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Is this is the first occasion on which such a peculiarity has The agreement between the observed and calculated values is n recorded or figured, I prefer to leave all speculation as to certainly remarkable, and the + and - differences are evenly cause out of the question. We need a good deal more distributed. earch before we can deal satisfactorily with the biological Ten years have now elapsed since the last reading was taken, blems involved in such appearances. As a help towards and if the thermometer is still in existence it would be of great , I bring together here a list of all those works which have interest to know what further rise bas taken place in its zero ne under my own and Prof. Andrews's notice, in which point. According to the equation the reading should now be normalities in annelids are recorded :
SYDNEY YOUNG • Andrews : “Proc. U.$. Nat. Mus.," vol. xiv., p. 283, University College, Bristol, January 20.
Andrews : “ Amer. Nat.," vol. xxvi., p. 725, 1892. , Bell: “Ann. Mag. Nat. Hist.,” vol. xvi., p. 475, 1885. Bell : “Proc. Zool. Soc., Lond.,” 1887, p. 3.
THE APPROACHING SOLAR ECLIPSE, . Bonnet : “Euvres d'Hist. Nat. et de Phil.," vol. i.,
APRIL 15-16, 1893. 67 seq. 1779.
THE total solar eclipse of April 15-16, 1893, is not, Breese : West Kent Nat. Hist. Soc., 1871
I only one of the longest of the century, but is the · Broome : “Trans. Nat. Hist, Soc." Glasgow, 1888,
last of the century from which we are likely to get any ?03. Bülow : “ Archiv. f. Naturg," vol. xlix., 1883.
addition to our knowledge of Solar Physics. The longest Brunette : “Travaux de la Sta. Zool, de Cette," p. 8,
duration of totality of this eclipse is 4 minutes 46 seconds, icy, 1888.
and as the path of the moon's shadow lies to a great 5. Claparède : "Les Chaet. du Golfe de Naples,” p. 436,
extent on land, there is a considerable choice of possible
stations with long durations of totality. Commencing 1. Fitch : “Eighth Report on Insects of State of New in the Southern Pacific the line of totality passes in a k," appendix, p. 204 seq. Albany, 1865.
north-easterly direction and enters Chili at Charañah in 2. Foster : Hull Scientific Club, February, 1891. Reported 29° southern latitude, crosses the South American eekly sup. Leeds Mercury.
continent, and issues at Para Cura, a village near Ceara, 1. Friend : “Science Go sip,” 1892, pp. 108, 161.
at the north-east corner of Brazil, in latitude 3° 40' south. bo Grube: “ Archiv. f. Naturg.," vol. x., p. 200, 1844.
It crosses the Atlantic at its narrowest part and enters | Horst : “Tydsch. ned. Dierk. Veren,” and ser., D.I.,
Africa at Point Palmerin, 'near Joal, almost midway la, . xxxii, 1882.
between Bathurst and Dakar, and in latitude 14° north; i. Laugerhaus : “Nov. Act., K.L.C.D. Acad.,” vol, xiii., 12, 1879.
the shadow finally leaving the earth in the interior of Marsh : “Amer. Nat.," vol. xxiv., p. 373, 1890.
Northern Africa. The eclipse will be observed by several . Macintosh : “ Challenger Reports," vol. xii., 1885.
parties of astronomers in Chili, Brazil, and Africa, there · Robertson : “Quart. J. Mic. Soc.,” vol. xv., p. 157,
being almost absolute certainty of fine weather in Chili
and Africa, and a reasonable probability in Brazil. · Zeppelin : “ Zeit. f. Wiss. Zool.," vol. xxxix., p. 615 The English arrangements to observe the eclipse have 1883.
been made by, a joint committee of the Royal Society, Catalogue Terat. Spec. in Mus. Roy. Coll. Surgeons, the Royal Astronomical Society, and the Solar Physics lon, 1872.
Committee of the Science and Art Department, South
Kensington ; Dr. A. A, Common, LL.D., F.R.S., underThe Zero Point of Dr. Joule's Thermometer. taking the duties of Secretary. Two expeditions will be the course of a discussion on “Exact Thermometry" I sent from England, one to Africa and the other to Brazil, ibed (NATURE, vol. xli. p. 488) the results obtained by the expenses being defrayed by a grant of £600 from the ig thermometers for a considerable time to 280° and 356°; Royal Society. ointed out by means of a diagram that at 356°, after about The African expedition will be in charge of Prof. Jurs, the rise of the zero point became—at any rate approxi- | T. E. Thorpe, and will consist of Prof. Thorpe, Mr. A. yra rectilinear function of the logarithm of the time;
Fowler, Mr. Gray, and Sergeant J. Kearney, R.E. The h at 280", even after more than 300 hours' heating, the
Brazilian expedition will be in charge of Mr. A. Taylor, ppeared to be rather more rapid than would correspond to
who will have with him Mr. W. Shackleton. 2 simple relation. Joule observed the rise of the zero point of a thermo
Prof. Thorpe and his party will leave Liverpool by the at the ordinary temperature during a course of no less
British and African mail steamer on March 18th, arriving hirty-eight years (“ Scientific Papers, vol. i. p. 558), and it at Bathurst on April 2nd. They will be met at Bathurst red to me that it would be of interest to ascertain the rela by a gunboat kindly placed at the disposal of the ► the logarithm of the time in this case also.
expedition by the Admiralty, and will be conveyed at : following table contains the dates of Dr. Joule's observa. | once to Fundium, a station on the Salum River, about
the total number of months from the date when the first sixty miles from Bathurst ; this being the station selected 3 was taken ; the corresponding logarithms; the total rise
by the Committee from the three which were offered by zero point in scale divisions (13 divisions to 1° F.); the
the French Government. The gunboat will remain with ise calculated from the formula R = 6'5 log. t - 4:12,
the expedition, and the officers and crew will assist in the is the time in months; and lastly the differences
preparations for and in the actual observations of the n the observed and calculated zero points.
eclipse. After the eclipse the party will be taken to Total rise of zero point in scale
Bathurst on the gunboat, and will return to England by a
British and African mail steamer, if one is available. 844 ...
From the time-tables of the steamers now published it 22 ... 1'342 ...
appears, however, that there will not be any mail steamer 45 ... 1'653 ...
available until the end of April, and in this case a cruiser ... 48 ... 1.681 ... 6'9 ... 68 ... -O'I ... 106 ... 2'025 ...
will meet the party at Bathurst and bring them to the 8:8 ... 90 ... +0'2
Canary Islands or to Gibraltar, from either of which ... 144 ... 2'158 ... 95 ... 99 ... +04
places they will be able to return by mail steamer, 200 ... 2 301 ... III ... 275 ... 2.439 ... 118 ... II
arriving in England early in May. 310 ... 2 491 ... 12'1 ... 12
The members of the expedition to Brazil will leave 346 ... 2'539 ... 1245 ... 12'4 ... -O'I
Southampton by the Royal Mail steamer on February ... 393 ... 2'594 ... 1271 ... 1274 ... +0'03 23 for Pernambuco, arriving at the latter place on March ... 427 ... 2.630 ... 12'92 .. 1298 ... +0'06 12. They will take passage by the local mail steamers
... 464 ... 2.667 ... 13.26 ... 13:22 ... -0'04 to Ceara, at which place they will arrive about March 20.
The Brazilian Government are willing to place a war which will be exposed simultaneously to the langes vessel at the disposal of the foreign expeditions to formed by the Abney lens and the enlarging combinat observe the eclipse, and it is hoped the English observers The six separate exposures, giving twelve photogapoi will be able to avail themselves of the privilege thus will be so arranged that the longest exposed pictures va gracefully offered. The station selected is at Para Cura, the enlarging combination will have received the 30 on the coast about forty miles west of Ceara, and the photographic action as the shortest exposed pictures ro party will rely upon obtaining any necessary help from the Abney lens. The whole of the pictures will that the Brazilian authorities and from local assistants. form a continuous series, all the short exposures in the The observers will return from Pernambuco by the Royal series having a direct enlargement of three diameters Mail steamer due to leave there on April 22, and expect In Brazil Mr. Taylor will take charge of this dorbe to be in England on May 5.
instrument, and in Africa the similar instrument will be The objects of the expeditions are—
entrusted to Sergeant Kearney. On the night beiore te (1) To obtain visual photometric measures of the light eclipse intensity scales for object 4 will be impressed by of the corona.
the use of standard lights and specially-constructed sale (2) To obtain photographs of the corona with the four kindly supplied by Captain Abney on all the plates to the inch lenses of a little over sixty inches focus belonging exposed to the corona. The plates will be developed af te to Captain Abney, which were successfully used in Egypt stations as soon as convenient after the eclipse, experience (1882), Caroline Island (1883), Granada (1836), and Salut on previous occasions, both by English and Americas Isles (1889), in order to continue the series.
observers, having shown that it is impossible to reper's (3) To obtain enlarged photographs of the corona undeveloped plates after exposure in the tropics, aal with small photographic action, so as to show details of bring them home without serious deterioration the structure of the brightest parts, i.e. those nearest the Similar spectroscopic work is to be carried out at the sun.
two stations. For the integrating spectroscope in Afrr (4) To measure the photographic intensity of the Mr, Fowler will use a six-inch objective prism with aus. light of the corona, by direct comparison with standard inch photographiclens of about nine-feet focas, mouales intensity scales placed on the margins of the plates used an equatorial stand, belonging to Prof. J. Norman Lockyer. for the negatives to be obtained under sections 2 and 3. and kindly lent for the expedition. At the Brazilan
(5) To obtain photographs of the spectrum of the station Mr. Shackleton will use two three-iach prisms 'n corona. These spectra will be obtained on three dif- front of a three-inch photographic lens of about two-fee! ferent plans :
focus ; the spectroscope, which belongs to South Kensing(a) With integrating spectroscopes, where no colli - | ton, being arranged horizontally and used with a teaunch mator is used and the prism or prisms are placed directly heliostat, also lent by the Science and Art Department in front of the object glass of the photographic camera. Very short exposures will be given at each station at the
(6) With ordinary slit spectroscopes, the slit being commencement and end of totality, so as to obtain. arranged as a radius of the sun.
possible, the very numerous bright lines which have been (c) With ordinary slit spectroscopes, the slit being observed in the chromosphere, and exposures of tom arranged as a tangent to the sun's limb.
5 to 45 seconds will be given during totality. The first of these objects will be attempted only at the In Africa the radial and tangential slit spectroscopes African station ; Prof. Thorpe and his assistant, Mr. Gray, will be mounted together on the Corbett equatorial making the observations. Their equipment will consist of stand lent from Greenwich, the spectroscopes sei a six-inch Simms equatorial of seventy-eight inches focus belonging to the Royal Society. Mr. Fowler and (lent from Greenwich) fitted with special photometric ap Sergeant Kearney will erect and adjust these instro. paratus lent by Captain Abney. The observations will be ments, but the actual exposure, which will extend through made on essentially the same plan as that pursued by Prof. the whole of totality, will be made by an officer of the Thorpe at Hog Island, near Granada, in 1886, separate gunboat who will be placed in charge of the instrumen. portions of the corona being compared with a standard in Brazil the radial and tangential slit spectroscopes ma glow lamp by means of a Bunsen photometer. An inte be mounted horizontally and used with a second tea-iach grating box for measuring the total coronal light with as heliostat lent by the Science and Art Department. The little light from the sky as possible, and an ordinary erection and adjustment will be made by the observer, Bunsen's bar photometer will also be used, these being but the actual exposure during totality will be entrusted entrusted to officers of the gunboat.
to a local assistant. Orthochromatic plates will be used As regards objects 2, 3, and 4, duplicate apparatus has for all the spectroscopic work, the spectra obtainai been arranged for use at the two stations.
extending from above D into the ultra-violet A photoheliograph mounting from Greenwich has Briefly summarised, the English programme is 25 been lent for Brazil, and an exactly similar instrument follows:from South Kensington for Africa. On each of these In Africa :-Prof. T. E. Thorpe, assisted by Mr. Gray mountings a specially designed new double tube will be and local assistance-Photometric measures of the fixed. An Abney lens will be mounted in one comparto visual intensity of the corona with the equatorial photo. ment of each of these tubes, and this, with a focal length meter, the integrating photometer, and the bar photo of sixty inches, will give pictures on the scale of rather meter ; Mr. Fowler-The six-inch integrating spectre more than half an inch to the moon's diameter. In the scope ; Sergeant Kearney-the Abney and Dallmeyer other compartment a four-inch Dallmeyer photohelio coronographs ; local assistance-the radial and tangen graph lens will be mounted in combination with a tial slit spectroscopes. specially-constructed two-and-a-half-inch Dallmeyerl In Brazil :--Mr. Taylor, the Abney and Dallimeyer negative lens of eight inches negative focus ; this arrange coronographs; Mr. Shackleton, the three-inch two-prism ment giving, with a total length of sixty-eight inches, | integrating spectroscope ; local assistance, the radial and pictures on the scale of over one-and-a-half inches to the tangential slit spectroscopes. moon's diameter. This latter arrangement is essentially It is not yet decided whether one of the 20-inch mirrors the same as that of Dallmeyer's new telephotographic of 45-inches focus specially constructed to photograpó lens. It will be so arranged that the ratio between the the faint extensions of the corona during the eclipse of photographic effect of the Abney lens and the new com 1889* (December 21-22) will be taken to Afric. If bination will be as 10: 1.
so it will be entrusted to a local assistant Rwas Special plate holders have been made to fit the double originally intended to use one of these in Africa, and tubes, each of these plate holders carrying two plates, was hoped that one would be used by the Harvard Codes
Observatory party, which is to occupy a station in Chili, and in those of others. Illustrations are almost needless ; but Prof. W. H. Pickering writes that difficulties of I may, however, mention one as a reminder; it was curtransport will prevent him from taking the 20-inch mirror rent in my boyhood, and the incident probably took place he has at Arequipa to the Harvard station; and owing to not many yards from where I now stand. Sir Humphrey this and to the already large programme of the English Davy had recently discovered the metal potassium, and party in Africa there is some doubt whether they will showed specimens of it to the greedy gaze of a philosotake one of the mirrors. April being the middle of the phical friend as it lay immersed in a dish of alcohol to rainy season in Brazil, it is not deemed advisable to send shield it from the air, explaining its chemical claim to be one of the mirrors to that station.
considered a metal. All the known metals at that time The duration of totality at Para Cura is four minutes were of such high specific gravity that weight was comforty-four seconds, the altitude of the sun being between monly considered to be a peculiar characteristic of metals ; 70 and 80°. At Fundium the totality lasts four minutes potassium, however, is lighter than water. The philosoeight seconds, the altitude of the sun being about 54o. pher not being aware of this, but convinced as to its
The Joint Eclipse Committee having arranged the metallic nature by the reasoning of Sir Humphrey, fished expeditions and the general scheme of work, final details a piece out of the alcohol, and, weighing it a while beas to the actual operations have been left to a sub-com tween his finger and thumb, said seriously, as in further mittee consisting of the Astronomer Royal, Captain confirmation, “How heavy it is !” Abney, Mr. H. H. Turner, Prof. Thorpe, Mr. A.Taylor, and In childhood the imagination is peculiarly vivid and the secretary, Dr. Common Prof. Lockyer, previous to notoriously leads to mistakes, but the discipline of after leaving England for Egypt, determined the exposures life is steadily directed to checking its vagaries and to to be given by Messrs. Fowler and Shackleton with the establishing a clear distinction between fancy and fact. integrating spectroscopes. These, with the final instruc- | Nevertheless, the force of the imagination may endure tions to observers drafted by the sub-committee, will be with extraordinary power and be cherished by persons of published in due course.
poetic temperament, on which point the experiences of At present very few details are available as to the our two latest Poet-Laureats, Wordsworth and Tennyactual work to be undertaken by foreign observers. The son, is extremely instructive. Wordsworth's famous Harvard College Observatory expedition to Chili has
| “ Ode to Immortality” contains three lines which long already been mentioned. Prof. Schaeberle, of the Lick puzzled his readers. They occur after his grand deObservatory, has already started for Chili, and will use a scription of the glorious imagery of childhood, and the six-and-a-half-inch equatorial, a five-inch horizontal "perpetual benediction” of its memories, when he pbotoheliograph of forty-feet focus, and a Dallmeyer | suddenly breaks off into-portrait lens. He will be assisted by Mr. Gale, an
“ Not for these I raise amateur, from Paddington, N.S.W. A Chilian party will
The song of thanks and praise, also observe the eclipse in Chili.
But for those obstinate questionings At Para Cura there will probably be two or three
Of sense and outward things, American parties, one being announced as probably under
Fallings, from us, vanishings," &c. Prof. H. S. Pritchett, from Washington University, St. Why, it was asked, should any sane person be “obLouis, and another will probably be brought to that stinately” disposed to question the testimony of his station by Prof. David P. Todd. A Brazilian party will senses, and be peculiarly thankful that he had the power also observe. The Bureau des Longitudes, Paris, are | to do so? What was meant by the “fallings off and sending a complete expedition to Joal, in Africa, under | vanishings," for which he raises his " song of thanks and MM. Deslandres and Bigourdan, the latter observer praise"? The explanation is now to be found in a note having already started for his station, The work under- | by Wordsworth" himself, prefixed to the ode in taken will be to obtain photographs of the corona and of Knight's edition. Wordsworth there writes-“I its spectrum. M. de la Baume Pluvinel will also go to was often unable to think of external things as Joal to photograph the corona. At present we have not having external existence, and I communed with all I heard of any Italian expedition, but it is hoped that Prof. saw as something not apart from, but inherent in, my Tacchini will be able to arrange to observe the eclipse. own immaterial nature. Many times while going to
A. TAYLOR. school have I grasped at a wall or tree to recal myself
from this abyss of idealism to the reality. At that time I was afraid of such processes. In later times I have
deplored, as we all have reason to do, a subjugation of MEASURE OF THE IMAGINATION.I
an opposite character, and have rejoiced over the rememTHE first perceptible sensation is seldom due to a
brances, as is expressed in the lines · Obstinate questionsolitary stimulus. Internal causes of stimulation
ings,' &c." He then gives those I have just quoted.
It is a remarkable coincidence that a closely similar are in continual activity, whose effects are usually too faint to be perceived by themselves, but they may combine
idea is found in the verses of the successor of Wordswith minute external stimuli, and so produce a sensation
worth, namely, the great poet whose recent loss is which neither of them could have done singly.
mourned by all English-speaking nations, and that a
I desire now to draw attention to another concurring cause
closely similar explanation exists with respect to them. which has hitherto been unduly overlooked, or only
For in Lord Tennyson's “Holy Grail" the aged Sir partially allowed for under the titles of expectation and
Percivale, then a monk, recounts to a brother monk the attention. I mean the Imagination, believing that it
following words of King Arthur :should be frankly recognised as a frequent factor in the
“Let visions of the night or of the day production of a just perceptible sensation. Let us reflect
Come, as they will ; and many a time they come for a moment on the frequency with which the im
Until this earth he walks on seems not earth, agination produces effects that actually overpass the
This light that strikes his eyeball is not light, threshold of consciousness, and give rise to what is indis
The air that smites his forehead is not air,
But vision," &c. tinguishable from, and mistaken for a real sensation. Every one has observed instances of it in his own person
Sir Percivale concludes just as Wordsworth's admirers
| formerly had done : "I knew not all he meant." 'Extract from a lecture on "The Just-Perceptible Difference," delivered Now, in the Nineteenth Century of the present month bofore the Royal Institution, on Friday, January 27, by Francis Galton, F.R.S. We hope to give next weck an extract on "Optical Continuity."
1 Knight's edition of Wordsworth, vol. iv. p. 47.
Mr. Knowles, in his article entitled " Aspects of Tenny- | by his imagination to declare that the light still ware son," mentions a conversational incident curiously and waned in unison with the sound after its ups an. parallel to Wordsworth's own remarks about himself : downs had been reduced to zero. But if the subject on “He [Tennyson) said to me one day, 'Sometimes as I | the experiment suspected its object he would be thot sit alone in this great room I get carried away, out of into a critical mood; his mind would stiffen itself, as • sense and body, and rapt into mere existence, till the were, and he will be difficult to deceive. accidental touch or movement of one of my own fingers Having made these preliminary remarks, I will mentis like a great shock and blow, and brings the body back one only of some experiments I have made and with a terrible start."
making from time to time, to measure the force of my mo Considering how often the imagination is sufficiently imagination. It happens that although most peran intense to stimulate a real sensation, a vastly greater train themselves from childhood upwards to distingua number of cases must exist in which it excites the physio imagination from fact, there is at least one instance : logical centres in too feeble a degree for their response to which we do the exact reverse, namely, in respect to ta reach to the level of consciousness. So that if the imagina auditory presentation of the words that are perused: tion has been anyhow set into motion, it shall as a rule the eye. It would be otherwise impossible to realise in originate what may be termed incomplete sensations, and sonorous flow of the passages, whether in prose or pier: whenever one of these concurs with a real sensation of that are read only with the eyes. We all of us value the same kind, it would swell its volume.
cultivate this form of auditory imagination, and it co This supposition admits of being submitted to experi monly grows into a well-developed faculty. I inserte ment by comparing the amount of stimulus required to when we are listening to the words of a reader while ce produce a just perceptible sensation, under the two condi eyes are simultaneously perusing a copy of the book fri.. tions of the imagination being either excited or passive. which he is reading, that the effects of the audan
Several conditions have to be observed in designing imagination concur with the actual sound, and proced. suitable experiments. The imagined sensation and the stronger impression than the latter alone would be he real sensation must be of the saine quality ; an expected to make. scream and an actual groan could not reinforce one I have very frequently experimented on myseli i another. Again, the place where the image is localised success, with the view of analysing this concurrent D in the theatre of the imagination must be the same as it pression into its constituents, being aided thereto is in the real sensation. This condition requires to two helpful conditions, the one is a degree of deafs be more carefully attended to in respect to the visual which prevents me when sitting on a seat in the mak imagination than to that of the other senses, because rows from following memoirs that are read in 128 the theatre of the visual imagination is described suitable to the audience at large ; and the ette by most persons, though not by all, as internal, whereas is the accident of belonging to societies in the theatre of actual vision is external. The im- | unrevised copies of the memoirs, that are aber! portant part played by points of reference in visual be read, and usually in monotones, are obtene illusions is to be explained by the aid they afford in order to be perused simultaneously by the end in compelling the imaginary figures to externalise them- | Now it sometimes happens that portions of these par selves, superimposing them on fragments of a reality. | however valuable they may be in themselves, do The visualisation and the actual vision fuse together in interest me, in which case it has been a never-rige some parts, and supplement each other elsewhere.
source of diversion to compare my capabilities of fulle The theatre of audition is by no means so purelying the reader when I am using my eyes, and when I external as that of sight. Certain persuasive tones of not. The result depends somewhat on the quality of voice sink deeply, as it were, into the mind, and even voice; if it is a familiar tone I can imagine what is simulate our own original sentiments. The power of much more accurately than otherwise. It depends localising external sounds, which is almost absent in those on the phraseology, familiar words being vividly re-pt who are deaf with one ear, is very imperfect generally, sented. Something also depends on the mood 3* otherwise the illusions of the ventriloquist would be time, for imagination is powerfully affected by al ir impossible. There was an account in the newspapers a of emotion. The result is that I frequently find myze few weeks ago of an Austrian lady of rank who purchased a position in which I hear every word distinctly so kana a parrot at a high price, as being able to repeat the they accord with those I am perusing, but whenever seen Paternoster in seven different languages. She took the is changed, although the change is perceived, the bird home, but it was mute. At last it was discovered word is not recognised. Then, should I raise IT that the apparent performances of the parrot had been from the copy, nothing whatever of the reading ce due to the ventriloquism of the dealer. An analogous understood, the overtones by which words trick upon the sight could not be performed by a con distinguished being too faint to be heard juror. Thus he could never make his audience believe a rule, I estimate that I have to appes that the floor of the room was the ceiling.
the reader by about a quarter of the prera As regards the other senses the theatre of the imagination distance, before I can distinguish his words by to coincides fairly well with that of the sensations. It is so alone. Accepting this rough estimate for the purpo with taste and smell, also with touch, in so far that an of present calculation, it follows that the potenci imagined impression or pain is always located in some hearing alone is to that of my hearing plus images particular part of the body, then if it be localised in as the loudress of the same overtones heard at the same place as a real pain, it must coalesce with it. 4 units of distance respectively; that is as about
Finally, it is of high importance to success in experiments | or as 9 to 16. Consequently the potency of my 2 on Imagination that the object and its associated imagery | imagination is to that of a just perceptible sound 25 should be so habitually connected that a critical attitude or as 7 units, to 16. So the effect of the imaginac of the mind shall not easily separate them. Suppose an | this case reaches nearly half-way to the level of comic apparatus arranged to associate the waxing and waning | ness. If it were a little more than twice as $* of a light with the rising and falling of a sound, holding would be able by itself to produce an effect indisti means in reserve for privately modifying the illumination able from a real sound. at the will of the experimenter, in order that the waxing Two copies of the same newspaper afford easily * and waning may be lessened, abolished, or even reversed. sible materials for making this experiment, a fer It is quite possible that a person who had no idea of the having been altered here and there in the copy to purport of the experiment might be deceived, and be led | from.
I will conclude this portion of my remarks by sug- upon the frontals, and the frontals also bear a pair of gesting that some of my audience should repeat these small conical processes just behind their junction with experiments on themselves. If they do so, I should'the nasals. But even more exceptional than these be grateful if they would communicate to me their results. parietal and frontal processes are the great ver
tical plates rising from the maxillaries, slightly
recurved, and reaching the full height of the PROTOCERAS, THE NEW ARTIODACTYLE. parietal protuberances. Seen from above, these plates
are found to be not in contact, but to enclose a LAST year the American Museum of Natural History long deep cleft, representing the anterior narial opening.
L established a department of mammalian palæon. This is bridged over posteriorly by the nasals, which, as tology for the purpose of securing and exhibiting collec- shown in the second figure, are extremely abbreviated. tions from all the tertiary horizons of the west. Dr. Correlated with the development of these processes are a 1. L. Wortman, well known by his discoveries while number of strong ridges, which form supporting butassociated with Prof. Cope, was put at the head of the | tresses for the horns. These extend, as above described, field work, and under his direction explorations have from the sagittal crest outwards, also from the anterior already been made in the Laramie or Upper Cretaceous, margin of the orbit forwards. This lateral maxillary and in three of the great divisions of the tertiary, namely, ridge, as it may be called, terminates in a process just the Wasatch, the Puerco, and the Lower Miocene or above the infraorbital foramen ; and this process, although White River.
small, seems to illustrate the remarkable tendency of this The discovery of the first example of Palæonictis found little skull to develop osseous projections at every availin America was mentioned in NATURE last year. From the Puerco are brought remains of about 400 individuals, adding many new facts to the discoveries of Prof. Cope. From the Laramie are 400 of the small isolated teeth of the kind recently described by Prof. Marsh. These are found by the writer to have a distinctly tertiary rather than mesozoic character, and while intermediate between the mesozoic and Puerco species, they decidedly resemble the latter. Meniscoëssus, for example, about which there has been so much discussion, proves to be a plagiaulacid,
and also an ancestor of Polymastodon, which is thus shown to be a huge Plagiaulax, in which the fourth cutting premolar is reduced.
By far the most perfect specimens have, however, been brought from the Lower Miocene; and here it appears that practically a new horizon has been developed, for the collection is full of fresh forms. Many of these are
Fig. 2.– Top view of skull. new species intermediate between the true White River or Titanotherium fauna, and the Middle Miocene, but able point. The character of these projections is different others are new genera, and represent distinct unrelated from that found elsewhere among the Artiodactyla ; they forms.
are not horn-cores, neither are they similar to the processes In this Lower Miocene collection are included portions upon the parietals of the giraffe. The development of of six skulls and the fore and hind feet of an Artiodactyle, these multiple bony protuberances suggests the skulls of of about the size of a sheep. The most complete skull is Sivatherium, Tetraceros, and other eastern ruminants; here figured exactly as found, and is seen at once to but the proportions of the skull are wholly different. The depart from all known Artiodactyles in many important olfactory chamber, which is usually so expanded in the characters. There are no less than four protuberances Artiodactyla, is here extremely reduced; the nasals upon each side of the skull. Hindmost are two processes | barely reach beyond the middle line of the skull. upon the parietals, which are placed upon the superciliary Up to this point the study of the skull appeared to ridges as they diverge from the sagittal crest. These present an entirely new form, but later the other skulls processes are close together and oval in section, reminding were removed from the matrix, and among them one was us of the posterior pair of horns in Uintatherium rather found with small canine teeth, entirely lacking all than of the conical or rounded horns found in the giraffes the processes upon the frontals, and giving indications and some other Artiodactyles. Their position upon the that those upon the maxillaries were either absent parietal bones is also peculiar. The superciliary ridges or comparatively small. The parietals were unfortuextend outwards into two widely projecting plates of bone, nately missing, but the idea at once suggested itself that which curve upwards above the orbits; these plates are this might be a female skull. Two years ago Prof.