December i, 1904] 



NA TURE 



113 



and Britain have issued three series of maps, containing 

 sixty-one sheets worlied out on the same scale and in the 

 ■same style of division of sheets. These maps cover nearly 

 10,000,000 square miles, and will ultimately embrace the 

 whole of Africa, and large parts of Asia and America. It 

 will be remembered that the congress adopted a resolution 

 proposing to the Government of the United States the 

 execution of a similar general map of America. 



In a recent number of the Bulletin of the Italian Aero- 

 nautical Society Dr. L. Palazzo, director of the Italian 

 Meteorological Service, gives a very interesting account of 

 the scientific experiments in Italy with unmanned balloons. 

 The paper contains photographic illustrations of the balloons 

 ■employed, of the methods of filling them, of their flight in 

 mid-air, and of the records of the instruments. The place 

 chosen for the aeronautical station is Pavia, principally 

 owing to its geographical suitability and its distance from 

 mountains and sea. The balloons used are a preparation of 

 india-rubber, and are made by the Caoutchouc Company, of 

 Hanover. They are sent up in tandem fashion, and are 

 spherical and closed, and have the faculty of expanding to 

 about seventy times their original volume, rising rapidly to 

 an altitude of 20,000 metres and upwards, where a tempera- 

 ture of 60° C. below zero may be recorded. The upper 

 balloon eventually bursts ; the second balloon, which is 

 smaller and not fully inflated, does not burst, but acts as a 

 kind of parachute, which commences to fall rapidly at first 

 and afterwards more gradually. It carries the registering 

 apparatus attached to it by a line, and is intended to attract 

 the attention of persons in the neighbourhood of its descent. 

 The instruments generally reach the ground somewhat 

 gently, and are seldom broken. Dr. Palazzo acknowledges 

 the assistance he has received from Profs. Hergesell and 

 Assmann in inaugurating these important experiments. 



We have received a reprint of a paper published by Prof. 

 A. Righi in the Atti del Lined, vol. xiii., ii., 233, under the 

 title of " Certain Phenomena Observed in Air which is 

 Ionised by Radio-active Substances " ; experiments are de- 

 scribed which show the necessity that exists in making 

 measurements of the ionising power of radio-active sub- 

 stances by means of the various forms of gold-leaf electro- 

 scopes to take into account the position of the leaves re- 

 latively to the walls of the electroscope, and to the direction 

 of the ionising rays. 



In a paper published in the Physikalische Zeitschrift 

 (No. 20), C. Liebenow calculates that the presence of 

 1/5000 of a milligram of radium per cubic metre distributed 

 uniformly throughout the earth's volume would be sufficient 

 to compensate for the loss of heat which is caused by con- 

 duction through the crust, and thus to maintain the earth's 

 interior at a constant temperature. The concentration 

 which is here assumed is considerably less than that actually 

 observed by Messrs. Elster and Geitel to hold for radium 

 in various kinds of natural earths, but it may perhaps be 

 assumed that the proportion of radium is greater in the 

 crust of the earth than at the interior. In any case, the 

 need becomes apparent of making allowance in all calcula- 

 tions dealing with the earth's rate of cooling, for the re- 

 markable thermal effects of radio-active substances. 



In No. 17 of the Revue Scientifique, Prof. R. W. Wood's 

 recent letter to Nature (vol. Ixx. p. 530) calling into 

 <|uestion the existence of the n-rays is reprinted, and in 

 No. iS an editorial article discusses in detail the character 

 of the evidence on which they are alleged to exist. In 

 No. ig of the Revue the opinions of Profs. Berthelot, Bouty, 

 Pellat, Langevin, and Abraham have been ascertained with 

 NO. I 83 I, VOL. 71] 



regard to the matter. Of these expressions of opinion, that 

 of M. Langevin is the most emphatic ; after making many 

 experiments, he concludes that in no case in which the 

 observer is unaware of the result he is to obtain is there 

 the slightest evidence of the existence of these rays, whilst 

 on the other hand the experimenter can readily so dispose 

 his mind as to see whatever he wishes to see. The general 

 attitude which is taken up in these articles is that the 

 observed phenomena are purely subjective, and due to 

 suggestion ; they are consequently more likely to prove of 

 importance to the psychologist than to the physicist. 



In the October number of the Gazzetla G. Bruni and A. 

 Callegari have established by means of cryoscopic measure- 

 ments the remarkable fact that in many cases the nitroso- 

 group in organic substances is isomorphous with the nitro- 

 radical. The formation of solid solutions in such cases is 

 also made evident by peculiar colour phenomena. Whilst, 

 for instance, a solution of nitrosobenzene in benzene is 

 green, but becomes colourless when frozen, a solution in 

 nitrobenzene, which has the same colour, remains green 

 after solidification. In the former case solid colourless 

 nitrosobenzene has separated, whilst in the latter a solid 

 solution of the substance in the solidified solvent is formed, 

 which, like the liquid solution, is coloured green. 



The numerous attempts which have been made to decide 

 by physical methods the nature of isodynamic substances 

 such as ethyl acetoacetate and acetylacetone have given rise 

 to widely differing opinions. Thus Bruhl, for instance, has 

 considered that the optical properties of acetylacetone 

 between 0° C. and 100° C. prove that, between these 

 temperatures, it exists solely in the di-enolic form 



CH3.C(OH):C:C(OH).CH„ 

 whilst Dr. W. H. Perkin, from a study of the magnetic 

 rotatory power of the same substance, considers that at 

 16° C. it consists of a mixture of this form with the keto- 

 enolic modification, and at 93° C. of a mixture of the keto- 

 enolic and diketonic varieties. In the October number of 

 the Gazzetta F. Giolitti shows that at about 70° C. a re- 

 markable change in the expansibility of acetylacetone occurs 

 which conforms with Perkin 's view of a change of struc- 

 ture at a temperature between the limits 16° C. and 93° C. 

 The variation in the expansion of ethyl acetoacetate between 

 ^ 10° C. and 100° C. is, however, perfectly linear, apparently 

 indicating that at these temperatures only one form exists, 

 or that the rate of change of one form into another is 

 uniform between these limits. 



A CORRESPONDENT points Out that in Nature of 

 November 24 (p. 88, line 19 from top, first column) the name 

 Sansaulito is a misspelling for a well known locality near 

 San Francisco. The correct spelling is Saucelito, which 

 means "little willow," from Sauce, willow, in Spanish. 



We have received from Messrs. F. Darton and Co., of 

 142 St. John Street, E.C., a well illustrated catalogue of 

 electrical novelties. The pieces of apparatus, toys, and 

 household devices of which particulars are given are in- 

 genious in design, and some of them would make instructive 

 presents for boys with a mechanical turn of mind. 



Messrs. W.^tts and Co. will issue on December 7 for 

 the Rationalist Press Association an English translation 

 of Prof. Haeckel's " Die Lebenswunder, " under the title 

 of " The Wonders of Life. " The chief aim of Prof. Haeckel 

 in this work is to present a mass of biological evidence for 

 the views as to the origin and nature of life which he 

 briefly advanced in the " Riddle of the Universe." 



