June 19, 1919] 



NATURE 



II 



the manufacture and uses of ferro-alloys and alloy 

 steels from the raw materials in Australia, and with 

 substitutes for tin-plate containers (tin cans). The 

 latter is a specially interesting report, giving informa- 

 tion as to the manufacture of wood and cardboard 

 containers and of the machinery used, varnishes, the 

 properties of the different materials, etc. 



Booklets have reached us from the firm of Messrs. 

 Adam Hilger, Ltd., describing the wave-length 

 spectrometer introduced in 1904 and various acces- 

 sories which may be employed in connection with the 

 instrument. The constant deviation prism is rotated 

 bv means of a fine steel screw, to which is fixed a 

 drum provided with a scale of wave-lengths. In the 

 most recent instruments this scale is on the side of 

 the drum towards the eye, so that the wave-lengths 

 can be read without quitting the eyepiece. In one 

 form of the instrument provision is made for the 

 use of a Fabry and Perot etalon, by means of which 

 wave-lengths may be determined to a very high 

 accuracy, or for a Michelson echelon or a Lummer- 

 Gehrcke parallel plate for demonstrating the Zeeman 

 effect. Another development of great importance is 

 the improved form of polarisation photometer, based 

 on that described by P. G. Nutting, which, when used 

 in conjunction with the constant deviation spectro- 

 meter, provides a powerful tool for spectro-photometry. 

 The attention of the technical chemist may usefully 

 be directed to this method of investigation, which has 

 already proved of service in research on dyes and on 

 photographic plates. 



In a paper 'on " Electrical Phenomena occurring 

 at High Levels in the Atmosphere," recently read 

 before the Institution of Electrical Engineers, Dr. S. 

 Chapman gives "a general outline of the subject, 

 without detailed argument or references." "The 

 account," he adds, "is not limited to what can be 

 regarded as certain conclusions; without departing 

 too far from the basis of observational evidence, con- 

 jectural views have also been admitted." Dr. Chap- 

 man seems finally to accept the Birkeland-Stormer 

 theorv as to the joint cause of magnetic storms and 

 aurora being electrical ions discharged from the sun, 

 but in opposition to Birkeland he thinks these must 

 be o-ravs, not cathode- or /3-rays. During magnetic 

 storms he accepts a highly ionised layer coming down 

 to about 100 km. above the earth's surface. At a 

 lower level he sunposes normally existent a second 

 conducting laver, its ionising agent being ultra-violet 

 light, which he identifies with 7-rays. In it are the 

 electrical currents to which the regular (solar) diurnal 

 variation is ultimately due-. Accepting as a fact that 

 magnetic storms are not accompanied by special 

 changes of electrical potential gradient at the earth's 

 surface, it is supposed that the upper atmosphere is 

 so good a conductor that the charge from the_ o-rays 

 almost instantaneously distributes itself uniformly 

 over a spherical surface, and so does not influence the 

 electrical field at lower levels. The sudden rise and 

 the subsequent slow decline of horizontal force charac- 

 teristic of magnetic storms in low and mean latitudes 

 are ascribed to vertical movements of the atmosphere, 

 cutting the horizontal lines of the earth's magnetic 

 field. "The general nature of the movement can be 

 readily inferred. The mutual repulsion of the en- 

 tangled charge spread over the world-wide spherical 

 layer produces an upward, outward movement, as in 

 a charged soap-bubble. Thus the air travels vertically 

 upwards, except during the first few minutes of a 

 magnetic storm. For at first the downward momen- 

 tum of the injected particles depresses the air before 

 the electricity has accumulated sufficiently to reverse 

 the motion." 



NO. 2590, VOL. 103] 



The possibilities of exploitation of the River Dee, 

 from its source in Wales to the city of Chester, for 

 the development of low-fall water-power, econcwnically 

 utilisable for the generation of electrical energy, is 

 the subject of a recently issued report by Mr. S. E. 

 Britten, arising out of" a conference held in June, 

 1917, by the Board of Agriculture and Fisheries. 

 The Engineer for May 30 contains a resume of the 

 report, from which we gather that Mr. Britten's 

 scheme provides for sixteen power-stations at various 

 points along the river's course, with falls generally 

 ranging from yi ft. to 12^ ft. (there is one case of 

 a 37-ft. fall), and capable of producing in the aggre- 

 gate 60,000,000 electrical units per annum. The 

 capital cost of the scheme is estimated at 702,240^, 

 and, with an average sale of about 48,000,000 units 

 at i^d. per unit, a surplus balance of 205,468^. is 

 counted upon. Included in the estimate are the six- 

 teen hydro-electric stations at 29,700^. each, a tunnel 

 at 60,000^., and sixty-one miles of transmission line 

 at 65,000^. The possibilities of the scheme for pro- 

 ducing power are equivalent to a consumption of 

 70,000 tons of coal per annum. The valuable charac- 

 teristics of the river for salmon-fishing have not been 

 lost sight of. The quantity of fish caught annually is 

 about 2500, with a gross weight of 13 tons, valued 

 ^t 3750/. From six years' observation made in con- 

 nection with the Chester Weir there is no evidence, 

 according to the report, that the fish suffer in the least 

 degree from the establishment of hydro-electric works. 



The following books are announced for early pub- 

 lication : — " Menders of the Maimed : The Anatomical 

 and Physiological Principles underlying the Treatment 

 of Injuries to Muscles, Nerves, Bones, and Joints," 

 Prof. A. Keith ; " Fractured Femurs : Their Treat- 

 ment by Calliper Extension," Major M. G. Pearson 

 and Capt. J. Drummond (H. Frowde and Hodder 

 and Sioughton) ; "Psychology and Parenthood," H. A. 

 Bruce (W. Heineniann); "Our Atlantic Flight," 

 H. G. Hawker and Lt.-Comdr. M. Grieve, with an 

 introduction bv Major-Gen. J. E. B. Seely {Methuen 

 and Co., Ltd.); "Opportunities in Chemistry; or. 

 Chemistry in Everyday Life," E. Hendrick (Univer- 

 sity of London Press) ; and " Senior Practical Chemis- 

 try," H. W. Bausor (University Tutorial Press, Ltd.). 

 The following works are in the press for publication 

 by the Carnegie Institution of Washington (Washing- 

 ton) :— ''The Cactaceae : Descriptions and Illustra- 

 tions of Plants of the Cactus Familv," N. L. Britton 

 and T. N. Rose, 4 vols.--vol. i., "The Ecological 

 Relation of Roots." J. E. Weaver; "The Carbo- 

 hydrate Economv of Cacti," H. A. Spoehr; "Climatic 

 Cvcles and Tree-growth," A. E. Douglas; "Plant 

 Indicators : The Relation of Plant Communities to 

 Conditions and Practices," F. E. Clements; and 

 "Hydration and Growth," D. T. MacDougal. 



The price of Norton's "Star Atlas," noticed in 

 Nature of June 12, was incorrectly given as 35. 6d. 

 The publishers ask us to point out that the selling 

 price of the book is 85. 6d. 



OUR ASTRONOMICAL COLUMN. 

 The Solar Eclipse of May 29.— We have received 

 through the office of the Scientific Attach^ of the 

 American Embassy the following message from Dr. 

 L. A. Bauer, director of the Terrestrial Magnetic 

 Laboratory of the Carnegie Institution of Washington, 

 referring to observations of the total solar eclipse of 

 May 29 :— " Cape Palmas.— Complete success ; inner 

 corona verv bright, marked outer corona extensions 

 S.S.E., N.N.W. ; brilliant red prominence W.S.W. ; 

 several stars seen region sun ; no shadow bands ; 

 magnetic effect confirmed." 



