relation to the vast quantities of deleterious matters which are vomited into the atmosphere from the chimneys of London. The horizontal movement of the air is at a minimum, and thus altogether insufficient to sweep these noxious matters out into the surrounding country. The impurities therefore ascend into the air over London; and when no longer buoyed up by the warmer air with which they began the ascent, they fall under the influence of the general downward movement of the atmosphere; and this downward movement is accelerated by the solid impurities becoming saturated with condensed aqueous vapour, coal-oil, and tarry substances. Hence the specially noxious fogs of large towns settle near the surface, are no more than a few fathoms in depth, and are at the maximum where chimneys are planted thickest, the situation low-lying and confined, and where consequently the horizontal circulation of the air is absolutely arrested. If we would then overcome, or in any way mitigate, the terribly fatal effects of our city fogs, it can be done in no other way than by Parliament interposing with a legislation which will not only effectually stop the emanation of deleterious exhalations from manufactories, but also compel the combustion of the smoke arising from ordinary fires in dwelling-houses. As regards the latter, where the real difficulty in legislating lies, it may be stated that we already have appliances for thoroughly burning coal, the use of which would be attended with an❘ immense saving of money to the community, as well as the prevention of the painful recurrence of periods of such widespread sickness and mortality as London passed through in the beginning of the present year. But it is of little use in science showing how this terrible evil may be cured if the authorities make no attempt to put her hardly obtained results into practice; it would cost little to give both Dr. Siemens's and Mr. Moncrieff's methods a fair trial on something more than a miniature scale. But what are some of the obstacles to such a practical course may be seen from our correspondence columns to-day. WHAT IS CIVILISATION? The Past in the Present. What is Civilisation? By Arthur Mitchell, M.D., LL.D. 8vo. pp. xvi. and 354. (Edinburgh: David Douglas, 1880.) THIS HIS interesting volume, as may be inferred from the title, embraces two cognate but at the same time somewhat diverse subjects-the one the survival, or possibly the reintroduction, of objects and customs, which are usually regarded as primitive, among the civilised nations of the present day; the other the nature and origin of civilisation. As Rhind Lecturer on Archæology Dr. Arthur Mitchell selected these two subjects as the topics on which to enlarge, and devoted six of his lectures to the first and four to the second; and these lectures, illustrated by nearly 150 excellent illustrations, form the body of his book, to which is added long appendix and a detailed analytical table of contents. The facts brought forward in the first portion of the work, though for the greater part by no means new to most archæologists, are of considerable general interest, and will appear sufficiently striking to the ordinary reader. The peregrinations of the author in the remoter districts of Scotland and the neighbouring groups of islands have brought him in frequent contact with those among whom ancient customs are most likely to have survived, whose domestic appliances are often of the same simple character as were those of their ancestors generations and generations ago, and whose ordinary life has also been but little affected by the advance in material civilisation of their fellow-countrymen. To these objects and customs so persistently surviving from the Past into the Present the term "neo-archaic" has been applied by Prof. Rolleston; and it is precisely these objects that a practised archæologist declines to regard as ancient, unless the circumstances of their finding justify him in so doing. Foremost among them is placed the whorl and spindle, an appliance for spinning still in use in parts of Scotland, as it is throughout the whole of the continent of Europe; and which indeed is never likely to be entirely supplanted by the spinning-wheel or other machinery, so long as the use of the spindle can be combined with an out-of-doors occupation, such as tending sheep or cows. All will agree with Dr. Mitchell that the mental power of those Scotch women who still use the spindle and whorl need not be a whit inferior to that of those who do not use it, and some will go farther, and place the shepherdess who spins in a higher rank than the one whose hands are idle all the day long. That a spindle should be made of a form to do without a whorl, or that a potato should be substituted for the latter, are regarded by the author as signs of the art of spinning by hand having reached a state of degradation; but if producing the greatest effect with the least possible trouble is any sign of progress, such an opinion is questionable. In all such cases the external circumstances of a family or group of families must be taken into consideration ; and if it be cheaper or more easy to employ articles of the simplest and rudest character than to purchase, it may be from a distance, the appliances of modern art, the simple methods and appliances will survive. Netting and knitting by hand will thrive by the side of netting and knitting by machinery, as the long hours of a winter's evening, which might otherwise be wasted, can thus be utilised at practically no cost ; and it seems more remarkable that the simple form of narrow loom for webbing, of which Dr. Mitchell gives a figure, should have become almost extinct, than that it should have survived. A flint for striking a light may be cheaper and in some respects more convenient than lucifers; and the "knockin'-stane" and mallet are not less effective for their purpose than the most expensive pestle and mortar. The earthenware " craggans are as cheap and as well adapted for the ends they serve as pots thrown on the wheel; and in countries where carriage is difficult or extensive water power scarce, the quern or hand-mill and the little Norse-mill may still hold their own; as they did in St. Alban's in the fourteenth century, when they competed with the high charges for multure at the Abbey mills. The survival of the black houses and beehive houses in the Hebrides may also probably be reduced to a question of cost. Perforated or grooved stones are cheaper than plummets of lead as sinkers for nets and lines; and for working in water a pivot and socket of stone is probably both cheaper and more durable than one of metal. The existence of sockets and other working parts formed of stone in our best clocks and watches can hardly be regarded as an instance of low civilisation, or of those who use them being in the Stone Age. In all these remarks Dr. Mitchell will perhaps agree, and if the object of his lectures were merely to inculcate caution in accepting such objects as those he describes as belonging of necessity to any remote antiquity or to an absolutely rude and barbarous people, most archæologists would fully endorse his views. But there is throughout these lectures a more or less evident intention that they should apply not to any minor questions of archæological classification, but to the far greater question of the progress of the human race. Though accepting the ordinary division of antiquities into those of the Stone Age, of the Bronze Age, and of the Iron Age, he does not regard the use of stone, bronze, or iron as in any way indicative of the culture and capacity of those who used them. No doubt many of those who use iron and steel are mentally barbarians, and certainly the instances the author brings forward of the superstitious beliefs still prevalent in Scotland show how deeply rooted are such relics of early beliefs, and how little material civilisation has done to elevate the mental culture of the mass of the population. The distinction Dr. Mitchell draws between culture and civilisation is one which is well illustrated by the continued existence of such low forms of belief; and all his readers will agree with him that it is an error to suppose that in this or any other civilised country the mass of the people can be spoken of as highly cultured. Civilisation he defines to be nothing more than a complicated outcome of a war waged with Nature by man in society to prevent her from putting into execution in his case her law of Natural Selection. Such a view of mankind being to a certain extent exempt from the operation of that law has already been held by many; but even if accepted does not appear to contradict the opinion that the human race may have been evolved from some lower form of mammalian life. For on such an assumption it is, as Dr. Mitchell insists, impossible that man in isolation could become civilised, while, on the other hand, it is evident that until he had become sufficiently intelligent or cultured to enter into association with his fellow men, he would remain subject to the law of Natural Selection in the same manner as any members of the brute creation. Nor even when the stage of association was reached can we expect that there should have been at once any great development of mental power; for there is a long interval between the banding together of a certain number of human units, and any one of them being in that position of ease and leisure which is so necessary for mental culture. of the secondary convolutions and by a want of depth in the grey matter. Dr. Mitchell's view, though we believe nowhere clearly expressed, appears to be that during the whole period of the existence of the human race there was in some part of the world a state of civilisation in existence, which would imply that those among whom it prevailed were possessed of the same average mental capacity as any people or nation of the present day. "May it not happen," he says, "that dealing with the human race as a whole, there never has been a time in its history when there did not occur among men states both of high and of low civilisation? Is it not also possible that there may have never existed a time in the history of mankind as a whole when there were not among those composing it persons potentially as good-persons exhibiting as high a capacity -as any among those who now go to make up mankind?" Were the history of our race confined to the last five or six thousand years it might be hard to answer these questions otherwise than in the affirmative; but who that appreciates the vast antiquity of man as established by recent geological discoveries will admit that such a term forms more than a small fractional portion of the period of man's existence upon the earth, or that there is any parity of reasoning between the circumstances of the beginning of the human period and of the comparatively recent times of Egyptian or Assyrian civilisation? Granted even that the potential mental capacity existed, of what use could it have been to those who were daily on the brink of starvation, who were unacquainted with writing, and with metal, and had not even succeeded in domesticating any of those animals which now seem almost necessary for human existence? This however is not the place to enter into a long discussion as to the origin and progress of civilisation. Those, and they are many, who are interested in this subject will do well to read Dr. Mitchell's book, and even should they not agree with all his conclusions, will feel that his cause has not suffered from the treatment it has received at his hands. They will also find in his Appendix much valuable matter extracted from the writings of Mr. Alfred R. Wallace, Mr. Herbert Spencer, and Mr. Bancroft. To the antiquary pure and simple the illustrations of the "neo-archaic" objects still in use in Scotland will be attractive and valuable; and should some stray politician take up the volume some of the reflections on the dangers to civilisation which may arise from over-legislation, as set forth in the last of the lectures, may profitably be studied. AUSTRIAN MYRIOPODS narchie. Von Dr. Robert Latzel. Erste Hälfte : Die Chilopoden. 8vo. pp. xv. and 228, plates i-x. (Wien: Alfred Hölder, 1880.) THE It is perfectly true that so far as osteological evidence. Die Myriopoden der österreichisch-ungarischen Mois concerned there appears to be no tangible difference between the earliest known remains of man and the human frame of the present day. But it is by no means certain that all the skulls which have been attributed to the Quaternary Period actually belong to so remote an antiquity; and it is worth while to remember that among the coolies of China and some of the Pelew islanders, while the weight of the brain is singularly great, it is balanced by a marked deficiency in the number and depth 'HE centipedes, millipeds, and their allies have hitherto not only been neglected by English naturalists, but practically by Continental workers, until the present generation. Our countryman, Newport, indeed (of whom it may be said with justice, that he touched nothing that he did not elucidate and adorn), has secured a permanent In place in the annals of the class referred to; but it is to the brothers Koch, Meinert, and the Italians Fanzago and Fedrizzi, with the Bohemian naturalist Rosický, and some few other writers of less importance, that we have had to look in recent times for anything approaching serious or continued work upon these creatures. America, Wood and A. S. Packard, jun., have also done good service. The writer of the book now under notice (Professor of Natural Sciences in the Imperial FranzJoseph Gymnasium at Vienna) has by this sterling treatise at once assumed a place in the front rank of authorities. We are not aware of any prior writings of his on the subject, beyond one or two of trifling local interest; but, from his five years' study and collection of material in various parts of Austria and in Western Hungary, it is clear that he is qualified for the task of monographing the species of his country, especially as he has examined nearly all the exponents in Austrian collections and museums. As he says, no work on the Myriopoda of Europe, or even of Germany and the Austro-Hungarian Empire, exists; so it is to be hoped that the present instalment towards such a desideratum may be from time to time succeeded by others of more extended area. As regards the preparation, &c., of specimens, Dr. Latzel recommends the use of small well-corked glass tubes, containing spirits of wine. Pinned examples are of no use. Adopting the Myriopoda as a separate class (Packard seems alone nowadays in uniting them with the Insecta), the following classification is proposed: Orders I. CHILOPODA; II. SYMPHYLA, Ryder (for the Scolopendrellida); III. DIPLOPODA, with sub-orders Chilognatha, Colobognatha (for the Polyzoniida), and Heterognatha (for the Pauropodide); IV. MALACOPODA (Peripatida). The present part discusses the Chilopoda only, the flat centipedes, with large sternum, and whose first pair of thoracic feet is transformed into foot-jaws. The common thin yellow Geophilus, which sometimes gives out a phosphoric light, is a type of the order. Thirty-one genera are recognised, whereof fifteen are European, one American (Notiphilides), and one European (Stigmatogaster) being described as new, and Opisthemega, Wood, renamed Megopisthus. Sixty-seven Austrian species are described (Lithobius, the largest, with thirty-seven), including many new ones. It is not within our scope to analyse the specific characters of such a work; Dr. Latzel seems to have performed his task conscientiously and exhaustively, giving the varied stages of development in each case where known ("juvenis," "adolescens," "pullus," and "fetus"), and combining biological and anatomical aspects with the purely descriptive accounts. ably well-executed lithographs (from his own designs) of such organs as are of general morphological importance, in addition to details illustrative of specific structure. Were it not for the general excellence of Continental work in such matters, we should congratulate Messrs. Hölder upon the result of their part in this matter. OUR BOOK SHELF Die Ethnographisch-Anthropologische Abtheilung des Museum Godeffroy in Hamburg. Ein Beitrag zur Kunde der Südsee-Völker. Von J. D. E. Schmeltz und Dr. med. R. Krause. (Hamburg: L. Friederichsen and Co. 1881.) THIS catalogue of the anthropological section "of the Museum Godeffroy in Hamburg is a model of its kind, and from the exhaustive manner in which it is treated the publishers are quite justified in calling the publication as they do in their prospectus a Handbook of EthnoGodeffroy collection is probably unique and unrivalled as graphy and Ethnology of the South Sea Tribes." The representing the area to which it is confined, and is another example of what private munificence can accomplish for scientific ends; and though the great merchant house may no longer have their collectors scattered throughout the South Seas, the town of Hamburg now possesses by their exertions the anthropological material which this somewhat bulky volume of 687 pages with 46 plates is found not too large to enumerate. However, this catalogue is not merely an enumeration, but contains much valuable geographical information, and some most useful bibliographical notes, which, in the present absence and way of our zoological work, is, if not perfect, much to of any anthropological record compiled in the method be commended, and not too critically received. The arrangement is geographical, and therefore ethnological in its true sense, as followed in most large museums, the Pitt-Rivers collection being of course a brilliant exception, which is rather designed to exhibit evolution in culture. " The first part, "Ethnographische Abtheilung," is written by Dr. Schmeltz, and naturally occupies the largest portion of the volume. Australia is treated first, and then Oceanien," commencing at New Guinea and terminating with the Sandwich Isles, including not only so large and well known an area as New Zealand, but also amongst others the smaller and much less known Exchequer Isles and Futuna. Of the last-named we are told incidentally that the fauna and flora is allied to that of Samoa. The Gilbert, Marshall, and Caroline Islands are then dealt with, the last very fully. This ethnographical portion concludes with Alaska and a few other of museums the usual few outside elements obtrude. various localities, thus showing that in the most special The second part, "Anthropologische Abtheilung," is the joint production of Messrs. Schmeltz and Krause, the first author treating the photographs and original drawings, whilst Dr. Krause enumerates and describes the osteological specimens. The cranial measurements are most desired by physical anthropologists, and it is to The Myriopoda have always afforded material for the be hoped that some of our own provincial museums comparative anatomist, as evidenced quite recently by which are still behind in that respect, though possibly MacLeod's researches upon the poison-bearing glands containing but few crania, will yet, where such can be of various Chilopods (in the Bulletin of the Belgian authentically localised, have the same at once properly Academy of Sciences, 2nd series, vol. xlv. p. 781 et seq.), measured, and for a method, the lately-published Cataand Voges's scheme for the classification of Tracheatalogue by Prof. Flower will supply all that anthropological science requires. Such Catalogues as the one under (in Siebold and Kölliker's Zeitschrift für wissenschaft- notice, taken with those of Prof. Flower and General Pittlische Zoologie, vol. xxxi. p. 143), &c. Dr. Latzel recognises Rivers, are in themselves real manuals of anthropology. the importance of this element, and gives some remark W. L. D. On the Digestive Ferments and on the Preparation and Use of Artificially Digested Food. By Wm. Roberts, M.D., F.R.S. (London: Smith, Elder, and Co., 1880.) THIS little volume contains the three Lumleian Lectures delivered before the College of Physicians, London, for the present year. The subject is treated in a manner worthy of the reputation of the author. He gives a summary of what is known on the subject of digestion as a function common to animals and plants, treats of the general characters and properties of the digestive juices and their ferments, with an account of the action of each on food material. After many trials the author adopts three solutions for the preservation of his solution of animal ferment, full details of the preparation of which are given. The researches of Musculus and O'Sullivan as to the transformation of starch are given, with the very recent researches on the same subject by Brown and Heron. The subject of the digestion of starch is excellently handled, and any dyspeptic reader would do well to consider the facts and reasonings here so well and clearly given. The second lecture chiefly relates to pepsin and the digestion of proteids; digestive proteolysis; the milk-curdling ferment. The third lecture is devoted to the effects of cooking on food, preparation of artificially-digested food, peptonised materials, the clinical experience of the use of peptonised food, and on the use of pancreatic extract as an addition to food shortly before food is taken. These lectures, though at times technical, may be understood by the ordinary reader, who would often derive advantage from a general knowledge of their contents. As long as man must live on food so long will the proper digestion of that food be of extreme importance to him. The Niger and the Benueh: Travels in Central Africa. By Adolphe Burdo. From the French by Mrs. George Sturge. (London: Bentley, 1880.) THERE is a good deal that is interesting in M. Burdo's lively story of his voyage up the Niger and Benueh, partly in the company of Bishop Crowther. He gives many details of the various towns and villages he visited on the banks of the two rivers, and of the appearance and habits of the people he met with, all welcome information in a region on which our information is even yet comparatively meagre., M. Burdo's journey was made in 1878. LETTERS TO THE EDITOR [The Editor does not hold himself responsible for opinions expressed by his correspondents. Neither can he undertake to return, or to correspond with the writers of, rejected manuscripts. No notice is taken of anonymous communications. The Editor urgently requests correspondents to keep their letters as short as possible. The pressure on his space is so great that it is impossible otherwise to ensure the appearance even of communications containing interesting and novel facts.] Smokeless London I HAVE read the letter of Mr. Scott Moncrieff in NATURE, vol. xxiii. p. 151, with much interest, and am satisfied that his data and conclusions are substantially accurate. This conviction is based on some experience in the commercial distillation of coal. One difficulty will arise which should at once be foreseen and provided against, or it may be exaggerated into a big bugbear by that class of self-styled "practical" men who oppose to every innovation the inertia of their own self-sufficient stupidity. The semi-coke remaining in the retorts, when only one-third of the volatile constituents of the coal has been run off, will be highly inflammable, and display this property by a great out. burst of lurid flame and dense smoke when the retort doors are opened for discharging, and unless the withdrawn charge is immediately quenched there will be a veritable Inferno where it falls. This is merely a matter of practical detail admitting of easy remedy where there is ability and willingness to grapple with it. A more serious difficulty is likely to arise in London from the peculiar position of the gas companies. They are suffering from commercial congestion due to a plethora of prosperity, and receiving no stimulation from wholesome competition, they display very low commercial vitality. The public welfare is no business of theirs. It is otherwise in those towns that are sufficiently advanced in civilisation and have abolished the gas and water joint-stock monopolies. There the public are helping themselves, and control the management of the Corporation gas works by their election of the members of the Corporation. Many of these towns are foggy and smoky enough for the experiment, and in these such a boon as that offered by Mr. Moncrieff will probably be appreciated, and, being appreciated by those most interested, will be at once practically tested. Birmingham, for instance, is likely to try it. I was there a few weeks ago and saw how they have eclipsed our electric lamps on the Embankment by the gas lamps around their town-hall. If it succeeds in any one of these towns our companies will surely follow, or if not, so much the worse for the companies. Stonebridge Park, Willesden, W. MATTIEU WILLIAMS December 17 Climates of Vancouver Island and Bournemouth I THINK it very probable that your correspondent Capt. Verney is right about the climate of Vancouver's Island. My only sources of information were maps of isothermals in Keith Johnston's and Phillips' Atlases, which show the mean temperature about the same as that of the south of England, while the winter temperature is shown as being decidedly colder, and it was to this I more especially referred. The mainland of British Columbia is 'unIsland itself and the adjacent sea may be really milder; and if doubtedly colder than that of Western Europe, but Vancouver's so it is another proof of the great power of the returning Japan current. benefit it. I shall be very glad of Prof. Haughton's criticisms on my hypothesis; and in the mean time will only say: 1. That unless Bournemouth is never cooled by north and north-east winds, any amelioration of the climate of the Polar regions would certainly 2. That as by my hypothesis the entrance of two new gulf-streams into the Arctic Ocean would entirely prevent the formation of ice; the return currents that would undoubtedly be produced would not be cold currents in the sense in which they are now, as they would probably be always considerably above the freezing point. ALFRED R. WALLACE Geological Climates IN relation to the discussion as to the importance to be ascribed to the distribution of certain trees and plants in the determination of geological climates, it may interest Prof. Haughton and Mr. Duncan to know that a specimen of the Australian Araucaria Cunninghami is now growing on one of the slopes of the Marlstone Hills near Belvoir Castle, in North Leicestershire, a position it has occupied for upwards of forty years. It has attained a height of about thirty-five feet. Having survived (without other protection than that afforded by the wooded heights about it) the cold of the winters of 1860 and 1879, its capability to withstand a greater degree of cold than is ever experienced in our southern counties may be with confidence asserted. Masses of a true and very characteristic bamboo, Bambusa metaké, are now growing vigorously and spreading rapidly on the same estate, the long elegant and slender canes and the delicate green foliage of this variety of bamboo not having suffered in the slightest degree from the severe frost of last winter or the early and equally trying severity of this. Arundinaria falcata, the bamboo found as high as the snow-line in the Himalayas, has also proved hardy at Belvoir, but it has been displaced as an ornamental plant by B. metaké. Arundo donax MAY I ask leave to offer a few remarks on the leading article on British Earthquakes which appeared in NATURE, vol. xxiii. p. 117. The author brings out very strongly the apparent connection between great lines of jointing or faulting and earthquake movements, and points out the great fault which traverses Scotland from sea to sea as a case in point. Now I had this same question before the British Association this year, and exhibited a map illustrative thereof. I had further, following up a theory submitted by me to the Royal Irish Academy, on the Correlation of Coast-Line Directions, and published by that body, drawn up on a Geikie's Geological Map of Scotland certain of those correlated lines, and on a smaller map of the British Isles had indicated both the lines in question and the localities wherein earthquakes have been noticed in later times, more essentially since 1860. One of those lines crosses the district about Comrie, and at the moment (August, 1880) could hardly be pointed out as in any notable way supporting the connection sought to be established between coast-line directions and earthquake localities. But the recent earthquakes in the north of Ireland and in Scotland go far to do this, as the direction shown by me both agrees with the great fault mentioned by the author of the paper on British Earthquakes in direction, and also fairly shows the direction of the earthquake band or zone, which apparently extends from Londonderry across Scotland. This direction is exactly at 40° with the coast-line direction between Carnsore Point and Wicklow Head, as shown on the accompanying map. I may add that having had occasion to examine Prof. Höfer's memoir on the "Erdbeben Kärntens und deren Stosilinien," and to compare his lines with those given on the map of Europe exhibited by me at the British Association meeting of this year, I find some very remarkable concordances as regards directions, which, having submitted to him, he quite recognised. I consider therefore that this memoir, Prof. Geikie's very remarkable article on the Volcanoes of North-Western Europe, and this late article on British Earthquakes, all point more and more distinctly to the importance of jointing and fissuring in connection with volcanic and earthquake action, and so far go in support of the theory submitted by me. J. P. O'REILLY Royal College of Sciences, Dublin, December 14 A General Theorem in Kinematics I AM very much obliged to Prof. Everett and Mr. J. J. Walker for having taken the trouble to point out that the theorem which I communicated to NATURE is, so far as it relates to uniplanar motion, already known. I am indebted to Prof. Unwin for more complete information on the subject. He tells me that the theorem (for the uniplanar case) has been employed by German engineers in the discussion of stresses produced in moving pieces exactly the use of the theorem which naturally presents, itself. Moreover, the theorem (for the uniplanar case) will be found in $198 of Collignon's "Cinématique," as well as in other foreign books, but not, so far as my information goes, in the work of any English author. None of your correspondents or of mine are however able to say that the general case was previously known. The simple method of proof given by Prof. Everett is that which I had used nearly a month ago in a paper which I wrote (and have since read) for the London Mathematical Society. I may mention in connection with this subject a kinematical theorem which Mr. Kempe communicated to NATURE some time back. I find that this theorem comes properly under a general theorem which holds for the areas of roulettes. It can be easily proved that the areas of the most general kinds of roulettes follow exactly the law of circular transformation which Steiner proved to hold good for the areas of pedals. For this theorem of Steiner's see Williamson's "Integral Calculus," P. 202, third ed. Mr. Kempe's theorem (as also Holditch's) is an immediate consequence, since every possible uniplanar displacement of a body can be produced by epicycloidal motion. Mr. Williamson, justly describing Mr. Kempe's as a singularly elegant theorem (ibid. p. 210), arrives at it quite differently. GEORGE M. MINCHIN Royal Engineering College, Cooper's Hill, December 13 A Correction IN NATURE, vol. xxiii. p. 44, Prof. Young has published some experiments proving that the thermo-electric power of a platinum-iron couple is to be observed in vacuo as well as in air; this fact is said to be contradictory to the results given in my papers. I presume that some error has caused this statement, as I never and nowhere asserted that the thermo-electric power is I have, on the contrary, dependent on the surrounding gases. stated (Phil. Mag., October 1880, p. 294) that no such influence has been hitherto observed. Thus the experiments of Prof. Young do in no way contradict my views. Jelly Fish FRANZ EXNER ON November 3, in the B.I.S.N. Co.'s steamer Arcot, Capt. Stevenson, while in lat. 16° 50' N., long. 55° 45′ E., with the Kuriyan-muriyan islands to the north, thirty to forty miles and three days out from Aden to Karachi, we passed through a vast quantity of brown anemones, the ordinary bell-shaped jelly-fish and strange worm-like (apparently) jelly-fish, floating on and just below the surface. These were first noticed about five in the afternoon, and we were still amongst them when we went below to dinner at six, the vessel steaming about eight knots. The anemones were only peculiar in that they appeared to be rounded at the base and without the ordinary flat surface for adhering to rock or stone; they were in vast numbers and had the feelers expanded. The worm-like or centipede-like jelly-fish were from six to eight feet long and as thick as a man's wrist. They appeared sometimes singly, sometimes many twisted together; they were in slow feeble snake-like motion. All agreed that they were ribbed in appearance; but there was a difference of opinion as to the colour. It was described by some as that of the sea, by others as violet, brown, or purple. Each apparent rib was divided from those next it by a bar of lighter colour. At night the sea was bright with many phosphoric lights of many shapes, so we were perhaps still passing through the mass. There was a dead calm at the time. The captain has read this account and stated it to be fairly F. C. CONSTABLE correct. Karachi, Sind, November 8 MR. PLIMSOLL'S CURE FOR COLLIERY EXPLOSIONS LE ET us suppose a person actuated by very powerful motives, who desires to solve the most difficult mathematical problem of the day, and who, after having neglected to acquire the most rudimentary knowledge of his subject, and after having contented himself with seeking the company of land surveyors, and trying to entrap civil engineers into conversations about it, suddenly startles the world with the cry of Eureka! Eureka! Eureka! should we, or should we not, be inclined to regard his solution with respect? Mr. Plimsoll has done for the mining world exactly what our suppositious person would have accomplished for the mathematical one. In an article contained in the December |