July 28, 1910] 



NATURE 



1 19 



Terrestrial Magnetism and Atmospheric Electricity for 

 June contains an article by Dr. L. A. Bauer and Mr. W. J. 

 Peters in which the complete magnetic results of the first 

 cruise of the Carnegie are given. After an extensive series 

 of tests of the vessel at Long Island, it was found that a 

 determination of any magnetic element could be made on 

 it with an absolute accuracy not far behind that attained 

 by experienced observers on land. This conclusion was 

 confirmed by further observations made at Falmouth at the 

 end of the trip across the Atlantic. The observations made 

 at sea show that the present charts of the Atlantic require 

 revision, as they show compass variations which are in 

 many cases more than i° in error, and in some cases more 

 than 2°. These errors appear to have been introduced by 

 the application of a correction for secular variation at 

 points at which no determinations of that quantity had been 

 made. A further paper by Mr. E. Kidson deals with the 

 observations of electrical conductivity and of radio-activity 

 of the atmosphere made during the cruise. The con- 

 ductivity was determined by means of a Gerdien apparatus, 

 and always proved low in the neighbourhood of land, and 

 persistently higher for positive than for negative electricity. 

 At night the conductivity appears to be nearly constant, and 

 about double what it is during the day. It will be seen 

 that these observations are likely to render some modifica- 

 tions of the current theories of atmospheric electricity 

 necessary. The radio-activity was determined by the nega- 

 tively charged exposed wire method, the decay of activity 

 of the wire being observed by means of an electroscope. It 

 appears to be due to radium emanation and to be derived 

 from the land. 



.\ " Short History of the Academy of Natural Sciences 

 of Philadelphia " has been prepared by Dr. Edward J. 

 Nolan, recording secretary and librarian, and published by 

 the academy. This sketch of the academy's activities is 

 to be regarded as preliminary merely to a detailed history 

 to be issued in connection with the proposed celebration of 

 the centenary of the academy in 1912. The academy 

 accomplishes its work in four departments — the library, the 

 museum, the publication oflfice, and the department of in- 

 struction and lectures. The library, exclusively for refer- 

 ence, now contains about 60,000 volumes, almost entirely 

 on the natural sciences ; in many respects it is the most 

 important collection of the kind in America. It is claimed 

 for the academy's museum that it is one of the most 

 important in existence. The vertebrate animals number 

 about 130,000 specimens, 12,000 being mammals, 60,000 

 birds, 20,000 reptiles, and 40,000 fishes. The insects are 

 estimated at nearly 400,000 specimens, and the shells at a 

 million and one-half. There are in the cases 50,000 speci- 

 mens of fossils, 30.000 minerals, 20,000 pieces of archaeo- 

 logical material, and more than 600,000 preparations of dried 

 plants. The remaining departments are equally extensive 

 and enterprising. The academy has twice received appro- 

 priations from the State legislature, 4000^. in 1905 and 

 30,000!. in 1908. 



A VALLABLE supplement to the meteorological observa- 

 tions undertaken by the University, Manchester, has 

 been described by Messrs. Hayhurst and Pring under the 

 title " Examination of the Atmosphere at Various Alti- 

 tudes for Oxides of Nitrogen and Ozone," in the Journal 

 of the Chemical Society. Previous estimates of the amount 

 of ozone have ranged from o-oi to 31-6 milligrams per 

 cubic metre for the minimum quantity found, and from 

 003 to 158-0 for the maximum quantity, figures which 

 appear to indicate a range of e.xperimental error in the 

 ratio of 3000 to i. The very high values found by several 

 NO. 2126, VOL. 84] 



observers are no doubt due to the catalytic action of oxides 

 of nitrogen upon potassium iodide solutions exposed to 

 air, whereby a mere trace of oxide may act as a " carrier " 

 of o.xygen to an indefinitely large quantity of iodide; the 

 similar action of sunlight in promoting oxidation of the 

 iodide is also important as a further source of error. In^ 

 the e.xperiments now described, air was blown through 

 bulbs containing potassium iodide either at ground-level or 

 attached to kites or balloons; the bulbs were protected 

 from light, and the presence of ozone was inferred, not 

 from the mere liberation of iodine, but from the produc- 

 tion of alkali and iodate. When this criterion was 

 employed, it was found that whilst oxides of nitrogen were 

 present in variable proportions, the amount of ozone at 

 ground-level and at altitudes up to 8000 feet was less thai* 

 0-003 mg- in 1 to 10 cubic metres, or less than i part by 

 volume in 4,000,000,000 parts of air. At very high alti- 

 tudes, up to ten miles, small amounts of ozone were 

 detected, the quantity found averaging 0-04 milligram in 

 o-i to 0-3 cubic metre of air, or i part in 3,000,000 to 

 9,000,000 by volume. These experiments are of value as 

 showing that the presence and merits of ozone in the 

 fresh air of sea and country are as much a matter of 

 fiction as the substantial excess of oxygen which was dis- 

 covered by over-zealous investigators prior to the researches- 

 of Cavendish ; in fact, the only method of enjoying the 

 effects of atmospheric ozone appears to be by ascending- 

 in a free balloon, which bursts and descends as a para- 

 chute after rising to a height of several miles. 



Commenting on the Bournemouth Aviation Meeting, 

 Engineering for July 22 remarks that perhaps the most 

 interesting feature of the meeting from the technical point 

 of view is the fact that all the best performances were done 

 with aeroplanes fitted with the Gnome rotary engine. Ir> 

 fact, it seemed as if no machine which was not fitted with 

 this engine had any chance of success. All engines of 

 other types appeared to give trouble, and not to be able to 

 furnish the desired power for any long time at a stretch. 

 In some cases the trouble was hot bearings, especially big 

 ends. In others the engine appeared simply not to be able 

 to maintain its power, and, after flying a short distance, 

 it could not sustain the machine in the air. The perform- 

 ances of the English engines were disappointing. 



A NEW book by Dr. Berry Hart, of Edinburgh, entitled 

 " Some Phases of Evolution and Heredity," will be issued 

 very shortly by Messrs. Rebman, Ltd. 



We have received from Messrs. Friedlaender, 11 Karl- 

 strasse, Berlin, a copy of the third part of a catalogue of 

 entomological books and papers, this being devoted to 

 Lepidoptera ; also a catalogue of books on natural history, 

 sports, travel, &c., offered by Mr. B. H. Blackwell, 50 

 Broad Street, Oxford. 



Messrs. Swan Sonnenschein and Co., Ltd., will issue 

 shortly a companion volume to Dr. Theal's " History of 

 South Africa," to be entitled "The Yellow and Dark 

 Skinned People of Africa." This will contain a summary 

 of all that is included in Dr. Theal's " History and Ethno- 

 graphy of South Africa " (3 vols.), and is especially in- 

 tended for the use of ethnographical students. 



The latest addition to the series of " Savants du Jour," 

 published by M. Gauthier-Villars, of Paris, deals with the 

 life and work of Prof. Emile Picard, of the University of 

 Paris. Prof. Picard was born in Paris on July 24, 1856, 

 and his biography, as here written by M. Ernest Lebon, 

 shows a growing regard from his school-days for algebra 

 and mathematical analysis, which eventually led in 1897 to 



