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matics, Physics, Meteorology, Geodesy, Surveying, Engineering, Architecture, and Irrigation, F. E. Kanthack; B-Chemistry, Geology, Metallurgy, Mineralogy, and Geography, H. Kynaston; C-Bacteriology, Botany, Zoology, Agriculture, Forestry, Physiology, Hygiene, and Sanitary Science, C. P. Lounsbury; D—Anthropology, Ethnology, Education, History, Mental Science, Philology, Political Economy, Sociology, and Statistics, J. E. Adamson. Among the papers to be read are the following:The fault system of the south of Africa, Prof. E. H. L. Schwarz; Some South African radio-active minerals, Prof. P. D. Hahn; Darwin's theory of natural selection, tested in the light of our knowledge of Crassulaceæ, Prof. S. Schönland; The economy of termites, C. Fuller; The history of the ostrich industry in South Africa, R. W. Thornton; Anti-venomous serum and its preparation, F. W. FitzSimons; The inheritance and characters of certain cross-bred sheep, J. BurttDavy; The Bagananoa (Malaboch), with notes on the traditional history of the tribe, Rev. N. Roberts; Sesuto etymologies, Rev. W. A. Norton; practical education, W. J. Horne; and The economics of the east coast fever, Rev. J. R. L. Kingon. A popular evening discourse will be delivered by Mr. C. W. Mally, on the house-fly under South African conditions, and one by Dr. E. T. Mellor on the Witwatersrand Goldfields. The medal and grant for 1915 have been awarded to Mr. C. P. Lounsbury, chief of the division of entomology, Union Department of Agriculture, and will be presented during the session.
DR. R. HAMLYN-HARRIS, the director of the Queensland Museum, has set himself the task of forming a collection of the "Implements of Superstition and Magic" used by the natives of Queensland. As these are dying out with appalling rapidity, ethnologists the world over will be grateful to him. A most welcome summary of the results so far achieved appears in vol. iii. of the Memoirs of the Queensland Museum. He prefaces his account with a word of warning which in the interests of science cannot be too widely circulated. The wily aboriginal, having discovered that his implements and weapons have a marketable value, has taken to manufacture on an extensive scale, but such specimens bear, in every detail, the mark of the bungler. Nevertheless, it would seem that tons of material are being exported to museums all over the world by unscrupulous dealers who are inciting the natives to pursue this reprehensible means of obtaining money or its equivalent. Death-bones, quartz crystals, magic stones, and rain-sticks are severally described in this essay, which contains a valuable collection of myths and customs which are fast disappearing.
THE Concluding portion of the paper by Prof. Flinders Petrie on the Stone age in Egypt, published in Ancient Egypt, part iii., for 1915, raises a very interesting question of synchronism. The writer notices a striking resemblance between the coarse flakes which abound in prehistoric Egyptian graves with those of the Magdalenian Cave type. In other cases the snubbing of the edge by scraping is characteristic of European Aurignacian flints. The Magdalenian flint types in Egypt are associated with bone harpoons, which are also of that age in Europe. A bone harpoon found in Egypt belongs to the first and part of the second prehistoric civilisation, say 80006000 B.C. This," he writes, "raises the question whether it will be possible to extend the Magdalenian Cave period as late as the Egyptian graves of about 7000 B.C., or to trace a descent of the type to a later time. This connection is an additional reason for
THE National Clean Milk Society (2 Soho Square, London, W.), which has been formed to improve the milk supply of Great Britain and Ireland, has published a pamphlet showing how by a system of marks it is possible to conduct the inspection of dairy farms in an efficient and educational manner. The score-card system which has been developed so largely in the United States for judging stock, agricultural produce, etc., has also been applied to the inspection of dairy farms, town dairies, etc. By making altera-keeping to the Egyptian chronology, and not adopting
tions that would bring the score-card more in touch with British conditions, it has been possible to arrive at what promises to be a most satisfactory way of judging of the sanitary condition of any farm that is producing milk for human consumption. score-card is divided into two main sections, one section dealing with equipment, the other with methods, and 60 per cent. of the total marks is allotted to the latter. Most excellent explanatory notes are appended to the score-card, and are presumably intended for the guidance of the inspector. A perusal of them would be of great value to the farmer himself, for frequently lack of cleanliness is due more to failure to appreciate the necessity of being careful in the handling of such an important food as milk than to any desire to evade regulations. Sanitary inspectors in particular should see this pamphlet, and if every landowner would take the trouble to observe how large a proportion of marks on the score-card depend upon the cowshed there might be improvements in farm buildings.
the arbitrary theories of Berlin which would bring down these Magdalenian types to about 3500 B.C." This suggestion of a possible synchronism between the Cave periods of Europe and graves in Egypt which can be dated with some approach to certainty may lead to important results. It is unfortunate that so much haphazard collection of flints has gone on in Egypt, without regard to their seriation or characteristics, and thus evidence of much value has been lost.
THE Miocene insect beds of Florissant, Colorado, promise to yield an even richer harvest than the celebrated beds of Oeningen in Baden. Prof. T. D. A. Cockerell, in the Proceedings of the Academy of Natural Sciences of Philadelphia (part iii., vol. Ixvi.), describes a number of species new to science collected by Prof. Wickham. In an excavation about 20 ft. long and 6 ft. deep he obtained more than ninety species of beetles, of which at least forty are new to science. But various other groups are also represented in this collection, of which apparently sixty are new species.
A NEW addition to the list of British fishes is made by Dr. R. F. Scharff in the Irish Naturalist for June. This is the long-finned bream (Brama longipennis) which was captured on May 18 last year, off the west coast of Valencia Island, Co. Kerry. Though brilliantly coloured at the time of capture, by the time it had reached the island it had faded to a uniform grey hue. Only one other species of the genus has been recorded from Irish waters. This is Ray's bream (Brama raii), which was recorded in 1888. To the same number Dr. Scharff contributes some interesting notes on Irish sharks.
barium, and has been constructed on practical lines. Hong Kong being essentially the key to the botanical position as regards China, we welcome any work, based on the collections of that herbarium, tending to set out in orderly form the vast wealth of the Chinese flora as regards particular natural families. Even now it is not possible to arrive at a definite phytogeographical survey of the empire as regards any one group of plants, but a key such as that just published is of value in helping forward the more detailed study of the flora of China.
THE Condition known as Peloria, in which the ex
THOUGH observations on the birds attracted to light-ceptional development of complementary irregularities ships and lighthouses during migration have been kept with much exactness during a number of years, no similar records had been made in regard to insects which in like manner are attracted by light, until recently, when the matter was taken up by Mr. W. Evans. The conclusion of his report on Lepidoptera and other insects at Scottish lighthouses appears in the Scottish Naturalist for June. It is usual, he remarks, "to think of moths alone as night-fliers, and attracted by light, but . . . not a few other insects have similar habits, and are similarly attracted. . . . Both sexes come to the lanterns, but as a rule males predominate." He also makes some interesting observations on the dominance of certain colour variations.
CONCHOLOGISTS will doubtless welcome the announcement of the rediscovery of Pourtales's Haliotis. This is made by Mr. J. B. Henderson in the Proceedings of the U.S. National Museum (vol. xlviii., 1915). The first intimation of the occurrence of this genus in western Atlantic waters dates so far back as 1869, when a specimen was dredged up in the Straits of Florida. This was unfortunately destroyed in the great Chicago fire before it could be described. Twenty years later it was described from memory by Dr. Dall, who named it in honour of Count Pourtales, under whose supervision the original dredging operations were carried out. Two years ago Mr. Henderson, while dredging from the Eolis, along the inner edge of the Pourtales Plateau off West Key, in ninety fathoms, secured a second specimen of Haliotis, which proved on examination to be an immature specimen of the long-lost Pourtalesii.
THE reclamation of peat bogs is always a matter of economic importance, and the results achieved by sowing Pinus pinaster directly on a peat-bog, described in Irish Gardening for June, are worthy of wider notice. Two photographs are reproduced, one showing the depth of the peat where the seeds were sown in the west of Ireland, the other three of the young trees, four years old. The soil is fatal to the Scots Pine, but P. pinaster, if sown on the spot, thrives remarkably. The tree transplants badly, and for this reason the success attending the method adopted at Abbeyleix by Mr. Macgregor is very interesting.
No. XXVIII. of vol. vi. of Notes from the Royal Botanic Gardens, Edinburgh, for May, is occupied by a useful paper in the form of a key to the Labiatæ of China, by Mr. S. T. Dunn. The key is based largely on the collections in the Hong Kong her
make a typically irregular flower regular, is fairly commonly met with in foxgloves and snapdragons under cultivation; indeed, in both plants a definite varietal form, with either the terminal or all the flowers peloric or regular, appears to be fixed and to come true from seed. In the foxglove the variety is known as var. monstrosa, and the terminal flower is a more or less regular erect bell, similar to the flower of a Campanula. In Antirrhinum a varietal form has been so far fixed by Lorenz, of Erfurt, that 60 per cent. of the plants raised from seeds bear peloric flowers; this form is figured in "Gartenflora" (1904, p. 113, t. 1524). Here all the flowers are tubular and perfectly regular, but a form recently received from a correspondent resembles the foxglove, variety monstrosa, in having the terminal flower only regular, with the characteristic lower lip of the snapdragon, forming a complete fringe round the actinomorphic tubular flower, while all the other flowers are zygomorphic. A further peculiarity of these pleoric varieties is that the terminal flower of the raceme is the first to open, whilst in normal forms the terminal flower is the last to expand.
HELMHOLTZ'S magnification formula of our elementary text-books on optics is known to be a particular case of a number of interesting reciprocal theorems; for example, the property that in a system of lenses the angular diameters of the object and image as seen from any position are inversely proportional to the linear diameters of the sections of the incident and emergent small pencils where they meet the eye. In the Atti dei Lincei, xxiv., 7, Prof. Levi Civita gives a general dynamical investigation of these reciprocal relations, including Straubel's theorem, and with applications to multi-dimensional hyperspace. This is based on the analogy between trajections in dynamics and paths of rays, which analogy results from the principles of least action and time respectively.
THE rapid increase of the electrical resistance of pure iron with temperature makes it very desirable that the behaviour of iron resistance thermometers should be thoroughly investigated with a view to their introduction into common use. Such an investigation has been made by Messrs. G. K. Burgess and I. N. Kellberg, of the United States Bureau of Standards, and the results are published in the May number of the journal of the bureau. The wire used was 99.98 per cent. iron, 0.24 millimetre in diameter, and was wound on a porcelain insulator and enclosed with
a similar platinum wire in an evacuted quartz tube. 'Six such combined thermometers were made and annealed at 1000° C. In the subsequent comparisons of the resistances of the platinum and iron wires at various temperatures the resistances were determined to the equivalent of 0.005° C. In all cases the resistance of pure iron was found to increase regularly to about 750° C., the temperature coefficient of increase reaching a maximum about seven times that of platinum at that point. At 757° C. the critical point A2 is reached, and the coefficient decreases. 894° C. the second critical point, A3, is reached, and the resistance decreases over a range of 10° C., to increase again at higher temperatures. On cooling the A3 change occurs at 880° C., while the A2 change Occurs again at 757° C.
THE June issue of the Journal of the Franklin Institute contains a second paper by Sir Robert Hadfield on sound steel for rails and structural purposes, the first having been published in February. The present paper gives some details of the production for the Pennsylvania Railway Company of one hundred tons of rail ingots made at Sheffield under his "sound steel" system. The dimensions of the ingots were 5 ft. 4 in. by 18 in. square. They were fed from sandheads, which permitted an average of 130 lb. of fluid steel to pass into the ingot, which contracted during freezing, thus continuously "following up" any pipe that tended to be formed. The average capacity of the cavity on the top of the ingots was 3'19 per cent. of the total capacity of the ingot. The author claims that after cutting off 10 per cent. from the top of the ingot the remaining 90 per cent. is sound, entirely free from blowholes, segregation, cr piping. Ingots sectioned through the long axis and photographed appear to bear out this contention, at any rate so far as soundness is concerned. In the rail ingot, as ordinarily cast, a discard of upwards of 40 per cent. is sometimes necessary, and even in the sound portion segregation is always present to a greater or less extent. It is interesting to note that the average carbon percentage in the ingots is 0'63a considerably higher figure than any English railway company permits. This gives a harder but more brittle rail. The wear in practice of rails rolled from these ingots will be watched with considerable interest.
THE Scientific American celebrated its seventieth anniversary on June 5, and the number for this date contains an interesting retrospect through the inventions and scientific discoveries of the past seventy years. When the journal was first established, we had only Davy's arc and electrolysis, Oersted and Ampère's revelations in electrodynamics, Daguerre's photography, Henry and Faraday's work in induction, and Joule's mechanical equivalent of heat. The telegraph and the reaper had just been born. Much of the transformation which has marked the last seventy years has taken place within the lives of men still with us. Prior to the invention of the telephone, our contemporary considers that the decade 1840-50 was the most fruitful in invention; during this period the reaper, the vulcanisation of rubber, the sewingmachine, and the telegraph were perfected. The
decade beginning with 1880 saw an outburst of inven tive activity that dwarfed all similar periods in the history of invention. It seemed that the discoveries in electricity during the last three or four years of the previous decade had been the signal for the pent-up genius of the world to be let loose. In the 'eighties the generation, transmission, and utilisation of current, the dynamo, the transformer, and the motor were all made practical propositions on a large and commercial scale for the first time. The electric furnace was perfected in the latter part of this period. The Harvey process for hardening armour plate was invented in 1888; smokeless powder, the Westinghouse brake, the transparent film which foreshadowed the moving picture and the pneumatic tyre are also contributions of the same decade. There are a large number of photographs of historical inventions and inventors included in this number, and there is also an interesting autobiographical sketch by Mr. Nikola Tesla.
IN view of the great interest at the present time in the Conventions and signed Declarations of the First and Second Hague Conferences, and particularly because of the need of accurate information as to ratifications of and adhesions to the Conventions and Declarations relating to war, the Carnegie Endowment for International Peace has prepared a series of pamphlets in order that the public may learn from trustworthy sources the status of these international agreements and the extent to which the Powers now at war are bound by their provisions. We have received copies from Washington of seventeen of these pamphlets, and find that among the subjects of vital importance considered are: the declarations of 1899 concerning asphyxiating gases and expanding bullets, and prohibiting the discharge of projectiles and explosives from balloons; and the conventions of 1907 relative to the laying of automatic submarine contact mines and concerning bombardment by naval forces in time of war.
THE Open Court Company, 149 Strand, W.C., has ready for publication "A Budget of Paradoxes," by Augustus de Morgan, revised and edited, with full bibliographical notes and index, by Prof. David Eugene Smith, professor of mathematics, Teachers College, Columbia University, New York.
MESSRS. G. P. PUTNAM'S SONS announce for early publication :-"The Alligator and its Allies," by Prof. A. M. Reese; "Plane Trigonometry," by Prof. A. M. Harding and J. S. Turner; and "Field Book of Western Wild Flowers," by M. Armstrong and Prof. J. J. Thornber.
THE announcements of the Cambridge University Press include:-"Mimicry in Butterflies," by Prof. R. C. Punnett; "The North-West and North-East Passages, 1576-1611," edited by P. F. Alexander (the first volume in the series of Cambridge Travel Books "); and "Stories of Exploration and Discovery," by A. B. Archer.
ERRATA.-In Prof. O. W. Richardson's Royal Institution discourse printed in NATURE of June 24, p. 468, col. 2, line 12, for "twice" read "half "; p. 469, col. 1, table, for "calories per n" read "calories per grammolecule of electrons,"
OUR ASTRONOMICAL COLUMN.
THE ORIGIN OF COMETS.-In the Publikationer og mindre Meddelelser fra Kobenhavns Observatorium, No. 19, Prof. Elis Strömgren publishes a research which he has concluded with the help of Mr. J. Braae on the subject of the origin of comets. In the introduction the author refers to the results of previous workers, and suggests that the question as to whether comets came originally from interstellar space or were formed in the solar system, depends on the method of discussion adopted. The author describes fully the procedure he has used in the present research, which involves the backward computation of planetary perturbations for eight comets, and gives the numerical calculations. He is thus led to form the conclusions that there is not one warranted hyperbolic orbit among the comets of the solar system, and that all the comets yet observed have their origin in the solar system.
COMPANIONS TO MELLISH'S COMET.-In the Astronomical Notes of the May-June number of the Journal of the Royal Astronomical Society of Canada, reference is made to two companion bodies near Mellish's comet discovered by Prof. Barnard. One of these bodies was conspicuous and had a distance of 28" and position angle of 285° on May 12 at 19h. 36m. The other was faint, and occupied an intermediate position on the same line. The above confirmation appeared in the Harvard College Observatory Bulletin, No. 580. THE ABERRATION CONSTANT AND LATITUDE VARIATION. -The floating zenith-telescope designed by the late Mr. Bryan Cookson has been in use since 1911 at the Royal Observatory, Greenwich, having been lent by the Cambridge University. It has been employed in the determination of the aberration constant, and a preliminary discussion by Mr. H. S. Jones of three years' observations with it appears in the May number of the Monthly Notices of the Royal Astronomical Society. This communication represents the results derived from observations made between September, 1911, and December 31, 1914, and the discussion is based on measures of 479 plates. The value of the aberration obtained is given as 20.467" ±0.006." The instrument being designed primarily for the determination of the aberration, it is interesting to note that, as a by-product of the investigation, excellent values of the latitude variation have been derived.
in the form of glass negatives is now being adequately dealt with by the generosity of Mr. George Agassiz, and the work of identification and reduction placed on a scientific basis. To give an idea of the work (other than observational) being done at the present time, Miss Cannon states that 199,196 spectra have been classified, and about 150,000 of these have been identified. It is hoped that the observations for the New Draper Catalogue will be finished in six months, and that the printing will be started soon after that time. It is proposed then to make a very careful study of the distribution of the various classes of stellar spectra, "as a portion of the contribution of the Henry Draper Memorial to the greatest of all investigations, the constitution of the sidereal universe." Attention should be directed to the excellent reproductions, which include a portrait of Henry Draper, views of the Cambridge and Arequipa stations, types of stellar spectra, spectra of stars in region of R Cygni, and many others.
THE REPORT OF THE CAMBRIDGE OBSERVATORY, 1914-15.—In the Cambridge University Reporter for June 19 a report is given of the proceedings in the Cambridge Observatory for the period May 19, 1914, to May 18, 1915. The director states that for various reasons not much progress could be made with observational work during the first half of the year under review, but from the beginning of 1915 the conditions of work became more normal. The Sheepshanks equatorial has been the chief instrument in use, and this has been mostly employed in securing photographs to complete the series of plates required for the parallax programme. At present the exposures at each epoch are made on separate plates, but it is hoped ultimately to secure the exposures at the two epochs on the same plate. The meridian circle has been confined to observations for time determination. The Northumberland equatorial seems to be used only on Saturday evenings during term time for the members of the University and their friends. As regards publications, the printing of the Ledger of the Zone Catalogue is near completion so far as the main catalogue is concerned.
THE DESTRUCTION OF FLIES.
The paper contains a representation in the form of A PAPER on "The Destruction of Flies and the
curves of the Cookson results, the international results, and the latter without the Z or Kimura term. The Cookson latitude variation is more in agreement with the last-mentioned curve, and it is pointed out that the agreement on the whole is improved, and more particularly so during the latter half of 1913, when the Z term attained its greatest value during this period.
THE HENRY DRAPER MEMORIAL.-In the work of the classification of the spectra of stars Miss Annie Cannon's name is well known, and as an able member of the staff of the Harvard College Observatory her position renders her admirably suited to describe the pioneer work and progress of the Henry Draper Memorial. Under this title Miss Cannon communicates to the May-June number of the Journal of the Royal Astronomical Society of Canada a most interesting account of the work that has been carried on at both the Cambridge and Arequipa stations of the Harvard College Observatory in the name of Henry Draper, the memorial having been presented by Anna Palmer Draper, the widow of that distinguished investigator and astronomer. A very clear survey is given of the progress of the many lines of research undertaken and successfully accomplished, but these cannot be referred to here, for they are too numerous and space forbids. The enormous amount of data collected
Disinfection of Corpses in the Battle Line," by M. E. Roubaud, is published in the Comptes rendus of the Paris Academy of Sciences for May 25. The author remarks that the hot weather will bring with it the menace of fly outbreaks and consequent epidemics of diseases, and that he has collected the simplest methods of dealing with the problem. For houseflies, he recommends heavy coal tar oils sprayed on the surface of excrement, etc., to prevent access of flies; for sanitary purposes he advises the following:Ferric sulphate Heavy tar oil Water
2500 grams. 500 c.c. 10 litres.
This is stated to be deodorising, larvicidal, and protective against flies.
Heavy tar oils are toxic to plants, and cannot be used when the material is to be employed as manure. Shale oils (miscible oils) he considers more toxic to plants than to larvæ, and he deprecates their use. Cresyl-i.e. miscible cresol-at 5 per cent. in water is not harmful to plants, and manure heaps are to be treated with 15 litres (four gallons) per superficial cubic metre. The exposed areas of the manure heap are then to be protected with a watering of 10 per cent, solution of ferric sulphate. This double treatment is to be carried out twice, in June and in
August; fresh manure as added is to be treated with ferric sulphate.
In regard to blow-flies, M. Roubaud discusses means of preventing access of flies to dead bodies, and the disinfection of corpses. In the first he states that heavy tar oil is to be used, as it preserves animal tissues when 10 per cent. cresyl, chloride of lime, formol, milk of lime, and 5 per cent. phenol fail to do so. Ferric sulphate is to be used as a protective covering, either powdered on or applied as 10 to 20 per cent. solution. The salt forms stable compounds with the tissues which cannot be attacked by flies, and the solution kills eggs and larvæ; the three substances required at the front then are ferric sulphate, heavy tar oil, and cresol.
Some of the author's statements, which are given without proofs, cannot be unreservedly endorsed; for example, it is practically certain that a dead horse powdered with ferric sulphate will still breed innumerable flies unless it is periodically treated. superficial treatment will clear a superficially dry manure heap of maggots; only a vapour treatment applied in liquid form. Also, a 10 per cent. solution of ferric sulphate is a very expensive dressing unless the substance is available in enormous amount; and one of the difficulties of the front is the transport of material. Concentrated treatments are required if possible, not 10 per cent. treatments at great bulk.
The problem of dealing with flies is very difficult, and is receiving much attention. One aspect is being carefully dealt with in this country, and the results will be available very shortly. This is the question of the treatment of the great aggregation of stable manure. The War Office have apparently accepted the American view of the value of borax; already a treatment with volatile liquid at a third of the present cost of borax has been found, which is satisfactory in that it spreads in the manure heaps and is not simply a superficial treatment; and it does not affect the value of the manure for horticultural purposes. Plants will stand very strong applications of volatile organic compounds, far stronger than are required to kill fly maggots, but which compounds are the best has yet to be determined.
HE Air Pollution Advisory Board of the Sanitary Committee of the Corporation of Manchester has recently issued its first report. We are told that this Board came into existence two years ago as the result of a memorial presented to the Corporation by members of various scientific and other societies in the city with the object of examining the latest and best methods of eliminating the smoke evil and of diffusing information on the subject.
The Board consists of representatives of various committees of the Corporation, distinguished men of science, and influential members of numerous public bodies. It is divided into four sections, namely, the chemical, statistical, administrative, and engineering sub-committees. This is not the first occasion on which the public spirit of Manchester citizens has been inspired by the smoke nuisance and exercised itself in an attempt to suppress it. In 1891 a committee of the town gardening section of the Manchester Sanitary Society issued a report on some of the evils of smoke affecting vegetation and the amount of daylight; and in 1895 a 'committee for testing smoke-preventing appliances" published a voluminous and comprehensive report on the various forms of apparatus used in steam boilers which were alleged to diminish or remove smoke.
What the ultimate fate of these two committees was,
the writer is unable to say; but though their activi ties ceased, there is no doubt that they stimulated an interest in the subject which led not only to the formation of the present Board, but had the effect of inducing other municipalities to adopt a similar action. Work of the same character is now being carried on in fifteen other cities. This growing interest which has spread out from Manchester in ever-widening circles also led to the formation of a Local Government Board Committee on Smoke Abatement, which held numerous meetings in the first half of last year. The present report deals mainly with the amount, nature, and extent of air pollution by smoke. The methods, which need not be described in detail, are based upon previous investigations of this character, and the results are not essentially different from those already recorded by other observers.
Valuable as the information is as indicating the extent of atmospheric contamination (which is as injurious as it is wasteful and unnecessary) and in keeping public interest alive to the importance of the economic use of fuel, the accumulation of statistics of a nature already well authenticated will not of itself bring about any radical reform.
We are glad to see, therefore, that the Board has in contemplation the study of all domestic coal-consuming grates and their efficiency, and an extensive propaganda by pamphlets, lectures, and exhibitions among builders and tenants in relation to domestic heating by coal, coke, gas, and electricity. Although a good deal of pioneer work has been done in this direction by various smoke abatement societies, it is just one of the subjects on which the views of the community are so firmly welded to the past that unremitting agitation is necessary before the deeplyrooted tradition in the efficacy of the old-fashioned coal fire can be loosened. When this work is complete, the time will be ripe for the consideration of more drastic measures of smoke abatement, and there is no doubt that had not the advent of the war postponed the deliberations of the Smoke Abatement Committee of the Local Government Board, the report of that committee would have greatly strengthened the hands of the municipalities in any future legisla tion which they may have in view.
In conclusion, we can only congratulate the Manchester Sanitary Committee on the scientific way in which it has set about steadily accumulating evidence and wish it a full measure of success in achieving its ultimate object. J. B. C.
RADIATIONS FROM EXPLODING ATOMS.1 T is now well established that the radio-active substances are undergoing spontaneous transformation, and that their characteristic radiations-the a. B, and y rays-accompany the actual disintegration of the atoms. The transformation of each atom results from an atomic explosion of an exceedingly violent character, and in general results in a liberation of energy many million times greater than from an equal mass of matter in the most vigorous chemical reaction.
In the majority of cases the atomic explosion is accompanied by the expulsion of an actual atom of matter-an a particle with a very high speed. It is known that the a particle is an atom of helium which carries two unit positive charges, and which leaves the atom with a velocity of about 10,000 miles per second. In some transformations no a particle is ejected, but its place is taken by a swift B particle or electron. These B rays carry with them Royal Institution on Friday, Jun: 4, by
1 Discourse delivered at the Sir Ernest Rutherford, F.R.S.