around the North Pole, but if clouds have Iestust invasion in the intervening countries of Arabia, Persia, and Biluchistan. It is much to be regretted that

in 1869 neither passed across the star, the trace is broken. the locusts found in Rajputana nor in the Red Sea appear to have for the registration of the velocity and direction of motion

The photo-nephograph designed by Captain Abney een preserved or determined, and their identity therefore cannot le definitely established.

E. C. Cores.

of clouds was exhibited by the Meteorological Council, as Indian Museum, Calcutta, February 28.

well as a model showing the manner in which the pair of photo-nephographs are mounted for use at the Kew

Observatory. One of the instruments is placed on the THE ROYAL METEOROLOGICAL SOCIETY's roof of the observatory, the other being at a distance of EXHIBITION.

800 yards; the observers at each end are in telephonic

communication. Both cameras being oriented with referTHE eleventh Annual Exhibition of the Royal ence to the same point of the horizon, the distant observer

Meteorological Society was held at the Institution is instructed as to the direction and elevation of his inof Civil Engineers on March 18 and three following days. strument. The chief observer controls the exposure, both Each Annual Exhibition is devoted to some special branch cameras being exposed simultaneously; another pair of of meteorology, which is illustrated by specimens of all plates are exposed after an interval of one minute. A known instruments (or drawings and descriptions of the slide rule designed by General R. Strachey for obtaining same) that have been employed in its investigation. the height and distance of clouds from the pictures This year's Exhibition was illustrative of the application yielded by the cloud cameras was also exhibited,

as well of photography to meteorology. Photographic meteoro- | as photographs of an experimental apparatus designed logical instruments are not numerous, and those used for by Mr. G. M. Whipple for the same purpose. recording the indications of the barometer, thermometer, The Exhibition included a large and interesting coland electrometer are very costly and delicate, and are lection of photographs of clouds. Padre F. Denza sent only made to order. The number of instruments in the a set of 80 cloud photographs which had been taken Exhibition was consequently less than in previous years, during the past twelve months at the Specula Vaticana, but this deficiency was fully made up by the large and Rome. M. Paul Garnier exhibited a magnificent set bughly interesting collection of photographs of meteoro- of 17 large photographs of clouds taken at hisoblogical phenomena.

servatory, Boulogne-sur-Seine, Paris. These are the The earliest application of photography for the con- best photographs of clouds that have been seen in this tinuous registration of the barometer, &c., was made by country, and they were consequently very much admired. Mr. T. E. Jordan, of Falmouth, in 1838. His plan was to M. Garnier has not yet explained the method he furnish each instrument with one or more cylinders con- adopts for obtaining such beautiful pictures. Dr. Riggen

bach, of Basle, showed some photographs of cirrus clouds a commentative summary of a lecture' by Dr. H. B. taken by reflection from the surface of the Lake of Guppy, on the flora of the Keeling Islands, Sarnen. In this case the surface of the water acts like It is hardly necessary to mention that Darwin vizitec a polarizing mirror, and extinguishes the sky light. Photo- these islands in 1836, except in connection with the fac graphs of clouds were also exhibited by Mr. Clayden, that Dr. Guppy's visit was in a measure an outcome of Dr. Drewitt, Dr. Green, Mr. Gwilliam, Mr. Harrison, that event. "In 1878, Mr. H. O. Forbes spent some time Mr. McKean, Messrs. Norman May and Co., Mr. H. C. there, and extended our knowledge of the flora. Primarily, Russell, and Mr. Symons. Mr. H. P. Curtis, of Boston, no doubt, the coral-reef question took Dr. Guppy to the U.S.A., sent a valuable and highly interesting collection scene of Darwin's early labours, though he was probably of photographs, showing the devastation caused by the not less interested in the flora, having been stimulated by tornadoes at Rochester, Minnesota, on August 21, 1883, practical botanizing in the Solomon Islands a few years and at Grinnell, Iowa, on June 17, 1884. After seeing previously; and a stay of nearly ten weeks enabled him these photographs, some idea can be formed of the to elucidate many points that were either obscure or immense destruction wrought by these terrible scourges, conjectural. 'which so frequently visit various parts of the United Mr. John Murray, of the Challenger Expedition, found States. Mr. Curtis also exhibited three photographs of funds for Dr. Guppy's mission, and he presented to the the tornado cloud; two of these were taken at James- Kew Herbarium the collections made of dried plants and town, Dakota, on June 6, 1887, when the cloud funnel drifted seeds and fruits; and there, such of them as were was 12 miles to the north ; the third, which was taken not already familiar to Dr. Guppy, and of which the male in New Hampshire, during the storm on June 22, 1888, rial was sufficient, were named, and a set incorporatet shows the spiral-shaped funnel trailing at a considerable For the sake of brevity it will be better to describe altitude in the air.

what Dr. Guppy has accomplished, rather than folloa Many interesting photographs illustrating meteoro- him through his account of it. logical phenomena were exhibited. These included floods, Specimens were taken of all the different species of snow-drifts, hoar-frost, frozen waterfalls, &c. A large plants found in a wild state in the islands; notes made number of photographs of flashes of lightning taken of the conditions under which they occurred, of the during the last twelve months were also shown, as well relative frequency, of their chances of propagation, and as some photographs of electric sparks, taken by Mr. of their natural enemies, besides other particulars. In Clayden and Mr. Bidwell

, which explain the formation addition to seeds, or fruits containing the seeds, of the of dark images of lightning-flashes.

plants actually established on the islands, many others Mr. Clayden exhibited a very interesting and instruc- were picked up on the beach, where they had been de tive working model, showing the connection between the posited by the waves. Whilst most of these were in monsoons and the currents of the Arabian Sea and the various stages of decay, others were actually germinaBay of Bengal.

ing, and the question arose, Why had they not succeeded Mr. Dines showed a model of the whirling machine in obtaining a footing? As we shall presently learn, thia used by him at Hersham for testing anemometers and question was easily answered. for experiments on wind-pressure ; he also exhibited a Another point on which we had little trustworthy remarkable curve showing the normal component of the formation was the length of time various seeds of essenwind-pressure upon a sloping surface 1 foot square, the tially littoral and insular plants would bear immersion, normal pressure being taken as 100, and the pressure at or, rather, flotation, in sea-water without losing their various angles of inclination being expressed proportion- vitality. With the exception of a few isolated instances ately. Mr. Munro sent two instruments which he has of seeds having germinated after having been carried recently constructed in conjunction with Mr. Dines. across the Atlantic to the western coast of Europe, very The first is for showing the velocity of the wind. The little was known, because the majority of the seeds shaft of an anemometer is connected with the shaft of the perimented with by botanists at home did not belong to instrument, and in turning works a small centrifugal this class of widely-spread plants. Dr. Guppy institutsi pump, thus raising the level of the mercury in the long experiments on the spot, and although his time was too cistern. The deflection of the pendulum from the vertical short to determine the extreme limits of endurance of position is proportional to the rate of turning, and thus the various seeds, he was able to prove that certain kinds gives a uniform scale. The second instrument is for germinated freely after being thirty, forty, or fifty days in showing the pressure of the wind from a velocity anemo- sea-water. Again, he observed that some seeds that do meter. The arrangement is the same as in the preceding not readily float, or only for quite short periods, are coninstrument, but the fall of the float in the small circular veyed hither and thither in a variety of ways—such as in cistern is proportional to the square of the velocity and the cavities of pumice-stone, and in the crevices of drifttherefore to the wind-pressure, thus giving a scale of wood. pressure with the divisions at uniform distances.

From all available evidence, it is almost absolately Mr. Hicks exhibited Draper's self-recording metallic certain that there were no permanent inhabitants of the thermometer ; a mercurial minimum thermometer with Keeling Islands till about the end of the first quarter of lens front; and a radial scale thermometer. Mr. Long the present century; and from the most trustworthy ac showed Trotter's compensating thermometer for taking counts the islands were covered with vegetation, the temperatures at any distance ; and Mr. Denton exhibited coco-nut largely preponderating in the arboreous ele his clinical thermometer case with new spring-catch. ment. Indeed, as the outer part was almost entirely

WILLIAM MARRIOTT. coco-nut, it seemed, as Darwin says, at first glance to

compose the whole wood. But there is evidence that

there were large "forests" in the interior of the islands, THE ORIGIN AND COMPOSITION OF THE

consisting mainly of the iron-wood, Cordia subcordaz FLORA OF THE KEELING ISLANDS.

The largest island is said to be only about five miles long;

and the group is between 600 and 700 miles from the AT T intervals I have contributed to NATURE the results nearest land, excluding the small Christmas Island.

of the more recent investigations of insular floras, Already at the time of Darwin's visit in 1836, the more especially in relation to the dispersal of plants by islands were in the possession of Captain Ross, the ocean currents, birds, and winds; and now, through the courtesy of the author and Captain Petrie, Honorary Cocos Islands Persa Paper read at a meeting of the Victoria Instituie

" The Dispersal of Plants, as illustrated by the Flora of the Keeibge Secretary of the Victoria Institute, I am able to furnish Monday, February 3, 1890, by Dr. H. B. Guppy.

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