Vieios on Prenehular Conditions. — A. WinrheU. 107 
compared with the dimenHions it must have possessed hefore 
any planets had l)een formed.' 
Tlie nehul;e have long been suspected to belong to the order 
of cosmic existence which served as the starting point of those 
rotations, annulations and planetations which marked the his- 
tory of our system. The constitution of the nebuhe and their 
antecedent history, have, however, been involved in great mys- 
tery. Tiie irresolvable nebulic — to which the present reference 
is restricted — have been generally conceived to consist of ten- 
uous matter heated to luminosity. Whether in the condition 
of a luminous gas, or that of a firemist, or that of the rings of 
Saturn and the matter of the zodiacal light, remained a ques- 
tion. The publication, in 1864, of Mr. Huggins' results of 
spectroscopic studies of certain nebuhi3,* seemed to demon- 
strate that at least some of the luminous matter of certain 
nebula? exists in the condition of a gas. Hydrogen, it was 
thought, was quite certainly identified, while the brightest line 
in the spectrum was exceedingly close to nitrogen.^ Huggins' 
later researches throw doubt on the identification of nitrogen, 
and tend to suggest the presence of lead." 
While making this brief reference to elementary matters in- 
dicated in the nebula', it may be stated that Mr. Lockyer, in a 
paper read before the Royal Society in 1887," stated that only 
seven lines in all had been recorded to that time in the spec- 
tra of the nebula}, three of which coincide with lines in the 
spectrum of hydrogen, and three correspond to lines in mag- 
nesium. Dr. Huggins, in his late memoir, has made a very 
critical examination of the claims of magnesium for recog- 
nition in the nebuhe and concludes, against Mr. Lockyer, that 
the coincidence of the lines is not sufHciently exact. 
Aside from the identification of substances, the recognition 
of gaseous states of very high temperatures is considered es- 
'Huijj^ins, Memoir reiul before the Uoyal vSociety, May 2, 1SS9. A 
beautiful ileliiiHation of the nebula of Andromeda i.s given i)y Father 
Seeehi in Le Soldi, voi-. n., i'L. .i. Fig. 2. He remarks, "One cireum- 
Btanoe deserves to arrest our attention. Certain planetary nebulre 
seem to offer luminous points. * * * Meantime the planetary nebula 
of Andromeda presents two spectra superposed" p. 4(54. 
*"On the spectra of some of the Nebtihe." Phil. Trans., lSt)4. 
*"0n the SpettruMi of the (ireat Nebula in Orion," etc. Proc. Roy. 
Soc. VOL. XX. See the results summarized bv Le Padre Secchi, "Le 
Soleil," vol. n. pp. 4f.l-4t;t). 
•In a memoir read ])efore the Royal Society Mav 2, 18S9. 
^Roy. Soc. Proc. vol xi.iii. p. 111. 
