50 MOUNTAIN OBSERVATORIES IN AMERICA Al-TD EUROPE. 



observations of Professor Burnham * should be referred to iu tliis con- 

 nection. 



Detection of very faint stars : The observations of Professor Schaeberle 

 and myself on the stars in the Lyra nebula,f and of Professor Barnard 

 on the stars of the trapezium of Orion ^ show stars of the last degree 

 of faintness. 



Observations of the structure of nebulce: Reference should be made 

 to papers by Schaeberle and myself § on the Lyra and Draco nebute. 



Observations of faint satellites: The faint satellites of Mars are ob- 

 served here as easy objects. They have been seen when their bright- 

 ness was but 0.12 of that at the time of their discovery in 1877. | The 

 fifth satellite of Jupiter was discovered here by Professor Barnard.!" 



Observations of the . Zodiacal Light : Professor Barnard's observa- 

 tions of the zodiacal light are noteworthy.** 



Observations of comets : The observations of the faint companions of 

 Brook's comet (1889, V) by Professor Barnard are especially instructive. 

 They were discovered with the 36-inch equatorial and two of them (D 

 and E) were seen, I believe, at no other observatory. The 12-inch 

 refractor here was never able to show the fainter companion comets f f 

 which is a fact of importance. 



Definition of the surface features of the planets Mars^ Jupiter^ and 

 Saturn : A long series of drawings of these planets by Messrs 

 Schaeberle, Keeler, Barnard, Campbell, Hussey, and myself Xt shows 

 details of surface features in a very satisfactory manner. The bright 

 projections at the terminator were first discovered and measured with 

 the 36-inch telescope §§ and the fine division of the outer ring of Sa- 

 turn, discovered by Professor Keeler in 1888, was not detected else- 

 where. |l| 



Nothing could be more satisfactory than the observations of the 

 phases of the eclipses of Jupiter's satellites, first regularly observed 

 here. It 



* Publications of the Lick Observatory, vol. ii. 

 t Monthly Notices, R. A. S., vol. xlviii, p. 383. 

 X Publications of the Lick Observatory, vol. ii, p. 48. 

 § Monthly Notices, R. A. S., vol. XLVIII, pp. 385, 388. 



II Astronomical Journal, No. 178. 

 nr JZwc?.,No. 375. 



** Ibid., No. 243. 



If Astronomische Nachrichten, No. 2919, and Publications of the Astronomical 

 Society of the Pacific, vol. ii, (1890), p. 26. 



IX Publications of the Astronomical Society of the Pacific, various vols. 

 §§ Ibid., vol. II, p. 348 ; vol. vi, p. 103 ; vol. vi. p. 385. 



III AstronomicalJonrnal, No. 193. 



H^ Publications of the Astronomical Society of the Pacific, vol. ill, p. 363. 



