i6 



NATURE 



[March i, 1917 



The youthful Society of Glass Technology has 

 begun its career with every indication of a vigorous 

 and useful futur. . Ai tin meeting- on January 18, 

 held at Leeds, two pajitrs were read on the subject 

 of British glass sands. The first, by Dr. P. G. H. 

 Boswell, on " British Sands : their Location and 

 Characteristics," dealt with the chemical, mechanical, 

 and mineral analysis of sands. The author stated 

 that the analysis "of British sands had proved their 

 value. The proof of the pudding, however, is in the 

 eating, and Mr. C.' J. Peddle, in the second paper, 

 "British Glass Sands: the Substitution of Foreign 

 Sands by British Sands for High-grade Glass-making," 

 demonstrated by actual melts made from native sands 

 what could be done with the material. A good glass sand 

 should attain the requisite degree of purity ; it should 

 be evenly graded, and the grains should be angular ; 

 consignments should not vary in character and should 

 be ready for use when they reach the manufacturer. 

 The author pointed out that all these essentials are 

 fulfilled by Fontainebleau sand, but not all by British 

 sand as at present supnlied. That some British sands 

 compare favourably with those of Fontainebleau as 

 regards puritA' and grading has been established by 

 the author, whose results in general were in agree- 

 ment with those of Dr. Boswell. Much depends upon 

 the treatment of the sand for the market. Excellent 

 results were obtainable with properly prepared British 

 sands, as was shown by the samples of glasses made 

 from them, some of which could not be distinguished 

 from similar melts made from Fontainebleau sand. 

 The question of transport charges is one which closely 

 affects the home sand industry ; in the past, on account 

 of through rates for carriage, foreign sands have fre- 

 quently been delivered at the w^orks at a lower cost 

 than it was possible to supply the British material. 



We have received from the Cambridge Scientific 

 Instrument Co., Ltd., a new list of their resistance 

 pyrometers for indicating or recording temperatures 

 from —200° to 1200^^ C. They all depend on the 

 platinum thermometer, of which four types suitable 

 for different purposes are figured and described. The 

 temperature is shown either on a Whipple indicator 

 or on a Callendar recorder. A sample chart shows 

 a continuous record of the temperature of a hot blast 

 in an ironworks during twenty-five hours. The in- 

 formation given is sufficient to enable anvone with an 

 elementary knowledge of electricity to set up and 

 understand the working- of the instruments. 



Messrs, Henry Holt and Co. (New York) are pub- 

 lishing very shortly new and revised editions of Prof. 

 A. L. Kimball's "College Text-book of Physics" and 

 Prof. Martin's " The Human Body : Advanced Course." 



The new list of announcements of Messrs. John Wiley 

 and Sons, Inc. (New York) (London : Messrs. Chap- 

 man and Hall, Ltd.) includes: "The Sun's Radiatian 

 and other Solar Phenomena," F. H. Bigelow ; "In- 

 terior Wiring- and Systems for Electric Light and 

 Power Service," A. L. Cook ; ^' Irrigation Works Con- 

 structed by the United States Government," A. P. 

 Davis; "Bio-Chemical Catalysts," J. Effront (being 

 vol. ii. of " Enzymes and their Applications "), trans- 

 lated by Prof. S. C. Prescott ; " Microscopic Examina- 

 tion of Steel," Prof. H. Fay; "Fats and Fatty De- 

 generation," Prof. M. H. Fischer and Dr. M. O. 

 Hooper; "Agricultural Chemistry," Prof. T. E. Keitt; 

 ^'The Essentials of American Timber Law," J. P. 

 Kinney; " Elem.ents of Hvdrology," Prof. A. F. 

 Meyer; "A German-English Dictionary for Chemists," 

 Dr. A. M. Patterson; "Mechanical' Equipment of 

 Buildings "—part ii., 'Power Plants and Refrigera- 

 tion," L. A. Harding and Prof. A. C. Willard; 

 " Printing : A Text-book for Printers, Apprentices, 

 NO. 2470, VOL. 99] 



Continuation Classes in Printing, and General Use 

 in Schools and Colleges," F. S. Henry; "The Efficient 

 Purchase and Utilization of Mine Supplies," H. N. 

 Stronck and J. R. Billyard ; "Stresses in Structural 

 Steel Angles," Prof. L. A. Wahrbury ; "Sanitation 

 Practically Applied," II. H. WOml; and "French 

 Forests and Forestry," T. S. Woolsey, jun. 



The classified list of second-hand instruments for 

 sale or hire, just received from Messrs. C. Baker, 

 244 High Holborn, London, includes particulars of 

 hundreds of microscopes, surveying and drawing in- 

 struments, telescopes, spectroscof)es, optical lanterns, 

 and other apparatus and accessories. The list is well 

 arranged, and should be of real service to intending 

 purchasers of second-hand optical instruments. 



OUR ASTRONOMICAL COLUMN. 



Determixatiox of Star Colours. — An expeditious 

 photographic method of investigating the colour-indices 

 of stars has been tested by Mr. F. H. Scares at Mt. 

 Wilson (Proc. Nat. Acad. Sci., vol. iii., p. 29). The 

 method consists of making a series of exposures with 

 graduated exposure-times, first through a yellow filter 

 and then without filter. In this way the ratio of 

 exposure-times necessary to give images of the same 

 size in yellow- and blue light is determined. The 

 colour-indices are then derived by reference to a curve 

 showing similar ratios for standard polar stars, the 

 colours of which have already been ascertained by a 

 comparison of their photographic and visual magni- 

 tudes. In general, the method of exposure-ratios 

 gives excellent results, showing no systematic errors 

 of any importance which dep>end upon stellar magni- 

 tude. The probable error of a colour-index derived 

 from a single exposure-ratio is 007 magnitude. The 

 method would appear to be of special value on account 

 of its indej>endence of stellar magnitude, and because 

 it gives a direct measure of the colour. The results 

 obviously include that part of the colour which is a 

 function of the star's intrinsic luminosity, and also 

 such colour effect as may be due to the scattering of 

 light in space. An interesting outcome of the new- 

 observations is the confirmation of the previously re- 

 ported conclusion that there are no faint white stars in 

 the vicinity of the pole, though this is apparently not 

 true of all parts of the sky. 



Manchester Astronomical Society. — It is gratify- 

 ing to note that the activity of the Manchester Astro- 

 nomical Society has been well maintained. Tlie 

 journal for the session 1915-16 indicates a membership 

 of about 120, and an average attendance at the meet- 

 ings of forty-seven, while no fewer than eighteen 

 members contributed papers relating to their own ob- 

 servations. A summary of the proceedings is given, 

 and the papers printed at length include "The Colours 

 and Spectra of the Stars," by Father Cortie ; " Satellite 

 Systems," by Prof. R. A. Sampson; and "Astro- 

 nomical Drawings," by W. Porthouse. 



C.-vnadian Observer's Handbook. — The Royal 

 Astronomical Society of Canada renders a valuable 

 service to amateur astronomers in the Dominion by 

 the annual issue of " The Observer's Handbook." 

 The volume for 19 17 includes the usual astronomical 

 information in a convenient form, and an extensive 

 set of tables by means of which the times of sunrise 

 and sunset in any part of the country can very readily 

 be determined. Another feature calling for special 

 mention is a catalogue giving the chief known facts 

 regarding 276 stars and 13 nebulae, including prof)er 

 motion, parallax, spectral type, and radial velocity. 

 There is also a simple guide to the constellations, wath 

 maps. The price of the handbook is 25 cents. 



