ASTRONOMICAL PHENOMENA AND PROGRESS. 



Gylden has reached the conclusion that the 

 mean parallax of stars of the first magnitude 

 i8 about one tenth of a second. With this re- 

 sult, the average distance of these bodies would 

 be two million times greater than that of the 

 sun a distance requiring more than thirty-one 

 years for the transmission of their light to the 

 earth. 



Distribntion of tbc Variable Stars. In the a Ob- 

 servatory " for June, 1883, T. E. Espin, Vice- 

 President of the Liverpool Astronomical So- 

 ciety, concludes his interesting paper on the 

 distribution of the variable stars. (See " An- 

 nual Cyclopaedia" for 1882.) The shortest 

 period in his second class of variables is 135 

 days; the longest, 570. The variation in 

 brightness is from one to nine magnitudes. 

 The number of stars in relation to different 

 periods is as follows : 



Period in dayg. Stars. 



185-170 7 



170-220 9 



220-270 10 



270-320... .. 15 



Period In days. Stars. 



820-870... .. 21 



870-420 15 



420^70 7 



470-520 3 



And the number of stars in relation to the va- 

 riation in magnitude is 



Var. mag. Stan. 



5 27 



6 25 



7 6 



Sand 9 3 



From his examination of these tables Mr. Es- 

 pin infers : 



1. That the number of stars increases with 

 the length of the period. 



2. That the number of stars increases with 

 the variation in magnitude. 



3. That more than two thirds of the varia- 

 ble stars of class second vary more than four 

 and less than six and a half magnitudes ; and, 



4. That nearly two thirds of the variable 

 stars of class second have periods between 320 

 and 420 days. 



Mr. Espin concludes as follows: "When, 

 nearly eighteen months ago, I commenced the 

 first of these papers, I believed that all cases 

 of stellar variation might, with the exception 

 of temporary stars, be included in classes first 

 and second. Lately, however, I have become 

 aware of the existence of a new class stars 

 which have a small fluctuation in magnitude 

 once in several years. The observations of 63 

 Cygni first led me to this conclusion, and some 

 of the stars suspected of variation now under 

 observation go far to confirm it. For the 

 greater part of the time the light of these stars 

 is constant, but then it alters a magnitude or 

 so ; but, after a month or two, it returns to its 

 ordinary magnitude. Many of the stars sus- 

 pected of variation undoubtedly belong to this 

 class third, and it is obvious that only long and 

 careful determinations of magnitude during 

 many years can determine the periods and 

 variation of such stars. 



" Summing up our results, then, we find 

 four classes of variable stars : 



" Class I. With short periods and small va- 

 riation. 



" Class II. Long period and great variation. 



" Class III. Period of several years and small 

 variation. 



" Class IV. Temporary stars." 



The " Monthly Notices of the Royal Astro- 

 nomical Society " for March, 1883, contains a 

 note by the Rev. T. E. Espin, of Birkenhead, 

 Eng., on the variability of Beta Cygni and 63 

 Cygni. The former is placed in the table of sus- 

 pected variables in " Chambers's Astronomy," 

 and this suspicion has been confirmed by Mr. 

 Espin. The change in brightness is not great 

 about one magnitude while the period, 

 though not well ascertained, is undoubtedly 

 several years. The period of 63 Cygni is about 

 five years, and the observe'd variation is from 

 the sixth to the 4'7 magnitude. 



Dr. Peters's Star-Charts. Dr. 0. H. F. Peters, 

 of Hamilton College, N. Y., has recently pub- 

 lished the first installment of a very elaborate 

 series of star-charts. They are to contain all 

 stars down to the 14th magnitude, as far as 30 

 degrees on each side of the equator, through- 

 out the whole of the twenty-four hours. Dr. 

 Peters has himself done all of the observing as 

 well as the draughting, and the charts are pub- 

 lished at his own expense, for gratuitous dis- 

 tribution. The construction of these charts 

 has occupied his time and attention for the 

 past twenty years. In his laborious observa- 

 tions, he not only carefully marked the place 

 of every one of the 60,000 stars or more al- 

 ready mapped, but, after receiving the proof, 

 he again compared the positions with the act- 

 ual condition of the heavens, so as to insure 

 the utmost possible accuracy. It has been 

 while engaged in this work that Dr. Peters has 

 picked up so great a number of small planets; 

 these interesting discoveries being merely inci- 

 dents connected with his systematic observa- 

 tions for another and, perhaps, more important 

 purpose. 



Recent Papers on Astronomy. The following 

 astronomical papers were read at the Minne- 

 apolis meeting of the American Association 

 for the Advancement of Science, August, 1883 : 



1. The Total Solar Eclipse of May 6, 1883; by 

 Prof. E. S. Holden. 



2. Internal Contacts in Transits of Inferior Plan- 

 ets ; by Prof. J. E. Eastman. 



3. Physical Phenomena on the Planet Jupiter ; by 

 Prof. G. W. Hough. 



4. Observations of the Total Solar Eclipse of May 

 6, 1883 by Dr. J. Janssen. 



5. Orbit of the Great Comet of 1882 ; by Prof. Ed- 

 gar Frisby. 



6. Some Observations on Uranus ; by Prof. C. A. 

 Young. 



7. Observations on the Transit of Venus made at 

 Columbia College, New York" city ; by Mr. J. K. 

 Kees. 



Astronomical Prizes. At the annual meeting of 

 the Royal Astronomical Society, Feb. 9, 1883, 

 the society's gold medal was awarded to Dr. 

 B. A. Gould, Director of the Observatory at 

 C6rdoba, South America. "The work for 



