Bickerton.—On the Birth of Nebula. 197 
and see, Phoenix-like, new suns arise from those cold masses of ashes, and 
as he watches the amazing flash of the collision, he may see flights of 
comets and meteors emerge from the flames and start on their long journey. 
Travelling on, he may see worlds absorb their enveloping nebular curtains, 
see others solidifying. In some, witness the garment of organized life 
gradually extending itself and clothing the surface with vitality; and should 
he stay to take a detailed look, he would probably sometimes see forms of 
life so strange, so weird, that the animated engines of Erewhon would be 
commonplace compared to them. Is it possible that in some white hot 
body he would see viscous silicon building itself into complex protoplasmic 
molecular skeletons, developing organ after organ, and breathing forth its 
halogen breath ? Perchance he might watch a silicon monster tenderly 
waiting on a sickly friend, and feeding it with delicately-flavoured molten 
flint broth. But methinks I hear someone whisper, *I thought so. Un- 
doubtedly he is mad." — So, remembering the fate of Solomon de Caus, and 
being desirous of retaining my liberty, I conclude by thanking you for the 
attention with which you have listened to me. 
Art. XVI.—On the Birth of Nebule. By Prof. A. W. Bicxerton, F.C.S., 
President of the Philosophical Institute of Canterbury. 
[Read before the Philosophical Institute of Canterbury, 3rd July, 1879.] 
Ix the following paper I propose to discuss the generic methods by which 
nebule may be produced ; and also attempt to show how the various kinds 
of nebule, of definite structure, may have had their special form given 
them. 
The word **nebulm," in this paper, will not apply to all gaseous bodies. 
Thus the Sun is not improbably gaseous, but of such density as to give a 
spectrum broken only by dark lines. On the other hand, I have shown it 
is extremely probable, that all space is filled with more or less diffused gas, 
not dense enough to be considered a nebula. I shall apply the term to 
bodies rare enough to give a bright line spectrum, and dense enough to be 
visible in the telescope, or to be associated by gravitation. 
Nebule may be formed by the aggregation of very diffused gas, by the 
volatilization and diffusion of dense masses, and by dense masses passing 
into diffused gases, being there volatilized and attracting gas towards them. 
The conversion of dense bodies into nebule is probably chiefly effected 
by impact, as already suggested by Croll and others, but I shall attempt to 
show that the ordinary idea of complete impact cannot play such an im- 
portant part as “ partial impact.” I have already shown, that the partial 
