NEBULA, CLUSTERS, ETC. 65 



Herschel, W. : MSS. in possession of Royal Society, London. [Unpub- 

 lished observations.] 



: refers to the nebula of Orion in P. T., 1785, p. 258 : 1789, p. 249 ; 



1791, pp. 72, 75, 77 ; 1811, pp. 27G, 320 ; 1814, p. 258. 



Eolden: Mon. Not. R. A. S., vol. xxxvii, p. 231. 



: Washington Astronomical Obs., 1874, plate vi, fig. 4. 



Hooke '. Micrographia, London, 1GG5, p. 242. [Discovery of the 4th and 

 5th stars in trapezium.] 



Huggins : On the spectrum of the great nebula in Orion. Proc. R. S., 

 xiv, 1864. p. 39. 



• Ditto, ditto. Proc. R. S., xx, 1872, p. 379. 



: Ditto, ditto. Proc. R. S., xxii, 1873, p. 251. 



: Mon. Not. R. A. S., xxvi, p. 71. [Nine stars in trapezium.] 



: Am. Jour. Sci., 3d series, v, p. 75. 



: P. T., 18G8, p. 541. [Spectrum.] 



Huyghens : Systema Saturnium. 4°. 1G59. [Drawing.] See Kaiser. 



Kaiser, F. : Amster. Tijdsch. v. Wiss. en Nat. Wetens, i, 1848, p. 7. 

 [Htjtghen's drawing, 1694.] 



: De Sterrenhemel, vol. ii, plate 3, pp. 533, 542. [Original draw- 

 ing.] 



Lalande : Astronomie, i, p. 272. [With a figure, Mairan's.] 



Lamont : Ueber die Nebelflecken. Munich, 1837. 4°. [With a plate.] 



Laplace : Exposition de la Systeme du Monde, p. 452. [Opinion that 

 nebuUe change.] 



Lassell, W. : Observations of the nebula of Orion, etc. Mem. R. A. S., 



xxiii, [1854,] p. 53. [Plate.] 



: Proc. R. S., xvi, p. 322. [Measures of- stars.] 



■ : A. N, xxxv, col. 383. 



: Mon. Not. R. A. S., xiv, p. 74. 



: Mon. Not. R. A. S., xvii, p. G8. [Relative visibility of 5th and 



6th star in trapezium ] 



: Mon. Not. R. A. S., xxii, p. 164. [New star in trapezium.] 



: Mon. Not. R. A. S., xxix, p. 165. 



Lefebvre : Eozier Obs. sur la Physique, xxii, 1783, p. 34. [With draw- 

 ing.] 

 5 



