50 INDEX CATALOGUE. 



PogSOIi: [Changes in 80 Messier.] Mon. Not. R. A. S., xxi, p. 32. 



Pond, J. : On an appearance hitherto unnoticed in the nehula of 0>-ion. 



Mem. R. A. S., iii, 182G, p. 93. [Recession of the nebulosity 

 from the stars.] See also Mem. R. A. S., iii, p. 187, for an 

 observation of J. Heksciiel and 11 am age on this point. 



Pons and de Zach : Corresp. Astronomique, vol. xiv, p. 410. [Changes 

 in nebula? ; new nebula in II. A. 268° 48'. N. P. D. 133° 47'.] 



Porro: Mem. dell'Owcr. Coll. Romano, 18-36-7, p. 3. [New star in trape- 

 zium of Orion.'] 



: A. N., xlvi, col. 171. [New star in trapezium of Orion.~\ 



: C. R., xliv, p. 1031. [New star in trapezium of Orion."] 



Pound: Positions of Nebula? in Hercules and Antinous for 1G90, by 

 Pound's observations ; deduced by Halley, 171G. Bradley's 

 miscellaneous works. [Rigaud.] p. iii. 



Pov/ell, E. B. : Mon. Not. R. A. S., xxiv, p. 171. [q Argus nebula; its 

 variation in brightness stated.] 



Ptolemy : Opera, Basilia?, 1551. [Catalogue of 5 nebulous stars.] 



Proctor, Ep. A. : Essays on Astronomy, 1872, 8vo, pp. 317, 338. 



; Other Worlds than Ours, pp. 231, 259, 280, 290. [" Are the neb- 

 ulas external galaxies ? " Relations of gaseous nebulae to the 

 milky way, etc.] 



: Borderland of Science, 8vo., 1875, pp. 1-31. [Historical account 



of the views of the Herschels on nebula?, etc.] Reprinted 

 from Cornhill Magazine 1871, July. 



: Mon. Not. R. A. S., xxix,p. 337, [Distribution of nebula?.] 



: Mon. Not. R. A. S., xxx, p. 184. [On the resolvability of star 



groups as a test of distance.] 



: Mon. Not. R. A. S., xxxii, p. 62. [Note on nebula of Argo.~\ 



: Mon. Not. R. A. S., xxxiii, p. 14. [Nebular regions of Virgo and 



Coma Berenices.'] 



: Mon. Not. R. A. S., xxxiii, p. 539. 



: Nature, vol. i, p. 331, 384. [Theoretical views of distribution, 



distance, etc. of nebula?.] 



