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millions sterling. From 1885 to 1902, during the period promoters of this exhibition are interested only in pictorial. the writer occupied the position of Director of Naval Con- work, the technician expects to find among the works: struction and Assistant Controller of the Navy, the total outlay on the 245 ships for the designs of which he was

they have selected for presentation expressions of the most responsible amounted to about 100 millions sterling. The

recent ideas as to approved methods, and the finest exstress of foreign competition and the growth in dimensions

amples that these methods can furnish. Last year's Photoand cost of warships is leading to still greater expenditure graphic Salon included a large number of colour photoon the Navy, and it is good to know that Canada, graphs on autochrome plates, but this year there is not Australia, New Zealand, and South Africa are ready and

a single colour photograph of any kind. This must mean willing to bear their share of the inevitable burden. All branches of engineering have been and will be drawn

that, in spite of the improvements in the manufacture and. upon freely in the execution of this great task. Mining

in the methods of using plates for colour photography, the and metallurgy assist by the production of materials of results obtained are not generally satisfactory from the construction; mechanical and electrical engineers contribute artistic point of view. The shortcomings of these plates. machines and appliances required in shipyards and engine are well known and appreciated by those who have studied factories, as well as guns, gun-mountings, and mechanical

them, but they do offer possibilities of a certain measure apparatus of all kinds required in modern warships in order to supplement and economise manual power ; marine

of success in the rendering of colour, and we were not engineers design and construct the propelling apparatus,

prepared for their total exclusion. The one hundred and and constantly endeavour to reduce the proportion of weight thirteen pictures hung, selected, presumably, from many and space to power developed ; naval architects design and hundreds submitted, include examples of many styles and' build the ships; constructional engineers are occupied in

all degrees of merit. They range from a fuzziness that the provision of docks, harbours, and bases adapted to the requirements of the fleet; and other branches of engineer

leaves the subject hardly recognisable to the keenest. ing play important, if less prominent, parts. The progress

sharpness of definition, from the darkest to the lightest of invention and discovery is increasing, rapid changes

possible, and from those that have large flat patches of occur unceasingly, the outlay is enormous, the task is

tint to those that show the most delicate. never ending, but its performance is essential to the con- and perfect modelling that can be desired. It is the tinued well-being of the Empire, and it must and will be possibilities of these great varieties of style that are performed.

of technical interest. The catalogue is defective in

not giving the niethods by which the various examples NOTES.

are produced, but we believe that we are correct in saying THE International Geodetic Association will meet in

that the portraits by Mr. E. O. Hoppe are all unsophistiLondon on September 21 and following days at the rooms

cated platinum prints. These, and some of Mr. Frederick of the Institution of Civil Engineers, Great George Street,

H. Evans's exhibits, and the portrait by Mr. Furley Lewis, Westminster. The permanent commission of the associa- will be specially instructive to those who print in platinum tion, consisting of one representative from each contributing

as showing the rich results obtainable by this method. country, is constituted follows :-Belgium, Lieut.

In addition to the new work, there are nearly thirty Colonel Gillis; Chile, M. Bertrand; Denmark, Major- examples of photographs by the late David Octavius Hill, General Madsen; France, General Bassot (president); made more than sixty years ago. These demonstrate that Germany, Prof. Foerster; Great Britain, Sir George the vast strides photography has made during the last Darwin (vice-president); Holland, Prof. H. G. van de half-century have tended rather to increase the output and' Sande Bakhuyzen (perpetual secretary); Hungary, Prof. multiply diversity of method than to raise the quality of L. de Bodola

Zagon; Italy, Prof. Celoria; the work from a pictorial point of view. Japan, Dr. Hisashi Terao; Mexico, Sen. Angel Anguiano ; Norway, Major-General Per Nissen ; Portugal, General the place at his residence in Norwich on September 5, science

By the death of Mr. Thomas Southwell, which took Marquis d'Avila et de Bolama; Russia, General Artomonoff ; Spain, Sen. Arrillaga; Sweden, Prof. Rosen ;

has lost an amateur naturalist of the very best type, and. Switzerland, Prof. Gautier ; United States, Mr. Tittmann.

one who, by the extremely careful and painstaking nature

of his work, set an example even to his professional The Argentine Republic will be represented by Prof. Porro de Somenzi, Roumania by Colonel Rimniceano, India by undertaken for the purpose of filling up the time of an

brethren. Moreover, his natural-history studies were not Colonel Burrard, Egypt by Mr. Keeling, Australia by Mr. G. H. Knibbs. Among the seventy or eighty delegates,

idle man, for during the best years of his life Mr. South-other than members of the permanent commission, are

well was in the employ of Gurney's (Barclay's) bank at Prof. Helmert, chief of the Central Bureau, Potsdam,

Norwich, and could study his favourite subject only in the Prof. Albrecht and Prof. von Seeliger (Germany); Vice

intervals of his professional work. In addition to possessAdmiral Ritter

ing a great knowledge of the ornithology of his county, Kalmar and Major-General

Mr. Southwell devoted special attention to whales and Sterneck (Austria), Lieut-Colonel Bourgeois and M. H. Poincaré (France), Baron Roland Eötvös (Hungary), Prof.

whaling, and for a long series of years his annual report

in the Zoologist on the product of the season's whaling. Kapteyn (Holland), and Dr. Backlund (Russia). Among the representatives of Great Britain are the Astronomer

and sealing expedition afforded a mine of valuable informa

tion which could be obtained nowhere else. The great Royal, Colonel Close, Major Leonard Darwin, Rear

value of these reports consists in the fact that the informaAdmiral Field, Sir Archibald Geikie, Sir David Gill, Dr. Glazebrook, Colonel Grant, Major Hills, Captain Lyons,

tion relating to the British portion of these industries was.

always at first hand, Mr. Southwell having got in touch and Colonel Sir William Morris. By command of the

with the whaling captains of Peterhead and Dundee. In King, the delegates are invited to visit Windsor Castle on

addition to giving statistics concerning the annual catch. Saturday, September 25. On Monday, September 27, the

of whales and seals, Mr. Southwell studied and collated meeting will be transferred to Cambridge, where the con

all the information he could acquire concerning the discluding sessions will be held.

tribution and migrations of the Greenland right-whale, and The seventeenth annual exhibition of the Photographic was thus enabled to formulate certain important theories. Salon is now open at the Gallery of the Royal Society on these points. In 1881 he published a small volume on of Painters in Water Colours, 54 Pall Mall East. As the the “ Seals and Whales of the British Seas "; and his.

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other writings include the third volume of Stevenson's fever, and Dr. Canovetti, to enable him to continue bis

Birds of Norfolk," a revised second edition (1890) of experiments on air resistance. From the same benefacLubbock's Fauna of Norfolk," Sir Thomas Browne's tion grants have also been made to Profs. Vinassy de “Notes and Letters on the Natural History of Norfolk," Regny and Gortani, for Alpine studies; Prof. Gorini, for a “ Guide to Norwich Castle Museum," and a paper on investigating discases of cheese ; Prof. Silvestri, noxious the former breeding of the in East Anglia. At the insects; Prof. Almagia, study of precipices; the Lombardy time of his death Mr. Southwell was in his seventy-ninth commission for seiches on Laghi di Garda and Maggiore; year.

Dr. Abetti, solar physics, in Prof. Hale's observatory, M. SANTOS-DUMONT has accomplished several successful

The Carpi prize for experimental physiology is divided

between Drs. Baglioni and Lombroso. The late Prof. fights with an aëroplane having a supporting surface of only nine square metres.

Sella has bequeathed to the academy a prize of 1000 lire, On September 13 he travelled

to be awarded annually to some assistant in an Italian a cross-country distance of about five miles in five minutes

physical laboratory, this being the second gift that the upon this machine.

academy has received during the year. Science announces that the President of the United States

The seventh annual meeting of the South African has issued a proclamation setting aside the Oregon caves

Association for the Advancement of Science will be held in the Siskiyou National Forest, in the State of Oregon, as a national monument.

in Bloemfontein on September 27 to October 2 inclusive, The area of the reservation is

under the presidency of Sir Hamilton Goold-Adams, about 480 acres.

G.C.M.G. The business of the meeting will be held in The Paris correspondent of the Times announces that three sections as follows :—Section I., astronomy, mathethe fourth International Aëronautical Congress will be held matics, physics, meteorology, geodesy, surveying, engineet: at Nancy on September 18-23. Major Renard (France) ing, architecture, and geography: president, Prof. W. A. will read a paper on the units of aëronautics and their Douglas Rudge, Bloemfontein ; Section II., chemistry, nomenclature, and will submit a report on the results and bacteriology, geology, botany, mineralogy, zoology, agrilessons of the recent aviation week at Rheims.

culture, forestry, sanitary science: president, Dr. C. F.

Juritz, Cape Town; Section III., anthropology, ethnology, MR, F. C. CONSTABLE, Wick Court, near Bristol, sends

education, history, mental science, philology, political notes of observations of a remarkable pink glow observed in the direction of the sun between 6.40 p.m. and 6.58 p.m.

economy, sociology, and statistics : president, Mr. Hugh on September 12.

Gunn, Bloemfontein. The second award of the South The pink colour seemed to be the same as that observed by him on

Africa medal and grant will be made to Dr. Harry Bolus a steamer journeying from Bombay to Karachi in 1883, a few days after the Krakatoa

at this meeting. The South African Ornithologists' l'nion

will meet in Bloemfontein at the same time and in the eruption.

same buildings as the association. A series of lectures, PROF. SILVANUS P. THOMPSON, F.R.S., has consented umder the auspices of the association, on Darwinism and to become the first president of the Illuminating Engineer- human life, by Prof. J. Arthur Thomson, is being ing Society, and influential support has been received from delivered in South Africa by way of celebrating the Darwin many distinguished authorities on matters of illumination centenary. The honorary general secretaries of the meeting in this country, on the Continent, and in America. The are Dr. J. D. F. Gilchrist, South African College, Ca society will enter upon its opening session in November, | Town, and Mr. R. T. A. Innes, Government Observatory, and has every reason to hope for a long and prosperous Johannesburg. existence. Anyone interested in the objects of the society

A LARGE portion of the August number of the Museums and desiring to become a member should apply to Mr. L.

Journal is taken up by the report of the meeting of the Gaster, hon. secretary, 32 Victoria Street, London, S.W. Museuns Association held at Maidstone in July. The proAt the autumn meeting of the Institute of Metals, which

gramme of the meeting included a visit to Ightham to will be held at Manchester on October 14 and 15, it is

inspect the collection of Alint implements brought together expected that the following papers will be presented :

by Mr. B. Harrison. the constitution and properties of the ternary alloys In the September number of Witherby's British Birds aluminium-copper-tin, J. H. Andrew and C. A. Edwards ; Mr. P. H. Barr appears to have disposed effectually of the the surface appearance of solders, C. 0. Bannister and remarkable idea that the black-headed gull acquires the H. J. Tabor; the technical assay of zinc, H. W. Green- feature to which it owes its name by means of a mysterious wood; notes on the production of pure spelter, J. S. Glen colour-change in the feathers of the head. He has proved Primrose; some causes of the corrosion of copper and that a moult takes place early in the year, usually in brass, E. L. Rhead; the elastic breakdown of ductile February, which embraces, not only the head, but the materials, Prof. C. A. Smith; the copper-zinc alloys-a breast and back, and that at the conclusion of the process, study of volume changes during solidification, Prof. T. which takes about a week, the black skull-cap is acquired. Turner and M. T. Murray.

Occasionally young birds assume the black cap of the The Reale Accademia dei Lincei makes the following breeding plumage while they are still in the immature dress

elsewhere. announcements :—The royal prize for mathematics is divided equally between Profs. Enriques and Levi-Civita, According to Bulletin No. 33 of the Biological Survey and that for social and economic sciences is similarly of the U.S. Department of Agriculture, which is devoted divided between Prof. Rodolfo Benini and Dr. G. to the brown rat in the States, serious efforts are being Mazzarella. From the Santoro foundation the academy made in North America and Japan to reduce the numbers has awarded a prize of 10,000 lire to Prof. Quirino of this rodent, which is regarded as the worst mammalian Majorana, for his researches on wireless telephony, which pest in the world. So far, however, the campaign has not have resulted in communication being established up to been crowned with success, the annual destruction of from distances of 300-400 kilometres more; in addition, several hundred thousand to a million head in Japan minor awards to Prof, Gabbi, for researches on Malta making no appreciable diminution in its numbers. In the

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paper before us Mr. D. E. Lantz has given a very full skull to his own satisfaction, Dr. Ameghino concludes account of the morphology, distribution, migration, and that it affords further evidence of his view as to the South ethology of the rat, with suggestions as to the best means American origin of the human race. Additional testimony of hunting and trapping, and the elimination of conditions in favour of this opinion is stated to be afforded by the conducive to its rapid increase.

Icwer jaw of a child with the angle inflected in marsupial The Belfast Naturalists' Field Club, the oldest club of

fashion. The extinct South American genus Microbiothe kind in Ireland, has always possessed a strong geo

therium is regarded as the fons et origo of most mammals, logical section. An interesting excursion was recently

and from this sprang Clenialites, the ancestor of the undertaken to the eskers at Drumfane and near Brough

Primates. shane. The accompanying illustration shows the fine The West Australian newspaper of July 7 contains the sections that occur in these glacial ridges in co. Antrim. report of an address, by Dr. J. B. Cleland, read before We learn from a report in the Northern Whig for the West Australian Natural History Society at its annual August 24 that determinations were made of the source meeting held at Perth. The subject was the Australian of the material, which proved to be mainly derived from fauna and fora, and especially the effects produced on local rocks. The Cainozoic rhyolites of Clough water and these by foreign invaders. After alluding to the rabbit. Ballycloughan 'were visited later in the day. Rhyolitic pest, the author stated that the inexcusable introduction of lavas are not so limited in the British Isles as the report the fox for sporting purposes has led to its rapid multiplibefore us would suggest, since the enormous outpourings cation in parts of Victoria, South Australia, &c., and the in the Snowdon area and in Borrowdale must be borne in loss of many sheep. Cats have become wild, and near mind; but those of Antrim have a thoroughly modern Perth, for instance, fierce and powerful in build, feeding

the native birds and smaller animals and rabbits where these are present. The Norway rat and the black rat seem not to have extended beyond man's more immediate sur. roundings. The dominant rat in Perth is the sociable black rat, the larger Norway rat being hitherto obtained only from the neighbourhood of the wharves at Fremantle and Perth. It is otherwise in Sydney, where both are found together in the town. These rats have brought with them several species of fleas, of which some will bite man when their original host is absent (e.g. has died). By this means plague, introduced by rats, is communicated

The sparrow, the starling, the goldfinch, the blackbird, and the Indian minah have all come to stay. Some of these eat much grain and fruit, while all tend to drive away and usurp the place of the beautiful, interesting, and useful native birds.

Dr. E. JANCZEWSKI contributes to the Gravel Pit, Drumfane, near Ballymena, County Antrim. Photographed by Mr. J. L. S. Jackson. Bulletin international de l'Académie

des Sciences de Cracovie (No. 6) aspect, and may be compared with types in Hungary or a short supplement to his monograph on the genus Ribes. in Mexico. Naturalists in the north of Ireland are

In the same part Mr. C. Rouppert presents a revision of fortunate in having established a tradition for good observa- the discomycetous fungus Sphærosoma. This genus, of tional work, in which amateurs have played a which a new species was discovered by the author, has important part.

been variously classed under the Pezizaceæ, Helvellaceæ, A Nice little question in nomenclature is raised by Dr.

and Tuberaceæ. It is here referred to the Helvellaceæ, Ameghino in a paper published in the An. Mus. Nat. de but is regarded as a connecting link with the other two Buenos Aires, vol. xix., pp. 107–209, under the title of families. "Le Diprothomo platensis, un précurseli. de l'homme du The latest issue of the Kew Bulletin (No. 7) opens with Pliocène inférieur de Buenos Aires." It appears that in a review of the known species of Impatiens from the 1884 the author proposed the generic term Diprothomo for Philippine Islands, communicated by Sir J. D. Hooker, one of the hypothetical ancestors of Homo sapiens. which forms a continuation of the extensive survey of the Recently Dr. Ameghino obtained from a superficial stratum genus, based on collections from India, China, and the in Buenos Aires, regarded as of Lower Pliocene age, a Malayan region. Out of twenty-five species, collected calvarium of apparently low type, which in his opinion chiefly in the neighbourhood of Luzon, only two agree is generically distinct from Homo. For this supposed new with previously determined species. The author is of genus he proposes to adopt the name Diprothomo with the opinion that further exploration will lead to the discovery new affix platensis. As having no tangible type, Diprot- of many more species. In the saine number there is pubhomo" will probably be regarded as a nomen nudum, and lished a decade of Diagnoses Africanæ (No. xxx.), which if this be so many naturalists will be likely to say that it includes the type of a new liliaceous genus, Neodregea, cannot be employed in a new sense. After restoring the allied to Dipidax.

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It will add to the general estimation of the common Islands, and to have travelled in a W.N.W. direction; on cruciferous plant, the shepherd's purse, when it is realised reaching the archipelago they were considerably modified that the species can be segregated into several elementary | in shape and extent, and crossed the China Sea in a species or biotypes. The latest investigation, undertaken somewhat more northerly direction. The rates of translaby Mr. G. H. Shull at the Station for Experimental Evolu- tion, during which the wind at times reached hurricane tion of the Carnegie Institution of Washington, and de- force, varied considerably, in one instance attaining the scribed in Publication No. 112 of the institution, bears unusual speed of twenty-one miles an hour, but on reachevidence with regard to the existence of at least four ing the China Sea the velocity of translation considerably biotypes which breed true under ordinary conditions and diminished in all cases. The barometric fall was can readily be crossed; they are distinguished by charac- rapid, the minimum at one station being 27.99 inches, teristic lobings of the leaf. The author has also investi- although it was some fifteen miles from the vortex. Foregated the type known as Bursa (Capsella) Heegeri, which warned by valuable observations from Guam (Ladrone bears round seed capsules; this plant was found in the Islands) and Yap (Western Caroline Islands), the Manila market-place at Landau, Germany, but has been lost except Observatory was able to give timely notice in each case under cultivation.

to its own stations and to foreign services. BLACK spots varying in size from 1/10-inch to 3/8-inch in Some interesting results are described and illustrated be diameter are occasionally noticed on chilled beef. Dr. Dr. A. S. King in No. 1, vol. xxx., of the Astrophysica? Klein has investigated their nature, and finds them to be Journal, where he publishes a paper on the Zeeman effect caused by the mycelium of a fungus, an oidium, which is in the spectrum of titanium. The experiments were carried quite harmless and does not alter the meat beyond their

out at the Mount Wilson Observatory, field strengths of limits (Report to the Frozen Meat Trade Association). 12,500, 13,800, and 18,400 gausses being employed between

the poles of a Du Bois electromagnet; the dispersion used An interesting contribution to the September number of

was, generally, such that there were 0-93 Angströms per Travel and Exploration is an account, by a writer calling himself “ Pousse Caillou,” of the region known as Chang- A table, containing nearly 300 lines, between ^_3904 and

mm., the spectrograph being the 13 feet vertical Littrow. chenmo, the home of the Tibetan antelope (Pantholops ! 6556, gives a summary of the results, and shows that hodgsoni) and the Ovis ammon, which lies north-east of į the great majority of titanium lines are resolved into Leh, on the Kashmir-Turkestan frontier. Here we find triplets. Notable among the exceptions are the lines at seventy or eighty miles of the most utterly forsaken

^ 4527.49 and a 4544.86, cach of which is resolved into country which can be imagined. The lower volcanic hills,

seven components, and shows a regularity of structure broken into Gothic pinnacles, are backed by a coal-black identical in both; the line at 1 4281.53 has eight comprecipice, featureless and rigid in outline, while the interponents. Two sextets and three quintuplets also show a vening valleys of pure sand are swept by bitterly cold certain regularity in their separations, which is not shown, winds. Game preservation is more rigidly enforced even however, by the lines having four components. Special than in Ladakh, only six licences for shooting being attention was paid to the forty-four lines given in granted annually, and the bag of antelope is limited to six Lockyer's list of "enhanced” titanium lines, which do specimens. The writer vividly describes the difficulty of

not appear to fall in any special class; thirty-five are shooting this shy animal, the success of the stalk being triple, six are quadruple, one quintuple, and two sextuple. often interfered with by the appearance of the kyang, Two plates, which accompany the paper, beautifully illushalf-wild horse ass, which

wild these

trate some of the more interesting separations. plateaux.

ATTENTION is directed by Mr. G. N. Huntly, in a brief The report of the committee on ancient earthworks and fortified enclosures, prepared for presentation

paper in the Journal of the Society of Chemical Industry,

the Congress of Archæological Societies for the current year,

to a curious case of corrosion occurring in a stand-by boiler

at the generating station of the London Electric Supply presents no features of startling novelty. Measures for protection of sites have been successful in the cases of

Corporation. The corrosion had been noticed two years Maiden Castle, Dorset; Thetford Castle Meadow and Hill,

previously, but attempts to check it by the addition of

caustic soda to the boiler-water had proved unavailing. Norfolk; Stokeleigh Camp, on the Somerset side of the

The interior of the boiler showed numerous blisters up to Avon; White Barrow, Wilts; the earthwork at Selsea ; the old landmarks of Epping Forest; and Pendina's Camp, each blister contained a clear liquid with a black powder

30 mm. in diameter, most of them near the water-level; Cardiganshire. On the other hand, the committee has to report that in many cases the laying out of golf courses

in suspension, and a pit was observed to be forming in has caused the mutilation of ancient ramparts and ditches.

the centre of each blister. Analysis showed the presence The discovery of a portion of the Roman Wall of London

of ferrous sulphate and free sulphuric acid in the liquid on the site of Christ's Hospital; excavations at Caerwent

contents, although the boiler fluid was alkaline and con

tained little sulphur. The action was traced to manganese and Caerleon, Caersws, in Montgomeryshire, and Elslack, sulphide in the steel, which had become oxidised with near Skipton, in Yorkshire, were the most important operations of the year. The bibliography of current literature

formation of sulphuric acid; as the water in the boiler on the subject is a useful addition to the report of this

was quiet, the acid remained trapped behind a film of rust, committee.

and acid corrosion could thus take place in an alkaline

medium, the oxygen required to convert the sulphur into It very rarely happens that three well-developed typhoons acid penetrating the blister more readily than the alkali occur within the space of ten days; in the Bulletin of the of the water. Addition of sodium arsenite to the boiler. Manila Weather Bureau for October, 1908, Señor Coronas water in place of caustic soda completely stopped the gives an excellent discussion, with charts, of three such trouble, perhaps by eliminating the dissolved oxygen. cyclonic storms which reached the central and northern These experiments confirm the growing impression that parts of Luzon on October 4, 8, and 13, accompanied by the injurious effects of sulphur in steel cannot be wholly photographs of the destruction caused. They all appear removed by the addition of manganese ; so far from being to have originated in the vicinity of the Western Caroline harmless, the inanganese sulphide appears to be a

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dangerous constituent, leading to fractures as well as to of the maximum shear stress from the mean of 1.87 per corrosion.

cent. only, this series including tests in tension, com

Taking all the Prof. O. Lehmann, of Carlsruhe, who is so well known pression, torsion, and combined stress.

results given, the average variation from the mean of the for his work on liquid crystals, has done a great service

maximum shear stress is about 2 per cent. The importto those wishing to repeat any of the beautiful experi

ance of these tests will be understood when the difficulties ments which can be performed with these bodies by

of testing solid specimens under combined stress are regiving, in the Physikalische Zeitschrift for August 15, de

membered, difficulties which seem to have been overcome tailed descriptions of thirty-two of the most convenient and suitable experiments to perform during a lecture on

successfully by use of the author's sphingometer, by means

of which the tension and compression measurements are the subject.

taken in three planes. The Physical Review for July contains the second of a series of communications from Mr. G. W. Pierce, of the

REFERRING to the letters published in NATURE of July 22

and 29 in regard to sonorous or musical sands, Prof. J. C. Jefferson Physical Laboratory of Harvard, on the behaviour

Branner, Stanford University, California, writes to direct of rectifiers of alternating electric currents such as are used

attention to articles on this subject by Profs. H. C. Bolton as detectors of electric waves. In the present case electro

and Alexis A. Julien, published in the Proceedings of the lytic rectifiers have been studied by the aid of the Braun

American Association for the Advancement of Science tube oscillograph, and the author finds that the theory of (vol. xxxii., pp. 251–2; vol. xxxiii., pp. 408–13 ; vol. electrolytic polarisation is capable of explaining all the

xxxviii., pp. 137-40). We may remind Prof. Branner that facts observed, if the slight polarisation capacity of the

the subject was discussed in NATURE by Prof. Bolton and small platinum electrode of the rectifier is taken into

Mr. Carus-Wilson twenty years ago (vols. xxxix.-xlvi.). The detector, when polarised by the superposition of a direct current, is almost perfect, that is, the current

A NEW edition of Mr. P. H. L'Estrange's “ Junior it produces is nearly all in one direction. It may there

Course of Comparative Geography " has been published

Part v. of this fore be compared with the crystal rectifiers dealt with in by Messrs. George Philip and Son, Ltd. the author's first paper.

The author proposes to examine book, too, has now been issued separately at the price of the behaviour of vacuum-tube rectifiers before giving

iod. In the new edition all the maps of the original definite shape to any theory of crystal rectifiers.

work have been reproduced in black and white, the names

and symbols required for this course only being retained. The Century Magazine for September contains two

The book has been revised throughout, and additional interesting engineering articles. The first of these deals

matter added, for example, on local geography. with the great aqueduct now being constructed for bringing water from the Catskill Mountains to the City of New York. This aqueduct will be ninety-two miles long, and,

OUR ASTRONOMICAL COLUMN. to supply the 500,000,000 gallons required daily, more than Halley's COMET RE-DISCOVERED.—To Prof. Max Wolf 600 square miles of collection area must be utilised and belongs the honour of re-discovering Halley's comet after several large reservoirs constructed. The article is well an absence of more than seventy years. A telegram from illustrated with photographs, sections, and maps. The

the Kiel Centralstelle announces that the comet was dissecond article is a first instalment giving an account of

covered at the Königstuhl Observatory on September 11.

Its position at 14h. 7-3m. (Königstuhl M.T.) was Fulton's invention of the steam-boat. While many

R.A.=6h. 18m. 125., dec.= + 17° 11', engineers in this and other countries experimented towards the end of the eighteenth century, Fulton was the first

and its magnitude 16.0.

Mr. Crommelin's ephemeris position for September 11.9 to secure real success. However, it may comfort some of our British patriots to be reminded that the American

R.A. =6h. 18m. 45., dec. + 17° 16', vessel was fitted with one of Watt's engines, constructed

to the Greenwich calculators, Messrs. Cowell and in Birmingham and shipped to America. The article con

Crommelin, must be given the credit of having prepared tains many original documents and drawings, and is of an ephemeris which agrees remarkably well with the interest as showing that the modern troubles which many observation. At present the comet is approaching the inventors have to face in working out their schemes and

northern limit of Orion from the south-western region of in overcoming red tape had their counterpart more than

Gemini, forming nearly a straight line with the stars

7 Geminorum and 143 O2, the three objects being about a century ago.

equally spaced in the order 7-143 02-comet. The The results of some experiments on solid steel bars following is an extract from Mr. Cronmelin's ephemeris :under combined stress are given in an article in Engineer- Ch. 14.6m., +170 8'; October 22-0, 6h. 4.9m., +17° 2'.

September 25.7, oh. 18.5m., +17°1'; October 9.1, ing for August 20. The author, Mr. C. A. Smith, of the East London College, University of London, has already of changes, during August, in the areas surrounding the

OBSERVATIONS OF MARS.-Some interesting observations presented useful work in confirmation of Guest's law, and

southern ice-cap of Mars are reported by MM. Antoniadi, in this series has loaded solid specimens in compression Quénisset, and Jarry-Desloges in the September number and torsion, and also in tension and torsion. The necessity of the Bulletin de la Société astronomique de France for doing this will be evident when it is remembered that (pp. 385-94). M. Antoniadi, observing at Juvisy on August Lord Kelvin suggested that, as a tension load lowers the

12, 14, and 16, found the planetary features so pale as to torsional yield point, a compression load would raise it.

be almost unrecognisable. On August 15 the Orontes was Four different grades of steel were experimented on,

suspected to be, and the Euphrates was certainly, double, of

whilst, later, the Amenthes was to be broad and carbon content ranging from 0.09 per cent. to 0.48 per cent. diffuse. M. Antoniadi suggests that the pale greyness of Under combined compression and torsion, the maximum the darker regions may be due to the interposition of very principal stress at yielding · varied from 19,800 lb. to light clouds or of a mist in the Martian atmosphere. Both 36,500 lb. per square inch, while the maximum shear stress MM. Quénisset and Jarry-Desloges also direct attention to varied from 18,900 lb. to 20,400 lb. per square inch, the

the unusual paleness of the dark regions of the planet average variation from the mean of the latter stress being by reproductions from the original drawings showing

during the past few weeks, and each account is illustrated 2.16 per cent. Another series shows an average variation various aspects of the planet.

was

SO

seen

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