years 1898-1903, he has constructed approximate isotherms between 50° and 80° S. latitude, and thus made an important addition to the valuable yearly isothermal charts published in Dr. Hann's "Handbook of Meteorology." Dr. Hann's southernmost isobar is 4° C., just below Tierra del Fuego; Mr. Krebs continues the isotherms for each 4° C. as far as -16°, which runs near the 70th parallel between longitude 60° E. and 60° W. He also draws portions of the isotherm of -20° C., reaching nearly to the 80th parallel. 66 THE Times of November 29 contains an interesting article on London fogs; although it deals principally with the most elementary physics of the atmosphere, and with the part played by aqueous vapour, the subject is very ably handled and is made both attractive and instructive. The author points out the well known facts that the amount of invisible vapour in the air varies directly with the temperature; by whatever process the cooling of the air takes place, the capacity of the vapour to remain invisible diminishes until the "dew point or saturation point" is reached; any further cooling produces cloud or fog. He states that it is more than twenty years since it was shown that the vapour molecules cannot of themselves combine to form cloud or fog particles, but that solid nuclei of dust, or other impurities, are necessary, on which the vapour molecules can condense. Taking this for granted, it is seen at once why fogs in London (or other large towns) are so much denser than in the open country. For instance, at an elevation of 6000 feet, say on the Alps, the number of dust particles per cubic centimetre may amount to less than 200, while in towns the number may reach 100,000 or 200,000. The vapour in the country, condensed on a few particles of dust, will result in a coarse grained form of condensation, whereas in town the same quantity of vapour being distributed over a very large number of dust particles, there results a fine grained fog. The author points out that it is not the large-sized visible dust that does the damage, but the infinitely small, ultra-microscopic particles produced by combustion of fuel and light; that, in fact, experiments have shown that it is possible for cloudy condensation to take place in the absence of dust. In 1897 (Trans. Roy. Soc. Edin., vol. xxxix.) Mr. Aitken stated that dust particles are not absolutely essential for the production of fog, but that, as the air is full of dust and condensation takes place on these by preference, therefore practically all our cloud particles have dust nuclei. The author concludes, justly, we are afraid, that London will always be liable to fogs, owing to its situation and meteorological conditions; all that can be hoped for is a reduction in the more disagreeable constituent elements; there seems to be, so far, no way of appreciably reducing their frequency or their bad effects. We hope that the experiments begun by Sir Oliver Lodge, with a view to their possible ultimate dissipation by electricity, will be energetically continued. THE Revue Scientifique (Nos. 20 and 21), in continuing its inquiries as to the existence of the n-rays, publishes a letter from M. Blondlot stating that the photographic exposures, the results of which he considers prove the reality of these radiations, were made by a laboratory assistant who was ignorant of the effects he ought to obtain, and was therefore not unconsciously biassed. The obvious rejoinder is made that the results obtained in this way are less to be trusted than if they were due to M. Blondlot himself. M. Lambert claims that his experiments showing that the n-rays exist were made in a manner excluding subjective phenoOn the other hand, MM. Cailletet, Lippmann, mena. Berget, Turpain, and Perrin have all failed to obtain experimental proof of their existence. PART X. of the Transactions of the Royal Dublin Society contains a continuation of the researches of Messrs. W. F. Barrett, W. Brown, and R. A. Hadfield on the physical properties of a series of alloys of iron. It is shown that a remarkable similarity exists between the diminution of the electrical conductivity and the change in the thermal conductivity of iron, which are caused by the addition of other elements. Not only is the general order of the electrical and thermal conductivities the same for all the alloys, but equal increments of any given element appear to produce a corresponding diminution of conductivity for both heat and electricity. It is remarkable that the effect of alloying iron with another element, even a better conductor, is always to reduce both the thermal and the electrical conductivities. The ratio of the two conductivities is, however, not exactly the same for all alloys; on plotting the electrical against the thermal conductivity, a fairly smooth parabolic curve is obtained showing that the ratio increases in magnitude as the conductivity of the alloys increases. THE October part of the Physical Review contains an account by Messrs. C. W. Waidner and G. K. Burgess of a number of measurements which they have made by photometric methods of the temperature of the electric arc. Wien's law of the distribution of energy in the spectrum was assumed as a basis of calculation, and three distinct types of photometers, namely, those of Holborn and Kurlbaum, of Wanner, and of Le Chatelier, were employed. The values obtained for the "black body temperature of an arc of pure graphite by the three methods agreed within 30° C., the average being about 3700° abs. The true temperature of the arc must be higher than this by an amount depending on the departure of the radiation from true "black body" radiation, and may possibly be between 3900° and 4000° absolute. Contrary to the usually accepted view, the temperature of the arc does not appear to be independent of the current, and it is undoubtedly influenced by the degree of purity of the carbons forming the arc. With impure carbons, the temperature is lower by 40° C. than in an arc of highly purified graphite. Such variations would appear to preclude the suggested use of the brightest part of the positive carbon of the electric arc as a standard source of light. THE second number of the Extensionist, which is a record of the University Extension Guild, has reached us. In addition to numerous descriptive notes on the work of the guild, this issue contains addresses by Sir Arthur Rücker, F.R.S., Mr. Hilaire Belloc, and Mr. Banister Fletcher. THE Infants' Health Society has published a pamphlet entitled "The Present Conditions of Infant Life, and their Effect on the Nation,' "which directs attention to the almost complete failure of our present method of rearing the infants of the working class. In the poorer parts of the larger towns and cities it is not uncommon for nearly half the children born to die in infancy. The dominating cause of this appalling mortality is the improper feeding of the infant. BECKER BECKER HATTON WALL LONDON' ER BECKER KER NOW READY. ILLUSTRATED CATALOGUE OF PHYSICAL APPARATUS, COVERING SOUND, LIGHT, HEAT, MAGNETISM, Nearly 4,000 Illustrations. "NATURE says: "The new illustrated catalogue of physical apparatus just issued by Messrs. F. E. Becker and Co. (Messrs. W. and J. George, Ltd.) is likely to prove indispensable in the physical laboratories of all our schools and colleges. It runs to 628 large pages, and is strongly bound in cloth. Full particulars are provided, not only respecting the apparatus required in elementary and advanced physical teaching, but also concerning that necessary to the physicist in his research work. All branches of physics are included, and the instruments throughout are explained by excellent illustrations and concise descriptions, and, what is of prime importance, the figure and its appropriate text are close together." "CHEMICAL NEWS" says: at "Messrs. F. E. Becker and Co. (W. and J. George, Ltd., successors) have just issued a new Illustrated and Descriptive Catalogue of Physical Apparatus, &c., manufactured by them. This is the largest and best English catalogue of its kind printed, and comprises some 680 pages and over 4,000 illustrations; herein will be found all the newest up to date apparatus with all the latest improvements as manufactured their works, while all obsolete apparatus has been omitted. The whole catalogue is arranged in a very clear manner under a number of principal headings, such as Magnetism, Heat, Sound, Light, Mechanics, Electricity, Pneumatics, Meteorology, X-ray Appar atus, &c., and a good index is provided; in fact, everything possible has been done to make this as perfect a guide as possible to users of apparatus in the subjects touched upon.' "KNOWLEDGE" says: "Messrs. F. E. Becker and Co. (W. and J. George, Ltd., Successors) have sent us a copy of their new list of apparatus in the various departments of Physics, including Sound, Light, Heat, Magnetism, Electricity, Mechanics, &c. This exhaustive catalogue consists of over 600 pages and some 4000 illustrations. One of its noteworthy features is that the requirements of science teaching in this country and its colo. nies are always kept in view, and the articles listed cover the latest developments in their subjects. The method adopted in the list itself, together with the completeness of the index, is such as to make reference to it simple and expeditious." 66 SCHOOL WORLD" says: "The science-master in every grade of school should possess a copy of the new catalogue of Messrs. George, for he will find here particulars as to the available apparatus in sound, light, heat, magnetism, electricity, mechanics, and other branches of physics, with information as to price and other necessary details. There is a profusion of welldrawn illustrations, which, together with the clearly expressed descriptions, will serve to explain to any buyer exactly what he is purchasing. This excellent catalogue will form a valuable addition to the reference library of any physical laboratory." BECKER BECKER BECKER BECKER LONDON CONSTABLE & CO.'S LIST. MAXWELL'S THEORY AND WIRELESS TELEGRAPHY. Part I.-Maxwell's ENTROPY: or THERMODYNAMICS, from an ENGINEER'S STANDPOINT. "... May be recommended to all who desire a true and thorough conception of the phenomena of heat and the principles that determine the efficiency of heat motors."-Mechanical Engineer. WANDERINGS IN THE GREAT FORESTS OF BORNEO. Travels and Researches OF A NATURALIST IN SARAWAK. By Dr. ODOARDO BECCARI. Revised and Edited by F. H. H. GUILLEMARD, M.A. Demy 8vo. With numerous Illustrations and Maps. 165. net. SCIENCE AND IMMORTALITY. By William Osler, M.D., F.R.S., Regius Professor of Medicine at Oxford. 25. 6a. CLINICAL AND PATHOLOGICAL OBSERVATIONS ON ACUTE ABDOMINAL DISEASES. By EDRED M. CORNER, B.Sc. Lond., M. A., M.B., &c. Demy 8vo. 35. 6d. net. ANTI-TYPHOID INOCULATION. A Short Treatise, containing an Exposition of the PRINCIPLES OF THE METHOD AND A SUMMARY OF THE RESULTS ACHIEVED BY ITS APPLICATION. By A. E. WRIGHT. M.D. (Univ. of Dublin), late Professor of Pathology, Army Medical School, Netley; Pathologist to St. Mary's Hospital, Paddington. Price 3s. 6d. net. By Dr. Laumonier. Translated and Edited NEW METHODS OF TREATMENT. By Dr. Laumonier. from the Second Edition by W. H. SYERS, M. A., M. D. Crown 8vo. Price 7s. 6d. net. THE SURGERY OF THE DISEASES OF THE APPENDIX VERMIFORMIS AND THEIR COMPLICATIONS. By WILLIAM H. BATTLE, F.R.C.S., and EDRED M. CORNER, M.B., B.Ch., F. R.C.S. Demy 8vo. Price 7s. 6d. net. THE LYMPHATICS. By G. Delamere, P. Poirier, and B. Cuneo. C. H. LEAF, M.A., M.D., F.R.C.S. With 117 Illustrations and Diagrams. Price 18s. net. Translated by "An excellent account of the present state of knowledge of the lymphatics . . . will prove useful to the anatomist, the physiologist, and the practitioner."-The Lancet. CLINICAL CAUSES OF CANCER OF THE BREAST. By Cecil H. Leaf, F.R.C.S. Demy 8vo. 16 JAMES STREET, HAYMARKET, S.W. 25. net. 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