« PrejšnjaNaprej »
pressure were not applied. In one case a cylindrical piece of steel, i" long and" in diameter, was bored through two-thirds of its length by a hole" in diameter, in which a thermal junction was placed. The mass was heated to 1000° C., and it was found that without the application of pressure recalescence occurred at 650° C., but when a load of 9 tons per square inch was applied, recalescence occurred at 620° C., and was comparatively feeble. The experiment, it need hardly be said, is one very difficult to make, and could only be done by those having command of special apparatus. Other experi
ments were carried out, the result showing that the recalescence point is lowered by pressure, but it was found that the lowering was not affected, unless the load was applied at a temperature well above that at which recalescence takes place. Experiments were made with Newton's alloy of bismuth, lead, and tin, the full results of which will be published at some future time. In considering the whole scope of the report, the author said that it might be asked what evidence had been gathered as to the mode of action of added elements, and whether it appeared that the atomic volume of the added element had a dominating influence on the mechanical properties of the mass in which it is hidden? The true action of an added element, the author pointed out, may readily be masked by its action as a deoxidiser. Notwithstanding these difficulties, it is undoubtedly proved that bismuth, potassium, and tellurium, all of which have atomic volumes, greatly lower the tenacity of copper. Arsenic, which has a larger atomic value (132) than copper (71) confers strength on copper, but it is very certain that the limit of elasticity, and the ductility of a metal are greatly influenced by the presence of an element with large atomic volumes. This fact may be of more molecular significance than the diminution of tenacity, to which, for the sake of simplicity, attention was mainly directed, when the early experiments on gold were made.
In the discussion which followed the reading of the paper a number of speakers took part. The most important contribution was that of Dr. Watson, of the Broughton Copper Company, who brought forward some practical experience to reinforce the deductions of the author. Mr. Arnold, of the Technical Schools, Cambridge, read a very long manuscript, which it would be rash on our part to attempt to abstract, and which we cannot afford the space to give in full. Mr. Hadfield, of Sheffield, questioned the accuracy of the beta form of iron theory promulgated by Osmond and adopted by the author. The point is one of considerable importance, but requires a wide field for its discussion.
On the whole it cannot be doubted that the report is a most valuable contribution to the scientific knowledge at the command of the engineer, and were the attention called to the action of bismuth on copper its sole result, the labours of the committee would not be without warrant.
The summer meeting of the institution will be held this year at Middlesborough on August I and three following days.
THIS is a bulky volume of nearly 600 pages, and contains a vast amount of information. If the Royal Horticultural Society had published nothing but this since 1891 they would have amply satisfied those who are interested in conifers, and have keenly felt the want of such a book of reference as the one now under notice. Some of the papers published in the report could have been omitted without loss, but on the whole the editors have done their work well. In the preface they say, in sending out this memorial of the Conifer Conference, 1891, we would draw attention to the fact that it contains far more than a mere verbal report of the conference, Dr. Maxwell T. Masters, F.R. S., and Prof. Carl Hansen, of Copenhagen, having promised at the time to recast their notes more fully. This they have done most kindly, and with infinite labour and research, but not without some little expenditure of time, the final sheets of MS. having only come into our hands in July, and the corrections extending up to September 29.
"The names adopted by Dr. Masters and Prof. Hansen may, of course, be relied upon as representing the latest decisions of botanical science in England and on the continent of Europe respectively, though future research may necessitate some still further slight alterations. However, the hitherto inextricably confused nomenclature of conifers may safely be described as settling down upon the lines adopted in this volume by these 1 Report of the Conifer Conference, 1891 (issued November, 1892).
two eminent authorities, who, although not yet in absolute agreement, will be found to approach very nearly."
The list of conifers and texads, by Dr. Masters, is by far the most important contribution to the nomenclature and synonymy of conifers which has appeared since the publication of Parlatore's monograph in De Candolle's“ Prodromus" in 1868; it is much more complete than Beissner's "Handbuch der Coniferen-Benennung," and the more recent "Handbuch der Nadelholzkunde,' of the same author. There seems no reason to doubt that Dr. Masters's list will be used and followed by English systematists generally. Dr. Masters, in drawing up the list of genera, follows Bentham and Hooker's "Genera Plantarum as the standard authority. A few deviations from it have, however, been made in accordance with more recently obtained knowledge. Pseudolarix is accorded generic rank (and not united with Larix, as in the "Genera Plantarum," whose authors had not seen male flowers); Keteleeria too, after a careful study of living material, has been separated from Abies and reinstated as a genus-Dr. Masters's studies having on these points proved the justice and accuracy of Carrière's views. The Chilian Prumnopitys is restored to generic rank, and separated from Podocarpus, with which it was united by Bentham and Hooker.
The Pinetum Danicum of Prof. Carl Hansen is unsatisfactory, and its omission from the report would have been desirable. It is a somewhat ambitious performance, but in bulk is very largely made up of extracts from books and periodicals. Many of the records are certainly useless; for instance, under Pinus longifolia, it is stated: "one plant, however, exposed out of doors does not appear to have suffered "; this Indian species is tropical in its requirements, and as it will not grow out of doors even in the south of England, it is in the highest degree improbable that it would, even under the most favourable conditions, exist in the open air in Denmark. A curious mistake occurs on p. 372, where the Viennese botanist, Prof. Günther Beck, Ritter von Mannagetta, figures as Prof. Günther, Knight of Beek von Managetta. On p. 330 Prof. Hansen remarks under Prumnopitys that its wood is much valued by "ebonists." He probably means cabinetmakers (ébénistes). Tsuga hookeriana and T. pattoniana are kept up as distinct species by Hansen; but Prof. C. S. Sargent, who is familiar with the two forms in their native habitats, has no hesitation in regarding them as specifically identical. Hansen accords generic rank to Biota, Thuyopsis, and Chamaecyparis, the first and second being merged into Thuya, and the third into Cupressus by Dr. Masters. It is rather annoying to find the obsolete geographical expression "New Holland" constantly used by Hansen. New Holland and South-east Victoria are given as the native countries of one species.
The coniferæ of Japan, by H. J. Veitch, is a valuable paper. From it we learn the somewhat startling fact that, in proportion to the area of the country, the flora of Japan contains more coniferous species than that of any other country in the world. Japan boasts of forty-one species and thirteen genera, whereas in the whole of Europe there are but eighteen species and seven genera.
A. D. Webster, "Conifers for Economic Planting." Mr. Webster is a practical forester of wide experience, and he considers that out of all the conifers cultivated in Britain only sixteen can be utilised in an economic sense, or for truly profitable planting. These are the larch, silver fir, Corsican pine, Douglas fir, Pinus Strobus, Scotch fir, Thuya gigantea, Spruce fir, Austrian pine, Pinus Pinaster, Abies nordmanniana, Sequoia sempervirens, Cupressus macrocarpa (or, as Mr. Webster calls it, C. lambertiana), Cedrus atlantica, Pinus rigida, and Cupressus lawsoniana. The order in which these names are given represent the relative value of the trees as timber producers. Under each heading Mr. Webster gives valuable data as to rates of growth under different conditions as regards soil, elevation, &c.
In a compact paper of thirteen pages Mr. W. Somerville gives a very good résumé of the present state of our knowledge of the quality of coniferous timber as affected by sylvicultural treatment. Mr. Somerville's remarks are sure to be perused with profit by landowners and foresters.
Mr. D. F. Mackenzie, on the timber of exotic conifers: uses and comparative value, contributes much valuable information. Taking the value of Scotch fir timber at 100, the author calculates that of Cupressus macrocarpa at 190 and that of C. lambertiana at 283; as these two names represent one and
the same species, the widely different results are probably due to the trees furnishing the timber having been grown under different conditions. Mr. Mackenzie mentions a curious fact "observed in the working of the various pine timbers I have named. It was found that the wood of pines having three leaves in a sheath was, as a rule, much harder than those having only two, whilst all those having five leaves in a sheath were uniformly soft, and when dressed had a silky appearance. So general is this characteristic that one could almost at once tell to what class a certain plank of pine timber belonged." These observations we do not remember to have seen previously recorded.
"The Diseases of Conifers." Although in German there is a literature of considerable extent on this subject, the publications in English are few. Prof. Marshall Ward is a very careful and competent observer, and his contribution to the report is of great value both to the man of science and to the practical forester.
Mr. W. F. H. Blandford's insects injurious to conifers is an excellent résumé of all that is known up to date of the lifehistory of the various insect pests, which have been noted as injurious to conifers. How important this subject is may be judged by the destruction wrought by the larvæ of Liparus monacha between 1853 and 1868 in East Prussia, Poland, and Russia, where the spruce was killed over an area of 7000 square German miles. A similar instance is that afforded in 1890 in the Bavarian forests by the same destructive insect, the loss caused by this to the revenue being estimated at £40,000. Those, however, who, like the writer of these notes, travelled over the districts affected during the ravages of the larvae, would realise much more vividly the gravity of the attack than others could from a mere perusal of statistics.
Not the least valuable portions of the report are the statistics of conifers in the British Islands, and the value in the British Islands of introduced conifers, by Mr. Malcolm Dunn. These statistics represent an enormous amount of energy and perseverance on the part of the compiler. The tabulated forms give particulars from a large number of places in the British Islands, and deal with the soil, altitude, age of trees, their height, girth, &c. The list of conifers and largest specimens, also by Mr. Dunn, gives the dimensions of the largest specimens taken from the above-mentioned tables and also the number of returns respecting each species. G. N.
THE EARTHQUAKES IN ZANTE. LAST week we noted the fact that another disastrous earthquake had occurred in Zante on Monday, April 17, and that it had been followed by various slighter shocks. According to a special correspondent of the Times at the town of Zante, the centre of the disturbance seems to have been under the sea about two miles from land. Before the great shock the inhabitants of the district of Vasilikos, near this centre, heard submarine rumblings, which increased in loudness till the earthquake occurred. Two huge boulders were detached from the neighbouring mountain and rolled into the valley beneath. The same correspondent records that on the afternoon of April 21 there were several violent shocks.
The conditions under which this series of earthquakes has occurred will no doubt be carefully studied. Meanwhile we may call attention to a good article contributed to the Mediterranean Naturalist for April by Mr. W. G. Forster, seismologist, manager, and electrician, Eastern Telegraph, Zante, on the earthquakes which did so much damage in January. From this paper we reprint the following historic statement :
"From the traditions of the place it has always been considered pretty certain that Zante must invariably expect a more or less severe earthquake about every thirty years. I find, however, that this cycle of seismic disturbances is common to all earthquake districts in south-eastern Europe and Asia Minor, and that there exists also a fairly proven and established law which governs these periods of visitation, for instance, whenever any long time has elapsed without the slight shocks-which average one or more a week in earthquake districts of non-volcanic regionsand when to these periods of comparative quiescence succeeds one of constant earth tremors, then a disastrous shock is nearly certain to take place. This is a very important point, and cannot be neglected when the question as to the origin of the shocks is under consideration.
"The last strong local earthquake previous to the present series of shocks occurred on October 26, 1873, and although it
was far less severe, it originated within a mile or so of the present one's centrum, as proven by a knot of submarine cable having been then lost, buried under the immense mass which fell into it, at the bottom of the sea; and by the measurements taken at the time.
"This earthquake had precisely the same characteristics as the present one, both previously and subsequently to its occur rence, and although very many severe and slight shocks have been felt since 1873, in no case were they of so pronounced a local nature as those just recently experienced. When the great earthquake of August 27, 1886, occurred, which destroyed Filiatra on the mainland to the south-east of Zante, this island was fortunately outside the direct vibrative waves of seismic forces radiating from the centrum of that shock; which covered up six knots of submarine cable in latitude 37°25', longitude 21°11' east of Greenwich; but still it did considerable damage, and its force was severe enough to cause the greatest alarm even in so distant a place as Malta.
"From that year until the spring of 1890 there were numbers of small shocks, but after then and up to August, 1892, only a very few tremors were recorded. On August 16 last year about twelve small shocks suddenly occurred during the day, purely local, and all from east to west. After three days of absolute tranquillity they began again, and although merely pulsations they were of a very pronounced character.
At midnight on August 27 the shock was strong, and from then until the still smarter shocks of September 3 and 5 the earth seemed always shaking. Another few days of quiescence were followed by a renewal of shocks. This state of things continued until the middle of January last-and was again succeeded by a fortnight of perfect tranquillity. At 9 p.m. on January 30 a very distinct rumbling occurred, which was followed by a short, sharp shock, as if from some falling mass, and then all was still again. I noticed after the shock a series of small ripples on the sea, which was previously and subsequently quite calm. The night passed very quietly until 5.34 a.m., local time, when the whole island began to sway terrifically from east to west, with a purely undulating motion, finishing up by a movement which I can only describe as being similar to that of some mighty force wrenching out the bowels of the earth. This shock lasted twelve seconds, and its centre was undoubtedly in the sea very close to the town, and due east of the same. From its apex of origin its range of destruction, on the frontage of the town, was not wider than two miles, spreading out to about fifteen when it reached the villages at the base of the range of hills, six miles off.
"The destructive force had a tendency to incline from due east to the north-west of the island, which is about 27 miles in length by an average breadth of eight, a subsequent shock taking a much lower range. During the whole day shocks were alarmingly frequent and numbered some hundreds between the first and nightfall when everybody went to the open ground in a most panicstricken condition. At 1.56 a.m. on February 1 another terrific shock took place-not so severe as the first, but with a range towards the south-west and of increasing destructive force. This shock lasted 20 seconds and was also succeeded by numberless others. After 23 hours a third severe shock occurred and periodically during the whole week others of decreasing intensity took place. Since the first shock until the present date, at least one thousand (including pulsations and tremors) have been felt.
"Of course the direct and indirect damage has been very great owing to the extensive zone of destruction, the scattered nature of the villages and to the bad construction of the houses in general and to their dilapidated condition owing to extreme poverty of the island. At least half a million sterling is re quired to rebuild the place, and as this amount can never be realised many of the ruins are likely to remain untouched and most of the population will have to emigrate.'
American Journal of Mathematics, vol. xv. 1 (Baltimore Johns Hopkins Press, January, 1893).-The pièce de résistance of this number is a memoir by Prof. Cayley on symmetric functions and seminvariants (pp. 1-74), in which the author further develops the theory of seminvariants, and in connection therewith is led to some investigations on symmetric functions The subject is treated with characteristic ability and affords ample evidence of the writer's recovery from his recent serious
illness. Prof. Cayley also contributes some tables of pure reciprocants to the weight S (pp. 75-77). Two short notes follow on the differential equation, Au+ku o by Maxime Bocher (pp. 78-83), and geometrical illustrations of some theorems in number by Ellery W. Davis (pp. 84-90, with a diagram). M. Halphen is the mathematician whose portrait is given with this opening number.
Bulletin de l'Académie Royale de Belgique, No. 3 (1893).Among the scientific papers communicated to the Academy are the following: On the common cause of surface tension and evaporation of liquids, by G. Van der Mensbrugghe. The author deduces from his theory an explanation of the fact that evaporation is more rapid from a convex, and less rapid from a concave, than from a plane surface.-Survival after the successive section of the two vagi, by M. C. Vanlair. Survival after successive section of both the branches of the vagus nerve can be obtained in full-grown animals as well as in young ones. The time necessary for the regeneration of its inferior laryngean branch is generally much longer than that hitherto accepted. In the full-grown dog the period exceeds at least ten months. The regeneration of one branch is quite independent of the section of the other. The question whether the pneumogastric, like the sciatic nerve, possesses the power of regenerating itself twice in succession remains as yet unanswered. It is, however, certain that an interval of six months and a half does not suffice for its second regeneration.-On the digestion of the coelenterata, by Marcelin Chapeaux. The action of the ferments secreted by the actinia upon starch, cellulose, chlorophyll, and fat, was investigated. Starch submitted to the action of an aqueous solution of these ferments, or injected into the gastrovascular cavity, was transformed into glucose. The action was slow in the case of non-hydrated starch. The transformation took place equally well in acid and in alkaline solutions. Cellulose and chlorophyll were not digested. The fats were emulsioned by the ferments contained in the endodermic cellules. These ferments were without effect upon the algae. Among the Siphonophora digestion is certainly exclusively intracellular. No dissociation of fibrine is, on the other hand, ever observed in the gastrovascular cavity, and no difference could be established between the alkalinity of the liquid contained in this cavity and the surrounding sea-water.— -Contribution to the nitrogen question, by A. Petermann. This is an experimental confirmation of the results of MM. Schloesing fils and Laurent, showing that free nitrogen is absorbed from the air by the micro-organisms of the soil.
SOCIETIES AND ACADEMIES.
Royal Society, March 2.-" Harmonic Analysis of Hourly Observations of Air Temperature and Pressure at British Observatories," by Lieut.-General R. Strachey, R.E., F.R.S. This paper is a discussion of the results of the compu'ations contained in a volume recently published by the Meteorological Office, of the harmonic components of the first four orders, for each month for twenty years, of the daily curves of temperature and pressure at Greenwich; and for the first three orders, for the temperature and pressure, for each month for twelve years, at the seven observatories maintained by the Meteorological Office.
This system of analysis supplies the means of establishing an exact comparison between various unsymmetrical curves, such as those representing hourly values of temperature, by resolving them into symmetrical components, having periods of twentyfour hours, twelve hours, eight hours, and six hours, and so forth, and its application to the records dealt with in the tables contained in the volume above referred to gives satisfactory proof of the important light it can bring to bear on the periodical changes of diurnal temperature.
In the usual expression the coefficients of the cosines of the arcs are designated by the letter p, and those of the sines by q. The total amplitude of the component is designated by P.
A modification of the usual notation is made by the introduction of the value of the epoch of the first maximum that occurs after midnight, which is designated by the letter μ, and estab lishes the connexion of the component with the hour of the day and the sun's place more conveniently than the method usually adopted.
1. Greenwich Temperature.
The examination of the tables shows that, with very considerable variations of absolute magnitude, there is on the whole very marked consistency in the main characteristics of the components.
Taking as a test the position of the epoch of maximum, which is more directly dependent on the sun's action and on his position than the amplitude, it will be seen that the values of μ indicate very clearly the closeness of this connexion.
In all the components a truly periodical variation of the value of u is apparent, and the period of maximum always travels backwards, that is, it becomes earlier as the year passes from winter to summer, while it returns in the opposite direction in the change back to winter.
For the first component the variation of the five years' mean of μ from the twenty years is in no month more than 24, or ten minutes of time, and the average for all months is less than half that amount.
In the second component the variation of the five-year mean from the twenty-year mean is in no month more than 6°, and the average is only 2° 3, or nine minutes of time.
In the third component the variation of the five-year from the twenty-year mean in no month exceeds 5°, and the average in all months is only 2° 1, or 83 minutes of time.
The largest variation of the five-year mean of the fourth component for any month from the twenty year mean is 10°, and the average for all months is 4° 3, or seventeen minutes. Considering how small are the absolute values of the coefficients and 74, on which the value of μ, depends, the average being a little less thanth of a degree Fahrenheit, it is rather a matter of surprise that the variations should be so small than that they should reach their actual amounts.
The component of the first order, which in the winter is more than double the magnitude of any of the others, and in summer more than ten times as great, gives the dominant character to the daily curves of temperature. In the series of twenty years variations in different years of as much as 100 per cent. are to be found for almost every month, but for the most part even these irregularities disappear in the mean of a series of five years, and the monthly means for the twenty years are remarkably consistent.
The progression of the value of P, in the course of the year, follows approximately the sine of the sun's meridional altitude and the empirical formula
The component of the third order varies in a converse manner, having two well-marked minima at the equinoxes, with a principal maximum at midsummer.
The component of the fourth order appears to combine the characters of the two previous ones, having two maxima about the time of the equinoxes, and a principal minimum in the winter.
The mean value of μ for the first component is 214°, corresponding to 2h. 26m. p.m., the variation due to season being 12° or 48m. of time, by which the maximum is earlier in summer than in winter.
In the second order the first maximum in June is 24°, or 1h. 20m. earlier than in January.
In the third order the difference in the same direction is 63°, or 4h. 12m. of time.
In the fourth order there is some doubt as to the manner in which the change of epoch of the summer and winter maxima is brought about. But remembering that the fourth component in cludes four series of undulations, the most probable explanation of these changes is to be found in a change of the position of these undulations, during which, between January and February, when the first maximum is about 10° after midnight, or ch. 40m. a.m., the first recedes, and its place is taken by the second, which leads to sudden appearance of a maximum about 60°, or 4 a.m. A similar change between October and November in an opposite direction would reproduce the maximum at 10° after midnight.
In the summer months (May, June, and July) the temperature curve during the day hours, from 8 a.m. to 8 p.m., hardly differs from a curve of sines, the first component being more than ten times as large as any of the others, which therefore influence the temperature, relatively, very little.
The relation of the epoch of the first maximum of the component of the third order to the time of sunrise is decidedly marked, the former occurring, on the average, about 12°, or 48m. after sunrise; the mean deviation of the interval from that amount being only 7, or 28m.
The periodical variation in the position of the maximum leads, during the winter months, to a positive maximum of this component about I p.m., which is combined with negative maxima four hours earlier and later, which correspond to the riduced temperature in the mornings and afternoons of the shorter days. In like manner, in the summer months, when this component has a negative maximum about I p.m., instead of a negative minimum, as in winter, there will be two positive maxima, one four hours earlier, the other four hours later, corresponding to the higher temperature in the mornings and afternoons of the longer days.
It will be seen that these positions of the midsummer and midwinter maximum phases correspond respectively to days of 16 hours with nights of 8 hours, or days of 8 hours and nights of 16 hours, and that at these seasons, when the variations of temperature, due to these differences, are greatest, the amplitudes of this component are also the greatest. At the equinoxes, with 12-hour days and nights, the component becomes a minimum ; and at this season the change in the position of the maximum takes place as already noticed.
It might be supposed that an analogous relation between the fourth component and the occurrence of days of 18 hours, combined with nights of 6 hours, and vice versa, is likely to arise. But the data are not forthcoming to test this.
In the summer months the time of mean temperature is nearly where the first component becomes zero, the second and third components then balancing one another.
In the winter the time of morning mean temperature is later than in summer, and occurs when a positive value of the first component is equal to a negative value of the second.
The time of afternoon mean temperature throughout the year is somewhat either before or after 7 p.m., and almost exactly coincides with the time when the first and second components are equal, with opposite signs.
In the summer the time of absolute minimum is between the hours of 3 a.m. and 6 a.m., during which the whole of the components are negative.
Sunrise in December is about an hour and a half before the time of mean temperature; while in June it is more than four hours earlier.
Sunset in December is rather more than three hours before the time of mean temperature; in June it is about half an hour after that time.
The rationale of some of the empirical rules for obtaining the mean daily temperature from a limited number of observations is supplied by reference to the harmonic expressions for the hourly deviations of temperature from the mean value.
In the first place, it will be seen that by adding together the harmonic expressions for any two hours twelve hours apart, the whole of the odd components disappear, and that the sum is twice the mean value, added to twice the sum of the even components of the selected hours, which are equal.
By taking the mean of observations at any four hours, at intervals of six hours, both the odd components and those of the second order will disappear, and the result will only differ from the true mean by the amount of the fourth component for the selected hours.
So, if the mean of any three hours at equal intervals of eight hours be taken, the sums of the first, second, and fourth components will disappear, and the result will only differ from the true mean by the amount of the third component for the selected hours, which in no case can be so much as 1.
2. Temperature at the Seven Observatories.
The examination of the tables will show that in their main characteristics the results closely resemble those for Greenwich, and it will not be necessary to discuss them in any detail.
The amplitude of the component of the first order is, however, in all cases less than that observed at Greenwich, the
lowest values being those for Valencia and Falmouth, no doubt due to their position on the sea coast, for which stations the means for the years are 2°.28 and 235 compared with 5'10 at Greenwich.
The Kew values most resemble those at Greenwich, but the mean maximum at Kew is more than 1° less, and the mean for the yearless.
The mean values of μ for the seven observatories lie between 205 and 220, that for Greenwich being 214. The means of the summer values are about 3 or 4 less than the mean of the year, and of the winter values as much above it. as in the case of Greenwich.
The amplitude of the first component conforms approxi mately, but not so closely as at Greenwich, with the sine of the sun's meridian altitude, but with a flattening of the curve in the summer months, and a tendency at some of the stations to a maximum value in May.
The components of the second and third orders, beyond which the analyis is not carried for these observatories, conform in all important respects to those for Greenwich, the numerical val ues of the latter being, however, in all cases somewhat higher. The epochs of maximum follow the same laws, with an increased divergence of the summer epoch from that of the winter at the more northern stations.
In order to test, and in some degree throw light, on the char acter and significance of the harmonic components of temperature that have been under discussion, and bearing in mind that they cannot be considered to represent separate effects of physical forces operating at the assumed periods of the components, I have, at the suggestion of Prof. G. Darwin, calculated the harmonic components from a curve representing an intermittent heating action such as that of the sun, continued only during a portion of the day, and commencing and ending abruptly at sunrise and sunset.
All cooling effects have been disregarded, and the sun's direct heating action is assumed to be proportional to the sine of his altitude, the power of a vertical sun being taken to be 10. Having calculated the sun's altitude for each hour of the day, for midwinter, the equinox, and midsummer, for certain selected latitudes, the corresponding heating effects have been computed to which the usual method of analysis has been applied.
The comparison of the results thus obtained with the cortesponding components derived from actual observation at places having nearly the same latitudes as those selected, establishes their close similarity, and the conclusion is unavoidable, that, although both in the actual and hypothetical cases the harmoni components when combined are truly representative of the peculiar forms of the curves from which they were derived, this affords no evidence of the existence of recurring cycles of action corresponding to the different components, but that the results are, to a great extent, due to the form of the analysis.
The diurnal curve of temperature is not symmetrical in relation to the mean value, the maximum day temperature being much more in excess than the minimum night temperature is in defect. To adjust the first component, which is symmetrical about its mean value, to the actual unsymmetrical curve, it must be modified by the other components. That of the second order, which has one of its maxima not far removed from the minimum of the first order, supplies the chief portion of the compensation due to this cause.
Further, from the character of the analysis, when the diurna curve is symmetrical on either side of the hour half way between noon and midnight—that is, when the day and night are equal in length-the third component becomes zero. Any departure from this symmetry introduces a component of the third order, with the result that with a day shorter than 12 hours one maxi mum will fall in the day between 6 a.m. and 6 p.m., and the other two in the night between 6 p.m. and 6 a.m.; while with a day longer than 12 hours, two maxima will occur in the day and only one in the night. In the former case the negative portions of the component correspond with the reduced morning and afternoon temperatures of the short day, and in the latter the two positive phases correspond with the higher temperature of the mornings and afternoons of the longer day.
These conclusions are in conformity with those previously indicated.
The available data are insufficient to enable us to say whether the corresponding results connected with the fourth component are as fully supported by observation as in the case of the third, but the facts so far as they go confirm this view.
Anthropological Institute, April 11.-Prof. A. Macalister, President, in the chair.-Mr. G. M. Atkinson exhibited a cranium and several metal ornaments found by Mr. A. Michell Whitley and Dr. Talfourd Jones in a grave at Birling, near Eastbourne, Sussex. The peculiar coffin-like shape of the skull seemed to point to its belonging to the early Saxon period, while the metal ornaments were assigned to the late Roman or immediately post-Roman age. -Mr. R. Duckworth read a paper on two skulls from Nagyr, recently added to the Cambridge University collection. One of them is a female skull, and is remarkably dolichocephalic, the cephalic index being 69'94. The other skull is that of an adult male.-Prof. Macalister read
a paper on Egyptian mummies. He described the manner in which they were prepared, the unguents used by the Egyptians and the various cloths in which the mummies were rolled. He explained the difference between the Egyptian cloths and those manufactured in England at the present day, and said that the object of using so few threads in the weaving was for the purpose of saving time and trouble. The material at the same time was brought to a high state of perfection as a manufacture, and indeed might even compare with some of the finest linen productions at the present day. Specimens of cloth were exhibited and the author stated, on the authority of a linen manufacturer, that there was only one specimen of linen manufacture in the United Kingdom which could be recognised as of similar structure to the Egyptian productions.-A paper on Damma Island and its natives by P. W. Bassett Smith, R. N., was also read.
Geological Society, April 12.-W. H. Hudleston, F. R.S., President, in the chair.-The following communications were read-On some Palæozoic Ostracoda from Westmoreland, by Prof. T. Rupert Jones, F. R.S. In 1865 the author determined for Prof. Harkness some fossil Ostracoda which he had obtained from the Lower Silurian rocks of South East Cumberland and North-East Westmoreland, and subsequently other specimens mentioned by Harkness and Nicholson in 1872. In 1891 Prof. Nicholson and Mr. Marr submitted a series of similar microzoa from the same district; and the author now endeavours to determine their specific alliances, and revises the list of those previously collected. He has to notice about eleven forms of Primitia, Beyrichia, Ulrichia, Echmina, and Cytherella-several of them being closely allied as varieties, but all worthy of study as biological groups, such as have been illustrated from other regions by writers on the Ostracoda, with the view of the exact determination, if possible, of species and genera, of their local and more distant or regional distribution, and of their range in time. -On some Palæozoic Ostracoda from the Girvan district in Ayrshire, by Prof. T. Rupert Jones, F.R.S. This paper aims at the completion of the paleontological account of the Girvan district, so far as the Ostracoda are concerned; and follows up the researches indicated in the "Monograph of the Silurian Fossils of the Girvan District in Ayrshire," by Nicholson and Etheridge, vol. i., 1880. In about a dozen pieces of the fossiliferous shales, submitted for examination some few years ago, the writer finds nearly thirty specimens of Primitia, Beyrichia, Ulrichia, Sulcuna, and Cypridina which show interesting gradations of form, not always easy to be defined as specific or even varietal, but valuable as illustrating modifications during the life-history of individuals, thus often leading to permanent characteristics of species and genera. Like those formerly described in Nicholson and Etheridge's "Monograph," the specimens have all been collected by Mrs. Elizabeth Gray, of Edinburgh. The reading of these papers was followed by a discussion, in which the President, Mr. Marr, and the author took part. On the dwindling and disappearance of limestones, by Frank Rutley. The existence of chert between two sheets of eruptive rocks at Mullion I-land seemed to the author to require some explanation. Cherts are usually associated with limestones, and the absence of limestones in many cases where cherts are found points to their removal by underground waters. The older the limestone the greater the probability of its thickness having dwindled. The thicknesses of the Ordovician, Silurian, Devonian, and Carboniferous Limestones seem to be in the ratio of 1:15: 15: 100. Many limestones once existing in Archæan rocks may have disappeared, as also limestones in later rocks. The author comments on the difficulty of distinguishing some cherty rocks from felstones. Two appendices are added to the paper, the first on the transference of lime from older to newer deposits, and the second on the formation of
nodular limestone-bands.-This paper gave rise to a discussion in which the President, Prof. Hull, Mr. Walford, Prof. Judd, General McMahon, Prof. T. R. Jones, Prof. Hughes, Mr. H. W. Monckton, Dr. G. H. Hinde, and the author took part.On some Bryozoa from the Inferior Oolite of Shipton Gorge, Dorset, Part II., by Edwin A. Walford.
Royal Meteorological Society, April 19.-Dr. C. Theodore Williams, President, in the chair. -The following papers were read -The direction of the wind over the British Isles, 1876-80, by Mr. F. C. Bayard. This is a reduction on an uniform plan of the observations made twice a day, mostly at 9 a.m. and 9 p.m., at seventy stations during the lustrum 187680; and the results are given in tables of monthly and yearly percentages. Notes on two photographs of lightning taken at Sydney Observatory, December 7, 1892, by Mr. H. C. Russell, F. R.S. These photographs were taken with a halfplate view lens, mounted in a whole plate camera, and, as a matter of course, there is some distortion at the edges. Both photographs show the gaslights in the streets as white specks, the specks being circular in the centre and crescent-shaped in other parts of the plate owing to distortion. The lightning flashes are also distorted. Mr. Russell believes that this distortion may account for the so-called "ribbon" flashes, which are seen in many photographs of lightning. He has also made some measurements of the length and distance of the flashes, and of the intensity of the light.-Notes on lightning discharges in the neighbourhood of Bristol, 1892, by Dr. E. H. Cook. The author gives some particulars concerning two trees in Tyntesfield Park, which were struck by lightning, one on June 1 and the other on July 18, and also some notes concerning a flagstaff on the summit of Brandon Hill, which was struck on October 6.Constructive errors in some hygrometers, by Mr. W. W. Midgley. The author, in making an investigation into the hygrometrical condition of a number of cotton mills in the Bolton district, found that the mounting of the thermometers and the position of the water receptacle did not by any means conform to the regulations of the Royal Meteorological Society, and were so arranged that they gave the humidity results much too high. The Cotton Factories Act of 1889 prescribes the maximum weight of vapour per cubic foot of air at certain temperatures; and the author points out that if the instruments for determining the amount present in the mills have an error of 20 per cent. against the interests of the manufacturer, it is necessary that the makers of the mill hygrometers should adopt the Royal Meteorological Society's pattern for the purpose.
Academy of Sciences, April 17.-M. Loewy in the chair. -Note on the observation of the partial eclipse of the sun of April 16, 1893, by M. F. Tisserand.-On the observation of the total eclipse of the 16th inst., by M. J. Janssen.— Effects of the drought upon this year's crops; reply to M. Demontzey's note on the planting of the highlands, by M. Chambrelent.-Expansion of water at constant pressure and at constant volume, by M. E. H. Amagat. At pressures higher than 200 atmospheres water has no maximum density above zero. At the lower temperatures, contrary to what takes place in the case of other liquids, the coefficient of expansion increases with the pressure. This increase is gradually effaced as the temperature rises, is sensibly zero at 50° or 60°, and changes sign for higher temperatures. If water is kept at a constant volume the pressure increases rapidly with the temperature. Thus, for unit volume the coefficient of pressure increases fourfold between 10° and 100°, and the variation is proportionately even more rapid between o° and 10°.-On the structure of simple finite and continued groups, by M. Cartan. -On a simple group with fourteen parameters, by M. F. Engel.-Demonstration of the transcendental nature of the number e, by M. Adolf Hurwitz.-Comparison of the international meter with the wave-length of cadmium light, by M. Albert A. Michelson.-Photography of gratings engraved upon metal, by M. Izarn. It is possible to reproduce opaque grat ings engraved upon metal in a manner analogous to the reproduction of transparent ones already described. On covering such a grating with a layer of bichromated gelatine, and exposing to the sun through this layer, a grating effect is produced which, although rather feeble, is due to successive differences of structure corresponding to the rulings. These differences of structure are probably due to stationary reflected waves, and