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appliances are made to the best of specifications, but that they should be sold at these ridiculous prices when they are of the distinctly dangerous tin-can type, liable to burst easily, is very near fraud.

It is to be hoped that the British Fire Prevention Committee will persevere in its propaganda and obtain legislation after the war is over, making it a penal offence to construct an extinguisher unless there are certain constructional safeguards to be settled from time to time by the Secretary of State as mechanical science advances. Good progress has already been made in this direction, and but for the war, the protection of the public against fraudulent fire appliances might have already been achieved.

To our readers, however, this article should serve as one of warning to insist on a written warranty before payment for any extinguishers purchased, that it complies either with the British Fire Prevention Committee's specification, or with those of the Board of Trade, H.M. Office of Works, or the Metropolitan Police. Further, for the best finished article they should not pay more than 25s. to 30s. when constructed to either of these specifications, but if in doubt as to the machine offered or the possibility of regularly testing and re-charging it, let them keep to the old bucket of water and hand-pump. They at least are trustworthy, and the most suitable for ordinary conditions.

with experiments on the surface friction of discs in air and water, the motion being one of rotation in their own plane. The agreement between theory and practice is complete. The second paper relates to the whole of the published information on the resistance of spheres in air and water, the results being very discordant amongst themselves. The conclusion is drawn that the conditions of the theory of dynamical similarity cannot in this case be satisfied experimentally with the necessary degree of exactitude. The results of the two papers are illustrated by Figs. 1 and 2. The first relates to the friction of discs, and in carrying out these experiments variations were made in three quantities of primary importance, the diameter and speed of rotation of the disc and the

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RESEARCH

THE

IN AERODYNAMICS.1

HE work of the Aerodynamical Laboratory at Koutchino is less affected by the necessity for technical work than any other of the European laboratories. It is for this reason, in all probability, that the latest bulletin makes a refreshing change from the publications of Eiffel and the Advisory Committee for Aeronautics.

The production of miniature whirlwinds forms the subject of one series of experiments, and the results are illustrated by some very interesting photographs. Rotations, as apart from eddies, are of frequent occurrence in nature; they may be seen in the autumn by the movement of leaves, due to a wind over open ground. Similar movements of air are found on the floor of the room below the intake of a wind channel, and the phenomenon indicates how little we really know of the motion of real fluids.

Perhaps the most interesting papers in the bulletin are two relating to the principle of dynamical similarity as applied to viscous fluids. Experiments with the same object were made by Osborne Reynolds, and recently Messrs. Stanton and Pannell have established the practical utility of the theory in the case of air, water, and oil flowing through pipes.

One of the two papers above mentioned deals

1 Bulletin de l'Institut Aérodynamique de Koutchino. Pp. 296. Fascicule v. (Moscow: I. N. Kouchnéreff and Co., 1914.)

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viscosity of the fluid. The ratio of the greatest diameter to the least was 10:1, the ratio of the extreme speeds 2:1, and the ratio of the kinematic viscosities 13: 1. The theory of dynamical similarity indicates that any one of these changes can be predicted from the effect of changes in either of the others, and the practical proof of this is the fact that the whole of the experimental results can be collected on a single curve as in Fig. 1. As the range of variation included a region of critical flow, as indicated by the dip in the curve, the practical agreement is a delicate test of the exactness with which the experimental conditions complied with the conditions of geometrical similarity.

The

The reverse picture is shown in Fig. 2. principle of dynamical similarity applies as rigidly to the resistance of spheres as to the surface friction of discs, but the experimental results vary very widely over almost the whole of the experiméntal range. An interesting contribution on the reasons for such large experimental discrepancies is made by Prof. Prandtl, who showed that a wire of small diameter put round a sphere in an appropriate place had the somewhat surprising effect of reducing the resistance to about one-third of that of the smooth sphere. It was further shown that a gauze screen introduced into the air current immediately in front of the sphere had a similar effect. The conclusion appears to be justified that the flow of air round a sphere is so very sensitive that small departures from strict geometrical similarity and from the condition of uniform

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DR. HUGO MÜLLER, F.R.S. THE death of Hugo Müller will be greatly deplored, by all who knew him he was one of those few men who only make friends and at once inspire regard in all who are brought into contact with them. He died suddenly, at his country home, at Camberley, Surrey, in the early hours of Sunday, May 23, in his eighty-second year. Though very deeply distressed by the war, he enjoyed his usual good health to the last; in fact, he was in his garden until late in the evening on the previous Saturday and had worked in the Davy-Faraday laboratory up till Friday afternoon. He was buried at Brookwood Cemetery on Thursday last alongside his old friend Dr. Atkinson.

He was born at Tirschenreuth in the Ober

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relative motion are sufficient to account. for the large experimental variations.

Further experiments are needed to clear up the position, but, obviously, no investigation can alter the fact that the resistance of a sphere must always be difficult to predict, except in very favourable circumstances. The possibility at least exists that the rough surface of a golf-ball has a very close relation to the instability of flow referred to, the advantage of the roughened surface being so great as to render it obvious in the direct test on the golf links.

It is fortunate for the future of aeronautics that similar troubles do not occur in connection with the important parts of an aeroplane, though an approach to such sensitivity has been found in the case of the fluid motion round certain struts.

FIG. 2.

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He was educated as a chemist at Leipzig, at Göttingen under Wöhler and at Munich under Liebig; but he also took special interest in mineralogy and was an ardent collector of minerals in his early days. It is clear that he was a precocious worker, as he described the geognostic-mineralogical features of his home district in 1852 in the Regensburg Corresp. Blatt. He came to this country sixty years ago, on the recommendation of Liebig, as assistant to Dr. Warren de la Rue. Their first joint work involved the examination of Burmese naphtha at a time when very little was known of the petroleums. But they took up a variety of subjects and one of their most valuable contributions was the wellknown chloride-of-silver-zinc constant battery which they devised. Dr. Müller also worked with

Stenhouse. His most noteworthy early discovery perhaps is that involved in the use of iodine as a catalyst in chlorinating. He was an intimate friend of Kekulé when the latter was in London.

A man of great personal charm of manner, of sympathetic nature and very versatile, he inspired confidence not only by the breadth and accuracy of his knowledge but also by his calm and clear judgment. His worth was soon recognised, so

A man of large and noble mind, he was torn with distress by the outbreak of the war, which he looked upon as a downfall of civilisation; he deplored his having lived to see it and there is little doubt that his end was greatly hastened by

recent events.

DR. M. W. CROFTON, F.R.S.

that he was consulted constantly by the firm of DR. M. W. CROFTON, whose death was

De la Rue and Co. long before he was induced to give up science and enter upon an industrial career in its service; ultimately he became a partner in the firm and remained in it until 1902 The Stamp department was his chief charge; in this he found full opportunity for the exercise of his scientific ability and great technical skill as well as of his artistic gifts. He was elected a fellow of the Royal Society in 1866. He joined the Chemical Society in 1859; he was its foreign secretary from 1869 to 1885 and president in 1885-87. He was a Ph.D. of Göttingen, an LL.D. of St. Andrews and a D.Sc. of Manchester. He became naturalised thirty-seven years ago, on his marriage to an English lady. He had two daughters, one of whom and his wife survive him.

When the Lawes Agricultural Trust was constituted by his old friend Sir John Lawes twentysix years ago, he was appointed a representative of the Royal Society on the Committee and became the treasurer; he held the office until the present year, when he retired, in spite of the urgent requests of his colleagues that he would not sever the connection; but he thought that German residents in this country, whether naturalised or not, were so seriously affected by the outbreak of the war that it was not desirable that a person in his position should be a member of or take part in the affairs of any public concern or enterprise. He consistently remained aloof from everything.

Although his time was fully occupied by his business avocations while in the firm of De la Rue and Co., he never lost his interest in his science; since his retirement he worked regularly in the Davy-Faraday laboratory of the Royal Institution. The work he did, which has been published by the Chemical Society, is remarkable as proof of his exceptional skill as a manipulator and of special value to science. Only recently he completed the investigation of the peculiar bloom which appears on the leaf and flower-stalk of a number of species of primula; he made the striking discovery that this consists of flavone, the parent substance of the great group of yellow colouring matters present in plants, a substance only prepared in the laboratory previously.

Dr. Müller was also a noted horticulturist and botanist; he was long an active member of the scientific committee of the Royal Horticultural Society. Beginning thirty years ago with a sandy. waste at Camberley, Surrey, he developed one of the most remarkable and beautiful gardens in the country. His knowledge of plants was quite exceptional, as it had long been his habit to grow them in order that he might know them; his garden, therefore, was always of special interest.

recently announced in NATURE, was born in Dublin in the year 1826, the son of Rev. William Crofton, of Sligo, a clergyman of the Established Church. Together with his brother Henry, who was two years his junior, he entered Trinity College, Dublin, in the year 1843 under the tutorship of Dr. Graves, who afterwards became professor of mathematics in the college, and later Bishop of Limerick. Diligent students both brothers must have been, for at the moderatorship examination in 1847 Morgan, who had captured on the way all the undergraduate prizes open to him, came out first of his class in mathematics, while Henry headed the list in classics, a double event rare, if not unique, in the history of the College.

When the Queen's University of Ireland was established, Dr. Crofton was appointed professor of natural philosophy at Queen's College, Galway, a position which he resigned in 1853 after three years' occupation. He was afterwards professor of mathematics and mechanics in the Royal Military Academy, Woolwich, from 1870 until 1884, and on his resignation was appointed to a fellowship of the Royal University of Ireland, retaining that position until 1895. Dr. Crofton published a treatise on the "Elements of Applied Mechanics" (London, 1881), and contributed several papers on geometry and mechanics to various journals, but his chief interest was in the mathematical theory of probability. There is a paper of his in the Phil. Trans. of the year 1868 "on the theory of local probability applied to random straight lines," and another in the Phil. Trans. of 1869 “on the proof of the laws of errors of observations." He wrote also the chapter on mean value and probability in Williamson's "Integral Calculus,' and the article, "Probability," in the ninth edition of the Encyclopædia Britannica.

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Dr. Crofton was elected a Fellow of the Royal Society in 1868. S. B. KELLeher.

NOTES.

We notice with much regret the announcement of the death, on May 31, in his eighty-first year, of Sir A. H. Church, K.C.V.O., F.R.S., formerly professor of chemistry in the Royal Academy of Arts.

MEN of science view with especial satisfaction the appointment of Admiral Sir Henry Jackson, K.C.B., F.R.S., as First Sea Lord of the Admiralty. So far as we are aware no precedent exists for the nomination of a fellow of the Royal Society as First Sea Lord of the Admiralty. Born on January 21, 1855, Sir Henry entered the Navy at thirteen, became Lieu

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tenant of the Active during the Zulu war of 1878-9, and was promoted Captain in 1896. He afterwards became Assistant-Director of Torpedoes (1902), Controller of the Navy (1905), and Chief of the War Staff at the Admiralty (1913-14). In science Sir Henry Jackson's work refers chiefly to electrical physics. In the 'nineties of last century he was among the first to engage in the practical application of electric waves transmission; in other words, wireless telegraphy. He early made the acquaintance of Mr. Marconi, the two collaborating in important researches. In 1895 Sir Henry began systematic experiments and trials under sea-going conditions (inclusive of the use of balloons and kites), with the view of utilising the effect of Hertzian oscillations for naval signalling purposes. The results were embodied in a paper read before the Royal Society, entitled "On Some Phenomena Affecting the Transmission of Electric Waves over the Surface of the Sea and Earth." From 1905-6 he was A.D.C. to King Edward VII.; in 1906 he was made K.C.V.O., and, in 1910, K.C.B. The Royal Society elected him into its fellowship in 1901. A member of the Institution of Electrical Engineers, and an associate of the Institution of Naval Architects, Sir Henry also serves on the general board of the National Physical Laboratory, and has consistently promoted its interests in official quarters. It may be of interest to give the names of those fellows on the Royal Society's current list who either are naval men or are engaged on Admiralty service. They comprise Admiral Sir A. M. Field, late Hydrographer; Capt. T. H. Tizard, late Assistant-Hydrographer; Sir Henry J. Oram, Engineer Vice-Admiral, Engineer-inChief of the Fleet; Capt. E. W. Creak, C.B.; Sir Philip Watts, late Director of Naval Construction; Mr. R. E. Froude, Superintendent of the Admiralty Experimental Works at Gosport; Sir J. A. Ewing, Director of Naval Education; Sir John Thornycroft;

and the Hon. Sir Charles Parsons.

WE learn from the Scientific American that Mr. Walter G. Davis, director of the Argentine Meteorological Service, recently retired on a pension, and was succeeded by Señor Martin Gil, described in the Argentine newspapers as a wealthy amateur meteorologist and astronomer, much interested in long-range weather prediction.

A WAR Exhibitions has been organised to assist the funds of the Belgian Red Cross Anglo-Belgian Committee, whose patroness is the Queen of the Belgians. The exhibition is designed to present an idea of the extent to which science and industry are being utilised in every branch of the present gigantic struggle. The exhibition comprises seven sections, which include, with others, armament and ammunition in the making, Red Cross work, science and industry applied to war, food and hygiene, and a maritime and aerial section. The exhibition will be held at Prince's Skating Club, Knightsbridge, London, from June to October.

DURING a thunderstorm near Gibraltar on May 25 a cloud is said to have belched forth millions of small frogs which had apparently been drawn up from a

lake twenty miles away. Such showers of frogs," when satisfactorily authenticated, are to be ranked along with showers of sticklebacks, herring, and even larger fishes. Some of these showers are well vouched for, and admit of physical interpretation. In an eddy of a whirlwind there is sometimes draught strong enough to suck up dust and leaves and sheaves, or water and fishes and frogs. The whirling column is borne on by the wind and may transport its burden for many miles until the rotational energy is expended and the little tornado is over. It must be carefully noted, however, that the sudden appearance of multitudes of small frogs often implies nothing more than the usual migration of the young frogs from their birthplace in the pond to their summer quarters in the fields. Similarly, as Gosse pointed out long ago, alleged "snail showers" are apt to disappear under scrutiny, and "a torrent of periwinkles" turns out to be a migration of Helix virgata or the like. In his "Romance of Natural History" Gosse inquired in a fair-minded way into the various kinds of animal "showers," and came to the conclusion that some of the records were worthy of credence as regards frogs, toads, and fishes. It is probable enough, then, that the Gibraltar shower was genuine.

A REMARKABLE discovery of flint implements has been made recently at Highfield, Southampton, and a large selection of them is now displayed in two new cases in the prehistoric section of the County Historical and Antiquarian Museum at Tudor House. The spot where they were found is apparently the site of the workshop or cache of a Palæolithic mastercraftsman in flint, and great numbers of implements in various stages of fashioning were brought to light on a limited area. The series shown covers the whole technique of manufacture, from the roughly-shapedout slabs of table flint to beautifully chipped and completed implements, with their edges still unabraded. It includes blanks or shaped forms of flint cut with astonishing precision, portions of implements broken in process of making, chips, etc. Some of the smaller implements vie in beauty of workmanship with the fine products of Neolithic culture, and are also of shapes generally associated with the later Stone Age, though their gravel patina is indisputable proof that they came from the river drift, and so are of Palæolithic origin. Series of both large and small implements, the latter including various forms of scrapers, arrow-points, etc., are shown in their different stages of making, so that the processes of manufacture become clear to the student. It is worthy of recording that the surface soil of the site yielded some interesting Neolithic implements, which are also shown.

STONEHENGE, the most remarkable of our national prehistoric monuments, is included in the Amesbury Abbey estate, Wiltshire, which is to be sold by auction in September. Much information about this notable structure and its significance will be found in Lady Antrobus's "Sentimental and Practical Guide to Amesbury and Stonehenge" and Sir Norman Lockyer's Stonehenge and other British Stone Monuments Astronomically Considered." The first British author who is considered to make unmistak

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able mention of Stonehenge is Henry of Huntingdon (twelfth century). He refers to it as the second wonder in England, and calls it Stanenges. Geoffrey of Monmouth (A.D. 1138) wrote of it about the same time, as did also the Welsh historian, Giraldus Cambrensis. The outer circle of thirty upright stones has a diameter of about 100 ft. These stones formerly stood 14 ft. above the surface of the ground. Within this peristyle there was originally an inner structure of ten stones arranged in the shape of a horseshoe formed of five (but some think seven) huge trilithons, which rose progressively in height from north-east to south-west, the loftiest uprights being 25 ft. above the ground. About one-half of these uprights have fallen; during the operations connected with the raising of one of the uprights in 1901 numerous flint axe-heads and large stone hammers were found at a depth of from 2 ft. to 3 ft. 6 in. underground-all tending to prove the great antiquity of the monument. From his investigations of the orientation of Stonehenge, upon the assumption of the structure having been erected as a solar temple, Sir Norman Lockyer concluded that the date of its foundation was 1680 B.C.

We regret to learn of the death of Dr. Aksel S. Steen, director of the Norwegian Meteorological Institute, and fellow of the Norwegian Academy of Sciences. Dr. Steen was for many years assistant director of the Norwegian Institute, and he succeeded the veteran Prof. Möhn in the directorship in September, 1913. He contributed many papers to meteorological literature on the climate and weather of Norway, but he is perhaps best known for his comprehensive report on the observations made at the Norwegian station at Bossekop in connection with the international exploration of the polar regions during the years 1882-83, and for his report on the terrestrial magnetic results of the second Norwegian Arctic Expedition in the Fram in 1898-1902. The latter report was supplemented by an interesting discussion on the diurnal variation of terrestrial magnetism in the northern hemisphere. Dr. Steen's visit to England in 1904 as a member of the International Solar Commission which met at Cambridge in that year, is pleasantly remembered by those who met him on that occasion. He was born at Christiania in 1849, and died there on May 10.

IN this country it is unfortunately so rare to find young men, equipped by a scientific training with the exact habit of mind essential to all historical studies, willing to turn their attention to art-history and museum-management, that the loss of such a promising recruit as Second-Lieutenant Percy Herman Charles Allen (3rd attached to 2nd Battalion East Lancashire Regiment), killed in action in France on May 9, is much to be deplored. Educated as a mathemathical exhibitioner of Christ's Hospital, and scholar of Caius College, Cambridge, Mr. Allen became for a time an assistant in the Victoria and Albert Museum, and in January, 1914, was appointed assistant keeper in the fine art department of the Ashmolean Museum, Oxford. His natural taste and exactitude of percep

tion were beginning to find true scope in the com plicated task of determining questions of states and copies amongst the early engravings forming part of the vast collections bequeathed by Francis Douce to the University. In a short time he did much valuable work. A remarkable memory and grasp of the nature of facts gave his judgment the sureness only acquired as a rule by long experience. It seemed safe to predict that his career, cut short at twenty-five years, showed promise of a future of much brilliance.

THE late Captain S. A. Macmillan, attached to the 58th (Vaughan's) Rifles, Indian Army, whose death at the front has recently been reported, had been engaged for about a year on the work of the survey of the mammalian fauna of India, Burma, and Ceylon. This survey was started in 1911 by the Bombay Natural History Society with the object of carrying out, in conjunction with the British Museum (Natural History), a systematic study of the Indian mammal fauna. Early last year the society secured the services of Capt. Macmillan as a collector in Burma to work with another of their collectors, Mr. Guy Shortridge, who is now serving in France as an officer of the 29th Bengal Lancers. Capt. Macmillan had been on a rubber estate in Tenasserim, and was not only a keen hunter, but also possessed a local knowledge of languages, etc., which proved of great value to both collectors whilst in Burma. They were doing splendid work for the survey, and had made a very fine collection of mammals from Monywa and Kindat in Upper Chindwin and elsewhere in Burma when the war broke out, and abruptly put a stop to their efforts in this direction, the activities of both being transferred to the military. Before leaving India Mr. Shortridge and Capt. Macmillan exhibited their specimens at a meeting of the Bombay Natural History Society, the fine series of different squirrels particularly creating much interest. The Society has lost in Capt. Macmillan a keen worker of the highest efficiency, who promised to accomplish still more valuable work towards bringing the survey to a completion.

By the recent death of Prof. D. A. Louis, at fiftyeight years of age, the technical Press has lost one of its most gifted representatives. A Londoner by birth, he studied at the Royal School of Mines in the year 1876 and 1881, devoting most of his attention to chemistry, metallurgy, and physics. From 1882 to 1886 he was employed at Rothamsted on agricultural research, and there carried out important experiments for Sir John Lawes. His connection with mining and metallurgy is to be traced to an appointment he had in Colorado, where he gained practical experience in mining. From 1891 he practised as a consulting mining engineer and metallurgist in London, making periodical visits abroad to most of the European and American mining districts. In 1893 he became an assistant examiner in mining to the Board of Education, and in 1900 was appointed professor of mining at the Yorkshire College at Leeds. In 1907 he took a prominent part in the third International Petroleum Congress at Bucharest. In 1910 he was hon. secretary of the metallurgical section of the seventh International Congress of Applied Chemistry; and as a

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