ASTRONOMY. 445 



gating- $450, for essays on the remarkable "red sunsets" which have been 

 l)reva]ent during the past few years, and medals have been awarded 

 to a number of other competitors. The total amount that has been 

 awarded by Mr. Warner for astronomical prizes since 1880, including a 

 small amount for the expenses of judges, is $3,750. The Warner comet 

 prize is continued from March 1, 1886, to March 1, 1887. It is reduced to 

 $100, but is open to the "world. 



On the apparent increase of size of the sun, moon, and constellations 

 when seen at the horizon. {From the Bulletin de VAcademie royale 

 de Belgique.) — "The apparent increase of the diameter of the sun 

 or moon is ordinarily attributed to the elliptical form of the celes- 

 tial sphere. According to the author this explanation was given as 

 early as the eleventh century in theOpticsof Alhazen. But by experi- 

 ments, comparing in a dark room the distances of two electric sparks 

 at the height of the eye and near the ceiling, M. Stroobant was led to 

 the conclusion that any object seen in the zenith appears only eight- 

 tenths as large as when seen at the horizon. But there is another fac- 

 tor which should be taken into account, that is, the variable brightness 

 of the star. The author thinks that a special stud}' should be made of 

 these very interesting physiological phenomena." {Bull. Astron., April, 

 1885.) 



Sammlung populacrer Astronomische Mittheilungen. — The eminent di- 

 rector of the Berlin Observatory HerrFoerster, has collected in this vol- 

 ume a series of scientific notices of a popular character, which have ap- 

 peared since 1880 in successive volumes of the oificial calendar {Normal- 

 Kalender). It contains a clear exposition of the state of our knowledge 

 of the fixed stars, their distances, and their distribution in space ; an 

 article upon the limits of our perceptions of celestial objects ; some in- 

 teresting remarks upon the auroras, the zodiacal light, and the recent 

 comets. In reviewing these notices, we are struck with the multiplicity 

 and the importance of the problems offered us by modern astronomy, 

 and are tempted to ask, with Herr Foerster, if the number of those at 

 work at these problems is not becoming too small for the task. 



An index to astronomical literature. — The need of some systematic 

 index to the current literature of astronomy (to say nothing of the 

 desired extension of the Royal Society's catalogue, or the completion 

 of Houzeau's work) is more strongly felt year by year ; and the difficulty 

 is aggravated by the poor and insufficient indexes furnished with most 

 astronomical publications. General periodical literature is provided for 

 by Poole's Index, which is kept up to date by the Co-operative Index 

 to Periodicals; and a committee of the American Association on index- 

 ing chemical literature reports each year favorable progress. It seems 

 highly desirable that some similar co-operation should bo organized 

 among astronomers. 



