134 



NATURE 



[April i8, 191 8 



Germany. But in the matter of health, as well as of 

 economy, advantages are to be gained by substituting 

 dried coltsfoot leaves (either smoked in a pipe or 

 made into cigars) for the more insidious narcotic. Mr. 

 Robinson's diagrams do not include fungi, but judging 

 from the British species, these would fill many pages 

 of the Illustrated London News. Instead of pityipg 

 our "ill-fed foes," we might learn a good many in- 

 teresting lessons from their dietary. 



The Board of Agriculture has issued a leaflet (Food 

 Production Leaflet, No. 34) on the canning of fruit and 

 vegetables which should be very useful to the large 

 number of growers and others who are desirous of 

 preserving the largest possible quantity of fruit and 

 vegetable food for winter use. The leaflet deals 

 specially with the use of small canning plants suitable 

 for domestic use by amateurs or small fruit-growers. 

 The instructions given for every stage of the process 

 are sufficiently detailed to ensure a reasonable prospect 

 of success for the veriest tyro. Demonstrations are 

 given daily at 11.30 a.m. in the Canning Kitchen, 

 Food Production Department, 72 Victoria Street, 

 S.W.I, and, in addition, periodical demonstrations are 

 arranged in provincial centres. The necessary outfit of 

 steriliser and cans can be obtained from the Depart- 

 ment on terms which are explained in the leaflet. 



A SOMEWHAT original method of reinforcing metals 

 is described in the Engineer for April 12. The process 

 has been devised by Mr. C. W. Denny, and lends 

 itself to the manufacture of tubes and plates. It con- 

 sists in reinforcing with perforated steel, of suitable 

 thickness, weaker metals such as copper and lead. In' 

 making reinforced copper sheets, the perforated' steel 

 plate is prepared by any well-known method for elec- 

 tro-deposition, and, finally, copper^plated to any re- 

 quired thickness, the deposition of copper going right 

 through the holes and forming a sheet of copper with 

 'the steel core inside. It. is claimed that a plate so 

 formed will stand bending and pressing without the 

 copper leaving the steel. In some cases the copper 

 can be rolled on hot. In producing reinforced lead 

 plates it has been found practicable to roll or press 

 the lead into the perforations. 



Messrs. Henry Frowde and Hodder and Stough- 

 TON have in the press "The Medical and Surgical 

 Aspects of Aviation," by H. Graeme Anderson. 



Messrs. Witherby and Co. announce an important 

 book which should be of interest to ornithologists, viz. 

 "A Monograph of the Pheasants," by W. Beebe. The 

 work, which is being published under the auspices of 

 the New York Zoological Society, embodies the 

 author's own observations and information from other 

 sources, and will contain many coloured plates and 

 maps ; also photographs showing the pheasants of the 

 world, their haunts, changes of plumage, nests, and 

 eggs. There will be four volumes, the first of which 

 is to be issued next month. 



A USEFUL catalogue (New Series, No. 82) of books 

 of science has just been issued by Messrs. J. Wheldon 

 and_ Co., 38 Great Queen Street, Kingsway, con- 

 taining 1328 titles of works relating to astronomy, 

 chemistry, electricity, engineering, mathematics, 

 meteorology, and physics, and, in addition, particulars 

 of sets of many scientific journals. The catalogue will 

 be sent to any applicant for the sum of twopence. 



Messrs Newton and Co., 72 Wigmore Street, W.i, 

 are offering for sale the collection of microscope slides 

 (some 650 in all) formed by the late Mr. Lewis Wright. 

 A classified list, with the prices asked, will be sent by 

 Messrs. Newton upon application. 

 NO. 2529, VOL. lOl] 



OUR ASTRONOMICAL COLUMN. 



The April Meteor Shower.— There is reason to 

 believe that this display may be more abundant than 

 usual at the ensuing return on about April 21. Of late 

 years it has been very disappointing, and very few 

 true Lyrids appear to have been seen since 1901. The 

 radiant point is like that of the August Perseids, for 

 it exhibits a diurnal shift of 1° to the eastward, the 

 positions on successive nights being : — 



The stream has been observed with certainty be- 

 tween April 16 and 26, but it has very probably a 

 longer duration than that. 



This meteoric shower has a cometary connection, for 

 the first comet of 1861 shows a suggestive similarity of 

 orbit, but the periodic time of revolution, either of the 

 comet or meteoric shower, is not exactly known. 

 There Avere rich displays of Lyrids in 1803, 185 1, 1863, 

 and 1884. This year moonlight will interfere some- 

 what with the phenomenon, as, at the time of the 

 maximum, our satellite will be a little past the first 

 quarter, and above the horizon until between 2h. and 

 3h. in the morning. 



Tempel's Comet. — The following ephemerides of 

 Tempel's first periodic comet have been constructed 

 by Dr. A. C. D. Crommelin on three assumptions of 

 the date of perihelion passage in 1918 : (A) May 9-37 ; 

 (B) May 17-37; (C) May 25-37. The ephemerides are 

 for 9 p.m. 



ABC 



Date 



R.A. 



S. Dec. 



R.A. 



h. m. 



S. Dec. 



R.A. S. Dec. 



1448 16 12 36 1255 



15 25 16 II 4 13 26 



16 3 16 7 39 14 2 



16 48 16 2 33 14 40 



1736 155628 1525 



April 17 16 51 18 16 30 16 32 4 



25 16 52 6 17 9 16 31 44 



May 3 165054 1755 162920 



II 164752 1843 1625 5 



19 164326 1934 16 19 41 



Search should be made along a line through posi- 

 tions A, B, C, or this line produced. The values of 

 log A on hypothesis B are 0-0959, 0-0749, 0-0574, 0-0440, 

 0-0357 foi" the five dates. This comet has not been 

 seen since 1879, so there is considerable uncertainty 

 as to its position. 



Absorption an^d Radiation of the Solar Atmo- 

 sphere. — A paper by Prof. Shin Hirayama appears 

 under this title in the Proceedings of the Tokyo Mathe- 

 matico-Physical Society, second series, vol. ix., p. 236. 

 Utilising observations of the radiation from different 

 parts of the solar disc which have been made bv 

 Abbot, Prof. Hirayama computes the transmission and 

 radiation of the solar atmosphere, on Schuster's sup- 

 position that a great part of the solar radiation comes 

 from an absorbing and radiating layer above the photo- 

 sphere. It is shown that the observations are better 

 represented in this way than by the previous calcula- 

 tions of Biscoe, in which the radiation of the atmo- 

 sphere was not considered. The coefficient of trans- 

 mission increases gradually with the wave-fength, and 

 the radiation due to the atmosphere ranges from one- 

 third of the whole radiation for the shorter wave- 

 lengths to nearly one-half as the wave-len-^th in- 

 creases. Assuming the effective temperature of the 

 sun to be 6000° Abs., it is calculated that the tempera- 

 ture of the photosphere is about 7040°, while that of 

 the absorbing layer is 5210°. 



