592 



NA TURE 



[April 23, 190; 



A second edition has appeared of the " Meteorologia 

 Dinamica," by P. A. Rodrigues de Prada, director of the 

 Vatica 01 rvatory. Il is published in Madrid, and deals 

 with atmospheric tides, winds, cyclones, and air currents 

 generally. 



Messrs. Hoepli, of Milan, have issued the second edition 

 of Ingegnere G. Vacchelli's book on " Le Costruzioni in 

 Calcestruzzo," the first edition of which appeared in 1899. 

 It is one of the Manueli Hoepli, and deals with the pro- 

 perties of concrete, cement, and hydraulic lime, and their 

 uses for building purposes. Special attention is given to 

 the use of cements in the construction of bridges and sub- 

 merged structures. 



In the Atti dei Lined, x i i . , 6, Signor G. Guglielmo 

 describes a method of determining the work-measure oi I It 

 specific heat of water, which resembles the classical experi- 

 ment of Joule in that the liquid is raised in temperature 

 by agitation, but the liquid is contained in a closed vessel 

 (the calorimeter of Fabre and Silbermann was used) having 

 paddles or blades fixed projecting into the interior, and the 

 agitation is effected by rotating the vessel alternately in 

 one sense and then in the other. 



Some months ago the French Physical Society commenced 

 the publication of a collection of elementary experiments 

 in physics, and invited the cooperation of the members in 

 describing experiments or details of apparatus which 

 they had found useful, especially for teaching purposes. In 

 a further circular the secretary, M. H. Abraham, states that 

 the first part, dealing with geometry, mechanics, gravita- 

 tion, hydrostatics and heat, is nearly complete, and the 

 second part, dealing with acoustics, optics and electricity, 

 is already in course of preparation. 



The French Physical Society held its annual exhibition 

 of apparatus in Paris last week. The entrance hall and 

 vestibule were lighted with " heliophone " lamps of the 

 French Incandescent Gas Company, the staircase and 

 ground floor by the French Oxyhydrogen Company, and the 

 entrance hall of the first floor by Nernst lamps. Con- 

 ferences were held in the Physics Theatre of the Faculty 

 of Sciences on April H>, 17 and 18, at which the following 

 papers were read : — On anomalous propagation of the form 

 of vibrations in the neighbourhood of a focus, by M. G. 

 Sagnac ; recent researches in radio-activity, by M. P. Curie; 

 experiments on electric convection, by MM. Cr^mieu and 

 Pender ; and further experiments on electric convection, by 

 M. Vasilesco Karpen. 



The Bulletin de la Sociiti d' Encouragement lor February 

 2S contains two papers of interest in connection with the 

 problem of aerial navigation. In the first of these M. 

 Barbet describes the latest experiments by M. Canovetti, 

 of Brescia, on the resistance of the air to moving bodies 

 of various shapes. The method, which has already been 

 described in previous papers, consists in attaching the body 

 under observation to a small trolley (chariot) which descends 

 under gravity, along a wire 380 metres long stretched 

 from the top of the fortifications at Brescia to a point on 

 the plain below, the difference of altitude being 70 metres. 

 By comparing the times of descent with those observed 

 when the resisting body was removed, an estimate was 

 formed of the coefficient of resistance. From experiments 

 with aeroplanes, M. Canovetti found that an aeroplane of 

 200 square metres, weighing 1000 kilograms, moving at 1 

 speed of 16 metres per second, would require 100 horse- 

 power to maintain it in the air, and that under these con- 

 ditions the problem was impossible ; further, that more power 



NO. 1747, VOL. 6/] 



was necessary for driving an aeroplane through the air than 

 for propelling an automobile of equal weight on a road. 

 By experiments on the resistance of two circular discs placed 

 one behind the other, M. Canovetti has plotted the form 

 of the cone of air entrained by a moving disc. 



In the second paper Commandant P. Renard discusses 

 the conditions of safety of navigable balloons, and suggests 

 to the Sociiti d 'Encouragement a list ol seventeen questions 

 which should be put to the inventor of every navigable 

 balloon before offering him official support or assistance. 

 These questions refer to the provision of an adequate 

 secondary gas bag (ballonet), which can be inflated by a 

 sufficiently powerful ventilator driven by an independent 

 motor, the satisfaction of the conditions of longitudinal 

 stability, the avoidance of rigid parts, especially in the 

 neighbourhood of the balloon, the arrangement of the 

 motor and the gas valves in such a way as to minimise 

 the danger of the escaping gases accumulating where they 

 could be set on fire by the motor, the refrigeration of the 

 gases escaping from the motor, the provision of fire ex- 

 tinguishing appliances, and last, but not least, the all- 

 important question, " Are you a good aeronaut, or do you 

 intend to take one with you? " 



To the March number of Petermann's Mitteilungen Heir 

 Arno Senfft contributes the first part of a paper on the 

 ethnography of the island of Yap, in the Carolines. The 

 botany of the Carolines has been treated by Prof. Volkens 

 in his memoir on " Die Vegetation der Karolinen," and the 

 geology by Dr. Kaiser in a paper published by the German 

 Geological Society in 1902 ; Herr Senfft's paper is an im- 

 portant contribution towards the complete description oi 

 the group. 



In the Zeitschrift der Gesellschajt fiir Erdkundc zu 

 Berlin, Dr. G. Wegener gives an account of the volcanic- 

 eruptions which occurred on Sawaii, in the Samoa islands, 

 in the beginning of November last. There seems to be a 

 good deal of evidence, geological and traditional, to show 

 that volcanic disturbances occurred in the island within 

 comparatively recent times, possibly about 200 years ago. 

 The present activity is particularly interesting, because, after 

 a long period of quiescence, the eruptions have recommem ed 

 without any violent display of energy. 



From the Smithsonian Institution we have received a . op) 

 of a paper by Mr. R. S. Bassler on the structure of the 

 extinct bryozoan genus Homotrypa, with descriptions of new 

 species. 



In a recent issue of the Proceedings of the Boston 

 Natural History Society (vol. xxxi., No. 1), Mr. M. T. 

 Thomson describes the larva of Naushonia crangonoides, a 

 rare shrimp, at present known in the adult condition by one 

 specimen from Naushon Island and a second from Rum 

 Island, both in the neighbourhood of Wood's Hole. 



In describing the best mode of rearing the curious larva 

 of the annelid Polygordius, Prof. W. K. Brooks, in the 

 Johns Hopkins University Circulars for March, comments on 

 the circumstance that the adult has not hitherto been taken 

 on the American coast. This he believes to be due to the 

 lack of a sufficiently careful search. 



According to Science of March 27, the American Morpho- 

 logical Society and the zoologists of the central and 

 wcsti-rn States have combined forces, under the title of the 

 American Society of Zoologists, of which there is to be a 

 western and an eastern branch. It is expected that the 

 new body will meet once in three years, the meetings to be 

 held alternately in the territories of the two branches. 



