SCIENCE- G OS SI P. 



317 



has been independently put forward, by Professor 

 Kapteyn and Mr. W. E. Wilson, to account for the 

 enormous proper motions of the nebulous matter 

 around the Nova observed on the Lick and Yerkes 

 photographs. It supposes that the motion is not that 

 of matter, but of light through the hitherto inv'sible 

 nebulous matter surrounding the star. The fact that 

 the nebula is spiral in structure would account for 

 the apparent diagonal direction of the motion, as 

 the further portions of the whorls are reached by the 

 light waves. If this theory be correct, the nebula 

 should be brighter at the outer portions of the 

 ever-enlarging circle, and then each portion should 

 slowly decrease in apparent brightness, because of 

 the constantly-decreasing luminosity of the central 

 body. If the theory be accepted, the real distance 

 of the outbreak must be about 250 light-years, and 

 must have occurred at least so long ago as in 

 the time of the Commonwealth. Were our sun 

 removed to such a distance, its lustre would not 

 exceed the tenth magnitude ; and to appear of the 

 same brilliance as did the Nova, its light-giving 

 power must be increased some 10,380 times. 



Hamburg Observatory, founded in 1825 and 

 furnished in 1868 with a 10-inch equatorial tele- 

 scope, has since the death of Professor G. F. W. 

 Riimker, March 3rd, 1900, been under the acting 

 directorship of Dr. R. Schorr, who has just now 

 definitely been appointed Professor and Director. 



" The Heavens at a Glance, 1902," by 

 Arthur Mee, F.R.A.S. This small card, 20 in. 

 X 12^ in., is published by the author at Llanishen, 

 Cardiff, price 7d., including postage. It is a most 

 useful calendar for the amateur observer, even 

 including a chart of the heavens and a sketch map 

 of the moon, enabling the student to locate the 

 whereabouts of objects. There are numerous useful 

 hints and facts. 



The Royal Astronomical Society held its 

 anniversary meeting at Burlington House on 

 February 14th. Its Gold Medal was given to Pro- 

 fessor J. C. Kapteyn, of Groningen, for his labour 

 in connection with the Cape Photographic Durch- 

 musterung and his researches in stellar distribu- 

 tion and parallax. The Jackson-Gwilt Medal was 

 bestowed on the Rev Dr. Anderson for his dis- 

 coveries of new stars, particularly Nova Aurigae 

 and Nova Persei. 



At the meeting of the Royal Society on the 

 afternoon of January 30th Sir Norman Lockyer 

 made a further communication on the new star 

 which appeared in Perseus early last year. As the 

 chemical origin of the lines in this star, deter- 

 mined from the Kensington photographs, had been 

 questioned, he has published an elaborate table, 

 which was prepared, from the study of these 

 photographs, especially one of unusual excellence 

 taken on February 25th, 1901. The lines in the 

 new star were compared with those observed in 

 the solar chromosphere during the eclipse of 1898 ; 

 those of the new star discovered about ten years 

 ago in the constellation of Auriga ; and those of 

 a Cygni. The correspondence of their lines 

 throughout supported his identification of the 

 substances — hydrogen, nickel, chromium, mag- 

 nesium, iron, etc. ^already announced. The re- 

 markable coincidences between the spectra of 

 both new stars and of t] Argus led to the conclusion 

 that in both outbursts temperatures had been for 

 a time reached which were permanent in the last- 

 named star. 



conducted by b. foulkbs-winks, bi.r.p.s. 

 EXPOSURE TABLE FOR MARCH. 



The figures in the following table are worked out for plates of 

 about 100 Hurter & Driffield. For plates of lower speed number 

 give more exposure in proportion. Thus plates of 50 H. & D. 

 would require just double the exposure. In the same way, 

 plates of a higher speed number will require proportionately 

 less exposure. 



Time, 10 a.m. to 2 p.m. 



Between 9 and 10 a.m. and 2 and 3 p.m. double 



the required exj)Osure. Between 8 and 9 a.m. and 



3 and 4 p.m. multiply by 4. 



Subject 



F.5-6 



F.8' 



F.ll 



F.I6 



F.22 



F. 32 



F.45 



F.64 



Sea and Sky . . 



^l-o 



^so 



T^u 



63 



^ 



i 



Open Landscape 

 and Shipping 



!■. 



ii 



sV 



tV 



I 



\ 



\ 



1 



Landscape, with 

 dark fore- 

 ground. Street 

 Scenes, and 

 Groups 



■h 



rV 



1 



i 



\ 



1 



2 



4 



Portraits in 

 Rooms 



V 



4 



8 



16 



32 



- 



- 



- 



Light Interiors 



4 



8 



16 



32 



1 



2 



4 



8 



Dark Interiors 



I 



h 



1 



2 



4 



8 



16 



32 



The small figures represent seconds, large figures minutes. 

 The exposures are calculated for sunshine. If the weather is 

 cloudy, increase the exposure by half as much again ; if gloomy, 

 double the exposure. 



The Royal Photographic Society of Great 

 Britain. — The members of this Society are now 

 in receipt of the report of the Council for the year 

 1901. The total number of Fellows and members 

 added to the Society during 1901 is 125, thus 

 bringing the roll of the Society up to 905, after 

 allowing for loss of members through death, &c. 

 The finances of the Society show a steady increase, 

 and is left in a satisfactory condition. The annual 

 general meeting of the . Society took place on 

 February llth, under the new rules of the Society 

 regulating the election of officers for the ensuing 

 year. From the results it will be seen that a 

 radical change has come over the management of 

 the Society, and the members may now look 

 forward to having their Society conducted on more 

 business-like lines. We shall watch with interest 

 the development of those reforms so much advo- 

 cated by the gentlemen who are now upon the 

 new Council. 



Windsor Exhibition. — An important Photo- 

 graphic exhibition was held at the Royal Albert 

 institute, in Windsor, on the 18th and 19th of last 

 month. A successful collection of photographs was 

 brought together, largely by the efforts of Mr. J. W. 

 Gooch, of that town. Mr. Henry Stevens contri- 

 buted examples of his beautful work, consisting of 

 flowers and other subjects, showing splendid detail. 



