necessary for the purpose are of the simplest kind; indeed, so far as mere training is concerned, the engineer's level, transit, and theodolite can be made to serve most of the purposes of the astronomical student. What the latter really wants is that training of the eye and the mind which will enable him to understand the theories of instruments, the methods of eliminating the errors to which they are subject, and the mathematical principles involved in their application. In this, as in nearly every department of professional education, we may lay it down as a rule that the wants of a liberal and of a professional education are, so far as the foundation is concerned, identical. We are too prone to lead the student into the minute details of a subject without that previous training in first broad principles which, though it may not immediately tell on his progress as a student, will be felt throughout his life to whatever field of work he may devote himself. Such a transit instrument as Hipparchus might have made-a wooden level mounted on an axis and supplied with slits to serve the purpose of sightsproperly mounted in the meridian, could well be made to take the place of the transit instrument for purposes of instruction. Scarcely any higher skill than that of a cabinet-maker would be required in its construction. The object at which the student should then aim would be, with the aid of this instrument, to determine the error of his clock or watch within a few seconds. If he is really acquainted with the principles of the subject, and has his eyes properly trained, he will have no difficulty in soon learning to do this. SIMON NEWCOMB NOTES THE following details regarding the sad accident by which Prof. Balfour lost his life have been received since Prof. Foster's article was written. It appears (from a letter from Mr. C. D. Cunningham to the Times) that on the 14th ult. Mr. Balfour crossed the Col du Géant, and on descending on the Italian side the idea first occurred to him of attempting the Aiguille Blanche de Peuteret, or, as it is sometimes called, the Aiguille de la Belle Etoile, a peak which is one of the buttresses of Mont Blanc, to the massif of which it is joined by an extremely steep snow arête. Mr. Cunningham's guide, Emile Rey, had previously attempted the peak, and was able to give Mr. Balfour many details as to the probable line of ascent. Having failed, however, to persuade Mr. Cunningham and the guide Rey to accompany him, Mr. Balfour started from Courmayeur on Tuesday, the 18th, with the guide Johann Petrus, for Aiguille, accompanied by a porter to carry blankets and wood as far as their sleeping place on the rocks. It was thought, the ascent being new and difficult, he might be absent two nights, and return to Courmayeur on Thursday. As he did not reappear, it was thought he must have crossed to Chamounix, or gone down to the Chalets de Visaille for more provisions. On Friday Mr. Bertolini and Mr. Baker, at the hotel in Courmayeur, became seriously alarmed, and finding the party had not been heard of either at Chamounix or at the Chalets de Visaille, they sent out a search party, which, early on Sunday morning, on reaching the rocks between the Glacier de Brouillard and the Glacier de Fre-ny, found the bodies of Mr. Balfour and Petrus, both partly covered with snow, at the foot of the steep snow arête. As there was little fresh snow about the place, it was probably not an avalanche that caused their death. One may have slipped, and the other not bad sufficient strength to hold his companion. The provisions at the sleeping-place having been untouched, the accident must have taken place on Wednesday, the 19th. But it, is not certain whether they fell in descent or ascent. Means were taken on the 25th to have the remains brought to the hotel. THE three missions designated for observation of the Venus transit in Patagonia left on the 20th ult. in the Messageries steamer from Bordeaux, for Buenos Ayres. The arrangement is as follows :-Rio Negro (41° S.), M. Perrotin, director of Nice Observatory, accompanied by Lieutenants Tessier and Delacroix, and M. Guénaire, photographer to the Observatory; Chubut (43° S.), M. Hatt, hydrographic engineer, assisted by Lieut. Leygue and M. Mion, engineer; Santa Cruz (50° S.), Capt. Fleuriais, assisted by Lieutenants Le Pord and de Royer de Saint Julien, and M. Lebrun, naturalist. Arrived at Monte Video, the first two missions will probably embark in the advice boat La Bourdonnais, the third in the advice boat Le Volage. In the course of observations, detachments from the Volage will try to ascend the Rio Santa-Cruz at least to the point reached by Darwin in the Beagle expedition. The Chili mission, composed of Lieut. de Bernardiére, assisted by Lieut. Barnaud and Ensign Favereau, embarked on the 15th ult. in an English steamer going by the Straits of Magellan. UNDER the name of a "North German Museum for Natural Science" Dr. G. Haller and Cie have opened at Putbus, on the island of Rügen, a storehouse of natural objects and aids to teaching, whence schools, museums, and private individuals may obtain specimens and collections, representing all the three kingdoms of nature. An institute for investigation of the Baltic forms part of the scheme, and a few students have been enrolled, we learn, for the current summer. Dr. Haller was formerly a privat-docent of zoology in Berne. With the aid of a well-known entomologist, collections of insects of all kinds (exotic included) are furnished; also biological collections of caterpillars, larvæ, pupæ, parasites, &c. It is intended, later on, to supply collections of the insect pests of agriculture. The utensils of entomo logists and other apparatus are also provided. Of European mainmals, birds, reptiles, amphibia, fishes, &c., many specimens are kept, preserved in the usual way; also preparations for the study of embryology and comparative anatomy, and for varied microscopical work. A variety of live animals for aquaria and terraria are provided. The dry preparations of frogs and other animals obtained by a modification of Semper's method have received special commendation, also the series of embryos and parasites. Yet a FREE libraries do not increase in number so rapidly in England as in America, where they have now reached to 4000. pamphlet or circular issued by the Bureau of Education must be of considerable interest to any who are engaged in starting or working libraries. It points out the disadvantages of the arrangements of existing library buildings, and gives a general The chief American plan by which they may be avoided. libraries consist of large halls open from floor to roof and surrounded by galleries five or six one over another like a theatre. The author of this paper (Mr Poole of Chicago) objects to this general plan, on account of (1) the waste of this central space, or if this central space is used for reading, for its publicity and noisiness; (2) the difficulty of getting any uniform temperature over the whole of such a building, for while the lower floors are kept at a mild warmth the upper floors become so intensely hot that not even an attendant can work there, and the bindings perish from heat; (3) the wasteful expenditure of the physical strength and time of attendants in going upstairs and round from one part of the library to another; (4) the special convenience for catching fire where all communicate with one centre instead of being divided into fireproof compartments; (5) the difficulty of enlarging such a circular building, as the principal American libraries already require enlarging; and (6) its great expense. In the plan which Mr. Poole suggests ten rooms surround a square space equal to only two of the rooms. Each room should be about 16 feet high, thus easily warmed uniformly. Books should be classified, and in a few cases duplicate copies kept so that a student should find all the books on the subject he wanted in one room, and there should be no journeying to distant galleries; of course where a library is so small that all its books can be stored in one room a great difficulty is avoided. Each room being separate and all being built of fireproof material and only communicating by a light iron gallery, which goes round the central area, they are both quiet and fireproof. In each room a row of reading tables will stand under the windows at one end, and the remaining space will be covered with double shelves, not more than 7 feet high, with passages 3 feet or 31 feet wide between. No ladders will thus be required, and the high temperature will be avoided. Yet twenty-five volumes to every square foot of flooring can be stored in this way, and hence a room 40 feet X 40 feet will hold 40,000 volumes ; ten such rooms on a floor give 400,000 volumes, and five storeys high will hold 2,000,000. MR. CLEMENT L. WRAGGE has written to the Times earnestly entreating all visitors to Ben Nevis to co-operate with him and the Scottish Meteorological Society to prevent damage to the instruments on the mountain. These are, of course, kept under lock and key, and till lately all has gone well with them. But on the morning of July 23 it was found that wanton mischief had been done to the intermediate station at the Red Burn Crossing, about 2700 feet above the sea. A hole had been made in the thermometer box, the louvre forced off, and the wet bulb thermometer forced from its screws, and broken. The compass points had also been removed. It seems difficult to account for such acts. Mr. Wragge's appeal to the British public will not, we trust, be in vain. IN connection with the forthcoming electro-technical exhibition in Munich, the Bavarian Kunstgewerbe-Verein has announced a prize competition for light-fittings (lustres, brackets, candelabra, &c.) suitable for the electric light. The Edison illumination, to be maintained by about 80 horse-power, will be no way inferior in extent to that in Paris; the restaurant-hall, with garden, library, and reading room, one or two streets, and the theatre, will be lit with Soo Edison lamps of various strength, from 8 to 100 candles. Mr. Edison's plans for centrally lighting up a whole city quarter with 14,000 lamps of 170,000 total candle-power will be shown; the system is to be tried in New York. Schuckert, of Nürnberg, will, from the roof of the crystal palace, light up the Frauenthürme with a reflector lamp of 10,000 candle-power; also the temporary theatre with an upper light of 4000 candle-power; he will also exhibit several transportable electric lights for war purposes, railways, &c. Special interest will attach to an effort to utilise the waterpower of the Hirschau, about three miles from the palace; the current will work a lift or thrashing machine in the palace by day, and illuminate the garden and the Königsplatz by night (11 lamp; of 1000 candle-power each). The copper wire will be 3 mm. thick. A provisional plan of the Exhibition is supplied with the Electrotechnische Zeitschrift for July. THE Council of University College, London, have accepted a fund raised in memory of Miss Ellen Watson, a former student. A Memorial Scholarship consisting of the income of the fund is open to students of either sex who display very marked merit in applied mathematics. THE Herald (N.Y.) correspondent with the party in search of the lost crew of the Jeannette has been impressed by the beauty of the teeth of natives of Northern Siberia. He saw old men of sixty and seventy with sets of teeth small and pearly white, polished and healthy. Decay and suffering are unknown. A physician of Yakutsk attributed this to the habits and the kind of food eaten by the natives, and to a certain care taken by them from childhood up. First, the natives do not touch sugar in any form, for the simple reason that they cannot afford to buy it. Secondly, they are in the habit of drinking daily large quantities of fermented sour milk summer and winter, which is antiscorbutic, and is very beneficial in preserving the teeth. And lastly, they have the habit of chewing a preparation of the resin of the fir tree, a piece of which, tasting like tar, they masticate after every meal, in order specially to clear the teeth and gums of particles of food that may remain after meals. The gum or resin is prepared and sold by all apothecaries in Siberia, and is much used by Russian ladies. THE International Committee of the Red Cross Society of Geneva have recently offered a prize of 2000 francs for three studies (to be complementary of each other), on the art of im provising means of help for the wounded and sick; the first to relate to the production of means of treatment, the second to means of transport, the third to the sudden providing of an ambulance or a field-hospital. Papers to be sent in before April 1, 1883. MM. HACHETTE AND CO. will publish in a few weeks the first volume of a new series-"Les Drames de la Science "entitled "La Pose du Premier Cable"; the author is M. W. de Fonvielle. FROM Signor Ricco's report on latitudes of groups of sun-spots in 1881, it appears that 258 groups or formations of spots and cavities were observed (82 presenting only cavities). The groups of the northern hemisphere seemed to have longer duration; more of them reappeared after one or more rotations. They were also richer in spots. The groups of latitudes under 15° were always displaced towards the equator, those of latitudes over 15° towards the poles. The development of groups is more rapid than their disappearance. The distribution was :-In the northern hemisphere, 132 groups in a zone of 22° between +7° and +29° with a maximum at +20°; in the southern, 126 groups in a zone of 30° (therefore broader) between -3° and - 33°, maximum at -18°, more pronounced than in the other hemisphere. The centres of the two bands of spots was at the same latitude, 18°. The band without spots or cavities, between the other, was about 10° in breadth, with centre at +2°. In the northern hemisphere the greatest duration belonged to the groups in the lowest latitudes (generally the groups richest in spots and most durable are at the latitudes of maxima). FOR determination of high temperatures at the Imperial Porcelain Manufactory in Berlin, pyroscopes of noble metal have been long used with the best success; the materials are pure silver and gold, silver alloys with 20, 30, 40, 60, and 80 per cent. of gold, and gold-platina alloys with 5, 10, or 15 per cent. platina. Silver-platina alloys are objectionable, because at high temperatures the silver is very volatile, so that the composition changes. Also alloys of gold with more than 15 per cent. platina are not used, because they do not suddenly melt down; but an alloy richer in gold separates out, while a skeleton richer in platina remains, to melt at a higher temperature. For the measurement with alloys, balls of 1 to 2 gr. weight, between parchment paper, are hammered on the anvil to about the thickness of a penny-piece; the pieces are bent so that they can stand upright, and placed in rows, arranged according to melting point in small cupels of clay, magnesia, or bone ash, in such a way that they can be seen from without, through a hole. For a new experiment they have merely to be flattened out again, and put into the same cupel. In this way temperatures from the meltingheat of silver to nearly that of cast-steel can be determined pretty exactly. WE have received "Fragments of the Coarser Anatomy of Diurnal Lepidoptera," by Mr. Samuel H. Scudder, being an account of dissections of caterpillars and chrysalids of butterflies; it is issued partly with the view of calling attention to the need of work on a subject which is very imperfectly known at present. The "Studies from the Biological Laboratory" of the Johns Hopkins University for June, contains original matter relating to the pulse wave in the coronary artery, the influence of digitaline on the heart, polar action in nerves, temperature and reflex actions, &c. A reprinted memoir by Staff-Commander Tizzard, R.N., and Mr. John Murray, on 'Exploration of the Faroe Channel during the Summer of 1880 in Her Majesty's hired Ship Knight Errant," with various subsidiary reports, has also reached us, and we hope soon to refer to its contents. "THE Photographic Studios of Europe," by Mr. H. Baden Pritchard (London: Piper and Carter) gives copious information that the professional photographer will appreciate and find helpful, but has also much to interest the general reader. It is the outcome of a house-to-house visitation of the principal studios in Europe, and a record, in colloquial style, of the practice observed. For convenient reference the information is tabulated in the introductory chapter, under nine headings (the reception-room, the studio, the dark room, &c.), and the rames of the photographers follow, in each case, with the pagenumbers. Among matter of a special nature we note accounts of photographing prisoners at Millbank and Pentonville, and at the Prefecture of Police in Paris; also a popular account of Dr. Huggins' photographs of the Stars. SIGNOR MAUDELIN affirms that the violets V. syrtica, V. tricolor, and V. arvensis contain from o'083 to 0 144 per cent. of salicylic acid. The other species contain none; at least no appreciable quantity. The wild violet has much more than the tricolor. It is the action of salicylic acid that explains the use of the violet in pharmacy. MR. W. B. COOPER has lately brought before the Franklin Institute a device for increasing the dynamic effect of the vibra tions of diaphragms. To one end of a wire or band he attaches a diaphragm or other pulsating body; the wire is passed a half turn or several turns round a drum or pulley, which is rotated towards the diaphragm. To the other end may be attached a lever having a point adapted to indentation of sheet metal passed under it at uniform speed. With such an arrangement (called a "phonodynamograph ") Mr. Cooper has embossed brass of the thickness of writing paper by impact of the voice on a diaphragm like that of the phonograph. (The force of the pull is augmented by force derived from friction on the surface of the pulley). The principle is applicable to the telephone, both for increasing the intensity of the electric impulses transmitted, and augmenting their effects at the receiving station, and Mr. Cooper shows how this may be advantageously done. THE northernmost place in the world where rye and oats mature is at Kengis, in the Swedish province of Norrbotten, 49 miles to north of the Polar Circle, whereas the northernmost spot where corn is grown is at Muoniovara, 98 miles to north of the Circle. The rye yields, it is stated, 98 per cent., and the oats about 90. THE additions to the Zoological Society's Gardens during the past week include a Malbrouck Monkey (Cercopithecus cynosurus &) from West Africa, presented by Mrs. Cumberleye; a Ring-necked Parrakeet (Palæornis torquatus) from India, presented by Mr. W. K. Stanley; four Egyptian Ouarans (Psammosaurus scincus) from Egypt, a Horseshoe Snake (Zamenis hippocrepis), eleven Snakes (Zamenis ventrimaculatus), an Ocellated Sand Skink (Seps ocellatus), South European, presented by Messrs. Wylde Beyts and Co.; a Greater Sulphurcrested Cockatoo (Cacatua galerita) from Australia, deposited; a Spotted Bower Bird (Chlamydodera maculata) from South Australia, a White-billed Parrakeet (Tanygnathus albirostris) from Celebes, a Yellow-billed Sheathbill (Chionis alba), captured at sea, off Cape Horn; a Shag (Phalacrocorax cristatus), North European, a Cornish Chough (Fregilus graculus), British, four Eyed Lizards (Lacerta ocellata), South European, purchased; a Humboldt's Lagothrix (Lagothrix Humboldti) from Upper Amazon, received in exchange; five Undulated Grass Parrakeets (Melopsittacus undulatus), a Geoffroy's Dove (Peristera geoffroii), bred in the Gardens. The following insects have emerged during the past week in the Insect House:-Silk Moths: Telea promethea; Butterflies: Vanessa antiopa, Vanessa polychlorus, Vanessa io, Melanagria galathea, Gonoepteryx rhamni, Thecla betula, Erebia blandina, Hipparchia janira; Moths: Deilephila euphorbia, Bombyx castrensis, Liparis monacha, Liparis dispar, Chelonia caja. OUR ASTRONOMICAL COLUMN CONTINENTAL OBSERVATORIES.-The last number of the Vierteljahrsschrift der Astronomischen Gesellschaft contains reports of the proceedings of some twenty of the observatories on the continent during the year 1881. At Berlin observations for the zone +20° to 25°, were actively continued, upwards of 10,000 being made in the year. The 9-inch refractor was employed for comets and small planets, &c., the physical appearances of the comet 1881 III. receiving special attention. With the Declinograph 1200 small stars were observed, making, up to the end of 1881, 12,329 stars, mostly from the eleventh to the thirteenth magnitudes, thus determined, in connection with the identification and observation of the small planets. At Bonn the southern "Durchmusterung" furnished observations of upwards of 14,000 stars, so that rapid progress is being made with this work under the direction of Prof. Schönfeld. At Brussels astronomical physics, as well as meridian observations, have been attended to; the meteors of the August period were extensively observed over Belgium; Christiania was mainly occupied, under Dr. Fearnley, with the zone 65° - 70°, and the curious circumstance of the existence of four variable stars in this zone within a radius of 1° is recorded, the first in 20h. 59m. 20s. +66° 8'5, has been estimated by various observers from 5m. (Lalande) to 9m. (Argelander), the second is in 20h. 59m. 48s. + 67° 35'9, the third in 21h. 7m. 33m. + 67° 54'4, and the fourth in 21h. 11m. 49s. + 66° o''9, for 18550. Baron v. Engelhardt, at Dresden, bas zealously observed the various comets of the year, and has made 111 observations of 19 minor planets, the principal instrument in the Baron's observatory is an equatorial refractor by Howard Grubb, of Dublin, aperture 306 mm. A new physical observatory has been erected at Herény, Hungary, by Eugen and Alexander von Gothard, the position of which is 12m. 49'8s. east of Berlin, with latitude 47° 16' 37"; the observatory is provided with a 10 inch equatorially mounted reflector by Browning, of London, observations consisted of the examination of star-spectra. At Keil an 8-inch were commenced in the second week of November, and chiefly refractor by Steinheil has been received: meridian observations here were largely devoted to circumpolar stars + 79° to 82°, but according to the present plan, the observations will be continued to the pole. Leipsic is now under the direction of Prof. H. Bruns. At Lund the zone undertaken by the observatory was continued, more than 5200 stars being determined. From the Observatory of Brera, Milan, Prof. Schiaparelli makes the welcome announcement that the late Baron Dembowski had confided to him all his astroncmical manuscripts with the condition that they were to be utilised to the best advantage for the science. His measures of double stars, upwards of 20,000 in number, will be published under the auspices of the Accademia Reale dei Lincei ; they are to form four volumes, of which the first will contain the measures made by Dembowski at Naples with his Plössl Dialyte in the years 1852-58; the second and third, the observations made at Galarate on stars of the Dorpat Catalogue, and the fourth, the measures of stars in W. Struve's appendix, the Pulkowa Catalogue, and double stars discovered by other astronomers, more especially by the eminent American observer, Mr. Burnham. The first volume is in course of preparation. At Plonsk Dr. Jedrzejewicz continues, in his private observatory, measures of double stars as his principal work. The passages of the red spot on Jupiter, by the middle of the disc, were micrometrically determined from November 25, 1880, to February 5, 1881, from 174 rotations, the period was found to be 9h. 55m. 34'41s. ± o'13s., and at the same time the jovicentric latitude of the centre of the spot was found -22°.8, and its length in degrees of the parallel 26°4; the third and fourth comets of 1881 and Encke's comet were also observed for position. The physical observatory at Potsdam was in full activity, and in addition to the more special subjects of observation undertaken by this important establishment, an extensive series of observations of varivble stars was secured in 1881. From Stockholm Dr. Hugo Gylden notifies his determination of the parallax of the star Bradley 3077, or No. 240 in Argelander's Catalogue of 250 stars, forming part of the seventh volume of the Bonn observations: the resulting value is o" 283 ±o"0468; this star has considerable proper motion. Prof. R. Wolf communicates, from Zurich, he monthly numbers of days with and without sun-spots, and the relative numbers: in the whole year's observing-days, the sun was free from spots on five days, and exhibited spots on 297. ATOMIC ATTRACTION THE theory of universal gravitation, as I understand it, asserts that the mutual attraction exerted by any two bodies, A and B, is dependent only on their respective masses and on the distance between them, being entirely uninfluenced by the presence of other bodies even in the immediate neighbourhood of A or B. Thus at a given moment the Earth and Venus, being in certain definite positions, exert upon each other a certain force of attraction; the attraction thus taking place between the masses of the two planets would be unaltered by the removal of the Moon from the sphere of action; the gravitation of the Earth and the Moon does not therefore tie up any portion of the attractive energy of the Earth, and so diminish the force with which other bodies gravitate towards it. A totally different assumption is usually made with regard to that form of attraction which gives rise to chemical phenomena. Here it is supposed that two or more atoms, having combined together, have thereby become incapable, at any rate in the majority of cases, of attracting others to any appreciable extent. Thus I imagine that most chemists hold the view that when hydrogen and oxygen combine together to form water they thereby exhaust, or nearly exhaust, their combining power, that the power of attraction residing in the oxygen atoms is all concentrated upon the hydrogen atoms, just as we might conceive all the attractive power of the Earth concentrated on the moon, thus leaving all other bodies in its neighbourhood free from the influence of gravity. We thus invest matter with two separate forms of attraction differing entirely in their mode of action, and having indeed nothing in common. It is however possible to a certain extent to assimilate chemical attraction and gravitation, and I propose here to discuss some of the results which ensue from the elaboration of this idea. Let us suppose then that the act of chemical combination in no wise alters the power of attraction which the combining atoms exert upon surrounding bodies, and let us see what effect this hypothesis has upon the explanation of various phenomena. In order to do this we must first render as precise as possible our notions of the construction of chemical compounds. It is now known with certainty that the atomic and molecular volumes of substances are but slightly altered by combination, that is to say, that under comparable conditions the atom of any substance generally occupies about the same space with whatever atoms, similar or dissimilar, it may be combined. This fact seems to me to point to the conclusion that the atoms which make up a molecule are as close together as their periodic motions will permit, and are not merely held in certain positions of equilibrium by various opposing forces; for if the latter supposition were true, I fail to see how it would be possible for the same atom, together with its surrounding proportion of space, to have always the same volume. The immediate proximity of the several molecules in the liquid and solid states must also be assumed, in order to account for the invariability of molecular volumes. The innumerable facts which have been brought to light by the efforts of those who have investigated the chemistry of the carbon compounds all lead one to suppose that there is some foundation for the ideas propounded by chemists concerning the position of the atoms, and that the constitutional formulæ ascribed to organic substances really represent the construction of the molecule. If this be so it certainly furnishes a further argument in support of the proximity of the atoms. The assumptions contained in the preceding paragraphs are in no way opposed to the views generally held concerning molecular and atomic motion which we owe to the development of the science of heat. They merely state that there is no force of repulsion exerted between contiguous atoms, and that the vibratory or other movements are small compared with the size of the moving masses. The object of the following remarks is to show that the hypothesis concerning chemical attraction mentioned above enables us to offer some explanation of the relative volatility of bodies. We all, I presume, look upon the maximum vapour tension of a substance at a given temperature as affording to a certain extent a means of estimating the attraction which its molecules exert among themselves; if there is considerable attraction there will be a low vapour tension, and with little attraction there will be a low boiling point. It follows from this that the attraction between the molecules of hydrogen is relatively extremely small; that in the case of oxygen and nitrogen it is also very small, though probably much larger than in the former case; the attraction mutually exerted by molecules of chlorine will be more considerable; while with bromine, iodine, and other liquid and solid elements it will be greater still. We must not however confound the attraction exerted between atoms of a substance with that between the molecules, for each atom attracts separately those of the contiguous molecule, so that the attraction between two molecules of bromine, for example, will be four times as great as between two atoms, and generally when the molecule of a substance contains n atoms the attraction between two molecules will be approximately n times that between two atoms. This is of course even approximately true only when the distance between the two molecules is great relatively to their size; when the two molecules are close together the several interatomic attractions will be exercised over very different distances, and will therefore be very unequal in amount. Nevertheless, the above remark enables us to see that in some cases the apparent attraction, as estimated by the boiling-point, may be very misleading. In sulphur, for example, of which the molecule in the solid and liquid states is probably somewhat complex, we have a substance of high boiling-point, though the mutual attraction of the atoms may be comparatively small. The same is the case with carbon and many other substances. Applying now the above considerations to a few actual cases, we shall see that the relative volatility of different substances is generally satisfactorily explained. Let us designate by (hh) the (oo) the attraction between two atoms of oxygen, and generally attraction at unit distance between two atoms of hydrogen, by by (s) the attraction at unit distance between any two atoms, R and S. Then in the case of water the molecular attraction will be represented by― 4A(h h) + 4B(ho) + C(oo), where A, B, and C are factors dependent on the distances which separate the atoms; now we have seen that (hh) and (oo) probably have small values, but (ho) is not small, hence the attraction between molecules of water should be far greater than that between molecules of oxygen, and the boiling point much higher, a result which is in accord with fact. The boiling-point of water would probably be much higher than it is, were it not tha the attractions between II and O are exerted over comparatively large distances, owing to the hydrogen of one molecule shielding its companion oxygen from the approach of other hydrogen. In the similarly constituted body, H2S, the value of the molecular attraction will be 4A(h h) + 4B(h s) + C(ss), not differing exce sively from those which hold good in the case of in which expression A, B, and C may be supposed to have value water (the sulphuretted bydrogen being supposed liquid). The value (ss) is in itself small, and since the force is exerted between two atoms which cannot approach each other very closely, C is also small. The affinity of hydrogen for sulphur being also feeble, the whole value of the molecular attraction is small; sulphuretted hydrogen should therefore be an extremely volatile body, which is actually the case. With hydrochloric, hydrobiomic, and bydroidic acids we have for the molecular attraction the several values A(hh) + 2B(hel) + C(clcl) As the three bodies are similarly constructed we may assume that A, A', A", &c., do not materially differ. As the third terms of these expressions increase the second terms diminish; we should therefore expect that there might be no great difference in the vapour-tensions of the three substances; experiment proves that they may be liquefied with about equal facility. It should be noticed that the thermal change accompanying the formation of any one of these gases, HCl, for example, is not a true measure of the attraction between the atoms, since it also includes the heat employed in separating the atoms of the original molecules H2 and Cly. We may also find a confirmation of the above views in the many homologous series of organic chemistry. In the alcohols of the ethyl series, for example, the larger the molecules the greater must be the attraction between them, and consequently the higher the boiling-point; this, as is well known, is in accordance with fact. In the case of isomeric alcohols, the influence of the position of the atoms comes conspicuously to the fore. It is clear that if the atoms of carbon of two different molecules cannot approach each other so nearly in the case of one isomer as in another, the attraction between the molecules will be less, and the boiling-point consequently lower. Now in secondary and tertiary alcohols the carbon atoms are more sheltered by each other, are, as it were, more removed from the exterior of the molecule than in primary alcohols; at the same time the boiling-points are lower, which is as it should be. If we replace two atoms of hydrogen in an alcohol by one of oxygen we increase the attraction of the molecules, since we substitute a certain number of attractions (ho) and (co) for the relatively small attractions (1⁄2 1⁄2) and (ch); the increase of boil ing-point which we should expect is confirmed by experiment. Many other examples might be brought forward, were it not that their discussion would transcend the limits of this article. Before concluding I should like to draw attention to one question which is of importance. The use of the above hypothesis renders it difficult at first sight to account for the formation of definite chemical compounds; it seems that if any number of atoms of hydrogen are equally attracted by one of chlorine, the combination of one of them with that atom would not prevent the adherence of a second and a third forming H2CI, H,Cl, &c. This difficulty is avoided by supposing that the chlorine atom is of such a form that only one atom of hydrogen can approach sufficiently closely to adhere permanently; such forms are difficult to imagine, though it may be remarked that an atom in the form of a ring offers in a certain sense a unique position to another which instals itself inside it. The existence of molecular compounds proves that the permanent adherence of other atoms is sometimes possible, and thus affords material support to the notion that the chemical affinity of an atom is not only exerted upon those atoms with which it is combined, but upon all others in its vicinity. FRED. D. BROWN The Museum, Oxford THE GESTURE SPEECH OF MAN' ANTHROPOLOGY tells the march of mankind out of savagery, in which different peoples have advanced in varying degrees, but all started in progress in civilisation from a point lower than that now occupied by the lowest of the tribes now found on earth. The marks of their rude origin, retained by all, are of the same number and kind, though differing in distinctness, showing a common origin to all intellectual and social development, notwithstanding present diversities. The most notable criterion of difference is in the copiousness and precision of oral speech, and connected with that, both as to origin and structure, is the unequal survival of gesture signs, which it is believed once universally prevailed. Where signlanguage survives it is, therefore, an instructive vestige of the prehistoric epoch, and its study may solve problems in philology and psychology. That study is best pursued by comparing the pre-eminent gesture system of the North American Indians with the more degenerate or less developed systems of other peoples. North America showed more favourable conditions for the development of gesture signs than any other thoroughly explored part of the world. In the pre-Columbian period the population was scanty, and so subdivided dialectically that the members of but few bands could readily converse with each other. The sixty-five families of the Indian language now known to have existed within the territory of the United States differed among themselves as radically as each differed from the Hebrew, Chinese, or English. In each of these families there were sometimes as many as twenty separate languages, differing from each Address by Col. Garrick Mallery, U.S.A., Chairman of the Sub-Section of Anthropology at the American Association (Cincinnati). other as the English, French, German, and Persian divisions of the Aryan linguistic stock. The conditions and circumstances attending the prevalence, and sometimes the disuse, of sign-language in North America were explained. The report of travellers, that among Indians, as well as other tribes of men, some were unable to converse in the dark, because they could not gesture, is false. It is the old story of aglossos and barbaros applied by the Greeks to all who did not speak Greek, repeated by Isaiah of the "stammering" Assyrians, and now appearing in the term slav (speaker) as contradistinguished by the Russians from the Germans, whom they stigmatise as njemez (tongueless). The theory that sign-language was the original utterance of mankind does not depend upon such tales or prejudices. After the immeasurable period during which man has been upon the earth, it is not probable that any existing peoples can be found among whom speech has not obviated the absolute necessity for gesture in communication between themselves. The signs survive for convenience used together in oral language, and for special employment when language is unavailable. The assertions made that the sign language of Indians originated from some one definite tribe or region supposes its conparatively recent origin, whereas the conditions favourable to its development existed very long ago and were co-extensive with the territory of North America occupied by any of the tribes. Such a solution would only be next in difficulty to the old persistent determination to decide upon the origin of the whole Indian race, in which most people of antiquity in the eastern hemisphere, including the lost tribe of Israel, the gypsies, and the Welsh, had figured conspicuously as putative parents. Numerous evidences were presented as to its antiquity and generality. But the signs are not now, and from the nature of their formation never were, identical and uniform. An argument for the uniformity of the signs of Indians was derived from the fact that those used by any of them were generally understood by others. But signs might be understood without being identical with any before seen. There was evidence that where sign language was found among Indian tribes it had become more uniform than ever before, simply because many tribes had for some time past been forced to dwell near together at peace. The process of the formation and introduction of signs was the same among Indians as often observed among uninstructed deaf-mutes when associated together. There was a similarity of development between the sign language of mutes and Indians. The longer and closer the contact between Indians while no common tongue was adopted, the greater would be the uniformity of signs. The inference that there was but one true Indian sign language, just as there was but one true English language, was not correct, unless it could be shown that a much larger proportion of the Indians who use signs at all, than present researches show to be the case, used identically the same signs to express the same ideas, and also because the signs are not absolute and arbitrary, as are the words of English. Are these signs conventional or instinctive? Sign language, as a product of evolution, had been developed rather than invented, and yet it seemed probable that each of the separate signs, like the several steps that lead to any true invention, had a definite origin arising out of some appropriate occasion, and the same sign might in this manner have had many independent origins due to identity in the circumstances, or, if lost, might have been reproduced. In regard to arbitrary or natural sounds, no signs in common use were in their origin conventional, and what appeared to be conventionality largely consisted in the form of abbreviation agreed upon. When the signs of the Indians had from ideographic become demotic, they might be called conventional, but still not arbitrary. Yet, while all Indians, as well as all gesturing men, have many signs in common, they use many others which have become conventional in the sense that their etymology and conception are not now known or regarded by those using them. The conventions by which such signs were established occurred during long periods and under many differing circumstances. Our Indians, far from being a homogeneous race and possessing uniformity in their language, religions, and customs, differ from each other more than all the several nations of Europe, and their semiotic conceptions have correspondingly differed. To insist that sign language was uniform were to assert that it is perfect. He next went on to prove the general ancient use of the system in North America. This fact might be recognised among tribes long exposed to |