« PreviousContinue »
answers that have been given to the great ontological of Halle, proposes to give a complete physical history of problem “What am I?”:
his adopted country, may not be unacceptable. Of the
octavo text, which is accompanied by folio atlases, in " In this search for information about myself from
order to give the illustrations on a large scale, we have eminent thinkers of different types, I seem to have learnt
seen four volumes, numbered 1, 2, 3, and 5. The fourth one lesson, that all science and philosophy, and every
volume, which we suppose will contain the birds, is not form of human speech, is about objects capable of being yet issued, and the atlases in some cases do not appear perceived by the speaker and the hearer; and that when
to be complete. our thought pretends to deal with the Subject, it is really
The first volume (issued in 1876) is devoted to the only dealing with an Object under a false name. The
history of the discovery and general geographical features only proposition about the subject, namely, “I am,' can
of the Argentine Republic; and the second, published in not be used in the same sense by any two of us, and,
the same year, to its climate and geological conformation. therefore, it can never become science at all.”
The third volume, of which the text was issued in 1879, Prof. Campbell has succeeded in presenting to us a has been already notice'l in our columns (NATURE, vol. most vivid picture of Maxwell's character. The view xxiv. p. 209). It contains an account of the Mammalwhich he gives will be fresh, and partly strange, to many ceived the first livraison of the folio atlas to this volume,
fauna both recent and extinct. We have now just reeven of those who knew Maxwell well. It is no reproach containing a series of plates illustrating the whales of the to him to say that, in our opinion, he has by no means
Argentine coasts, a subject to which Ör. Burmeister has exhausted the different aspects of his subject. So many devoted special attention for many years. Of the fifth sided was Maxwell's character, that it would have re volume, devoted to the Lepidoptera of Buenos Ayres, we quired the united efforts of several biographers to do it have already like wise spoken (see NATURE, vol. xx. p. the fullest justice.
358). In the second part of the book will be found a good author, who, for fifty years at least, has been a most
It remains, therefore, for us only to wish the venerable account by Mr. Garnett, of Maxwell's scientific work. Of energetic worker in many branches of zoology, health and this nothing further need be said, for an excellent sum strength to bring this important work to a conclusion. mary has already been given in the pages of NATURE by Prof. Tait (vol. xxi. p. 317).
Nomenclator Zoologicus. An Alphabetical list of all It may be questioned whether the literary merit of
Generic names that have been employed by Naturalists
for Recent and Fossil Animals, from the earliest Times many of the pieces of occasional poetry in the third part
to the close of the Year 1879. In two parts. I. Supplewill be sufficient to secure for them the interest of the mental List. By Samuel H. Scudder. (Washington : general reader ; but many will greet with pleasure the Government Printing Office, 1882.) reappearance of old friends among the serio.comic verses.
EVERY working naturalist must be acquainted with We are glad to find among them our favourite, “ To the Agassiz's “ Nomenclator Zoologicus," published Committee of the Cayley Portrait Fund”; finer compli- Solothurn in 1846, which is, in fact, a dictionary of ment to a mathematician surely never was penned. generic terms used in zoology. Without its valuable aid Among those hitherto unpublished may be mentioned the
it is almost a fruitless task to endeavour to ascertain Paradoxical Ode to Hermann Stoffkraft, beginning as
where or by what author any particular generic term has
been instituted, or whether a generic term has been follows :
already used in zoology or not. Agassiz's work, in the My soul's an amphicheiral knot,
preparation of which he was assisted by some of the best Upon a liquid vortex wrought
zoologists of the day, though by no means perfect in its By Intellect, in the Unseen residing.
manner of execution or free from occasional errors, And thine doth like a convict sit,
answers very well for all practical purposes for genera With marlinspike untwisting it,
established prior to the date of its preparation, and Only to find its knottiness abiding ;
affords an excellent basis to work upon. It contains upSince all the tools for its untying In four-dimensioned space are lying,
wards of 32,000 entries of names of generic terms and of Wherein thy fancy intersperses
names of higher groups. In 1873 Graf A. v. Marschall, of Long avenues of universes,
Vienna, prepared and issued for the Imperial and Royal While Klein and Clifford fill the void
Zoological and Botanical Society of Austria, a suppleWith one finite, unbounded homaloid, 1
mentary volume, on something of the same plan. But to And think the Infinite is now at last destroyed.
Marschall's “Nomenclator" no general index was attached, We ought to mention in conclusion that the book is it is neither so accurate nor so complete as the work
and, as those who have used the volume know full well, beautifully illustrated ; there are vignettes of Maxwell which it purports to supplement. and of his father and mother ; some quaint and suggestive A new “ Nomenclator Zoologicus,” carrying the subillustrations of scenes from his early life, after originals ject up to the present day, and correcting the errors and by Mrs. Blackburn; and a variety of diagrams, several of
omissions of its two predecessors, has therefore long been them beautifully coloured, reproduced from originals-by The question was who would undertake the ungrateful
a work of paramount importance to working naturalists. Maxwell's own hand-in illustration of his researches on
task, which was likely to confer neither fame nor fortune light and colour.
G. C. on the performer, and would be, above all others, long
and laborious. Mr. Samuel H. Scudder of Boston, a
well-known American entomologist, in response to apOUR BOOK SHELF
peals from his friends, has consented to devote his Description Physique de la République Argentine d'après energies to the subject, and the first portion of his work des Observations Personelles et Étrangères. Par le
is now before us. Dr. H. Burmeister. (Buenos Ayres, 1876-82.)
The present part of the new Nomenclator is of a sup-1 SOME account of the progress of this extensive work, in
plemental character, as is explained by Mr. Scudder in which the veteran naturalist, Dr. H. Burmeister, formerly blished previous to 1880, not recorded, or erroneously
his preface, and contains “ 15,369 entries of genera esta1 Here the author takes a poetic licence.
given in the nomenclators of Agassiz and Marschall.
The second part, which will be of still greater conse develosed within our area of observation during the hours when quence to naturalists will be a universal index to the first there is no telegraphic communication, and storms in their first stage part and to the previous nomenclators and will contain of development are often ihe most dangerously rapid and intense. altogether about 80,000 references. We shall thus shortly The telegraphic observations transmitted at 6 p.m. on October have, it is to be hoped, a most useful general work upon 23 and at 8 a.m. on October 24, afford no materials for deciding this
important though technical subject brought up nearly whether this may not have been the case in the instance under to the present date.
consideration, although this question can be decided from data since received. On the whole, to the minds of many students of
the subject it will appear rather “strange” that the Office, with LETTERS TO THE EDITOR
the materials at its disposal, does not more often fail to furnish (The Editor does not hold himself responsible for opinions expressed
satisfactory warnings of the more serious of our gales. It is easy
to say, in view of occasional failures, “the system itself must be by his correspondents. Neither can he undertake to return, at fault :” it is still easier to reply, “better it!”. If the country or to correspond with the writers of, rejected manuscripts. cares enough for the welfare of " fishermen and others" to do
No notice is taken of anonymous communications. [The Editor urgently requests correspondents to keep their letters
so, let it provide the necessary funds for a system of night teleas short as possible. The pressure on his space is so great
grams, and if possible for a series of oceanic stations. If it does
not, it must be content with things as they are. that it is impossible otherwise to ensure the appearance even I have been careful to speak of instrumental observations only. of communications containing interesting and nor el facts.)
It is already well known that observations of the movements of " Weather Forecasts"
the higher clouds commonly give indications of the position and HAD the Bishop of Carlisle, in his letter in NATURE (vol.
advance of distant cyclonic systems. But it has hitherto been xxvii. p. 4), instead of extracting from the Times a description
found impossible to train our observers in the difficult art of of some results of the storm of October 24 last, quoted the
taking these observations. To the accomplishment of this task, statements as to the passage of this storm, issued in the reports
which would greatly add to the utility of our weather forecasts, of the Meteorological Office on October 24 and 25, his query
some of us are now devoting ourselves with every prospect of
W. CLEMENT LEY concerning the failure of the weather forecasts would scarcely have needed reply.
Ashby Parva, Lutterworth, November 3 A system of six pickets is e: tablished on our extreme western P.S.-Since the above was sent to press a storm-centre has coasts, along a line which may be roughly regarded as describing | crossed Scotland with a velocity of about 45 miles per hour. the third of a circle, from Stornoway in the north-west, to Brest Indications of its progress were hou ever afforded by cloud obserin the south-west. The enemy whose movements these outposts vations at a distance of more than 800 miles in advance of the are to watch, pours in upon us a series of attacks in the form of centre, the velocity of propagation being supposed uniform.cyclonic disturbances, by which the weather experienced in our W. C. L. islands is affected on 63 per cent. of our days. These circulations vary indefinitely in intensity. This element, and also their size, figure, direction, and velocity of propagation, are in great
The Comet measure dependent on the distributions of atmospheric pre sures
Your engraver has missed what I thought the most im. and temperatures over a larger area than that occupied by our
por tant feature in the drawings which I made of the comet on network of telegraphic stations. It will be enough to mention the 21st inst., viz. the shadow beyond the end of the tail, of the here that the velociiy of advance of the cyclonic centres, as also length of 3 or 4 degrees, very obviously darker than the surof the front arcs of those exterior isobars which form closed rounding space, in which it was lost, without demarcation, curves, varies from zero to about 70 English miles per hour. In This was expressed in my sketch hy a shade of lampblack, very stormy periods like the present, the number and variability of slight, to avoid exaggeration, and perhaps just sufficient to escape the cyclonic circulations which attack us is extremely great, more than one per diem passing over some part of the British Isles.
the engraver's notice. The comet, as seen this morning, is Now let it be remembered that our pickets sleep through the
diminished much in size, and still more in brightness, and tbe night, or that however wakeful they may be, they have, during present moonlight much impairs its beauty
C. J. B. WILLIAMS. the night hours, no means of communication with their com
Villa du Rocher, Cannes, France, October 30 manding officers. How often a phalanx of the enemy will pass these outposts so as to occupy a position fairly within our area at 8 a.m., no instrumental indications having been given at 6 p.m. of the previous day-this, if treated as a question of pro
Noticing Major J. Herschel's remark in NATURE, vol. xxvii. babilities, may be left to the Bishop of Carlisle. It is certainly :: 5, as to the difficulty he experienced in London of observing obvious tbat such an advance, instead of being “very strange,
the comet, apparently owing to the moonlight, I may state that must at times occur, if there be no miraculous interference in
on the morning of the same Sur day to which he refers, I saw behalf of the Meteorological Office. At 8 a.m. on October 24,
the comet very plainly when at Rothsay, Isle of Bute, Scotlard. the centre of the disturbance referred to lay over Dorset, and was
The time was betu een 5 and 6 a.m., and therefore before sunthen moving to north-east at the rate of thirty-five miles per clear, and but few stars noticeable, on account of the moonlight,
rise. The moon was brilliant, and the whole sky wondersully hcur. Supposing the direction and velocity to have been uniform, the position occupied by the centre at 6 p.m. on the 23rd would nevertheless, the comet showed well, extending about 20° across have been about 180 miles north of Cape Finisterre, and, sup- about as bright as the tars then visible.
the sky due south, magnetic ; the nucleus was well defined, and
The tail was straight, posing the extent of the storm to have been also uniform, our outposts at that bour could bave received no instrumental indication spreading outwards to the extreo ity. No glass was used in the of the storm's progress, of a character distinct enough to justify
W. J. MILLER the Meteorological Office in the issue of warnings. As a matter
Glasgow, November 3 of fact the 6 p.m. observations telegraphed to the Office on the 23rd did show, as I think, no indications whatever of the It might be interesting to some of the readers of your paper existence of the storm.
to know that this morning, at 5 a.m., Mr. Manning, the agent It is obvicus that the extreme velocity of the propagation of here for Messrs. F. and A. Swanzy, merchants, and myself, saw some of our severest storns is the element that especially renders a very fine comet bearing south-ea:t, and the tail of which was it possible “that a storm of the first magnitude” may
as long as my first finger, from tip to last joint; its head, upon us unawares.” As a matter of fact, the velocity of propa. bearing a little to the east, was pointing into the sea, and was gation on October 24 was considerably above the average. But about ihe height from the sea of my four fingers held at arm's ií we refer to the charts for March 12 and 13, 1876, we find, at length; it was very brilliant, and we seem to have seen it 10 8 a.m. on the former morning, a cyclone centre occupying the great advantage. Unfortunately we had only a field glass to precise position of that of the 24th ult., and that this disturbance view it through, and being also without instruments, were unable moved to east-northeast with a mean velocity of 62.5 miles to take its proper altitude or bearings. We were standing on per hour.
the verandah of the house at the time, which is on the beach, There is a further risk, against which our system of telegraphy and about forty feet above the level of the sea. cannot protect as, viz., that of a storm centre being primarily We should be glad to know if the comet has been seen further
north by anyone else. Quitta is situated 5° N. latitude, and 1° cause it to be transported by them to the stigma of the next E. longitude.
WALTER HIGGINSON visited flowers. Also differentiation in the pollen of the two
kinds of anthers in our Tinnantia has begun to take place, but Quitta, West Coast Africa, September 25
contrary to Melastoma, the pollen-grains of the short stamens here are smaller than those of the longer ones. I measured
numerous pollen-grains of two individuals in a moistened state Two kinds of Stamens with Different Functions in the (where they are of elliptical form), and found in the one stem same Flower
the pollen grains of the short stamens (in I-1000 m.m.) 62-75 It may be worth mentioning that cases strongly analogous to long, 31-38 broad, those of the longer ones 68.94 long, 38-44 those described in NATURE (vol. xxiv. p. 307, and vol. xxvi.
broad; in the other stem, those of the short stamens 53-69 p. 386, are also to be observed among the Monocotyledons in long, 28-37 broad; those of the longer ones 59-78 long, 31.40 the family of Commelynacex, ani that these cases offer some broad. Both kinds of pollen proved to be quite fertile. graduations.
Commelyna coelestis, Willd. (Fig. 2) possesses in general the In Tradescantia virginica, L., the flower:, as is generally
same contrivances for cross-fertilisation, but has gone a step known, are turned upwards and quite regular, the leafy organs
further in differentiation. Its upper sepal is plainly smaller, its of each whorl (3 sepals, 3 petals, 3 outer, 3 inner stamens, 3 united
lower petal plainly larger than the two other ones; its upper carpels) being alike ani equal in size. As Delpino bas clearly anthers (a, a' a) have differentiated in themselves; two small shown (Ulteriori osservazioni, parte ii. fascic. 2, p. 297) these lateral portions of each of them (po) produce a little pollen and flowers are adapted to A pidæ, which in order to collect pollen
four cross-like diverging flaps (A), which are much larger, take hold of thic articulated hairs of the filaments. In some altract insects by their bright yellow colour strikingly contrasting other species here to be considered the adaptation to pollen with the azure corolla, and perhaps at the same time serve as collecting bees has remained, but the flowers have turned late.
food to the visitors. The articulated hairs of the filaments thus rally, and thus not only has their form become irregular (bi-laterally having lost not only their original function (which they have in symmetrical or zygomorphous), but also the function of the all stamens of Tradescantia) as supports for the feet of pollen. stamens baš gradually changed.
collecting bees, but also their secondary function (which they In Tinnantia undata, Schlecht. (Fig. 1), sepals and petals have in the upper stamens of Tinnantia) of attracting insects, have are still almost unaltered in form and size, only stamens and disappeared altogether. The middlemost of the lower anthers, pistil have become markedly irregular. The broad roundi:h which in Tinnantia is nearly useless from its position behind the petals, which are light purple, spread in a perpendicular plane. style here, bas erected and become much larger than the two The 3 upper stamens, with shorter filaments projectiug from lateral ones, so as to be eminently useful.
The pollen-production of the upper anthers appears to be vanishing, not only from the diminution of the quantity of pro
duced pollen, but also from the great variability of the size of -po. the pollen grains. For whilst the pollen grains of the two lateral fl lower anthers only differ in length from 75 to 90, in breadth
from 45 to 68, and those of the middlemost lower anther in
length from 56 to 82, in breadth from 37 to 56, those of the р
three upper anthers fluctuate from 50 to 87 length, and from 31 to 56 breadth.
In Cummelyna communis, differentiation has gone still further; the upper sepal and the lower petal are relatively very small; the upper filaments, like the upper petals, are blue-coloured ; the lower filaments, like the pistil and the lower petal, are colourless. The upper anthers, as far as I have seen (without
microscope) produce no more pollen gr
The examinatin of other species and genera of Commelynacea probably would show a longer scale of gradations. Lippstadt, October 25
A Curious Halo Fig. 1.-Front view of the flower of Tinnantia undata, Schlecht. FIG. 2.
Front view of the andræceum and gynæciuin of Commelyna cælestis, THERE appeared in NATURE, vol. xxvi. Pp. 268, 293, two Willd. s, s, s', sepals; DP: ' petals; a, a, a', outer whorl of anthers; articles headed “A Curious lalo," which reminded nie of an a, a, a', inner whorl of anthers, or ovary i gr, style (** Gr.ffel"); st, analogous and still more curious phenomenon occurring somestigma.
times here in China, during the hot season. I beg to hand you the middle of the flower, are highly conspicuous by a diverging a few lines on that subject, from the Monthly Bulletin of tuft of bright yellow articulated hairs, which on the last third of the Zi-ka-wei Observatory for August, 1877 :the light-purple filaments surround the golden yellow anthers “A phenomenon to wbich I wish to call the attention of like a cone of golden rays. At the tips of these filaments golden meteorologists was observed many times duriog that month yellow pollen-grains are presented by the whole front side of (August), as also in July. It does not seem to take place in the three upper anthers.
Europe, and I am inclined to think that it cannot occur except The three lower stamens are much longer, directed obliquely with an atmosphere over-charged with aqueous vapour, as it downwards and forwards, with only their tips bending upwards, is the case with us in July and August. in the evening, just a little overtopped by the pistil, which has the same direction after sunset, or in the morning even long before sunrise, no and incurvation. These parts, like the same parts in the de matter what the direction of the wind and the barometric scribed Melastomaceæ, will hardly be perceived by an advancing in pressure may be, provided the day or night were very warm, sect, “ owing to their projection against the broad-petalled corolla bands of a tint varying from the faintest to the deepest blue are of the same colour in the background,” for not only the style and the seen to appear upon the whitish or roseate vault of heaven. filaments, but also the hairs on the base on the two lateral lower They usually are first seen in the east at evening and in the west filaments are of the same purple colour as the petals, and even at morning time, seemingly radiating from a common centre the bluish lower anthers with their yellowish pollen are but diametrically opposite the sun's position. At other times they feebly conspicuous. Any one of the Apidæ or Syrphidæ of emerge from the very position of the sun, or from both points at suitable size, however, when making for the upper yellow once, the interval being either free from bands or completely stamens in order to collect their pollen (I have only once ob encircled by them. served the honey-bеe doing so), will involuntarily repose on the “Last year (1876), on the morning of September 4. I enprojecting part, and at first bring the stigma and then the two joyed a most interesting sight. It was about 5 a.m., the moon, lateral of the lower anthers into contact with the under-side of then on her nineteenth day, was above the western horizon, and its abdomen, and thus regularly effect cross fertilisation.
ju·t being partially eclipsed; now from her bright disc, as froin Here, then, as in Heeria, &c., the anthers have differentiated a radiating centre, shot out a number of those bands, or blue into upper ones, which attract insects and afford food to them, beams; they traversed the whole expanse of the sky. and and lower ones which attach their pollen to the visitors, and seemed to converge towards a point whose situation in the east
below the horizon corresponded with that of the moon in the optical illusion which shows us the two rails of a railway track west above the horizon.
or the walls of a tunnel as converging. “These bands or shoots are more or less numerous, bright, Let this explanation be worth what it may, the fact in inself is and persistent ; some have been observed in the evening, forty. interesting, and I would beg you, Sir, to notice it in NATURE, five minutes after sunset, and in September, 1876, I saw them dealing, however, with this long communication as you may appear with the first break of day. They are evidently movable
MARC DECHEVRENS in the sky, and there is no doubt that they are due to cumuli Zi-ka-Wei Observatory, near Shanghai, (China), August 28 floating about the horizon, below or above, through which the light of the sun is sifted and split; they are, in fact, nothing else than the shadows of the clouds in the faint white or rosy
Habits of Scypho-Medusæ tint of the twilight. According as the clouds before the sun are more or less compact or loose, the bands may be blue, white, or
The communications to NATURE of Mr. Archer (vol. xxiv. red. More than once also have I seen the sky half white and
P. 307), and of Mr. Alexander Agassiz (vol. xxiv. p. 509), on half blue, the separation of the two colours being plainly per
the subject of Medusæ lying upon the bottom with their tenceivable, and Venus shining brilliantly in the blue sky close to
tacles upuard, lead me io forward some observations which I that limit, whilst it would probably have been almost invisible
made on a similar habit of Medusæ in the island of Simbo, one through the milky sky hard by.”
of the Solomon Islands. The Medusa in question frequents a Any one who gazes for the first time at this beautiful pheno
su all mangrove swamp, which lies inclosed in the low point menon cannot help wondering and acknowledging it to Le
that forms the south shore of the anchorage. Numbers of these greatly different from anything to be seen elsewhere. The cele.
animals of a large and dirty-white colour were lying Jazily on brated Jesuit, Father Bouvet, an old missionary to China, wit.
the mud at the bottom of the water, which varied in depth from nessed the phenomenon when on his way from China to Europe
one to three feet, with their umbrellas lowermost, and a mag. as envoy of the great Emperor Kang-hi, in the year 1693; the
nificent mass of arborescent tentacles well displayed. When relation of the voyage (du Halde, vol. i., 1755) gives the fol.
one of them was disturbed and turned over with a stick, it lowing account of his observations:
immediately began to contract the umbrella, until, after swim-/ “25 Juillet, 1693.—Ce jour-là, environ un quart d'heure avant
ming a short distance, it resumed its former position on the le lever du soleil, je vis dans le ciel un phénomène que je n'ai
bottom, of tentacles upward. The dark mud which formed the jamais vu et dont je n'ai point ouï parler en France, quoiqu'il bottom of the swamp was composed of decayed vegetable matsoit fort ordinaire en 0.ient, surtoui à Siam et à la Chine ; car
ter-low confervoid growths, and a few infusoria and living
diatoms. je l'ai observe distinctement plus de vingt fois, tantôt le matin,
But I invariably observed, after raising several of tantôt le soir, dans chacun de ces deux Royaumes, sur mer et
these Medusæ from the bottom, that a layer of white sand sur terre, et même à Péki
covered over the place where each had lain, its light colour "Ce phénomène n'est autre chose que certains demi-cercles forming a marked contrast wish the dark mud around. The d'ombre et de lumière que paraissent se terminer et s'unir dans
form of these patches of sand corresponded with the outline of deux points opposés du Ciel, savoir d'un côté dans le centre du
the animal ; but when the Medusa lay in its usual position, the Soleil, et de l'autre dans le point qui est diametralement oppose sometimes fine, at other times coarse, and was derived from the
umbrella completely concealed them from view. The sand was à celui-là. Comme ces demi-cercles sont tous terminés en pointe, tant en Orient qu'en Occident, c'est-à-dire vers les points
coral and trachytic rocks in the vicinity, with occasionally fragopposés de leur réunion et qu'ils vont en s'élargissant uniformé.
ments of shells intermingled. The sand did not adhere to the nent vers le milieu du Ciel à mesure qu'ils s'éloignent de
surface of the umbrella. l'horizon, ils ne ressemblent pas mal pour leur figure aux
The Medusæ measured generally some eight or nine inches Maisons Célestes, de la manière dont on les trace sur les Globes,
across the umbrella, and appeared to belong to the Rhizostoà cela près seulement que ces Zônes d'ombre et de lumière sont
H. B. GUPPY ordinairement fort inégales pour la largeur et qu'il arrive souvent
H.M.S. Lark, St. Christoval, Solomon Islands, June 29 qu'il y a de l'interruption entr'elles, surtout lorsque le phénomène n'est pas bien formé.
Prof. Owen on Primitive Man “Toutes les fois que je l'ai observé, et je l'ai vu quatre fois différentes dans ce voyage en moins de quinze jours, j'ai toujours In the first number of Longman's Magazine Prof. Owen remarqué que le temps était extrêmement chaud, le ciel chargé criticises an article of mine on Primitive Man, in the Fortnightly de vapeurs, avec une disposition au tonnerre et qu'un gros nuage
Review. In doing so, he quotes some words from my article, épais entr'ouvert était vis-à-vis du Soleil. Ce phénomène semble wbich are there given as a quotation from Prof. Schaafhausen. pour la figure fort différent de ces longues traces d'ombre et de He proceeds to make them the text of his paper, as though the lumière qu'on voit souvent le soir et le matin dans le ciel aussi opinions expressed in them were my ou n. On the question at bien en Europe qu’ailleurs et auxquelles leur figure pyramidale a issue—the Neanderthal skull-I am not competent to form fait donner le nom de verges. Si l'on demande pour quelle any personal opinion; I merely abstracted the opinions of raison ce phénomène paraît plutôt en Asie qu'en Europe et en Rolleston and Schaafhausen. Prof. Owen would hardly have eté que dans les autres saisons, il me semble qu'on pourrait en spoken in the same lofty magisterial tone had he attributed those attribuer la cause à la nature des terres de l'Asie, qui étant pour opinions to their real authors, whose reputation can take care of la plupart beaucoup plus chargées de nitre que celles d'Europe, itself. The respect I feel for Prof. Owen's work makes me remplissent l'atmosphère, surtout en été, et lorsque le soleil a deeply regret the necessity for this explanation ; but I cannot plus de force pour les élever, d'exhalaisons nitreuses, lesquelles allow him to quote as mine words which I placed between etant répandues également dans l'air, les rendent plus propres à inverted commas, attributing i hem at the :ame time to their real réfléchir la lumière et par conséquent à former le météore."
GRANT ALLEN The phenomenon described by the old Jesuit astronomer is andoubtedly the same I have witnessed hundreds of times at Zi-ka-Wei. He evidently considers it as different from any
Magnetic Arrangement of Clouds hitherto observed atmospheric phenomenon ; but his explanation There is a curious arrangement of clouds which, though is tainted with the false science of his time. It is quite certain seen my elf for the first time this year, may doubtless have been that the phenomenon is due to the atmospheric yapour, but I
observed ty others, though I have never seen it referred to anyam rather at a loss to give a more satisfactory explanation. The where. Light clouds of the cirrus formation apparently at great dispersion of the direct rays of the sun into the minute drops elevations range themselves round two poles--one about in the resulting from a partial but wide-spreading condensation of the direction of the magnetic north pole, and the other in that of the aqueous vapour in the upper strata of the air, might account for south. The space between the two poles is filled more or less the milky or roseate appearance of the sky at morning and completely by wispy cirri. The exact point where the various evening time. Besides, the interposition of a light cloud in the threads or wisps should form themselves into a pole I have way of the sun's rays does not impair the transparency of the never been able to clearly see, owing to the dense stratum of drops, and the blue sky may be visible. Now, in the morning vapour which even on the clearest day accumulates at the horizon. and evening the rays of the sun are almost parallel with the On Sunday, October 29, the arrangement above noticed was horizon ; they traverse the whole expanse of the sky, and their
remarkably distinct in the afternoon. C. H. ROMANES apparent convergence on the both sides is only due to the same Worthing
The Umdhlebi Tree of Zululand
piece of mahogany about 10 cms. long. This groove is The word "umdhlebi” does not, I think, appear in Döhne's widened at one end to a circular space a little greater in "Zulu-Kaffir Dictionary.” I presume it to be a derivative from diameter than the diameter of the mirror. The piece of the root hlaba, which Döhne interprets as denoting, among other wood is then fixed with that end down in a horizontal basethings, the giving of pain. Some native tales of the tree will piece of wood furnished with three levelling screws. The be found in part iv. of Bishop Callaway's "Religious System groove is thus placed vertical; and the fibre carrying the of the Amazulu,” in which it is asserted that “there are several mirror is suspended within it by passing the free end of kinds, not one kind only of umhlebe; some are small.” I
the fibre through a small hole at the upper end of the should be disposed to think the kernel of fact will be found to
groove, adjusting the length so that the mirror hangs lie in native observation of the deleterious properties and weird
within the circular space at the bottom, and fixing the aspects of certain Euphorbiacere.
H. M. C.
fibre at the top with wax. When this has been done, the Charlton, November 4
chamber is closed by covering the face of the piece of
wood with a strip of glass, which may be either kept in The Weather
its place by cement, or by proper fastenings which bold it The past month has probably been one of the wettest on tightly against the wood. By making the distance berecord. I have registered here 5'14 inches of rain during the tween the back and front of the circular space small, and month ; only on seven days out of the thirty-one has the gauge its diameter very little greater than that of the mirror, shown less than o'l; and on three days out of the seven rain the instrument can be made very nearly “dead beat,' has been recorded.
J. M. FOUNTAIN
that is to say, the needle when deflected through any Hillingdon, Uxbridge, November 2
angle comes to rest at once, almost without oscillation
about its position of equilibrium. A magnetometer can ON THE GRADUATION OF GALVANOMETERS accurate and convenient than the magnetometers fur
be thus constructed at a trifling cost, and it is much more FOR THE MEASUREMENT OF CURRENTS nished with long magnets frequently used for the deterAND POTENTIALS IN ABSOLUTE MEASURE
mination of H ; and as the poles of the needle may always TH 'HERE are several methods by which galvanometers in practice be taken at the centre of the mirror, the calcu
may be graduated so as to measure currents and lations of results are much simplified. potentials in absolute measure, but they all involve, The instrument is set up with its glass front in the directly or indirectly, a comparison of the indications of magnetic meridian, and levelled so that the mirror hangs the instrument to be graduated with those of a standard freely inside its chamber. The foot of one of the levelling instrument, of which the constants are fully known for screws should rest in a small conical hollow cut in the the place at which the comparison is made. There are table or platform, of another in a V-groove the axis of various forms of such standard instruments,as, for example, which is in line with the hollow, and the third on the the tangent galvanometer which Joule made, consisting of plane surface of the table or platform. When thus set up a single coil of large radius, and a small needle hung at its the instrument is perfectly steady, and if disturbed can in centre, or the Helmholtz modification of the same instru- an instant be replaced in exactly the same position. A ment with two large equal coils placed side by side at a beam of light passing through a slit, in which a thin verdistance apart equal to the radius of either; or some form tical cross-wire is fixed, from a lamp placed in front of of “dynamometer," or instrument in which the needle of the the magnetometer is reflected, as in Thomson's reflecting galvanometer is replaced by a movable coil, in which the galvanometer, from the mirror to a scale attached to a whole or a known portion of the current in the fixed coil lamp-stand, and facing the mirror. The lamp and scale flows. The measurement consists essentially in deter- are moved nearer to or farther from the mirror, until the mining the couple which must be exerted by the earth's position at which the image of the cross-wire of the slit magnetic force on the needle or suspended coil, in order is most distinct is obtained. It is convenient to make to equilibrate that exerted by the current. But the former the horizontal distance of the mirror from the scale for depends on the value, usually denoted by H, of the hori- this position if possible one metre. The lamp-stand zontal component of the earth's magnetic force, and it is should also have three levelling screws, for which the necessary therefore, except when some such method as arrangement of conical hollow V groove and plane that of Kohlrausch, described below, is used, to know the should be adopted. The scale should be straight, and value of that quantity in absolute units.
placed with its length in the magnetic north and south The value of H may be determined in various ways, line, and the lamp should be so placed that the incident and I shall here content myself with describing one and reflected rays of light are in an east and west vertical or two of the most convenient in practice. The easiest plane, and that the spot of light falls near the middle method is by finding (1) the angle through which the of the scale. To avoid errors due to variations of needle of a magnetometer is deflected by a magnet placed length in the scale, it should be glued to the wooden in a given position at a given distance, (2) the period of backing which carries it, not simply fastened with drawing vibration of the magnet when suspended horizontally in pins as is often the case. the earth's field, so as to be free to turn round a vertical The magnetometer having been thus set up, four or axis. The first operation gives an equation involving the five magnets, each about 10 cms. long and i cm. thick, ratio of the magnetic monient of the magnet to the hori- and tempered glass-hard, are made from steel wire. This zontal component H of the terrestrial magnetic force, the is best done as follows. Froin ten to twenty pieces of second an equation involving the product of the same steel wire, each perfectly straight and having its ends two quantities. I shall describe this method somewhat carefully filed so that they are at right angles to its length, in detail.
are prepared. These are tied tightly into a bundle with A very convenient form of magnetometer is that devised a binding of iron wire and heated to redness in a brighi by Mr. J. T. Bottomley, and made by hanging within fire. The bundle is then quickly removed from the fire, a closed chamber, by a silk fibre from 6 to 10 cms. and plunged with its length vertical into cold water. The long, one of the little mirrors with attached magnets wires are thus tempered glass-hard without being seriously used in Thomson's reflecting galvanometers. The fibre warped. They are then magnetised to saturation in a is carefully attached to the back of the mirror, so that helix by a strong current of electricity. A horizonta! the magnets hang horizontally and the front of the magnetic east and west line passing through the mirror is mirror is vertical. The closed chamber for the fibre now laid down on a convenient platform (made of wood and mirror is very readily made by cutting a narrow put together without iron and extending on both sides groove to within a short distance of each end, along a of the magnetometer) by drawing a line through that