SCIENCE- GOSSIP. 



contributed by w. h. cadman. 



Use of Kites in Studying the Atmosphere. 

 During- the last few years kites carrying meteoro- 

 logical instruments have been employed at 

 several observatories for exploring the upper 

 regions of the atmosphere. One great difficulty, 

 well known to every kite-flyer, prevented anything 

 like systematic observations being made. Unless 

 a sufficiently strong wind was blowing, the kites 

 carrying the physical instruments could not be 

 flown. Strange to say, this obstacle is now over- 

 come by a practical application of that instinctive 

 action of every child when attempting to fly a kite 

 in little or no wind. The artificial wind created 

 by the running child to raise his kite is ob- 

 tained on a larger scale by means of a rapidly- 

 moving tug-boat. In this way large kites can be 

 raised in comparatively calm weather by the motion 

 of the earth-end of the kite string or wire. Mr. A. 

 L. Rotch raised his instruments to a height of 

 2,670 feet, and states that his kites rose easily and 

 steadily in the artificial wind. His experiments 

 show conclusively that, with a steamer which can 

 be manoeuvred at will, kites can be flown at sea in 

 almost all weather conditions. A great field is 

 thus opened for investigation of the conditions 

 existing at various heights of the atmosphere above 

 the ocean. All such records of the barometric 

 pressure, air temperature, relative humidity, and 

 wind velocity will be of great value to science. 

 It is gratifying to learn from the " United States 

 Monthly Weather Review " that the German South 

 Polar Expedition will systematically make kite 

 ascensi ns in the Antarctic regions. The expedi- 

 tion was fully equipped before starting with kites 

 " of three sizes suitable for lifting and sustaining 

 the instruments in high or light winds. An account 

 of the exploration of the upper air conditions in 

 the Polar regions will be very welcome. 



Density op Aqueous- Solutions. — The 

 " Comptes Rendus " contains an account by L. C. 

 de Coppet on the " Maximum Density of Aqueous 

 Solutions." The author has made a careful study 

 of the lowering of the temperature of maximum 

 density of water produced by the solution of vari' us 

 chlorides, bromides, and iodides, chiefly those of 

 the alkali metals. In accordance with the law of 

 Despretz, the lowering of the temperature of 

 maximum density is found to be proportional to 

 the quantity of substance dissolved, and except in 

 the case of lithium the molecular lcwerings are 

 nearly constant. 



Attraction of Mosquitoes by Sounds.— At 

 this time, when the destruction of these insects is 

 so much needed, because of the relation between 

 them and the spread of yellow fever, any informa- 

 tion about their habits must be of general interest. 

 Sir Hiram S. Maxim's observations in New York are 

 remarkable. One evening he found everything in 

 the neighbourhood of a box containing the dynamo 



machine, under an electric lamp, covered with 

 small insects, which were identified as mosquitoes. 

 On closer inspection he perceived that the box 

 emitted a feeble musical note, the sound of which 

 attracted the mosquitoes. Although there was a 

 larger proportion of female mosquitoes in the dis- 

 trict, only the males were attracted to the box by 

 the sound. Sir Hiram Maxim remarks that " when 

 the lamps were started in the beginning of the 

 evening, every male mosquito would at once turn 

 in the direction of the lamp and, as it were, ' face 

 the music,' and then fly off in the direction from 

 which the sound proceeded. It then occurred to 

 me that the two little feathers on the head of the 

 male mosquito acted as ears, and vibrated in unison 

 with the music of the lamp ; and as the pitch of 

 the note was almost identical with the buzzing of 

 the female mosquito, the male took the music to be 

 the buzzing of the female." This explanation seems 

 quite feasible when it is remembered that in no 

 case was a single female attracted by the sound. 

 The above observation may prove of valuable assist- 

 ance to those who are now experimenting upon the 

 best means of destroying these fever-spreading 

 insects. 



Zeeman Effect. — A paper on •' Asymmetry of 

 the Zeeman Effect " has been communicated to the 

 London Physical Society by Mr. G. W. Walker. 

 An asymmetry of the normal triplet was predicted 

 by Voigh and verified by Zeeman, and as the result 

 of mathematical investigation it is now found that 

 asymmetry may arise as a second-order term clue 

 to the magnetic field. The effect, which is ex- 

 tremely small, would be more distinct the greater 

 the field, and it is claimed that the theory provides 

 an explanation of the reason why a line may not 

 be resoluable. 



Change of Magnetic Resistance of Metals. 

 Some very interesting results upon the change 

 of magnetic resistance for various metals have 

 recently been obtained by Mr. Guy Barlow, one of 

 the first Fellows of the University of Wales. The 

 conclusion arrived at by previous investigators on 

 this subject was that the change of magnetic 

 resistance is directly proportional to the square of 

 the magnetisation. Mr. Barlow's experiments, 

 carried out in the laboratory of Professor E. Taylor 

 Jones at Bangor, prove that this is not the case. 

 The metals were used in the form of wire sur- 

 rounded with non-conducting material and enclosed 

 in glass tubes. These were further surrounded by 

 other glass tubes, through which a steady flow of 

 water passed. In this way great care was taken to 

 keep the temperature of the wires perfectly constant. 

 The importance of these precautions will be seen, 

 when it is remembered that the change of resist- 

 ance of a metal wire placed in a magnetic field is 

 always small, so that variation of resistance, with 

 any alteration of temperature, might easily swamp 

 the effect of magnetisation. Mr. Barlow's first 

 series of experiments were made with the axis 

 of the wire along the lines of magnetic force. 

 Electro-magnets of widely different strength were 

 used for obtaining the magnetic field. The ordinary 

 Wheatstone's bridge method was used for measur- 

 ing the resistance, though elaborate precautions 

 were taken to avoid contact currents; and eventu- 

 ally very consistent readings were obtained with 

 the galvanometer. The results of the experiments 

 were plotted in curves, which in the case of soft 

 iron, nickel, and steel, the metals employed, were 



