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tion is turned somewhat intently on the political conditions of the Oriental despotism which has so anomalously maintained itself to the west of our prime meridian. Hence the politician has a temporary interest in what would otherwise have appealed mainly to the geographer and man of science, the publication by the Royal Geographical Society of a Supplementary Paper," the "Bibliography of Morocco." This is a work of splendid thoroughness, almost, if not quite, exhaustive in its list of 2243 titles, and made convenient for reference by two copious indexes of subjects and authors. But it is much more than a catalogue. ments, judiciously brief, but in some cases of exceptional interest extending to a couple of pages, give information as to little-known authors, or record some striking circumstance in or concerning the books referred to. There is a specially-compiled map, and an introduction which is really an essay on the growth of knowledge regarding Morocco in European countries. With regard to the map, it is explained that only the coast-line has been surveyed. As to the interior :

Com

"The best mapped districts are laid down solely from running reconnaisances or sketch-maps. Positions fixed by astronomical observations are few. Many wide areas have never been visited by any Europeans, and most of the Atlas is at this hour as little known as it was in the days of Leo Africanus. There are cities within a few hours' ride of Tangier, which no person capable of giving a correct account of his observations has visited; and there are others not much farther away, to attempt to enter which-Zarhoun, for example-would, were the intruder detected, be certain death. There is scarcely a river laid down with even approximate accuracy, and, not to enumerate more distant provinces, the entire Riff country, that bold massif which is familiar to the thousands who every year sail up and down the Mediterranean, is less explored than many regions in the centre of the continent."

The present population of Morocco is a puzzle almost as difficult, although on a smaller scale, as that of China. The authors of the Bibliography give 4,000,000 as an estimate, but the guesses of various authorities vary between 1 and 15 millions. The roads shown on the map are mere mule and camel tracks made by the feet of the pack-animals, unaided by any engineer. Ferries are rare, and, of course, bridges are unknown in the interior. The distribution of towns and villages is often at variance with the rules holding for civilised countries. The villages are built out of the way of the main tracks, because people never travel in Morocco for the good of the inhabitants, and it is safer to live off the path of the tax-collector and the Government official, who demands free food and quarters. The great number of placenames on the map of so thinly-peopled a country is due to the fact that the tombs of saints are such important landmarks that they must be indicated, even if only a few persons live beside them. "All the places beginning widh 'Sidi' (Lord, master) are either actually tombs or the tomb has formed, as in so many of our cathedral cities, the nucleus of the town or village." "Sok," another affix of frequent occurrence, means market-place, and many of the established sites for periodical fairs are uninhabited between the gatherings of people from far and near, Many of the place-names on the coast exist in two forms at least-the native word and its Portuguese or Spanish translation; Casablanca and Dar-elbeida (both meaning White house) for example. We regret that the authors did not see their way to lay down precise rules for the spelling of Moorish place-names, either by giving a standard transliteration of the Arabic, or a uniform phonetic system. Indeed, even in the introduction a few anomalous spellings are found, eg. Zarhoun and Zerhun, Moulai and Mowlai.

The physical geography of Morocco appears to be

changing, and the natural conditions of the country are less favourable for agriculture than they were a few centuries ago. The forests have been destroyed with such recklessness that the soil has been dried up and swept away in many places; there is evidence that the rainfall has diminished, lakes have dried, and rivers formerly navigable have become silted up, or alternate as dry tracts of stone and raging torrents.

In one respect alone the enthusiastic Moslemism of its people does Morocco show no sign of degeneration. Although the Moors can no longer seize and hold the Christian slaves, whose stories bulk so largely in the bibliography, their hatred and contempt towards "unbelievers" is in no sense abated. Into such a land no Europeans could penetrate far, except in the past as slaves, or now as official messengers of European Powers under special protection, jealously watched and prevented from studying places or people. The last serious attempt at scientific exploration-that of Mr. Joseph Thomson-was again and again almost stopped by the fanatical Kaids, and only his remarkable persistence and daring stratagems carried him as far as he reached. Such stratagems would hardly serve again, and for the present the exploration of the Atlas Mountains, with their half-guessed topography, imperfectly-known flora, and unsurveyed mineral wealth is at an end. The futility of disguise as an aid to exploration is fully proved in the records before us, where the ghastly fate of many who tried to pass as Moslems, and the unsatisfactory results obtained by others who escaped alive, are briefly told.

It seems to us that an attempt might well be made to open communications with fanatical Mohammedan countries either by explorers or diplomatic agents of the same faith, and there must be many amongst the educated Mohammedans of India who are well suited for such work. The religious beliefs of a people with whom belief and conduct are so closely related, must be taken into account in dealing with them, just as much as the physical features of a country. And as Arctic sailors have been proved to be the natural explorers in the Antarctic seas, Swiss mountaineers the safest pioneers on New Zealand glaciers, and Canadian boatmen the most expert in shooting the Nile cataracts, so Mohammedan envoys might be expected to make the most favourable impression on the people of Morocco or of the Mohammedan Sudan.

Sir Lambert Playfair and Dr. Brown deserve the heartiest thanks for completing their Bibliography of the Barbary States in such an admirable way, and we do not doubt that the work will be very widely consulted in the immediate future.

THE RATE OF EXPLOSION IN GASES. THE HE following is an abstract of the Bakerian Lecture before the Royal Society by Prof. Harold B. Dixon, on on "The Rate of Explosion in Gases," delivered January 19:—

1. Berthelot's measurements of the rates of explosion of a number of gaseous mixtures have been confirmed. The rate of the explosion wave for each mixture is constant. It is independent of the diameter of the tube above a certain limit.

2. The rate is not absolutely independent of the initial temperature and pressure of the gases. With rise of temperature the rate falls; with rise of pressure the rate increases; but above a certain crucial pressure variations in pressure appear to have no effect.

3. In the explosion of carbonic oxide and oxygen in a long tube, the presence of steam has a marked effect on the rate. From measurements of the rate of explosion with different quantities of steam, the conclusion is drawn that at the high temperature of the explosion wave, as

well as in ordinary combustion, the oxidation of the carbonic oxide is effected by the interaction of the steam.

4. Inert gases are found to retard the explosion wave according to their volume and density. Within wide limits an excess of one of the combustible gases has the same retarding effect as an inert gas (of the same volume and density), which can take no part in the reaction.

5. Measurements of the rate of explosion can be employed for determining the course of some chemical changes.

In the explosion of a volatile carbon compound with oxygen, the gaseous carbon appears to burn first to carbonic oxide, and afterwards, if oxygen is present in excess, the carbonic oxide first formed burns to carbonic acid.

6. The theory proposed by Berthelot--that in the explosion wave the flame travels at the mean velocity of the products of combustion- although in agreement with the rates observed in a certain number of cases, does not account for the velocities found in other gaseous mix

tures.

7. It seems probable that in the explosion wave(1) The gases are heated at constant volume, and not at constant pressure;

(2) Each layer of gas is raised in temperature before being burnt;

(3) The wave is propagated not only by the movements of the burnt molecules, but also by those of the heated but yet unburnt molecules;

(4) When the permanent volume of the gases is changed in the chemical reaction, an alteration of temperature is thereby caused which affects the velocity of the wave.

8. In a gas, of the mean density and temperature calculated on these assumptions, a sound wave would travel at a velocity which nearly agrees with the observed rate of explosion in those cases where the products of combustion are perfect gases.

9. With mixtures in which steam is formed, the rate of explosion falls below the calculated rate of the sound wave. But when such mixtures are largely diluted with an inert gas, the calculated and found velocities coincide. It seems reasonable to suppose that at the higher temperatures the lowering of the rate of explosion is brought about by the dissociation of the steam, or by an increase in its specific heat, or by both these causes.

10. The propagation of the explosion wave in gases must be accompanied by a very high pressure lasting for a very short time. The experiments of MM. Mallard and Le Chatelier, as well as the author's, show the presence of these fugitive pressures. It is possible that data for calculating the pressures produced may be derived from a knowledge of the densities of the unburnt gases and of their rates of explosion.

NOTES.

THE forty-sixth annual general meeting of the Institution of Mechanical Engineers will be held on Thursday evening and Friday evening, February 2 and 3, at 25, Great George Street, Westminster. The chair will be taken by the president, Dr. William Anderson, F. R.S., at half-past seven on each evening. The annual report of the council will be presented to the meeting on Thursday, and the annual election of the president, vice-presidents, and members of council, and the ordinary election of new members will take place on the same evening. The following papers will be read and discussed, as far as time permits :-Description of the Experimental Apparatus and Shaping Machine for Ship Models at the Admiralty Experiment Works, Haslar, by Mr. R. Edmund Froude, of Haslar (Thursday); description of the Pumping Engines and Water-Softening

Machinery at the Southampton Water Works, by Mr. W Matthews, Water works Engineer (Friday).

PROF. CAYLEY, we are glad to learn, is now convalescen

WE greatly regret to have to announce the death of Mr. F. Blanford, F.R.S. He died on Monday at the age of eight.

PROF. MICHAEL FOSTER, Sec. R. S., has been appan Rede Lecturer at Cambridge for the present term. His in lecture will be delivered early in June.

THE Bill for the introduction of a standard time solar time of the fifteenth meridian) was read a second time: the German Imperial Parliament on Monday. The meas was accepted without much discussion.

AN excellent report on technical education in Londra been submitted to the London County Council by a spe committee appointed to investigate the subject. The report prepared by Mr. Llewellyn Smith, the committee's sear and displays a thorough grasp of the essential conditions of a problem. It is proposed that a Technical Instruction Board be appointed, and that it shall consist of some members cf2 Council, and of representatives of the School Board, the Cr and Guilds of London Institute, the City Parochial Chart the Head Masters' Association, the National Union of Es mentary Teachers, and the London Trades Council. The

mittee think that one-third of the amount derived from the and spirits duties should be handed over to this body for provision of adequate technical instruction in all parts London.

THE French Minister of the Interior has established at seilles, in connection with the university, an institer botanical and geological research, and a museum. The de is Prof. Heckel, who, as well as a curator and a librarian, §o his services gratuitously.

IN the year 1793 was published Christian Konrad Spre "Das entdeckte Geheimniss der Natur,im Bau und in der Ber tung der Blumen," the work which first directed the atten naturalists to the contrivances which, in many flowers, self-pollination difficult, and promote the visits of insects to cross-pollination. The copper-plate illustrations of this still maintain their character as among the best that have ** published in this branch of science. Sprengel was in respects a forerunner of Darwin, and centenaries have celebrated on slighter grounds than the publication of this wo

THE chief characteristics of the weather during the past have been its general mildness and dampness; the day peratures have at times exceeded 50° in most parts al P kingdom, but at night slight frosts occurred towards the e last week in Scotland and the south-eastern parts of Epis The distribution of pressure has been complex, a series 3 pressions have passed over the coast of Norway from the ward, while an anticyclone lay over the south-western par our islands, the reading of the barometer in the south being about an inch higher than in the north of Scotland. passage of the low-pressure systems in the north was a panied by strong north-westerly winds and gales in Scrwith hail or sleet in many places. Owing to the dist ance of the anticyclone from the continent, north-wa winds became prevalent over western Europe, and = " rise of temperature occurred there, amounting to P Germany between the 20th and 21st instant. Deri last few days fresh depressions have approached our western coasts, with increasing winds from the south-west

ntinuance of mild, unsettled weather appeared probable. Weekly Weather Report shows that for the week ending Ist instant there was a large deficiency of rainfall in the of Scotland, south-west of England, and south of Ireland. percentage of possible duration of sunshine ranged from the south-west of England to 7 in the south of England 03 in the north of Scotland.

E Repertorium für Meteorologie, vol. xv. recently issued by mperial Academy of Sciences of St. Petersburg, contains cussion by P.A. Müller, of the Ekaterinburg Observatory, foot of the Ural Mountains, in the Government of Perm, e question of the evaporation from a snow surface. Several Rs, among whom are Drs. Brückner and Woeikof, differ Painion as to whether the evaporation from a snow surface ids the condensation of the aqueous vapour of the air imtely above it. The method generally adopted for the on of the question is to find whether the temperature of low surface is above or below the dew-point of the suring air; in one case there would be evaporation, and in ther condensation. The paper occupies forty-seven small pages, and the observations were made hourly from -mber 21, 1890, to February 28, 1891. The result of the igation shows that according to the temperatures of the oint and of the surface of the snow, the evaporation of the greatly exceeds the condensation of the aqueous vapour, e condensation occurred at only 27 per cent, while the ration occurred at 73 per cent. of the hourly observations.

F. FLINDERS PETRIE, to whose introductory lecture at rsity College, Gower Street, we referred last week, red on Saturday the first of his regular course of lectures Edwards Foundation. He said the Egypt of the early ments was a mere strip of a few miles wide of green, boundless deserts, and beneath a sky of the greatest ncy; a land of extreme contrasts of light and shadow, of d death. These conditions were reflected in the art. e one hand was the most massive and overwhelming conon, and, on the other, the most delicate and detailed On the one hand, the most sublime and stolid statuary; e other, the course and accidents of daily life freely 1. On the one hand, masses of smooth buildings that tdo the native hills on which they stand, gaunt and bare, ›n the other, the vivid and rich colouring in the interiors. asequence of the climate also Egypt is a land of great city of life, and simplicity is especially the characteristic : oldest Egyptian buildings. Speaking of the early ian statues, Prof. Petrie said that the race represented by appears as "one of the noblest that ever existed."

Leeds, on Monday, Lord Playfair presided at a public , held in support of the Yorkshire College.

In pro

the principal toast-"The Yorkshire College "-he of the efforts made half a century ago to secure for science ice which rightly belongs to it in the educational system. s glad, he said, that these efforts had met with a temporary ace, because if the Universities had at once yielded there have been no colleges now in our great provincial towns. lleges, he thought, were adapting themselves rapidly and pon the whole, to the genius of their several localities. Yorkshire College he said that she had fitted herself for eral culture and life-work of a great industrial centre. oubt her technical courses are peculiar. Actual laboratories aning, for dyeing, for tanning, for engineering, are novel Es to a college. What does it mean? That you are trystrengthen and embellish industrial pursuits, as the ities acted upon the professions when they were obliged de them. Surely a great town like Leeds is right when

it imbues its producers with intellectual knowledge, as well as with technical expertness. Such men in future carve out industrial professions for themselves, and illumine them by appropriate culture."

THE interesting address lately delivered by Sir Henry Roscoe on the occasion of the prize distribution at the Birmingham Municipal Technical School has now been issued separately. He describes the report of the first year's work as "more than encouraging." Speaking of the building which is to be erected for technical training at Birmingham, he says:-" You in Birmingham have, in my judgment, taken the right course. You are not going to squander your money by using it for a thousand different purposes. You are, I hope, going to do a good thing, and a big thing, in building and equipping a really great institution, worthy of your city and of your well-earned renown as being foremost amongst our towns in educational matters. You will have a place of higher technical instruction to which all the Midlands will look up. It will be the gathering ground for all the youthful talent of the busy millions of the district. It will be here that the future Faradays, and Priestleys, and Watts will get that sound though elementary scientific training which will enable them to pursue that training to its highest point at the Mason College here, or in other colleges elsewhere, which may in the end make both them and their country great."

THE new technical schools connected with University College, Nottingham, which were formally opened the other day, promise to be of immense service, not only to Nottingham itself, but to the wide district of which it is the educational centre. A remarkably clear description of the buildings, with plans, is given in a pamphlet prepared for the ceremonial opening. The pamphlet also includes an interesting summary of the facts relating to the history of the Nottingham College and its technical department.

Mr. C. F. JURITZ, Senior Analyst in the Department of Lands, Mines, and Agriculture, Cape Colony, announces in the Agricultural Journal, issued by the Department, that a comprehensive series of investigations with reference to the chemical composition of the various soils of the colony is about to be undertaken. The samples of soil are to be collected by one of the officers of the analytical branch of the Department. In the first instance the southern part of the Malmesbury district will be visited, and soils will be taken from several localities representative (a) of primary and (b) of alluvial soils belonging to the Malmesbury beds of clay slate. Mr. Juritz proposes next to collect soils from the more northerly portion of the same district, in the vicinity of Hopefield, for instance, after which the Caledon district will be taken in hand. These analyses when

completed will afford, he points out, an insight into the general composition of the clay slate soils, lying around the southwestern coast of the Colony between Donkin's and Mossel Bays. The Government of Cape Colony look upon the proposals that have been made as "a move in the right direction," and have promised their warmest support.

MR. KEDARNATH BASU, describing in Science some relics of primitive fashions in India, says he does not see the same profusion as he saw ten or twelve years ago, of tattoo-marks and red-ochre or red oxide of lead (sindur) over the forehead and crown among the women of Bengal. The rapid progress of female education and the consequent refinement in æsthetic taste are, he says, the causes of the decline of this rude and savage adornThe people of Behar, the North-western provinces, and other districts, however, still cling to these remnants of savagery. The up-country women, besides tatooing their bodies and painting the head with red paint, bore the lower lobes of their ears,

ment.

and insert big and heavy wooden cylindrical plugs, which almost sever the lobes from the ears. The plugs are sometimes as big as two inches in length with a diameter of an inch and a half, and as much as two ounces in weight. These heavy plugs pull down the lobes of the ears as far as the shoulders, and give the wearers a hideous look.

MR. F. J. BLISS contributes to the new "Quarterly Statement" of the Palestine Exploration Fund a most interesting report on the excavations at Tell-el-Hesy during the spring season of 1892. Speaking of the now famous tablet discovered in the course of these excavations, he says:-"On Monday, May 14, ten days before we closed the work, I was in my tent at noon with Ibrahim Effendi, when my foreman Yusif came in with a small coffee-coloured stone in his hand. It seemed to be curiously notched on both sides and three edges, but was so filled in with earth that it was not till I carefully brushed it clean that the precious cuneiform letters were apparent. Then I thought of a day, more than a year before, when I sat in Petrie's tent at the pyramid of Meydûm, with Prof. Sayce. He told me that I was to find cuneiform tablets in the Tell-el-Hesy, which as yet I had never seen; and gazing across the green valley of the slow, brown Nile, and across the yellow desert beyond, he seemed to pierce to the core, with the eye of faith, the far away Amorite mound. As for me, I saw no tablets, but I seemed to be seeing one who saw them!" Mr. Bliss also notes that the discovery was a triumphant vindication of Mr. Flinders Petrie's chronology-established, not by even a single dated object, but by pottery, mostly plain and unpainted. It is announced in the "Quarterly Statement" that the excavations at Tell-el-Hesy are now being vigorously carried on by Mr. Bliss, who has recovered

from his serious illness.

It seems that in Yucatan and Central America, as in Egypt and other countries, ancient monuments are held in small respect by certain classes of travellers. According to Mr. M. H. Saville, assistant in the Peabody Museum, who writes on the subject in Science, enormous damage is being done to many of the most interesting antiquities in these regions. The magnificent "House of the Governor" in Uxmal, described as probably the grandest building now standing in Yucatan, is almost covered with names on the front and on the cemented walls inside. These names are painted in black, blue, and red, and among them are the names of men widely known in the scien tific world. The "House of the Dwarfs" in the same city has suffered in like manner, and many of the sculptures which have fallen from the buildings in Uxmal have been wilfully broken. In Copan, when the Peabody Museum Honduras Expedition compared the condition of the "Idols" to-day with the photo graphs taken by Mr. A. P. Maudslay seven years ago, it was found that during that time some of the very finest sculptures had been disfigured by blows from machetes and other instruments. The Stela given as a frontispiece in Stephens' "Incidents of Travel in Central America," vol. i., has been much marred by some one who has broken off several ornaments and

a beautiful medallion face from the northern side. One of the faces and several noses have been broken off from the sitting figures on the altar figured by Stephens in the same volume, opposite page 142; and on some of the idols and altars names have been carved. While excavating in one of the chambers of the Main Structure, members of the Expedition uncovered a beautiful hieroglyphic step, but before they had time to secure a photograph of it, some visitor improved the opportunity while no one was about to break off one of the letters. In Quirigua a small statue, discovered by Mr. Maudslay and removed by him to a small house near the rancho of Quirigua, had the head and one of the arms broken from it during the interval between two visits. This statue was of the

highest importance, as it very much resembled the cele "Chaac-mol" now in the Mexican Museum, but discover Le Plongeon at Chichen Itza. Much mischief is also cal natives, who think nothing of tearing down ancient straces order to provide themselves with building material. authorities of the Peabody Museum, to whom the care

antiquities of Honduras has been granted for a period with the evil. They have caused a wall to be built room years, deserve much credit for the efforts they make principal remains in Copan, and a keeper has been p charge with strict orders to allow nothing to be destres carried away.

WHAT is the true Shamrock? Most Irishmen are p of opinion that they can answer the question correctly. == fortunately they do not all give the same reply. Mr. X Colgan, who has been investigating the subject, c thirteen specimens from the following eleven countiesAntrim, Armagh, Mayo, Clare, Cork, Wexford, W Carlow, Queen's County, and Roscommon. Shamrocks thus secured from northern, southern, eastern, westem central Ireland, Mr. Colgan's correspondents in the counties taking pains to have each sample selected by r of experience who professed to know the genuine plant the specimens were planted and carefully labelled wi places of origin, and flowering within some two month gave the following results: eight of the specimens turne to be Trifolium minus of Smith, and the remaining Trifolium repens of Linnæus. Cork, Derry, Wicklow, County, Clare, and Wexford declared for Trifolius c Mayo, Antrim, and Roscommon for Trifolium repen. Armagh and Carlow, each of which had sent two spec were divided on the question, one district in each county T. repens, while the other gave T. minus. These rese set forth by Mr. Colgan in an interesting paper in the? volume of the Irish Naturalist, to which we referred last va Elsewhere in the same volume Mr. R. L. Praeger s that authentic specimens of shamrock should be obtaine every county in Ireland, and he adds that he has no do F. W. Moore would gladly grow them at Glasnevin Garim Mr. Colgan did not care to undertake so large an orde. ' Praeger notes that in his own district, North Down, I minus is always regarded as the true shamrock, but luxuriant specimen, or one in flower, is generally disca an impostor.

THE waters of the Great Salt Lake, Utah, are known 3* in salinity at different times. Dr. Waller, of Columbia C gives the results of his recent determination of the salts in the School of Mines Quarterly. A compariso results with those obtained by Gale, Allen, Bassett, and shows a constant change of salinity, and a closer exama reveals a variation from place to place. This is de differences in the amount of evaporation, and to the i water, fresh or saline, in many cases from sabte springs which give no indication of their presence. Fu of the constituents the water is nearly at saturation p differences of temperature are also apt to cause slight of composition. The presence of lithium and strengthens Captain Bonneville's conclusions with the basin of the ancient lake called after his name, and 20 presented by the Great Salt Lake and its lesser De The benches of sand and gravel seen high up on the the Wahsatch mountains and the Oquirrh range induar eastern and western shores of the old lake, whose waters have covered an area equal to that of Lake Hures, times that of the Great Salt Lake. Successive lowe level finally cut off its outlet to the north, by which flow into the Pacific Ocean.

BEAUTIFUL optical phenomenon, which has not yet been ctorily explained, is described by M. F. Folie in the in of the Belgian Academy. It was observed about a From Zermatt on August 13 at 8.30 a. m. "On our right, ds the east, on the steep flanks of the mountains which le the valley of the Viège, rose a group of fir trees, the mit of which projected themselves against the azure of the at a height of 500 m. above the road. Whilst I was sing my son exclaimed: 'Come and look: the firs are overed with hoar-frost !' We paid the most scrupulous son to the phenomenon. To make sure that we were not by an illusion we made various observations, both with ked eye and with an excellent opera-glass." It was ed that not only the distant trees, but those lining the glittered in a silvery light, which seemed to belong to the hemselves, and that the insects and birds playing round inches were bathed in the same light, forming an aureole the tops of the trees, somewhat resembling the light effects ed in the Blue Grotto. It is suggested that the light was ed from the snow. Since it disappeared as soon as the se above the hill, and has never been seen except in the ce of snow, this explanation appears plausible, but it is desirable that further and more detailed observations be made of this spectacle féerique.

: Tasmanian Official Record is henceforth to be issued ually instead of annually, and a handbook has been to take its place during the intervening years. This hand(which is described on the title-page as "for the year contains a brief epitome of the historical portion of the . Record, and summarises in a convenient form the more ant statistical information contained in the detailed tables last volume of the general statistics of the colony.

SRS. ASHER AND Co. will publish shortly an English tion of the " Recollections of the Life of the late Werner emens," the well-known electrician, and brother of Sir n Siemens. Two editions of the German original, pubin December last, were issued in the course of a few

course of four winter lectures in connection with the n Geological Field Class will this year be delivered by H. G. Seeley, F.R.S., on Tuesday evenings, at the rial Hall, Farringdon Street, the subject being "The Reptiles of the Thames Basin." All particulars may be the Hon. Sec. Mr. J. H. Hodd, 30 and 31, Hatton Gar..C.

bacterial purification which takes place in a river during

has been recently attributed in part to the process of ntation which the micro-organisms in the water undergo, would seem that yet another factor must be taken into . Buchner, in some investigations which he has recently ed ("Ueber den Einfluss des Licht es auf Bakterien," 'blatt für Bakteriologie, vol. II, 1892, also vol. 12, shows that this diminution of the numbers present may be isted by the deleterious action which light exercises upon micro-organisms. A systematic series of experiments ..le by introducing typhoid bacilli, B. coli communis, paneus, Koch's cholera spirilla, also various putrefactive 1, into vessels containing sterilized and non-sterilized y drinking water. As a control, in each experiment one thus infected was exposed to light, whilst a second was der precisely similar conditions, with the exception of its covered up with black paper, by means of which every of light was excluded. The uniform result obtained in e experiments was that light exercised a most powerful cidal action upon the bacteria in the water under observaor example, in one water in which at the commencement periment 100,000 germs of B. coli communis were present

in a c.c., after one hour's exposure to direct sunlight none were discoverable, whilst in the darkened control flask during the same period a slight increase in the numbers present had taken place. Even the addition of culture fluid to the flasks exposed to sunlight could not impair in the least the bactericidal properties of the sun's rays. In the flasks exposed to diffused daylight the action was less violent but still a marked diminution was ob served. In his later experiments Buchner has employed agaragar, mixing a large quantity of particular organisms, pathogenic and others, with this material in shallow covered dishes and then exposing them to the action of light and noting its effect upon the development of the colonies. For this purpose strips of black paper cut in any shape (in the particular dish photographed by Buchner letters were used) were attached outside to the bottom of the dish, which was then turned upwards and exposed to direct sunlight for one to one and a half hours and to diffused daylight for five hours. After this the dish was incubated in a dark cupboard. At the end of twenty-four hours the form of the letters fastened to the bottom of the dish was

sharply defined, the development of the colonies having taken place in no part of the dish, except in those portions covered by the black letters. Some interesting experiments on the same subject have also recently been made by Kotljar (Centralblatt für Bakteriologie, December 20, 1892). In the course of these investigations the author found that of the coloured rays of the spectrum the red favoured the growth of those bacteria experimented with, whilst the violet rays acted prejudicially, although less so thin the white rays. The exceedingly interesting obser. vation was made that the violet rays actually favoured the sporu. lation of the Bac. pseudo anthracis.

THE additions to the Zoological Society's Gardens during the past week include a Macaque Monkey (Macacus cynomolgus 8) from India, presented by Mr. A. Sandbach; a Triton Cockatoo (Cacatua triton) from New Guinea, presented by Mr. Arthur Harter; a Gannet (Sula bassana) British, presented by Mr. F. W. Ward; two Tuatera Lizards (Sphenodon punctatus) from New Zealand, presented by Mr. W. H. Purvis; two Wanderoo Monkeys (Macacus silenus) from the Malabar Coast; a Strawnecked Ibis (Carphibis spinicollis) from Australia; four Snow Buntings (Plectrophanes nivalis); six Wild Ducks (Anas boschas, 383) British, purchased; a Meadow Bunting (Emberiza cia) European, received in exchange; two Shaw's Gerbilles (Gerbillus shawi) born in the Gardens.

OUR ASTRONOMICAL COLUMN. COMET HOLMES.-Edinburgh Circular, No. 37, announces that Palisa, telegraphing from Vienna, states that Comet Holmes now resembles an 8 m. star with a nebulous envelope 20" of arc in diameter.

A further observation made by Prof. Schur in Göttingen on January 19 showed that the nucleus was of the 10th magnitude, and could not be considered at all brighter than that magnitude. For the latter observation the air, as regards clearness, was all that could have been desired.

At South Kensington, on January 18, the comet was observed as a hazy star and estimated to be about the 8th magnitude. The following ephemeris is that given by Schulhof:R.A app. Decl. app. h. m. S.

Date.

Jan. 26... I 35 330

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42 48'1

44 17 0 2... I 45 46'5

[blocks in formation]

On January 30 the comet will lie very nearly between 8 Andromeda and 8 Trianguli, about one-third of the distance from the latter star.

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