OcTOBER 26, 1899] NATURE 617 
ON THE DISTRIBUTION OF THE ark Us see them ; but there are reasons for supposing that there 
; Bite re" en = Se 7a is a very considerable number. 
CHEMICAL GROUPS OF STARS We have deal with the masses of matter in 
CS! Y)ME few years ago it was my duty to give a course 
~ of lectures here relating to the sun’s place in nature 
I attempted to give an idea of the relation of the sun, as 
to age and temperature, to other stars, and also its re- 
lation to bodies supposed to be of a different ordex 
altogether. 
Since that lecture was delivered our knowledge on this 
and allied subjects has advanced with giant strides. We 
now know, thanks to spectrum analysis, the principles of 
which I then explained, a great deal of the chemistry of 
the stars, so much that we can now classify them into 
groups, defining those groups by the chemical elements 
involved in each. I shall not bring 
before you to-night the detailed classi- 
fication of these bodies, but shall, for 
the purposes of this lecture, ask you 
to consider the four following kinds 
only : 
. Hishest temperature. 
f Proto-hydrogen stars. 
\ Cleveite-gas stars. 
Proto-metallic stars. 
Metallic stars. 
Stars with fluted spectra. 
Gaseous stars 
Lowest temperature. 
The table almost explains itself: I 
may add that by “ proto-metallic 
stars I mean those stars in the spectra 
of which the metals we know here are 
ehiefly represented by lines—the so- 
called “ enhanced-lines ”—we can only 
obtain here by using high-tension 
electricity, and there are other evi- 
dences which show that these stars 
are hotter than the metallic ones, 
while they, in their turn, are cooler 
than the gaseous stars. In discussing 
the work of other observers I have as 
far as possible transposed the different 
notations employed into the chemical 
one given above. 
In relation to the sun’s place we 
had a great many comparisons to make 
with different stars quite independ- 
ently of their position in space. I 
propose now to touch upon a still 
more general inquiry to consider the 
distribution of all stars in space, not 
in relation to their magnitudes, but in 
relation to their chemistry. 
It is obvious that we are among 
the first from the beginning of the Fic. 
world who have been able to do this, 
because formerly the chemistry of 
these celestial bodies was entirely lacking. I think, there- 
fore, you will agree that it is a very important thing, now 
that we have the chemistry, to inquire into the distribu- 
tion of the various chemical conditions in the different 
parts of the universe in which our lot is cast. For that 
purpose, I will deal with the stars as generally as I can, 
considering only the wider division into the gaseous stars, 
the proto-metallic stars, that is to say, the stars represented 
by the enhanced lines, then the metallic stars in which 
we are dealing with arc lines, and then the metallic fluting 
stars and the carbon fluting stars. As star-life begins 
with nebula and meteoritic swarms, it ends with dark 
stars which it is possible may be very numerous in space. 
How many there are we do not know, because we cannot 
lelivered at the Museum of Practical 
rman Lockyer, K.C.B., F.R.S 
1 A Lecture to Working Men, 
yn April 10, by Prof. Sir N 
NO. 1565, VOL. 6o| 
1.—Photograph of a g 
only to 
space which are visible, and it is obvious that any inquiry 
into the distribution of the chemical conditionings, as 
revealed by spectra, of these masses must be preceded 
by an inquiry into the distribution of these masses 
considered merely as masses and quite independent of 
chemistry. 
This work has already occupied the altenvion of many 
eminent astronomers, and I will begin by placing the 
results of their labours before vou as shortly as I can. 
I call your attention to the Milky Way. If you have 
seen the Milky Way from a high mountainous country, as 
I have done, you will acknowledge what a very wonderful 
zlass globe showing the relation of the Milky Way to the Equator an 
to Gould's belt of stars. 
thing it is; I was most struck with the Milky Way when 
I was in the Rocky Mountains some years ago. It 
was not merely the pale milky belt we generally see 
running across the sky, but it had lights, shades, shadows, 
brightnesses and dimnesses ; it was full of the most 
ellous details. I have seen it, I am bound to say, 
Kent, but not often. You 
mary 
just as well on the coast of 
want an extremely fine sky to see the Milky Way 
properly ; but, at all events, whether you have seen it 
well or ill, all of you, 1 am sure, are familiar more or less 
with it. What is it? It is a-bnght belt encircling the 
heavens ; its position with regard to the equator of the 
earth, and the equatorial plane extended to the stars, I 
can show you roughly by means of a glass globe. Those 
who are familiar with Dante know that the old view 
of the heavens was that the earth was immovable in the 
