THE 
MONTHLY MICROSCOPICAL JOURNAL. 
SEPTEMBEE 1, 1869. 
I. — Micro-spedroscopy. — BesuUs of Spectrum Analysis. 
By Jabez Hogg, F.L.S., Hon. Sec. K.M.S., M.K.C.S., &c. 
(Bead before the Koyal Microscopical Socie'J'y, June 9, 18G9.) 
When we look back upon an important discovery in science, how 
frequently it occurs that a great fact wholly unexpected is pre- 
sented to us, and even unconnected with the subject which had 
engaged the attention of the explorer. It has been so with 
spectrum analysis, the origin of which may fairly be referred to 
Newton's discovery of the composition of the solar spectrum. This 
physical phenomenon, made known to the world more than two 
hundred years ago, led to the inquiries which step by step have 
conducted us to the most delightful and wonderful discoveries of 
the age. 
The rise and progress of spectrum analysis are known to most 
of the Fellows of the Microscopical Society ; it is therefore unneces- 
sary for me to trouble you with any preliminary observations con- 
nected with either.* I am, however, desirous of directing your 
attention to that very interesting field of research immediately con- 
nected with the colouring matter of flowers, the composition of 
which, and the part played by the action of light in its formation, 
is left for sjiectrum analysis to reveal. It is my purpose on the 
present occasion to make some observations upon the results ob- 
tained in the preparation of the colouring matters for spectroscopic 
examination. I must also request you to receive my paper as one 
suggestive of a subject to those whose opportunities and leisure are 
greater than my own, trusting it may prove to be a finger-post 
* It is simply necessary to remark that this paper was preceded by a few 
introductory observations on spectrum analysis of a general and historical cha- 
racter, but which were not intended for publication. I purposely confine myself 
to original observations on the colouring matter of flowers, wJiich have more 
particularly engaged ray attention. With regard to certain remarks, purp.irtiiig 
to be a criticism on my paper which appear in the Procee.dings of the Society 
' Juue meeting), they are so perfectly irrelevant and discourteous to me, personally, 
that I must decline to answer them. 
VOL. II. 
K 
