NA TURE 



[January i6, 1908 



tions, tile lir-.t dealing mainly with qualitative characters — 

 such as health, ability, temper, temperament, and success 

 in life — the second, not ^et completed, with certain 

 measurements on the hand, eye-colour and hair-colour, as 

 well as health. 



In the current number of Science Progress, published 

 by Mr. John Murray at five shillings net, there are several 

 articles of interest on applied science. In the first place 

 we notice a paper by Dr. J. S. Haldane, F.R.S., on work 

 under pressure and in great heat, giving a verv good 

 precis of the author's researches in this department, which 

 have altered the .\dmiralty practice as regards diving, and 

 should alter the factory-mining regulations, when these 

 -well-meant rules are inspired by knowledge as well as 

 good intention. The article by Dr. F. H. A. Marshall, on 

 nutrition and fertility, touches on matters of great 

 Importance to breeders of stock, and furnishes a curious 

 i(and unintentional) commentary on the work of Prof. 

 'Chittenden on the minimum of food-stulTs. Articles that 

 also call for mention are those of Prof. Halliburton on the 

 repair of a nei-i-e, and Mr. A. D. Darbishire on .Mendelism. 

 A fine portrait of the late Lord Kelvin appears as frontis- 

 piece. 



Amono the subjects of lantern-slides from photographic 

 negatives, in the supplementary list just issued by Messrs. 

 Newton and Co., are : — steel-making, showing operations 

 at a great steel-works ; coal-mining ; wild life ; pathological 

 tissues ; animal life in earlier times ; eruption of Vesuvius 

 in 1906; hacteriology- of tropical diseases; and colour 

 photography. The slides should be of real service in 

 Illustrating popular lectures upon scientific subjects. 



TiiB old students of the Finsbury Technical College are 

 to be congratulated on the first number of the magazine 

 produced and published by their association. The cover 

 of the magazine carries a medallion portrait of the prin- 

 cipal of the college. Prof. Silvanus P. Thompson, F.R.S., 

 and a portrait of the first president, Dr. M. O. Forster, 

 F.R.S., forms a supplement. The reading matter includes 

 a greeting from Prof. J. Perry, F.R.S., in which he refers 

 to reformed methods of teaching mathematics and physical 

 scien<:e. 



The tenth issue, that for 1908, of " Wellcome 's Photo- 

 graphic Exposure Record and Diary," will prove of assist- 

 ance to photographers. Much useful guidance is provided, 

 and the mechanical calculator attached to the cover will 

 be found serviceable. In addition to a complete diary for 

 1908, the hook also contains tables for interior work, tele- 

 photography, copying, enlarging and reducing, moving 

 objects, night photography, and for printing by artificial 

 light. Three editions, , adapted respectively to the con- 

 ditions of various latitudes, are published, and the price 

 of the volume is one shilling. 



We have received a copy of the first number of a new 

 rnonthly technical magazine entitled the lUuminating 

 Engineer, which is to be devoted to the subject of scientific 

 illumination. The periodical is edited by Mr. Leon Gaster, 

 and the price of each issue will be is. The first number, 

 ■which runs to eighty-eight pages, contains a variety of 

 articles and notes, some of which are well illustrated. 

 Prof. J. A. Fleming, F.R.S., describes vacuum tube electric 

 lighting; Dr. C. V. Drysdale deals with the production 

 and utilisation of light ; Mr. A. P. Trotter discusses the 

 .listributlon and measurement of illumination ; and Dr. 

 Hugo Kriiss gives an account of some researches on re- 

 flected transmitted light. The new periodical should appeal 

 to all enginicrs concerned with illumination. 



NO. 199;. VOL. yy] 



OUR ASTRONOMICAL COLUMN. 



Comets due to Return this Year. — In No. 392 of the 

 Observatory (January), Mr. W. T. Lynn publishes a, 

 number of particulars concerning the periodical comets due 

 to return during the present year. The first named is 

 that discovered by M. Giacobini in December, igoo, and 

 found to have a seven-year period. 



The comet discovered by Mr. Denning on October 4, 

 1881, has, according to the calculated elements, a period 

 of 8-8 years. In 1890 and in 1898-9 its position was not 

 favourable for observation, so there is a likelihood of its 

 being re-discovered in the early part of this year. 



Encke's comet has been observed at every return since 

 it was recognised as a periodic comet in 1819, and has 

 already been found by Prof. Max Wolf. The comet dis- 

 covered by Tempel in 1869 November 27, and recognised 

 as periodical by Swift in 1880, should reappear during 

 the coming summer; its period was found to be a little 

 greater than 51 years. It was not seen in 1903, when it 

 was last due, or in the preceding return of 1897, but was 

 well observed in 1891. 



Determination of the Moon's Light with a Selenium 

 Photometer. — Some interesting results, accruing from pre- 

 liminary experiments on the determination of the amount 

 of light received from the moon at different phases, by 

 means of selenium cells, are published in the December 

 (1907) number of the Astrophysical JoiirnaJ (vol. xxvi., 

 -No. 5, p. 326) by Messrs. J. Stebbins and F. C. Brown. 



The moonlight was compared with the light of a standard 

 candle burning under known conditions, the values obtained 

 being subsequently reduced by correcting for atmospheric 

 absorption, &c. For the light given out by the full moon 

 the observers derived a value of 0-209 candle-power, but 

 other cells employed gave different values, the mean value 

 being very near to the 0-23 candle-power adopted by 

 Miiller as the mean obtained from visual observations. 



The results show that at full moon we receive about 

 nine times as much light as at half moon, and they also 

 indicate that the moon is brighter between first quarter 

 and full than in the corresponding phase after full moon. 

 Observations made during the partial lunar eclipse of July 

 24, 1907, gave the instant of least light as i6h. 23m., 

 whilst according to the American Ephemeris it was 

 1 6h . 24m . 



The differences obtained by using different cells are 

 probably due to the fact that the cells are not equally 

 colour-sensitive, and to this point the authors propose to 

 pay considerable attention ; presumably the question of 

 colour would not enter into the determination of the values 

 at various phases when the same cell was employed 

 throughout. 



The Appearance of Neptune in Small Telescopes. — A 

 paper recently communicated by Mr. Holmes to the British 

 .Astronomical Association gave rise to an interesting dis- 

 cussion at the November (1907) meeting. The question 

 discussed was the planetary appearance of Neptune in small 

 telescopes, and whilst some jf the members averred that 

 it was difficult to recognise the disc with a 6-inch telescope, 

 others, including Mr. Maw, stated that they had found 

 such an instrument sufficiently large for this observation. 

 The general result of the discussion appears to have been 

 the conclusion that some of the earlier descriptions of the 

 size and brightness of the disc of Neptune are misleading, 

 although the form should be clearly recognised with an 

 instrument of equivalent power to a 6-inch achromatic 

 telescope (the Observatory, No. 392, p. 47). 



The " Annuaire .Astronomique " for 1908. — The excel- 

 lent year-book of astronomy and meteorology issued by 

 M. Flammarion is one of tlie most useful of its type and 

 price to the amateur astronomer who reads French. It 

 contains practically all the data he is likely to require in 

 his work, besides a valuable annual review of the progress 

 of astronomy. Many of the notes and directions are illus- 

 trated, and, in addition to the diary giving the astro- 

 nomical phenomena for each day of the current year, there 

 is a map of the sky for different times and dates in each 

 month. The price of the volume is 1.50 francs. 



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