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and with superheating,
paring together engines with different cycles bas been a source
of considerable misapprehension, and very probably the language E,
used in the passage in question may be insufficiently guarded.
The use of superheated steam on this method of comparison is
not a gain, but a considerable loss, for the heat might ideally all S+A
S+A have been used at the maximum temperature, and is so used in
the standard of comparison.
The practical case in which the boiler pressure is given is, of 5
course, quite different. There is a gain by superheating, but, Numerical example. Say that A = 800°, B = 600°, S = 1000°.
putting aside cylinder condensation, the gain is small, because Substituting these values, we get
such a small percentage of the heat is employed at temperatures E '2301 without superheating,
above that of the boiler. 2389 with superheating.
The process was originally introduced with the object of That is, less than 4 per cent. is gained by superheating 200°. drying the steam and diminishing cylinder condensation; and So far, I support Lord Rayleigh's view, or, rather, he says
now that the practical difficulties attending its use have been in what I have been impressing upon engineers for the last twenty
great measure removed (as I ani informed), by the employment years. If this had been all I had to say, I would not have of mineral oil for lubricating purposes, it may be hoped that it written now; but Lord Rayleigh adds to his statement what is
may be revived, and be the means of a considerable economy. to me an astounding announcement, that, “by the addition of The action of superheated steam in a cylinder was explained saline malters, such as chloride of calcium or acetate of soda,
and its economy experimentally demonstrated by Hirn some the possible efficiency, according to Carnot, may be in
fifteen or twenty years ago. I have given the explanation briefly creased.” I hasten to call this assertion into question, because
on p. 352 of my book, but I purposely avoided discussing questhere are so many people ready to bring engines on new prin
tions relating to it, being of opinion that, in the present state of ciples into the field of joint-stock bubbles ; and I am afraid we
our knowledge, theoretical investigations are of doubtful value. may be having, quite apart from Lord Rayleigh, a new field I am certainly, however, under the impression that the true engine syndicatel and loated on the strength of this communica- nature of the economy obtained by its use has for a long period tion and the signature thereto, before its meaning is understood. been very generally recognized, though some writers in dealing As I understand thermodynamics there would be no gain from
with the theory of heat engines may have expressed themselves superheating by a saline solution, over the usual method of incautiously. It would, I think, be very desirable, in teaching superheating steam raised from pure water. The saline mixture
the subject, to introduce as early as possible the idea of a mean is not the working substance. Carnot's law refers to the work. temperature of supply. I have dwelt on the importance of this ing substance only, and not to anything left in the boiler. The conception in the latter part of my book, and I am sure its first step in evaporation from the saline mixture is to separate a
introduction would remove many difficulties. particle of water from the salt. In the act of separation, the
Greenwich, February 24.
JAMES H. COTTERILL, temperature of the water particle falls to the temperature due to the pressure, and at that temperature it is evaporated into
LORD RAYLEIGH's interesting communication on superheated steam particles, which immediately become of the same tem- steam in your last issue (p. 375) leads me to ask whether it is perature as the saline mixture. These steps are followed by generally known that solutions can be heated up to temperatures every particle of water, each independently of every other par.
higher than 100° by passing into them steam at 100°. ticle. Of course, we cannot practically test those temperatures,
The late Peter Spence at the Exeter meeting of the as the complete series is run through for each particle in a frac
British Association in 1869 called attention to the fact tion of the twinkling of an eye, and immersed in a liquid of
ibat by simply passing steam at 100° directly into a strong greatly higher temperature. A thetaphi diagram for this would
solution of nitrate of soda (other salts will of course answer) give, at BA, and extending upwards to temperature S, a very
it was possible to raise the liquor to its boiling point, about 121°. narrow figure 8, whose loops are equal, and drawn, as in a
Superheated steam is frequently used for heating up liquors in figure 8, one right-hand and the other left-hand. The line for chemical processes on the large scale, but where a slight diluthe reception of latent heat would be identically the same line, tion is no disadvantage, the simpler operation of heating with the horizontal through A, as when the evaporation was from ordinary low pressure steam might be adopted more generally pure water. It is evident, therefore, that, according to my
than it is. Spence used steam in this way for the purpose of lights, the efficiency will be precisely the same as without the i extracting sulphate of alumina from alum shales. salt in solution.
G. H. BAILEY. Some ten years ago this plan was submitted to me for my
The Owens College, Manchester, February 22. opinion by an eminent mechanical engineer, Mr. S. Geoghegan, who, I understood, bad then patented it. The above is the
Poincaré's “Thermodynamics." substance of the opinion I then expressed, and nothing I have PERMETTEZ-MOI de repondre en quelques mots à l'article que learned since induces me to change my view of it now.
M. Tait a consacré à ma ihermodynamique, non que je veuille The “complete elaboration of this method," hinted at in the prendre la défense de mon imprimeur, ou résuter des reproches last paragraph of Lord Rayleigh's communication, is not clear généraux, contre lesquels ma présace proteste suffisamment. to my mind ; and it is just possible that a few sentences of J'abuserais ainsi de votre hospitalité et de la patience de vos explanation would show me that I have been hitting away at lecteurs ; je me bornerai donc à discuter une seule des critiques something that was not intended by the writer.
de M. Tait, et je choisirai celle que ce savant paraît regarder excuse must be that I have read the statement, as every prac- comme la plus importante et qu'il a formulée avec le plus de tical engineer would, to mean that the latent heat is imparted précision. Je commence par en reproduire le texte : along the isothermal of the superheat. When I get to under- “ Even the elaborate thermo-electric experiments of Sir W. stand the first sentence of the last paragraph of the communica. Thomson, Magnus, &c., are altogether ignored. What else can tion, I may be able to confirm the anticipation of higher we gather from passages like the following ?-economy. J. MACFARLANE GRAY.
. . Si l'effet Thomson a pu être mis en évidence par
l'expérience, on n'a pu jusqu'ici constater l'existence des forces The passage quoted by Lord Rayleigh from my book on the électromotrices qui lui donnent naissance. steam-engine, in some remarks on this subject in your number Rappelons d'abord que, dans l'étude des phénomènes élecof the 18th inst: (p. 375), is taken from one of the earlier triques et thermiques qui se produisent au contact de deux chapters, which is devoted to engines which receive and reject métaux, il faut soigneusement distinguer trois choses :: heat at constant temperature. When such an engine is used as (1) Le phénomène calorisque condu sous le nom d'effet a standard of perfection, by comparison with which some other Peltier. Dans le cas d'un métal unique mais inégalement engine is tried, it appears to me that the maximum and mini- chauffé, le phénomène correspondant s'appelle effet Thomson mum temperatures of the working fluid must in the first instance be
et se manifeste par vn Transport de chaleur. adopted as the temperatures of reception and rejection of heat ; (2) La différence de poieniiel vraie ou sorce électromotrice de and in fact, without entering on questions reserved for discussion contact. in a later chapter, no lower value than the maximum could well (3) La force électromotrice apparente ou différence de potenhave been adopted. There is no doubt that the practice of com- tiel entre les couches d'air voisines de la surface de deux métaux.
If so, my
L'effet Thomson a été mis en évidence par l'expérience. M. of his doubts as to the validity of this application I cannot Tait croit qu'il en est de même de la différence de potentiel remove, because he has not stated his reasons. But it may be vraie.
permitted to me to feel some doubts as to the validity of his Ou la phrase que j'ai citée plus haut n'a aucun sens, ou elle
For no other than van der Waals himself has taken signifie qu'il me blâme d'avoir dit le contraire.
up this very question, and has discussed (of course much more Or cette manière de voir ne soutient pas un instant d'examen. fully than I was able to do) the application of his formula to Nous n'avons aucun moyen de mesurer la différence de potentiel solutions, including also the case of interactions between the vraie.
substances. His papers on this subject are inserted in the Les méthodes électrostatiques ne nous font connaître que la Zeitschrift für physikalische Chemie, v. p. 133, and viii. p. 188 ; différence de potentiel apparente; les méthodes électrodyna- and also in the Archives Néerlandaises of 1889 and 1891. miques ne nous font connaître que la somme des forces électro. Leipzig, February 16.
W. OSTWALD. motrices vraies dans un circuit fermé.
Enfin les méthodes indirectes, fondées sur l'écoulement ou sur les phénomènes électrocapillaires, ne sont pas applicables
A Lecture Experiment on Sound. dans le cas qui nous occupe.
H. POINCARÉ. The following experiment may be of interest to your readers.
A piece of glass tubing is drawn out to a fairly fine point, P,
attached by string crosswise to a short lath of wood, w, conThe Theory of Solutions.
nected by india-rubber tube to water-lap, and a jet of water It seems that, unfortunately, the period of misconceptions, directed on to a tambourine, T. whose victim the theory of solutions is, has not yet ended. For, after an explanation from my side of the theory of solutions as
T I understand it, Mr. J. W. Rodger, my critic, asserts (NATURE, p. 342) that "it cannot be admitted that a number of exact relationships constitutes a theory." From his further remarks, it must be concluded that he designates by the name theory what I would name a hypothesis, and that, according to him, van 'n Hoff's application of the “gaseous laws” to solutions involves
W the hypothesis that there exists no interaction between the solvent and the dissolved substance.
It was therefore in vain that I stated in my letter, in italics, that many properties of the solutions, according to the new theory, " can be treated entirely independently of the question of a possible interaction between the parts of the dissolved substance and the solvent"; it was in vain that I pointed out that all the laws concerning these properties are solely consequences of the one law relating to the volume energy to be gained by making up a solution. This law, whose expression is pv = RT, in its various applications to solidification, vaporization, osmosis, &c., of solutions, is the issue of a great many special laws, the whole of which I name the new theory of solutions.
Such a complex of laws, grouped around and derived from a main law, is what I call a theory ; and if the theory, as in the present case, is everywhere in accordance with experience, the main law is to
A tuning-fork held in one hand is made to touch the lath held be regarded as correct. There is nothing of hypothetical nature in the other while vibrating, and the whole moved nearer to or in this theory, for, if once the main law, pv = RT, is given (by further from the tambourine. osmotic experiments or otherwise), all the special laws are
At a certain distance the note of the fork will be produced on merely thermodynamical consequences of it. And, repeat,
| the tambourine (this of course is not a new experiment). the main law involves no hypothetical assumption upon the
While this was going on, the lath, jet, and fork were slowly moved mutual rôle of solvent and dissolved substance, but is solely the
towards the tambourine, and I was able to sound the octave condensed expression of a great number of experimental facts
below. Mr. Rodger asks why I did not state clearly in my book that,
This showed that at a certain point the vibrations of the fork in my opinion, interactions between solvent and dissolved sub- were not individually capable of separatir.g the fine stream into stance were possible. I can only reply that on suitable occasions
drops, but that two complete vibrations did so ; thus half as I have done so. Besides the sentences quoted by Mr. Rodger many drops per second were set free as there were vibrations himself, I have devoted (pp. 251, 252) half a page to the evi
from the fork. dence that considerable interacions take place in salt solutions The fork gave C = 512; the note on the tambourine was on dilution. But as the existence of such interactions, as I
C = 256. have shown, is of no consequence in the statement of the general
Probably the drops at that stage were of a dumb-bell shapelaws, I have treated them as secondary, however interesting
since at a greater distance the actual note of the fork was they may be as experimental facts, and I am more than ever produced on the tambourine. REGINALD G. DURRANT. persuaded by this discussion that I was right in doing so. For The College, Marlborough, February 13. I have not written my book for readers prepossessed by some non existing chemical theory of solutions, but for such as wish
The Formation and Erosion of Beaches, &c. plainly to learn what is known about solutions.
Similar remarks are to be made as to the definition of solu- As you have more than once permitted me to discuss the tions as mixtures. Even in the case of interactions, if, e.g., problem of sea-waves in your columns, I venture to point out hydrates are formed in a solution, the solution is finally a mix- that in your interesting article on Signor Cornaglia's work on ture of the hydrates and the remaining solvent. For the con- sea beaches (p. 362), in your summary of the causes which affect trary assumption-that the whole of the solvent is combined with beaches, sand-banks, &c., you have omitted the very important the dissolved substance, that, e.g., in a somewhat diluted solution one of wind-raised surface currents. Sea-waves, tidal-currents, of common salt, there exist compounds, as NaCl + 1000 H,O- and river-currents can be observed, and their effects recorded; is in such a degree at variance with all known facts that I did but it is the occasional, irregular, and sometimes powerful windnot think it worth while to di'cuss such an idea.
raised current, prevalent during storms, which performs such Lastly, Mr. Rodger terms the application of the formula of erratic seats, and deludes the unwary observer. For instance, van der Waals to solutions as in general “highly questionable" a beach may resist the sea for years, yet in a few hours it may and as “meaningless,” if it is admitted that "something of the be stripped bare to the solid rock. Shells may be covering the nature of a chemical reaction” between solvent and dissolved bottom a mile offshore, undisturbed by on-shore gales ; a substance may occur. Mr. Rodger may convince himself from storm, with wind and waves apparently much the same as usual, my book that this application is limited to cases in which I do | may sweep them all on shore. One beach will be invari not suppose the occurrence of chemical reactions. The reasons I kept clear of shells which will be found off sho
another beach will have a constant supply, and for no obvious
A Simple Heat Engine.
MR. FREDERICK SMITH described in NATURE of January 28 The causes which affect the movement of sand and silt are so
(p. 294) a simple heating machine, which he constructed with a numerous, and their resultant effects so well balanced, that if
nickel disk, so that when healed before a magnet it began to one of the former be increased or diminished the combined
revolve. A similar heating machine was shown by Prof. Dr. T. result may be completely reversed. I have just come across an interesting instance. For more than twenty years I kept a
Stelan, Vice-President of ihe Imperial and Royal Academy in
Vienna, in the course of a lecture to his students, among whom I 6-ton boat in the tidal harbour here, where, when at her moor
was, in the year 1885. A memoir on it appeared in the publicaings, she took the ground in all weathers twice a day without
tions of the above-named Society. The machine was thus conany damage whatever. Since the erection of the new harbour
structed : nickel plates were fixed on a wheel, like that of a arm, the silt has been cleared out of the harbour, leaving a hard bottom, and the coxswain of the lifeboat informs me that a
water-mill, and a magnet was placed before it. By heating a
nickel plate before the magnet, it was repulsed by the magnet, and boat moored in my old berth sprung a leak in a few days and
a succeeding plate was attracted, so that the wheel commenced had to be removed. The mode of accumulation of sand on the
to rotate. Torre Abbey beach is also changed in character. I cannot but think that it is a pity experiments are viewed with dis
So much I thought it necessary to communicate about the favour. The Torquay inlet and harbour works were eminently priority of such a heating machine.
KONSTANTIN K RAMATE. adapted for reproduction in an experimental tank. The then
Buccari next Fiume, Austria, Nautical School, local surveyor, who had practically planned the new works, was anxious to carry the experiments out. We had begun to con
February 18. sider the details of the tank, when my intended colleague told me that superior authority“ did not favour” the idea, and it was
New Extinct Rail. useless to proceed further. I am now informed by practical seafaring men that the pre
[Telegram.] sent plan must ultimately be amended, and clearly at considerable I HAVE just obtained from the Chatham Islands a nearly cost. Whether this be so or not, the question could have been perfect sub-fossil skull of an extinct Ocydromine rail, closely decided in a tank in a few minutes, at the cost of, say, £15. resembling the Mauritian Aphanapieryx, tive and quarter inches The experimental tank for waves playing upon beaches was the long, beak arched, slender, very pointed, for which I propose suggestion of the late Mr. W. Froude, C.E., F.R.S. ; so it is no the specific name Hawkinsi.
HENRY O. FORBES. mere fad of an unprofessional outsider.
Canterbury Museum. Southwood, Torquay, February 19. A. R. HUNT.
ON A RECENT DISCOVERY OF THE REMAINS In the last volume of NATURE (vol. xliv. p. 223) an account
OF EXTINCT BIRDS IN NEIX ZEALAND. is given by "E. W. P." of a cuckoo which was brought up in A , a house, and which disappeared one day in November, and was for many years, has just been discovered near the found in the following March on a shelf in the back kitchen, town of Oamaru, in tbe province of Otago, in the South "still alive, and asleep, with all its feathers off, and clothed Island of this colony. Their presence was indicated by only in down, the leathers lying in a heap round the body." the disinterring of a bone during the ploughing of a It is rather interesting to note that Aristotle, who firmly be.
field, by the proprietor of which the circumstance was lieved that some birds hybernate, seems to have come across
communicated to Dr. H. de Lautour, of Oamaru. This cases of birds in a similar condition. In his "
History of Animals ” (Book viii., chap. xviii.), he says, Many kinds of
gentleman, wbo is well known through his papers on the birds also conceal themselves, and they do not all
, as some diatomaceous deposits discovered by him in his district, suppose, migrate to warmer climates ; but those which are near at once inspected the spot. Finding that the deposit was the places of which they are permanent inhabitants, as the kite large, he first secured, through the kindness of the proand swallow, migrate thither ; but those that are farther off prietor, the inviolability of the ground, and then ielefrom such places do not migrate, but conceal themselves ; and graphed the information to the Canterbury Museum. I many swallows have been seen in hollow places almost stripped lost no time in proceeding to Oamaru with one of my of feathers ; for the stork, blackbird, turtledove, and assistants, and superintended the digging out of the bones lark hide themselves, and by general agreement the turtledove in a systematic manner. The site of the deposit was at most of all, for no one is ever said to have seen one during the | Enfield, some ten miles to the north-west of the town, on winter. At the commencement of hybernation it is very fat, ground elevated several hundred feet above the level of the and during that season il loses its feathers, though they remain thick for a long while." I have adopted the translation in
sea, in a shallow bayleted hollow, into which the unbroken Bohn's edition. The italics are mine.
surface of the expansive slope gently descending from the A. HOLTE MACPHERSON.
Kurow hills to the open vale of the Waireka (a stream 51 Gloucester Place, Hyde Park, W., February 22.
that rises further to the west) has sunk here for some 7 to 8 feet below the general level, and which, proceeding with
a gentle gradient valleywards, becomes a ditch-like conA Swan's Secret.
duit for a tributary of the Waireka. In the centre of this Now that the breeding-season for birds is coming near, it depression, which does not exceed 10 to 12 yards in width, would be interesting to note if the following sight I saw last the ground was of a dark brown colour, damp and peaty. spring is common to swans. A pair of swans built on an On removing the upper layer of soil for a depth of 3 to 4 island on the River Wey, which runs through our grounds, and I inches rourd where the bones had first been brought to stood on the bank opposite their nest, and watched for a view the surface, and whereon was strewn abundance of small of the cygnets, which were just hatched out. The male bird
crop-stones, a bed of very solid peat was reached, and presently picked up an empiy half egg-shell lying beside the firmly embedded in it were seen the extremities of nest, and carefully carried it to the edge of the water, some 20 feet from where the nest was built, and proceeded to
numerous Dinornis bones, most of them in excellent pre
Further digging fill it with mud, and then pushed it into the river, where it servation, though dyed almost black. sank to the bottom. He then setched the only other remaining showed that certainly many of the skeletons were compiece of shell, and did the same. On returning to his nest the plere, and had been but slightly, if at all, disturbed since last time, he placed a few sticks across the small track he had | the birds had decayed. Owing, however, to the close made, as is to conceal his actions. Evidently this process had manner in which they were packed together, and espebeen done to each piece of shell
, as no other pieces were to be cially in which the limbs were intertwined, it was rarely seen, although five cygnets were hatched out.
possible to extricate the bones in the order of their relaJessie GODWIN-AUSTEN. tions, or to identify with certainty the various bones of Shallord House, Guildford, February 22,
the same skeleton, each bone having to be extracted as the circumstances of the moment directed. In many the ground in the neighbourhood for a considercases, again, only the pelvis and femora could be traced able radius around, and in other peaty spots not far in situ, the vertebræ and remaining leg-bones being in-off, failed to afford indications of other deposits. The distinguishable in the general agglomeration. It seemed number of perfect femora of Dinornis brought away evident that the birds had not died in an erect posture, exceeded 600 ; a large number were so decomposed as to but more probably with their limbs bent under them or fall to pieces in the handling ; while a great many others in the same plane with the body. In some instances, disintegrated, after removal from the ground, on exposure beneath the sternum were found, lying quite undisturbed, to the atmosphere. I believe I do not over-estimate, the contents of the stomach, consisting of more or less therefore, in saying that from 800 to 900 moas at least triturated grass mingled with crop-stones. The quantity were entombed in this shallow hollow. So many moas of these smoothed, rounded (chiefly white quartz) pebbles- (leaving out of the reckoning the other species of birds) in size from about that of a bean to that of a plum- could not by any possibility have found standing-room, mingled with the bones was enormous, and would, if col- however crowded together, in the entire area of the delected, bave formed more than a cart-load. Except where pression. It would appear evident, therefore, that they the bones were, there were no pebbles of any sort, no did not perish all at one time. To account for their small stones nor even sand, anywhere around. The burial in such numbers in areas so circumscribed seems nearest place where pebbles of the same composition are to me at present impossible. That their bodies were to be found is, I was informed, several miles distant. entire when they were deposited is clear, from the pre
Four trenches, or pits, in all, were sunk. The dimen- sence in such abundance of the crop-stones, from the sions of the first, which was excavated entirely in peat, position of the bones, and from the finding of the intact did not exceed 3 feet square and 3 to 4 feet in depth. contents of the gizzard. No stream of any size could When it was exhausted of its treasure, a second search find origin in the immediate neighbourhood, and no was made about 20 to 25 feet higher up the hollow. The stream which could have transported the entire carcasses dimensions of this pit extended to about 7 feet square and of birds of such huge proportions as Dinornis ingens or to the same depth as the first. Two more trenches, a few D. elephantopus could ever have occupied this ravine-head feet apart, were dug at about 30 yards still further up the without leaving traces of its action on the surface which depression. They were not so large as the other two, would be visible to-day, or without washing away the but they extended down to about the same depth, 31 to 4 very fine silt mixed with the clay on which the bones lie, feet, the bottom of both being (as it was in the second) a in the bottom of the most upland of our excavations. bluish clay, with which, in the pit furthest up, wassparingly None of the bones are waterworn. This little hollow mingled a small deposit of the finest silt. In the first pit was, in the early days of its present proprietor, very wet portions of both Cnemiornis and Hapagornis bones were and boggy, and several springs have origin in it. If the found in abundance, and remains of several hundreds of moas made this a highway from one part of the country moas of all ages. It was from the second pit, however, to another, it seems difficult to believe that birds so that the largest deposit of moa bones was obtained, and powerful of limb, and standing at least 10 to 12 feet in the most perfect specimen of food remains from beneath height, could stick fast in so shallow a bog; and to conjeca sternum. Here, also, numerous bones of the giant ture why eagles of powerful flight, slender rails, small buzzard and of the great extinct goose were exhumed, ducks, and comparatively light-footed kiwis also should and a cranium as large as, if not slightly larger than that of become ensnared. Driven by fire in the surrounding Cnemiornis, but of a species with complete bony orbits, bush-which may have covered the country then, for the as in the Cape Barren goose, and indistinguishable from plough has, I am informed, brought to light the stools of Cereopsis. Bones from other parts of New Zealand, now many large trees at no great distance, while logs of wood in my possession, which I hope shortly to describe, in- were found among the bones-did they, in a struggle for dicate with certainty that several species of Cnemiornis life in a narrow space, trample each other to death? The formerly existed in this colony. Some of these bones are presence of the strong-winged Harpagornis in considerremarkable for their slender elegance, and indicate able numbers seems to militate against this explanation, species less in size and lighter in build than Cnemiornis and no calcined bones have been discovered. An excalcitrans. Among the bones so far examined, I have ob- planation offered some years ago, to account for the served no remains of Aptornis, of Ocydromus, or of Notor- presence of a great number of moa and other bird bones nis; but I possess an adult tibia of a rail smaller than in a somewhat similar situation in the Hamilton swampPorphyrio inelanotus, yet larger than any other existing that during severe winters these birds congregated at the New Zealand species. The tarso-metatarsus of a species springs rising warmer from below, and were overtaken of Anas, about the size of Anas finschi, the metatarsus and by a severe and fatal frost as they stood in the watersternum of Apteryx Oweni, and crania of A. australis, are appears unsatisfactory in the present case, as there are among the bones recovered at Enfield, in addition to the numerous springs and equally boggy ground near at metatarsus of a Bisiura, somewhat larger than Biziura hand, round which no remains can be found, and so lobata, the musk duck of Australia, an interesting species close to the sea such excessive frosts are now unknown. for which I have proposed the name of Biziura de Lau- That these were individuals who, during an excessive touri, after the gentleman to whom I am indebted for the drought, arrived at the springs too far exhausted to acquisition of these bones. There are still other bones revive-an occurrence common enough in Australiawhich I have not yet been able to identify. The Dinornis and that the water there was charged with poison, have remains belong chiefly to the species elephantopus (of also been offered as explanations. But the permanence unusually large proportions), to ingens, and to rheides. of glacier rivers, highest in the hottest seasons, precludes l'ery fine specimens of pelves and sterna have been ob- the idea of animals dying of thirst in this island, or at all tained, with numerous crania more or less perfect. In events in this locality so near to the great snow river this second trench the excavation penetrated through the Waitaki. Poisoned water-holes or exhalations of carpeat into a bluish clay charged with water (which was, bonic acid might be a sufficient reason, yet in those indeed, reached in all the diggings at about 4 feet below springs elsewhere where bones have been found chemical the surface), and into this clay the bones just protruded, analysis has failed to detect any substance harmful to life but no more. The osseous remains dug from the last in their waters at the present day. Not a single indicatwo holes belonged to the same species as those from the tion of human intervention was observed. No bones others. Digging and probing the ground beyond the were discovered which had been broken in their recent boundaries of the irenches showed that we
state ; neither kitchen-middens, nor remains of ovens or had exhausted their contents ; while the probing of of native encampments, occur anywhere near the deposit.
I a.m. + 2
6 7 8 9 IO
One piece of egg-shell dug out of the highest trench is though the places are only about ten miles apart, the not sufficient evidence on which to base the supposition diurnal fluctuation at Boston is o‘017 inch greater than on that the spot was frequented as a nesting-place.
the top of Blue Hill. In June, when this feature of the At Glenmark, in the north of this province, the historic pressure is at the annual maximum, the following are the spot where the original (somewhat larger than the hourly results, where the plus sign indicates that pressure present) find of Dinornis reliquice was dug out by my at Boston rose above its daily average by these amounts, predecessor, the late Sir Julius von Haast, the bones of expressed in thousandths of an inch, greater than did numerous species of birds besides moas were found. pressure on the Blue Hill above its daily average ; and Their occurrence in the situations where they were dis- the minus sign that it fell lower by these amounts at the covered, and the way in which they were lying-entire former than at the latter place. bodies with their sterna covering crop-stones in situ—have been explained by the supposition that the moas were
Diff. overtaken by a fierce and sudden storm, and their entire
9 a.m. + 6
5 p.m. carcasses piled by wind and flood into vast heaps, an ex
3 planation against which the presence here also of the
Noon same powerful buzzard and other flying birds rises as an
ip.m. - 3 objection. Yet there is nothing either in the situation or
- 5 the disposition of the bones to make it impossible ; still I
- 5 cannot help feeling that that cannot be the true explana
- 7 Midnight tion which satisfies only one instance out of so many assemblages of dead birds of nearly always the same The explanation is that, during the night, cold airspecies in situations almost similar. I hope, however, currents flow down the sides of a valley and accumulate that when I have made a thorough examination of all the below, and thus a higher pressure is maintained in valleys localities where, and the conditions under which, moa during the night; but, on the other hand, during the day remains have been found, in the light of the personal the valleys become more highly heated by the sun, and experience gained in the exhumation of the present de- | under the strong ascending currents thereby generated, posit, and when I have completed the identification (on pressure falls lower than in open situations. The amounts which I am now engaged) of the smaller bird bones increase in proportion to the daily range of temperature, associated in them with the moa bones, some light may and as the mean velocity of the wind diminishes. This have been gained on this at present mysterious episode diurnal variation is greatest in the deep valleys of Switzerin the history of the ancient Avians of New Zealand. | land and other mountainous regions, and, though small
HENRY O. FORBES. in amount is a well-defined and steady fluctuation Christchurch, New Zealand.
in the valley of the Thames, as shown by a comparison of the Kew and Greenwich barometers. A weak point in the meteorological publications of the Signal
Service of the United States is the all but complete THE BLUE HILL METEOROLOGICAL absence of the results of the hourly phenomena of OBSERVATORY.I
meteorology. In filling up this hiatus, the Blue Hill THE Annals of this high class Meteorological Obser
Observatory will prove of the greatest service, as offering
a truly normal Observatory, at which, from its mere since we have here presented not only the observation's position, several disturbing elements affecting diurnal of the year, which are made with remarkable fulness and phenomena are eliminated. exactness, but also a well presented and discussed résumé
During the whole year, the time of occurrence of the by Mr. Clayton for the lustrum ending with 1890, together minimum temperature is very near sunrise ; and it is with an account of the hourly and other observations made interesting to note that the maximum occurs at all at the Signal Service Station at Boston. The Observatory seasons from 2 to 3. p.m., approaching in this respect is situated about ten miles south of Boston, on the summit the time of the maximum at truly high-level Observaof a peaked hill 640 feet above the sea, and as the ground tories, or at Observatories situated on peaks. For the falls down from the buildings in every direction for five years, the mean monthly temperatures deduced from several hundred feet, the Observatory occupies a unique the maximum and minimum thermometers exceed those position among Observatories in the investigation of some
deduced from the hourly values every month, the smallest of the more important phenomena of meteorology.
excess being co2 in December, and the largest 1 2 in The hourly means of atmospheric pressure show for all August, the mean for the year being 07. the months the double tide well marked. The chief The prevailing winds are north-westerly from February maximum steadily recedes from 10a.m. in winter to 8 a.m.
to April, southerly in May, and westerly and northin summer, and the chief minimum advances from 2 p.m. westerly for the other months. These winds are ruled in winter to 5 p.m. in June. The evening maximum by the different distributions of atmospheric pressure shows a slight tendency towards displacement in the same over the Atlantic and America in the respective months ; direction as the afternoon minimum, and the night these being in winter the low pressure round Iceland, and minimum a similar displacement in the same direction as
the high pressure over the United States and Canada ; the morning maximum. A third barometric maximum, and in summer the high pressure in mid-Atlantic, together which is generally met with in middle latitudes, is par- frequency of each wind has been worked out for the lustra
with the low pressure over the Middle States. The hourly ticularly well marked at this place.
But the important position of this Observatory appears period, with results that are very suggestive. The period in the most striking manner on comparing the hourly is sufficiently extended to give fairly good averages, from barometric results of 1890 from the Blue Hill with those which accidental phenomena may be regarded as elimifrom Boston for the same year. The Blue Hill Observa- nated; and the result is more completely attained by tory is situated on a true peak, but the station at Boston
the height of the Observatory above the surrounding is in the mouth of the rather broadish valley which country all round removing from the observations the stretches northward from the town. The result is that,
more purely local causes of disturbance. The mean
hourly frequency of each wind shows a clear tendency of 1 "Annals of the Astronomical Observatory of Harvard College," vol. xxx., the wind to veer around the compass each day. Thus,
“ Observations made at the Blue Hill Meteorological Observatory, Mass., U.S., in the Year 18yo, under the direction of A. Lawrence Rotch,
the greatest frequency of southerly winds occurs at 8 p.m., Esq.' With Appendices. (Cambridge : University Press 1891.)
south-westerly at 10 p.m., westerly at i a.m., northerly at