318 COSMOS. 



forms, which are either regular (globular, more or less 

 elliptical, annular, planetary, or resembling the photosphere 

 surrounding a star), or irregular and almost as difficult to 

 classify as those of the aggregated aqueous vapour of our 

 atmosphere the clouds. The elliptical (spheroidal) form 45 

 has been regarded as the normal type of nebulae ; this form 

 is most readily resolved into clusters of stars, when it 

 assumes a globular shape in the telescope; but when, on 

 the other hand, with instruments of equal powers, it appears 

 much flattened, elongated in one dimension, and discoidal, it 

 is less easy of resolution. 46 Gradual transitions of form from 

 the round to the elongated, elliptical, or awl-shaped form, are 

 of frequent occurrence in the heavens. (Philos. Transact. 1833, 

 p. 494, pi. ix. figs. 19-24.) The nebula is always condensed 

 around one or more central points (nuclei). It is only among 

 the class of round and oval nebulce that we recognize 

 double nebulce, in which, as no relative motion is perceptible 

 among the individual nebulous bodies, either in consequence 

 of its absence or its extreme slowness, we are deficient in a 



could be distinctly recognized, and appeared to be nearly in 

 contact." 



45 Observations at the Cape, 44, 104. 



46 Cosmos, vol. iii. p. 190 and note. As we have already 

 remarked in reference to clusters of stars (Ibid., p. 193), 

 Mr. Bond, of the United States, succeeded, by means of the 

 great space-penetrating power of his refractor, in completely 

 resolving the very elongated, elliptical nebula of Andromeda, 

 which, according to Bouillaud, had been already described 

 before the time of Simon Marius in 985 and 1428. It has a 

 reddish light. Near this celebrated nebula lies the still unre- 

 solved, but very similarly shaped nebula, discovered on the 

 27th of August, 1783, by my honoured friend, Miss Caroline 

 Herschel, who died at an advanced age, universally esteemed. 

 (Philos. Transact. 1833, No. 61 of the Catalogue of Nebula;, 

 fig. 52.) 



