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enough commingled in one and the same accumulation. It is to account for this remarkable commingling that a large portion of my book was written.

3. Mr. Dawkins seems to be ignorant of the fact that the ossiferous deposits of Mont Perrier occur on two separate and distinct horizons. The lower bed, characterised by the presence of Mastodon arvernensis and other extinct forms, is unquestionably true Pliocene. It is overlaid by the "pumiceous conglomerate," with its far-transported and glacially-striated erratics. Upon the denuded surface of this well-marked morainic accumulation rests the upper bed, which contains a very different mammalian fauna-Elephas meridionalis, Rhinoceros leptorhinus (Cuv.), hippopotamus, tapir, horse, cave-bear, hyæna, hedgehog, &c. The flora associated with this fauna is not Pliocene but Pleistocene. The upper bed is overlaid in turn by a newer set of glacial moraines and erratics. The list of Upper Pliocene Mammalia from Mont Perrier and Issoire, given by Mr. Dawkins in his "Early Man in Britain," consists of a "hash-up" of the species derived from those two separate and distinct horizons.

4. The most recent list of mammalia from the liguite-beds of Leffe and Borlezza is quoted by me from Prof. Stopanni, on the authority of Dr. Forsyth Major. All the species in that list, without exception, have frequently occurred in Pleistocene beds, the age of which is generally admitted. The plants and shells associated with these species are all likewise Pleistocene forms. Moreover, as Stopanni has demonstrated, and as I can testify, the stratigraphical evidence proves that the beds pertain to the Glacial series. Prof. Mayer, no mean authority, has shown that the upper beds of the so-called Pliocene of the Val d' Arno (containing Elephas meridionalis and hippopotamus) are not the equivalents of the marine Pliocene, as has hitherto been the belief of paleontologists, but must be classified as Quaternary or Pleistocene.

5. All that I say with regard to the age of the skull of Olmo occurs on p. 318 of my book, and what I say is simply this, "It pertains to Pleistocene times—to the period during which Elephas meridionalis belonged to the European fauna." I do not assert its Interglacial age. It may be either Preglacial (i.e. early Pleistocene) or Interglacial as the Leffe beds are.

I was not aware that geological classification is always based on zoology alone. I am under the impression that botanical evidence, when it can be obtained, is not despised, and that stratigraphical and other physical evidence is not usually ignored. In trying to work out the historical geology of the Pleistocene, I have considered the paleontological as fully as the physical evidence. Mr. Dawkins would have me rest contented with that of the mammalia alone, as interpreted by himself. Perth, February 19.

JAMES GEIKIE

As my name has been imported into the controversy between Prof. Dawkins and Dr. James Geikie, will you kindly permit me to state that I am quite prepared, after re-reading the account given by Dr. Geikie of the Victoria Cave, to accept all responsibility for its correctness.

I

Without entering into the general question, in the particular case of the Victoria Cave the evidence for the contemporaneity in the same area of the reindeer and hippopotamus is not very cogent; a review of all the evidence from that source indeed points the other way. The specimen mentioned by Prof. Dawkins was, according to his Report, found in digging a shaft, a method of exploration unfortunately at that time (1872) employed by the Committee. The subsequent explorations, which were not conducted in this manner, but by carefully removing the deposits, layer by layer, to prevent any possibility of accidental mixture of the remains, gave abundant evidence of rein deer in the upper beds, but not any satisfactory evidence of its presence in the lower beds, containing Hippopotamus, Elephas antiquus, Rhinoceros leptorhinus, &c. This is a point, amongst others, to which, as Reporter to the Committee, I paid careful attention, and the details were impartially given in the Reports.2 The absence of reindeer from a lower bed, the only one containing the same fauna in the Creswell caves explored by the Rev. M. Mello and Prof. Dawkins, is worthy of note as bearing on the same subject.

As regards the evidence for the antiquity of man from the Victoria Cave, Dr. Geikie has fairly stated both sides of the question, and he certainly does not deserve the accusation that

1 Report on the Victoria Cave; British Assoc. Report, 1872, Sections, p. 179. 2 Victoria Cave; British Assoc. Reports, 1871-78.

he "has only called those witnesses which count on his side." Prof. Dawkins, in dismissing the whole of this evidence as "founded on a mistake," must be aware that he is using a convenient formula which can only apply fairly to a part of it, the doubtfulness of which has already been fully conceded. He entirely shelves other evidences which are the result of a long and careful exploration.1

To state that he doubts their cogency would be to take a course of which no one would complain; but to say as if it were a matter of general agreement that they are "founded on a mistake," looks like an attempt to stifle discussion.

But his remarks are so obviously polemical that to most geologists they will probably carry more amusement and less conviction than the writer contemplated. Hastings, February 19 R. H. TIDDEMAN

Les lettres d'Outre-mer

IN the Notes, published in NATURE of January 13, p. 254, the last paragraph gives, as a fact, an announcement of "the simplest post-office in the world" in Magellan Straits, as still in

existence.

At least fourteen years ago there was published a graphic account of this unique establishment by the most eminent of all living French writers, M. Victor Hugo, who introduces the circumstance into his famous work of fiction, "Les Travailleurs de la Mer"; and ever since reading the account I have wondered where the great author obtained his circumstantial relation, which refers to the year 1823. Nor can I believe that such a system of oceanic exchange ever really was in existence, at least on the spot indicated, for a very good reason; that at the point indicated, viz. the neighbourhood of Port Famine, when the Beagle was there in 1834 (see Darwin's "Naturalist's Voyage," chap. xi.), "the Fuegians twice came and plagued " the crew; so that an open barrel would hardly be safe. Darwin, also, who ascended Mount Tarn, the most elevated point in this district, would surely have mentioned this famous barrel post-office, had it existed (?).

I am therefore curious to know whence the note in NATURE was compiled, but I fancy the account is apocryphal. That there were however other oceanic post-offices somewhat similar in principle is a fact in reality.

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In 1673 Ascension was visited by the Dominican, Father Navarette, who speaks of it then as the "Sailor's Post-Office. "Mariners of all nations being accustomed at that time to leave letters here, sealed up in a bottle, in a certain known cranny of some rock, to be taken away by the first ship which passed in an opposite direction" (Mrs. Gill's "Six Months in Ascension," p. 61). And again in 1769 we find the following extract :

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Three creeks caught turtle.

N. E. creek. N. W. creek. English creek, S.W. “In the afternoon the bottle was brought to me which contains the paper whereon the ships of every nation generally write their name, when they touch at Ascension Island.

"This bottle is deposited in a cavity of the rocks of this bay, where it is equally sheltered from rain and the spray of the sea. In it I found written the Swallow, that English ship which Captain Carteret commanded, and which I was desirous of joining. He arrived here the 31st of January, and set sail again on the 1st of February; thus we had already gained six days upon him, after leaving the Cape of Good Hope. I inscribed the Boudeuse and sent back the bottle."

At page 4 of Mellies' "Account of St. Helena (1875) is a wood-cut of the South Atlantic Post Office of 1645. Speaking of the island of St. Helena, Mr. Melliss says:

"It became about this time-little more than a century after its discovery-a resort of Dutch and Spanish ships, as well as Victoria Cave Report, op. cit. 1877, pp. 218-220, and 1878; Journ. Anthrop. Inst. vol. vii pp. 166-173

2 La Boudeuse caught up the Swallow, 25th February.

English; and Portuguese authority seems to have been lessened, through that Power being interested in acquiring possessions elsewhere, and the island was for a while deserted, though still used by the captains and crews of ships as a South Atlantic post-office. It was customary to place letters under huge boulders of stone, marked in a conspicuous manner, so that the crews of ships returning from India might obtain news from home. An interesting record of this period is still to be seen on a rude block of lava measuring nearly five feet high and two feet six inches wide, which has been preserved by being subsequently built into a large mass of masonry in the Jamestown burial-ground."

In the Galapagos Islands there is a bay named Post-Office Bay, which seems to indicate an analogous nautical exchange

station.

I subjoin Victor Hugo's description, and shall be much obliged to any of your readers who can refer me to any account of the earlier voyagers whence this scene was derived. S. P. OLIVER

2, Eastern Villas, Anglesey, Gosport, February 28 P.S.-If any one can give me a reference, also, where I can find an account of the wreck of the Grosvenor on the south-east coast of Africa in 1782, I shall be extremely obliged.

"Les Travailleurs de la Mer, édition illustrée (1866). Livre cinquième, ix.

-Renseignement utile aux personnes qui attendent, ou craignent, des lettres d'outre-mer" (p. 91).

"Ne disiez-vous pas, Capitaine Gertrais que la Tamaulipas ne relâchera point?

-Non. Il va droit au Chili.

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-Ensuite vous doublez le cap Isidore.1 -Et puis?

-Vous doublez la pointe Anna.1

Bon.

de la mer?

Mais qu'est ce que vouz appelez la boite aux lettres

-Nous y sommes. Montagnes à droite, montagnes à gauche. Des pingouins partout, des pétrels tempêtes. Un endroit terrible. Ah! mille saintes mille singes! Quel bataclan, et comme ça tape! La bourrasque n'a pas besoin qu'on aille á son secours. C'est là qu'on surveille la lisse de hourdi! C'est là qu'on diminue la toile! C'est là qu'on te vous remplace la grande voile par le foc, et le foc par le tourmentin! Coups de vent sur coups de vent. Et puis quelque-fois quatre, cinq, six jours de cape sèche. Souvent d'un jeu de voiles tout neuf il vous reste de la charpie. Quelle danse! des rafales à vous faire sauter un trois-mâts comme une puce. J'ai vu sur un brick anglais, le True Blue,' un petit mousse occupé à la 'gibboom' emporté à tous les cinq cent mille millions de tonnerres de Dieu et la 'gibboom' avec. On va en l'air comme des papillons, quoi! J'ai eu le contre-maître de la Revenue, une jolie goëlette, arraché de dessus le fore-crosstree, et tué roide. J'ai eu ma lisse cassée, et mon serre-gouttière en capilotade. On sort de là avec toutes ses voiles mangées. Des friégates de cinquante font eau comme des paniers. Et la mauvaise diablesse de côte! Rien de plus bourru. Des rochers déchiquetés comme par enfantillage. On approche du Port-Famine. Là c'est pire que pire. Les plus rudes lames que j'ai vues de ma vie. Des parages d'enfer. Tout à coup on aperçoit ces deux mots écrits en rouge: POST OFFice. -Que voulez-vous dire, Capitaine Gertrais?

-Je vous dire, Capitaine Clubin, que toute de suite après I Sta. Anna Pt. is at entrance of Port Famine, but Cape S. Isidro is past to the south.

à

qu'on a doublé la pointe Anna on voit sur un caillou de cent pieds de haut un grand bâton. C'est un poteau qui a une barrique au cou. Cette barrique, c'est la boîte au lettres. Il a fallu que les anglais écrivent dessus: POST OFFICE. De quoi se mêlent ils? C'est la poste de l'océan; elle n'appartient pas cet honorable gentleman, le roi d'Angleterre. Cette boite aux lettres est commune. Elle appartient à tous les pavillons. POST OFFICE, est-ce assez chinois? Ça vous fait l'effet d'une tasse de thé que le diable vous offrirait tout à coup. Voici maintenant comment se fait le service. Tout bâtiment qui passe expédie au poteau un canot avec ses dépêches. Le navire qui vient de l'Atlantique envoie ses lettres pour l'Europe, et le navire qui vient du Pacifique envoie ses lettres pour l'Amérique. L'officier commandant votre canot met dans le baril votre paquet et y prend le paquet qu'il y trouve. Vous vous chargez de ces lettres-la; le navire qui viendra après vous se chargera des vôtres. Comme on navigue en sens contraire, le continent d'ou vous venez, c'est celui ou je vais. Je porte vos lettres, vous portez les miennes. Le baril est bitté au poteau avec une chaîne. Et il pleut! Et il neige! Et il grêle! Une fichue mer! Les satanicles volent de tous côtés. Le Tamaulipas ira par là. Le baril a un bon couvercle à charnière, mais pas de serrure ni de cadenas. Vous voyez qu'on peut écrire à ses amis. Les lettres parviennent. -C'est très-drôle, murmura Clubin rêveur."

Explosive Gas in a Lake

A FRIEND, on whom I can rely, informs me that during the late frost, Loch Ken in Kirkcudbrightshire was frozen over, affording pastime to curlers and skaters. Here and there, however, small spots of the surface, near to the shore, resisted the frost longer, and when they did freeze the ice was very thin. These pot-holes were dangerous to skaters, the largest being about size enough to admit an ordinary curling stone. Gas was emitted from them, and when the ice for the first time was formed over them one person got his face severely burned by boring a small hole in the thin ice and setting fire to the gas thus liberated, with a match. After a while the gas seemed to lose its power of combustion and the experiment could be repeated with impunity, a feeble flame only being evoked, when the hole was first drilled. J. SHAW

Dumfriesshire, March 4

Colours of British Butterflies

THE sober colouring of the under-wings of many of our butterflies is universally accepted as being "protective." Let the gorgeous "peacock," for instance, but close his wings, and it takes a sharp eye to see him. Why then should he and so many other kinds flaunt their most brilliant hues in the brightest sunshine, and often be rendered even more conspicuous by perching on a yellow flower? One would think that this was the exact way to attract birds, especially as the colours are not likely to be "warning" ones, for if so, why the sober hues of the under sides of the wings? The colours can hardly be "warnings" to particular kinds of birds and "protective" against the attacks of others. The explanation may be that the facilities for recognition, and thus for the continuation of the species, are so much greater in bright light, as to render it advantageous on the whole to run the chance of easier capture in the brighter parts of the day: or it may be that relatively few birds feed at the times that butterflies choose to display their beauties.

In watching butterflies it appears clear that they are, so to speak, shortsighted, for it is the commonest thing p ssible: see two entirely different sorts circle round each other for some time as if they had to decide whether they are of the same kind or not. In doing this it will be observed that they fly, as it were, over and over each other, so that for quite half the time the gambols are going on, the dark side of the "protected" kinds is shown to the insect below. t'ere steps in a provision which seems admirably adapted for enabling recognition to take place. It will be found that though the wings of protectively coloured butterflies appear very dark at a casual glance, yet that if they are held up to the light, in many cases there are bright spots or colourings or semi transparent spaces, that, by enabling the sun to shine through, make even the dark wings very conspicucus. The bright spots on the "peacock" are a case in point. I have not an opportunity of actually handling a complete collection of our British butterflies just now, but in thirty of our commonest sorts I find fiftecr. that have distinctly protectively

coloured under-wings. Of these fifteen all have some more or less transparent spaces or colourings. In some cases portions of the under-wings are brightly coloured, though not transparent, but both in this case and when there are transparent places they appear chiefly on parts that are apparently invisible when the wings are closed. If these observations are correct, the insects are carefully protected when at rest or when they are laying their eggs. Whether they pair on the ground or with shut wings I do not actually know, for after carefully watching every butterfly I have come across for two summers, I have not succeeded in seeing any of the protectively coloured sorts pairing. It seems likely enough therefore that their protective colours come into lay then. My opportunities for observation are however extremely limited, and it is to draw the attention of those more favourably situated to the subject of the colours of our common butterflies that I write this. In the fifteen protectively-coloured butterflies mentioned above I did not include the "fritillaries," because of the strange metallic lustre on their under-wings. Still they seem suddenly to disappear when they settle, and the metallic spots may take the place of the transparent or coloured ones in other sorts by throwing off the light, and thus enable the insects to recognise each other. Eight kinds more or less transparent but not seemingly protectively coloured, and two common "Blues," make up the thirty kinds I have been able to handle. The under-wings of the "Blues' are certainly protectively coloured, but there seems to be no transparency or bright markings in them. J. INNES ROGERS

Putney, February 24

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Dust, Fogs, and Smoke

THE present endeavours to alleviate the smoke nuisance in London give some interest to the description of the effects of coal smoke on London life in former ages.

I do not mean to speak of the well-known petition presented to Edward the First by the nobility and gentry against the use of sea-coal in London and the consequent proclamation of that monarch interdicting its use. But I allude to the following lines written and published by Evelyn in 1661 in his "Fumifugium," but which I borrow from the 66 History of London," by Noorthouck, London, 1773.

"The immoderate use of, and indulgence to sea-coale alone in the city of London, exposes it to one of the fowlest inconveniences and reproaches, that can possibly befall so noble, and otherwise incomparable city: and that, not from the culinary fires, which for being weak and lesse often fed below, is with such ease dispelled and scattered above, as it is hardly at all discernible, but from some few particular tunnells and issues, belonging only to brewers, diers, lime-burners, salt, and sopeboylers, and some other private trades one of whose spiracles alone, does manifestly infect the aer, more than all the chimnies of London put together besides. And that this is not the least hyperbolie, let the best of judges decide it, which I take to be our senses whilst these are belching it forth their sooty jaws, the city of London resembles the face rather of Mount Etna, the court of Vulcan, Stromboli, or the suburbs of hell, than an assembly of rational creatures, and the imperial seat of our incomparable monarch. For when in all other places the aer is most serene and pure, it is here ecclipsed with such a cloud of sulphure, as the sun itself, which gives day to all the world besides, is hardly able to penetrate and impart it here; and the weary traveller, at many miles distance, sooner smells, than sees the city to which he repairs. This is that pernicious smoake which sullyes all her glory, superinducing a sooty crust, or furr upon all that it lights, spoyling the moveables, tarnishing the plate, gildings, and furniture, and corrodding the very iron bars and hardest stones with those piercing and acrimonious spirits which accompany its sulphure; and executing more in one year than exposed to the pure aer of the country it could effect in some hundreds. It is this horrid smoake which obscures our churches and makes our palaces look old, which fouls our clothes, and corrupts the waters, so as the very rain and refreshing dews which fall in the several seasons precipitate this impure vapour, which with its black and tenacious quality, spots and contaminates whatever is exposed to it. It is this which scatters and strews about those black and smutty atomes upon all things where it comes, insinuating it-elf into our very secret cabinets, and most precious repositories: finally, it is this which diffuses and spreads a yellownesse upon our choysest pictures and hangings; which does this mi-chief at home, is Avernus to

fowl, and kills our bees and flowers abroad, suffering nothing in our gardens to bud, display themselves or ripen; so as our anemonies and many other choycest flowers will by no industry be made to blow [sic] in London, or the precincts of it, unlesse they be raised on a hot-bed and governed with extraordinary artifice to accellerate their springing; imparting a bitter and ungrateful tast to those few wretched fruits, which never arriving to their desired maturity seem, like the apples of Sodome, to fall even to dust when they are but touched. Not therefore to be forgotten is that which was by many observed, that in the year 1644 when Newcastle was besieged and blocked up in our late wars, so as through the great dearth and scarcity of coales, those fumous works many of them were either left off, or spent but few coales in comparison to what they now use; divers gardens and orchards, planted even in the very heart of London (as in particular my lord Marquesse of Hertford's in the Strand, my lord Bridgewater's and some others about Barbican), were observed to bear such plentiful and infinite quantities of fruits, as they never produced the like either before or since to their great astonishment: but it was by the owners rightly imputed to the penury of coales and the little smoake, which they took notice to infest them that year; for there is a virtue in the aer to penetrate, alter, nourish, yea and to multiply plants and fruits, without which no vegetable could possibly thrive."

The improvement mentioned by Evelyn, when the use of coal was for a time less extensive in London, is particularly worthy of notice, and ought, I think, to be considered as an encouragement to persist in the attempt of rendering London as smokeless as possible. CHATEL

Jersey, February 25

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THE GERMAN CHEMICAL SOCIETY

N November 11, 1867, a meeting of about eighty chemists was held in Berlin to take steps for inaugurating a new Chemical Society. On January 13 of the succeeding year (1868) the first meeting of the Society was held, when Prof. A. W. Hofmann was elected president, and the roll-call of the Society contained 105 names. During the first year of its existence 97 papers were read before the Society; at the close of the year the membership had increased to 275, and the Society found that a volume of 282 pages was needed to contain the papers communicated to it.

Since 1868 the German Chemical Society has steadily increased in size and in usefulness; the Berichte for 1880 consists of two large volumes numbering, between them, 2473 pages, and containing the 563 papers communicated to the Society during the year, besides numerous abstracts of papers published elsewhere. The income of the Society for 1880 amounted in round numbers to the sum of 2000/., and of this about 1400/. was set against the cost of publishing the Berichte.

During the thirteen years of its existence the German Chemical Society has published in its Berichte most of the important discoveries in pure chemistry made in that period. It has been the aim of the Society to publish papers communicated to it with as little delay as possible. Meetings are held twice monthly during the session, and the papers read at one meeting are published in the Berichte, which appears on the day on which the next meeting takes place. Papers appearing within so short a time after they are communicated are necessarily brief and concise; but this rapid publication confers a great benefit on all chemists, as they are thus put in possession of at least the leading facts concerning all recent work almost as soon as these facts have been established by the workers. If papers in the Berichte are sometimes wanting in completeness and symmetry, many of them are full of life and stir, telling as they do of work actually proceeding in the laboratory; appearing sometimes in short abrupt snatches, they convey something of the enthusiasm of the worker as he compels nature, bit by bit, to yield her treasured secrets.

The system of printing abstracts of papers published in the various chemical journals has recently been adopted

by the Society; formerly a correspondent in London or Paris, &c., sent a general account of chemical work published in the country from which he wrote. The abstracts of the German Society are on the whole shorter than those which have for many years made the Journal of our own Chemical Society of such great value to the student; they are, however, published at a shorter interval after the appearance of the original paper.

Brief accounts are given of recent chemical patents, but little space is devoted to purely technical chemistry. Is not the Journal of the Chemical Society sometimes overburdened by abstracts which might better find a place in a book professing to collect receipts for the purely "practical man"?

The German Chemical Society in 1877 appointed Dr. C. Bischof of Berlin to prepare a general index for the first ten volumes of the Berichte. The arduous task has been admirably fulfilled. Fellows of the Society have now in their hands not only an index to the Berichte, but a volume which is really a general guide to the chemical work published during the period 1868-1877.

The "Generalregister" extends to 1020 pp.; of these, 162 pp. are devoted to an index of authors, 732 pp. to an index of subjects, 42 pp. to an index of patents, and 84 pp. to a systematic classification of the carbon compounds referred to in the index.

Under an author's name are given, not the exact title of his paper, but a very succinct statement of the leading points in the paper. The same method is pursued in the subjects-index. Taking, for instance, such a general subject as "Dissociation," one finds, first, references to work on the general Theory of Dissociation, e.g. connection between dissociation and temperature, tension, &c. ; then follow special instances of dissociation, inorganic compounds preceding organic. In the case of individual elements or compounds, the references begin with those papers on the existence of the substance in question, then follow its preparation and formation, its properties, its action on other substances, the action of other bodies on it, its estimation, &c., &c.

A systematic nomenclature is adopted, more especially for the carbon compounds: the principles which guided the compiler are stated in a few introductory pages.

The "Generalregister" cannot but be of the greatest value to chemists generally. Almost every chemist is a Fellow of the German Society; many possess the Berichte complete up to date; with the Berichte and this admirable guide which Dr. Bischof has supplied, they can find almost everything that has been done in experimental chemistry within the period 1868-1877. M. M. P. M.

IRISH ESPARTO GRASS

IT T is now over two years ago since attention was called in our pages to the importance of the purple Molinia (Molinia caerulea) as a material for making paper. Mr. Christie of Edinburgh sent a small quantity of it to be operated on by Mr. T. Routledge of Sunderland, and the report on this was most favourable. In January, 1879, a notice appeared in the Times also calling attention to the subject, and referring to the above favourable report; it expressed the hope that some effort would be used to have this grass collected on an extensive scale. It would seem to be ripe for gathering in the early autumn, when some hands could be spared for such work, and as the ground on which it flourishes-wet or partially drained bogs-pays, at least in Ireland, little if any rent, the crop Since would cost little over the expense of reaping it. the first notice appeared in our columns, the Spanish and African Esparto grass has been getting more difficult to obtain, and the demand for it has been steadily on the increase. It is said that the greater part of what is gathered in Morocco finds its way to the Times papermills, and its value for paper-making is now known in

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This freedom from silica of the purple Melic grass is very remarkable.

From a paper by Mr. W. Smith in the recent number of the Proceedings of the Royal Dublin Society, we learn that a very successful trial has been made in the county of Galway to grow this grass in some quantity. As a native plant it is found in every county in Ireland, both on wet heaths and boggy pastures. It flowers in July and August, and its seeds are ripe early in September; it would seem to grow well on partially drained bogs, and if the surface of these has been burnt, the purple Melic grass grows thereon most luxuriantly. It seems fond of growing in tufts, of somewhat large size, and it does not form a sod like so many other grasses. It would appear that in Ireland alone there are over 1,000,000 acres at the present moment not worth sixpence a year each for any agricultural purpose; each acre would easily grow half a ton weight of dried Melic grass, which at its lowest value would be worth 27. Would not this crop, in time, more It seems a than compensate for the loss of the potatoe? pity that the manufacturer should have to go to the Port of Mogador for what he might get with so much greater ease at the Port of Dublin.

UP

SIBERIAN METEOROLOGY

P to the present time Yakutsk, in North-east Siberia, has often been cited as the place of our earth where the winter is coldest, while the minima observed during Arctic expeditions are believed to be the lowest known. Neither the one nor the other is true. In Maak's book, "Olekminski Okrug," I find many data which prove that the coldest winter as well as the lowest well-authenticated minima were observed at Werkhojansk, to the north-east of Yakutsk. The name of the author gives us some guarantee that the observations are trustworthy. I give below the minima at some places cited by Maak, and compare them with those observed in Central and Western Siberia, and the Arctic Archipelago of America :

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Arctic Archipelago.

[British Expedi- 83 N. Floeberg Reach (Nares) - 737 F. tions, 1875-76. 81 N. Discovery Bay (Nares) - 70'7 F. The temperature at Werkhojansk is the lowest of all given here, and it must be borne in mind that the observations lasted but one year, while we have more than thirty-five years at Yakutsk, and eight and a half at Yenisseisk.

The mean temperatures are as follows:

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SPHYGMOGRAPHY

THE pulse has in all ages been held by physicians to be a valuable aid to the diagnosis of disease, but until the invention of the sphygmograph, or pulse-writer, the determination of the character of the pulse was left to the tutored tact of the doctor's finger, which varies much in delicacy of perception in different operators, and in the same practitioner at different times. At most the finger, even of the most experienced, can only detect, regarding the pulse, that it is soft or hard, quick or slow, jerky or languid, regular or irregular; but the finger is Feb. March incapable of analysing the beats, and detecting any departure from the normal standard of each of their component elements. The sphygmograph, which is quite a modern invention, causes the pulse to write its own autograph, enables us to see at a glance the peculiar characters of the pulse, and to ascertain how and where it differs from the healthy or normal pulse.

13'1 -132 6'9 -38 9 -369-175

-555-545-29 0 -46.8 -37'7 0'0 -41 4 -308 87 -330-380 - 39'8 40'7 350-37 4

Though the observations were made only during one year at Werkhojansk, it is probable that it would have the coldest winter of all observed till now, as even at Yakutsk, which is the next coldest, January and February were in no single year colder than at Werkhojansk in 1869. From a comparison with the other stations of North-east Siberia it is probable that here in 1869 February was too cold and December too warm.

Now as to the reason why the winter should be colder in North-east Siberia than on the North American Archipelago farther to the north, it is to be found in the extent of the continent, the distance from any sea open in winter, and the prevailing calms. How important is the last reason is best seen by the comparison of the December and January temperatures of the last British expedition. The more northerly Floeberg Beach is warmer, because more exposed to winds. Now in Eastern Siberia calms prevail to a large extent in winter, except near the coast.

There is a phenomenon to be considered, which is noticed everywhere in winter in high latitudes : during calms with clear sky the valleys are colder than the surrounding hills and slopes, because the cold air sinks downwards and stagnates there. This is confined to the night where the mid-day sun rises high enough, but in high latitudes during some months the mid-day heat of the sun is too small and the day too short to interfere much with the equilibrium of the strata of air established during the night. Even in middle latitudes (45°-50°), when calms and clear weather prevail very largely in December, the valleys are regularly colder than the hills. So it was felt in December, 1879, in Central Europe. What is an exception here is the rule in North-East Siberia, because calms and clear sky are the rule in winter; the valleys are much colder than the hills. On this account the exceedingly low temperature of Werkhojansk in winter is probably not common to the whole surrounding country, and especially in the mountains rising to a short distance south we may expect a much higher temperature. The more we consider the conditions of the winter temperature of North-East Siberia, the more difficult it seems to draw isotherms. We know that plains and valleys there are colder than hills and mountain-slopes, but how much, and what conditions are most favourable to that so-called interversion of temperature? I consider it as highly probable that both at Yakutsk and at Werkhojansk the local topographical conditions are very favourable to winter cold. This being the case, it is quite natural that the latter place is colder in winter than the former, being situated 5° farther to the north, and yet far enough from the west to have a continental climate. A. WOEIKOF

1 According to Maak.

2 Older series of Neverof (1829-54).

Hitherto, however, the sphygmograph has been but little used, for those that have been introduced are large and expensive instruments, requiring a great amount of skill and trouble to fix them on the arm and bring them into action; and for these reasons they are not available for general or private practice. Hence their use has almost been confined to hospital practice; but even here

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they are not always available, for Dr. B. Bramwell, who is a strong advocate for employing the sphygmograph, relates that a patient of his was so terrified by the proposal to employ the instrument that he preferred leaving the hospital to allowing it to be fixed on his arm.

The objections to the general use of the sphygmograph do not apply to the instrument recently introduced into medical practice by Dr. Dudgeon, and from its portability called "the pocket sphygmograph." Though this instrument is so small as to deserve the name of "pocket," it is not inferior in sensitiveness to the most elaborate and complicated of the cumbrous instruments hitherto in use, indeed in some respects it is greatly superior in accuracy to any that have yet appeared. Its size is 2 by 2 inches; its weight only four ounces. the artery exactly fifty times. The spring that presses It magnifies the movements of on the artery can be regulated to press with a weight of from one to five ounces, and the pressure can be altered at will while the instrument is in situ. It requires no wrist-rest; all the other sphygmographs have to be used with wrist-rests of more or less complexity. It can be used with equal facility whether the patient is standing, sitting, or lying. With it an accurate and extremely distinct tracing of the pulse can be made almost as quickly as the pulse can be felt with the finger. Its

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