The Micrographic Dictionary-Pollen Grains I READ your criticism of this book in last number of NATURE with a good deal of interest, and I fully agree with your reviewer in his statement that "workers in different fields will place a different estimate on the importance of their own depart ment." Allow me to call your attention to the two singularly erroneous figures of the pollen grains of Mimulus moschatus (Pl. 32, Fig. 24) in this work. I have frequently examined the pollen of this plant, and have never seen it anything like the figures in the "Dictionary," or in any way differing from the grains of many other members of the Scrophulariacea. pollen of M. moschatus is like a grain of wheat, and not like the wonderful convolute ball shown in the Dictionary." The In his "Common Objects for the Microscope," Plate 3, Fig. 21, the Rev. J. G. Wood reproduces the first of these two extraordinary figures, and describes the pollen as "belted with wide and deep bands," &c., but by an oversight he omits to give the source from which the erroneous figure is copied. In his "One Thousand Objects for the Microscope," Plate 2, Fig. 6, Mr. Cooke copies the second extraordinary figure of this pollen, and says, "these curious granules resemble a band or cord rolled or folded in a spherical mass," as if he had so seen them. The " Dictionary" plate certainly does look like this, but in the letter-press the folds are referred to as "slits or furrows." By an oversight Mr. Cooke also omits to give the source from which his erroneous figure is copied. W. G. SMITH The Phylloxera IN the report to the Department of the Interior of the Canton of Geneva by the commission appointed to inquire into the best means of stopping the ravages of Phylloxera, which I have just received from Prof. Forel, of Morges, it is stated that the insect was most probably introduced from England in some vines which were taken to Geneva to certain graperies of Baron Rothschild in 1869. These graperies are in the middle of the infected district-they were found to be infected within twelve months of the arrival of the plants, and no vineyards but those in the neighbourhood of these graperies have been infected in all Switzerland. Prof. Forel, in his letter to me, says that while the surrounding vines have perished, those attacked in Baron Rothschild's houses have suffered very little indeed, and bear plenty of fruit. These vines, he says, are Black Hamburgh and Muscat d'Alexandrie or d'Alicante. He asks if in England anything is known which points out any kind of vine as suffering less than other kinds. Can any of your readers tell me anything about it? Clifton, Jan. 23 G. H. WOLLASTON Thermometer Scales I SHALL feel greatly obliged if any reader of NATURE can inform me what scale the thermometer referred to in the following extracts was made to :-"7 Feb., 1775. This day the thermometer was down to 80, two hours after sunrise." "This thermometer has five inches divided into 75 degrees above temperate (sic); and 63 inches below temperate, divided into 100 degrees; the spirit at So was about an inch from the bottom. In the frost in 1739 the spirit sunk below all the marks in this thermometer." Also-" Dec. 30, 1739. Thermometer sunk below all the marks. . . . This thermo was marked down to 7 below Fahrenheit's freezing point of 32; so this was below 25 of Fahr." Some very hot days in July 1757 are marked (I presume by the same thermometer) at 40, 41, 46, and 47 degrees; another day, "very near 50" is spoken of as the hottest day the writer thinks he ever remembers in England, "except the famous hot Saturday on the 11th of June, 1748." In 1783-4, 13 below o of Linnæus is mentioned as very severe cold. The scale of Linnæus is mentioned several times. I have failed to discover the scale of the first thermometer, and never heard of that of Linnæus. If any of your readers can enlighten me as to the relation of these scales to that of Fahrenheit or Réaumur, I shall feel greatly indebted. Norwich, Feb. 1 THOMAS SOUTHWELL OUR ASTRONOMICAL COLUMN THE NEXT RETURN OF HALLEY'S COMET.--In the year 1864 the late Count G. de Pontécoulant made an important communication to the Paris Academy of Sciences relating to the perturbations of this famous comet. He remarked at the outset: "I propose, in my new researches on the comet of Halley, to follow the course of that body from the epoch when it was observed for the first time in a manner sufficiently precise to allow of determining the orbit, until that of its next return to perihelion, which will take place in 1910, ie. during an interval of nearly three hundred and eighty years, including five entire revolutions of the comet. I shall describe here, as succinctly as it is possible to do, the results of the immense calculations which it has been necessary to effect in order to attain this object." We shall confine ourselves in the present remarks to a few particulars relating to the appearance of the comet in 1910, reserving a further account of Pontécoulant's memoir for a future occasion. It is, however, impossible to avoid an expression of regret that the astronomer who has completed the enormous work indicated in the above extract, should have passed away without (so far as we know) putting upon record the successive steps of his calculations in sufficient detail to be of service to the future investigator, and it is to be hoped his papers may yet be made available for this purpose. Mere statements of final results, necessitating for their attainment such a prodigious amount of labour and such unusual skill, are hardly all that is required, though in this remark we imply no want of confidence in the accuracy of the work performed. It is almost certain that the perturbations of Halley's comet will be recomputed before the year of its next return, and it is as certain that the possession in detail of the various numerical results of Pontécoulant's work would be of very great service to anyone who may undertake its verification, not only by way of check as he proceeds, but as a guide to the effective management of the formidable mass of figures involved. The perihelion passage in 1835 is fixed to Nov. 15'95 Paris mean time, at which moment the comet is found to have been moving in an ellipse with a period of 27895.81 days. The influence of the planet Jupiter upon the length of the present revolution is greater than in any of the four previous ones, and amounts to 679:37 days, by which the next perihelion passage is accelerated. Saturn retards the comet 279 days, while Uranus accelerates it 2:30 days, therefore nearly negativing the influence of Saturn. The attraction of other planets is neglected. The total effect of perturbation during the actual revolution is thus found to be 678 88 days, the period being shortened thereby ; and hence the time of revolution corresponding to 1835, Nov. 16, is diminished to 27216'93 days, and the next perihelion passage is consequently fixed to 1910, May, 23.87 Paris time, the comet then completing the shortest revolution since 1531, the preceding revolution having been the longest, and their difference is upwards of two years. The periodic time corresponding to the comet's motion at perihelion in 1910 is 27,790 days. A notable change is produced by the action of the planet Jupiter in the perihelion distance, which is increased by upwards of a tenth of the earth's mean distance from the sun, and the comet's orbit is thus brought into very close proximity to that of the earth at the descending node. In 1835 the comet at this point passed o 1511 from our track; in 1910, according to Pontécoulant, it will be distant only 00157. The excentricity of the orbit in 1910 is found to be o9617332; the semi-axis major, 17'95546; the longitude of perihelion, 305° 38′ 14"; the ascending node, 57° 10′ 33′′; inclination, 17° 46′ 51′′; the motion is retrograde. The longitudes are counted from the mean equinox at perihelion." The track of the comet calculated from these elements is a very favourable one for observation. At the end of October 1909 the comet has the same theoretical intensity of light as when it was last glimpsed by Dr. Lamont with the Munich refractor, on the 17th of May, 1836. (It is often erroneously supposed that the last observations were made at the Cape of Good Hope.) Its position, according to the above data, is in the neighbourhood of 130 Tauri. Thence retrograding with a slow southerly motion in declination, it passes through the constellation Aries, in January 1910, and is situate in Pisces until it has approached our globe within the mean distance of the earth from the sun, or until about the beginning of the last week in May. Its apparent motion then rapidly accelerates. On June 12 the calculated position is close to the bright star Capella, and, five days later, on the confines of Lynx and Leo Minor. At this period the comet attains its least distance from the earth, which may be taken as o25. Descending pretty quickly towards the equator, we find it in the neighbourhood of 84 Leonis at the beginning of July, afterwards gradually losing itself in the evening twilight. With the date for perihelion passage assigned by Pontécoulant, the comet would be most conspicuous in the first half of the month of June, in the absence of the moon, which is full on the 22nd. ENCKE'S COMET has been detected very close upon the calculated position at more than one of the private observatories in this country, but up to the interference of moonlight it was extremely faint. We shall continue the ephemeris next week. ANTARES. The measures of this star communicated last week by Mr. J. M. Wilson, of Rugby, are pretty conclusive as to a physical connection of the components. If the angle and distance used as a starting-point (1848) in our former notice be brought up to Mr. Wilson's epoch, 1873 42, by applying Leverrier's proper motions in the interval to the place of the large star, we have Angle ... 287°.8. Distance 3" 53. The observation gives the angle 268°6 (differing 19°) less than any yet assigned by previous measures; but in 1845, Mitchel thought the small star was on the parallel preceding, and all subsequent observations except the one in question have placed the companion in the .p. quadrant, Dawes in 1864 finding the angle nearly 276. .. LALANDE'S ÉTOILE SINGULIÈRE. On the 4th of March, 1796 ("Histoire Céleste," p. 211), Lalande observed meridionally a star of 67 magnitude, the position of which for the beginning of the present year is in R.A. 8h. 13m. 35., N.P.D. 68° 51'5; on the 15th of the same month he again obscrved the star, and the resulting places for 1800 belong to Nos. 16292-3 of the reduced catalogue. On March 4 he attaches this remark to his observation" Étoile singulière." The observation of the 15th is without note. We have examined this star telecopically on several occasions, without being able to detect any unusual appearance about it. The light is yellowish. Has any reader of NATURE had the curiosity to look at it? The remark is a strange one for the observer of so many thousands of stars to attach, unless there was really something singular in the star's aspect at the time. NEWS FROM THE "CHALLENGER”* THE HE_Challenger left Port Nicholson on the 7th July, 1874, and proceeded under sail along the east coast of New Zealand. On the 8th we rounded and trawled in 1,100 fathoms, lat. 40° 13′ S., long. 177° 43′ E., with a bottom-temperature of 2o Č., and a bottom of soft greenish ooze. Many animals were brought up by this trawl, resembling closely those which we had taken at a corresponding depth in other portions of the Southern Sea. On the 10th we again trawled and sounded in 700 fathoms about forty miles to the east of East Cape. We then continued our course northwards towards the Report on the Cruise of H-M.S. Challenger, from July to November 1874," by Prof. Wyville Thomson, F.R.S., Director of the Civilian Scientific Staff. A paper, dated H.M.S. Challenger, Hong Kong, read before the Royal Society, Feb. 4. Kermadec Islands, and on the 14th we took our usual series of observations midway between Macaulay and Raoul Islands in the Kermadec group. At this station we trawled at a depth of 630 fathoms; and we were greatly struck with the general resemblance between the assemblage of animal forms brought up in the trawl and the results of a good haul in about the same depth off the coast of Portugal or North Africa. Among the more interesting objects were a very large and splendid specimen of a Hexactinellid sponge allied to Poliopogon, several other fine sponges referred to the same group, and three or four examples of two species of Pentacrinus new to science, resembling generally P. asteria, L., from the Antilles. We trawled on the following day in 600 fathoms, forty-five miles to the north of Raoul Island, with nearly equal success. On the evening of Sunday the 19th we arrived at Tongatabu and called on the principal missionary, Mr. Baker, from whom we received every possible attention during our short stay. After spending two days in visiting different parts of the island, we left Tongatabu on the 22nd of July, and after taking a few hauls of the dredge in shallow water we proceeded towards Kandavu in the Fijis. On the 24th we stopped off Matuku Island and landed a party of surveyors and naturalists; and while they were taking observations and exploring on shore we trawled in 300 fathoms, and received among other things a fine specimen of the pearly Nautilus, Nautilus pompilius, which we kept living in a tub for some time in order to observe its movements and attitudes. On Saturday the 25th of July we arrived at Kandavu, on the 28th we went to Levuka, and we returned to Kandavu on the 3rd of August, where we remained until the 10th. At Fiji the civilian staff were occupied in examining the reefs and generally in observing the natural history of the islands; and in this we received all friendly assistance from H.M. Consul, Mr. Layard, and from Mr. Thurston, Minister of King Cacobau. During our stay, a mixed party of naval and civilian officers went in the ship's barge to Mbaw and visited the king. Between New Zealand and the Fiji group only two soundings were taken to a greater depth than 1,000 fathoms. Of these, one at a depth of 1,100 off Cape Turnagain, New Zealand, gave a bottom of grey ooze, and a bottom-temperature of 2° C.; and the second at 2,900 fathoms, lat. 25° 5' S., long. 172° 56′ W., midway between the Kermadecs and the Friendly Islands, gave "red clay," and a temperature of o°5 C. Four serial temperature-soundings were taken; and the distribution of temperature was found to correspond in its main features with what we had previously met with in oceans communicating freely with the Antarctic Sea. The dredgings, which, with the exception of one near the New Zealand coast, were all at depths varying from three to six hundred fathoms, yielded a great number of very interesting forms; but, as I have already remarked, they tended to confirm our impression that even at these comparatively moderate depths, at all depths, in fact, much greater than a hundred fathoms, while species differ in different localities, and different generic types are from time to time introduced, the general character of the fauna is everywhere very much the same. On the 10th of August we left Kandavu and proceeded towards Api, one of the least known of the New Hebrides, where there is as yet no permanent missionary station. On the 12th we sounded and trawled in 1,350 fathoms, with a bottom of reddish ooze; we sounded again on the 15th in 1,450 fathoms with red clay; and on the 18th, after passing through the channel between Makuru and Two-Hill Islands, we stopped off Api in twenty-five fathoms, close to the edge of the reef and opposite a landing-place. In order to receive, as far as we could, the good-will of the natives, Capt. Nares had given a passage to eleven Api men, who had been employed for a three-years' term in Fiji under the arrangement which exists there for the regulation of Polynesian labour. Two or three of us, with an armed party, took the returned labourers ashore ; and as the natives, although they appeared somewhat mistrustful, and were all armed with clubs and spears and bows with sheaves of poisoned arrows, were sufficiently friendly, nearly all the officers landed and spent a few hours rambling about the shore. It was not thought prudent to go far into the forest, which was very dense and luxuriant, and came close down to the beach. The natives were almost entirely naked, and certainly bore a very savage and forbidding aspect. One of them was manifestly greatly superior to the others, and appeared to exercise a considerable influence over them. He wore trousers and a shirt and a felt hat, and could speak English fairly. He recognised me at once as having seen me at the sugar plantation in Queensland, where he had been for the usual three-years' engagement, and showed me, with great pride, a note from his former employer, saying that the bearer was anxious to return to his service, and that he would willingly pay his passage money and all expenses in case of his being given a passage to Brisbane. I had been paying some attention to the South Sea labour question, and had formed a very strong opinion of the value to the inhabitants of these islands of the opportunity given them by this demand for labour, of testing their capacity to enter into and mix with the general current of working men, and thereby possibly avoid extermination; and I was greatly pleased to see the result in this instance. From the island of Api we shaped our course to the north-westward towards Raine Island in a breach of the great barrier reef not far from the entrance of Torres Strait. On the 19th of August we sounded, lat. 16° 47′ S., long. 165° 20′ E., at a depth of 2,650 fathoms, with a bottom of "red clay," and a bottom-temperature of 1°7 C. (35° F.) A serial temperature-sounding was taken to the depth of 1,500 fathoms, and it was found that the minimum temperature (197 C.) was reached at a depth of 1,300 fathoms, and that consequently a stratum of water at that uniform temperature extended from that depth to the bottom. Serial temperature-soundings were taken on the 21st, the 24th, the 25th, the 27th, and the 28th of August, in 2,325, 2,450, 2,440, 2,275, and 1,700 fathoms respectively; and in each case the minimum temperature of 17 C., or a temperature so near it as to leave the difference within the limit of instrumental or personal error of observation, extended in a uniform layer, averaging 7,000 feet in thickness, from the depth of 1,300 fathoms to the bottom. It will be seen by reference to the chart that on our course from Api to Raine Island we traversed for a distance of 1,400 miles a sea included within a broken barrier, consisting of the continent of Australia to the west; the Louisiade Archipelago, the Solomon Islands, and a small part of New Guinea to the north; the New Hebrides to the east ; and New Caledonia and the line of shoals and reefs which connect that island with Australia to the south. The obvious explanation of this peculiar distribution of temperatures within this area, which we have called for convenience of reference the "Melanesian Sea," is that there is no free communication between this sea and the outer ocean to a greater depth than 1,300 fathoms, the encircling barrier being complete up to that point. The "Melanesian Sea" is in the belt of the S.E. tradewinds, and the general course of a drift-current which traverses its long axis at an average rate of half a knot an hour is to the westward; evaporation is, as it is usually throughout the course of the trade-winds, greatly in excess of precipitation, so that a large amount of the surface water is removed. This must, of course, be replaced, and it is so by an indraught of ocean-water over the lowest part of the barrier at the proper temperature for that depth. We had previously found a temperature of 17 C at a depth of 1,300 fathoms on the 16th, the 19th, and the 21st of June between Australia and New Zealand, on the 17th of July in lat. 25° 5' S., long. 172° 56′ W., and earlier on the 10th of March in lat. 47° 25' S. The bottom within the Melanesian Sea may be described generally as "red clay," with a small but varying proportion of the shells of Foraminifera, sometimes whole but more usually much broken up and decomposed. In one or two soundings the tube showed curiously interstratified deposits, differing markedly in colour and in composition. The trawl was sent down on the 25th of August to a depth of 2,440 fathoms. The animals procured were few in numbersome spicules of Hyalonema, a dead example of Fungia symmetrica, two living specimens of a species of Umbellularia, which appears to differ in some respects from the Atlantic form, and a very fine and perfect Brisinga, also living. The existence of animal life is therefore not impossible in the still bottom-water of such an enclosed sea; but, as we have already seen in the Mediterranean, the conditions do not appear to be favourable to its deve lopment. On the 29th of August we trawled in 1,400 fathoms, about 75 miles to the east of Raine Island, with somewhat greater success. This might have been anticipated, as the depth was not much greater than that at which the free interchange of water was taking place, and diffusion and intermixture was no doubt much more rapid than at the bottom. On the 31st of August we visited Raine Island, which we found to correspond in every respect to Jukes's description in the "Voyage of the Fly." We observed and collected the species of birds which were breeding there. In the afternoon we dredged off the island in 155 fathoms with small success, and proceeded towards Port Albany, Cape York, where we arrived on the 1st of September. We left Somerset on the 8th, and proceeded across the Arafura Sea to the Arú Islands, reaching Dobbo on the island of Wamma on the 16th. We found no depth in the Arafura Sea greater than 50 fathoms, and the average depth was from 25 to 30 fathoms. The bottom was a greenish mud, due apparently in a great degree to the deposit from the great rivers of New Guinea and the rivers falling into the Gulf of Carpentaria. Animal life was not abundant. Many of the animals seemed dwarfed, and the fauna had somewhat the character of that of a harbour or estuary. The specific gravity of the surfacewater was unusually low, falling on the 23rd off Dobbo Harbour to 1'02505; the temperature reduced to 15°5 C., distilled water at 4° C. =,1. After spending a few days shooting Paradise Birds and getting an idea of the natural history of the island of Wokaw, we left Dobbo on the 23rd and proceeded to Ké Doulan, the principal village in the Ké group. We then went on to the island of Banda, where we remained a couple of days, and thence to Amboina, which we reached on the 4th of October. On the 20th of September, after leaving the Ké islands, we sounded and trawled in 129 fathoms. The trawi brought up a wonderful assemblage of things, including, with a large number of Mollusca, Crustacea, and Echinoderms of more ordinary forms, several fine examples of undescribed Hexactinellid sponges, and several very_perfect specimens of two new species of Pentacrinus. Temperature-soundings were taken on the 28th of September and on the 3rd of October at depths of 2,800 and 1,420 fathoms respectively, and on both occasions the minimum temperature (3° C.) was reached at a depth of 900 fathoms, indicating that the lowest part of a barrier inclosing the Banda Sea, bounded by Taliabo, Buru, and Ceram on the north, the Arú islands on the east, Timor and the Serwatty islands on the south, and Celebes and the shoals of the Flores Sea on the west, is 900 fathoms beneath the surface. From Amboina we went to Ternate, and thence across the Molucca passage and into the Celebes Sea by the passage between Bejaren Island and the north-east point of Celebes. On the 13th we trawled and took serial temperatures near Great Tawallie Island. The trawl brought up several specimens of a very elegant stalked halichondroid sponge new to science, and the thermometer gave temperatures sinking normally to a bottomtemperature of 2004 C. On the following day we sounded in 1,200 fathoms, with again a normal bottom temperature of 1°9 C. It seems, therefore, that the Molucca passage communicates freely with the outer ocean; it does so at all events to the depth of 1,200 fathoms, and most probably to the bottom, if it include greater depths. In the Celebes Sea we had two deep soundings on the 20th, to 2,150 fathoms, and on the 22nd to 2600 fathoms. On both occasions serial temperature-soundings were taken, and on both the minimum temperature of 307 C. (387 F.) was reached at 700 fathoms. A passage of this depth into the Celebes Sea is therefore indicated very probably from the Molucca passage. This temperature corresponds almost exactly We with that taken by Capt. Chimmo in the same area. trawled on the 20th, and although the number of specimens procured was not large, they were sufficient to give evidence of the presence of the usual deep-sea fauna. We reached Zamboanga on the 23rd, and on the 26th we passed into the Sulu Sea and trawled at a depth of 102 fathoms. On the 27th we sounded to 2,550 fathoms, and took a serial temperature-sounding. A minimum temperature of 10° C. was found at 400 fathoms, so that the Sulu Sea must be regarded as the fourth of this singular succession of basins cut off by barriers of varying height from communication with the ocean. This observation in the main confirmed those of Capt. Chimmo in the same locality. The minimum temperature reached was the same in both, but we appear to have found it at a somewhat higher level. We arrived at Ilo Ilo on the 28th, and proceeded by the eastern passage to Manila, which we reached on the 4th of November. The collections have been packed and catalogued in the usual way, and will be sent home from Hong Kong. We have had an opportunity during this cruise of making a very large number of observations of great interest. Ï believe I may say that the departments under my charge are going on in a very satisfactory way. one of these birds with the muscles and integuments preserved. Several portions of the external covering of the bird have also been discovered, along with bones, which show signs of recent interment. Beside feathers, the complete skeleton in the museum at York has the integument of the feet partly preserved, from which it is evident that the toes were covered with numerous small hexagonal scales. We are now able to supplement our knowledge with a description of the covering of the tarsus from a specimen sent by Dr. Haast to Prof. Alphonse MilneEdwards, which is to be seen in the Museum of Natural History at Paris. This specimen is figured, one-fourth the natural size, in the accompanying drawing, for which we have to thank the proprietors of our enterprising French namesake La Nature. It was obtained at Knobly Range, Otago, and belongs to the species Dinornis ingens. From it we learn that the tarsus, as well as the toes, was nearly entirely covered with small horny imbricate scales, and not with broad transverse scutes, as it might quite possibly have been. It is also evident that the hind toe, or hallux, which is not present in either the Ostrich, Rea, Emu, Cassowary, nor in some species of Moas, was articulated to the metatarsal segment of the limb a little above the level of the other toes. Those species of Dinornis which possess the hind toe, Prof. Owen includes in the genus Palapteryx. Amongst the struthious birds, the Moas agree most with the Apteryx, in the presence (occasionally) of a fourth toe; and in their geographical distribution. They resemble the Cassowaries and the Emus most in the structure of their feathers; and in the structure of the skull differ from all to an extent which has made Prof. Huxley arrange them as a separate family of the Ratitæ. A knowledge of the anatomy of their perishable parts would be an invaluable assistance in the determination of their true affinities, but it is almost too much to hope that the material for such an investigation will ever present itself. THIS THE RECENT STORMS IN THE ATLANTIC HIS subject has attracted the notice of the New York Herald, which, in an article on the 23rd January, remarks that "the successive gales appear to have been connected with the high barometer or polar airwaves which have recently swept across the northern part of the United States." Our contemporary says, moreover, that the last "great barometer fluctuation was followed by a storm centre which the weather reports recorded on the 19th inst. as then moving eastward over the Gulf of St. Lawrence. . . . In fact, the lesson apparently deducible from the recent steamer detentions and ship disasters we had to record is, that the severest cyclones may be looked for as the sequel phenomena of the great winter areas of high barometer and intense cold; or, in other words, the rising glass should be studied by the seaman as carefully as the falling glass." Certainly, there is some truth in this assertion; but our contemporary ignores the startling fact that at the very same moment we had in Europe low pressure, southern gales, and high temperature. On the 15th a strong southwesterly gale was raging at Valentia. Evidently the danger is very great when a rising barometer in America is coupled with a falling barometer in Europe, or vice versa. Unhappily, the Transatlantic Telegraph is not in use now for sending meteorological summaries between Europe and America. It is deeply to be regretted that the practice was discontinued, and we hope the recent disastrous gales will induce the nations on both sides of the great ocean to neglect no longer that useful channel of mutual information. W. DE FONVIELLE THE PAST AND FUTURE WORK OF ON the 29th ult. Prof. Prestwich, who, as our readers know, nomers. "The wonderful discoveries with respect to the solar atmosphere, made by means of the spectroscope, have now presented junction with the argument derived from figure and plan, gives us with an entirely new class of evidence, which, taken in conirresistible weight to the theory of a common origin of the sun and its planets; and while serving to connect our earth with distant worlds, indicates as a corollary what of necessity must have been its early condition and probable constitution. "The whole number of known elements composing the crust and atmosphere of the earth, the lecturer went on to say, amount only to sixty-four, and their relative distribution is vastly disproportionate. It has been estimated that oxygen in combination forms by weight one-half of the earth's crust; silicon enters for a quarter; then follow aluminium, calcium, magnesium, potassium, sodium, iron, and carbon. These nine together have been estimated to constitute of the earth's crust. The other consist of the remaining fifty-five non-metallic and metallic ele |