cb. 8, 1883] 
NATURE 
349 
is distant from the orbit of Jupiter only 07145, a sufficient ex- 
planation of a probable cause of the short period of revolution. 
THe GREAT Comer oF 1882.—The positions subjoined are 
extracted from an ephemeris published by Herr Stechert, of 
Berlin (Astron. Nach. No. 2486), and founded upon the elliptical 
elements of Dr. Kreutz :— 
At Berlin Midnight 
Plummer figures it appears that in longitude 223°*4 the comet 
Right Ascension. Declination. Distance from 
h. ms. z i Earth. Sun. 
February 8... 6 I 57 —20 5°8 ... 2°412 ... 3'008 
TOM NON OE7 <.. 19.3455 
Tete 5 S640 .. TQ) 3a7) eeskZ1500) 5. 34003 
DAwes. Sb y 2h e198 3374 
REM SESORE2 Ie.) wilO, (36) 4.0 21002 eS uTilo 
8 ..555 8 17 34°4 
20 wens S A aS, DeSean TOD) enc Spee 
ASTRONOMICAL TELEGRAMS.—Mr. Spencer F, Baird, Secre- 
tary of the Smithsonian Institution, notifies that arrangements 
have been completed with the Director of the Harvard College 
Observatory for conducting the system of telegraphic announce- 
ments of astronomical discoveries, which was established by the 
Institution in 1873, and that henceforward the American centre 
of reception and distribution of telegrams will be ‘‘ The Harvard 
College Observatory, Cambridge, Massachusetts,” to which all 
astronomical telegrams should in future be sent. 
THE MATTER OF SPACE 
OF late years there has been a growing tendency towards the 
belief that matter is present everywhere throughout the 
universe, as well in interstitial space as in the bodies of the spheres. 
Yet an older hypothesis is still widely held. The phenomena of 
light seem to require some substantial medium in space, but this 
substance has been viewed as specifically distinct from matter, 
and named ether. Another class of thinkers has devised still 
another species of substance. This is required to meet the 
demands of the new gravitation hypothesis; and consists of 
excessively minute particles, moving with intense speed, and 
pressing vigorously on the larger and slower particles of matter. 
In the past still other species of substance were imagined ; heat, 
electricity, etc., were each ascribed to a specifically distinct 
substance. 
Now, however, the tide has turned, and the inclination is to 
believe in only a single form of substance. There are, - of 
course, countless distinct conditions produced by the aggregations 
of substance, and variations from simplicity to complexity, but 
this may not necessarily require more than a single hind of 
basic particle, or whatever we may call it. If the substantial 
contents of space are similar in constitution to the matter of 
the spheres, their state of existence must be much more simpli- 
fied. In the spheres we have matter ranging from the simple 
elementary gases of the atmosphere, through the complex 
mineral compounds of the solid surface, to the highly com- 
pounded organic molecules. In outer space the variation is 
probably in the opposite direction, and substance may exist 
there in a condition much more highly disintegrated than the 
atmospheric gases. This view is not held by all theorists. Dr, 
Siemens argues that space holds molecules of considerable 
intricacy, comprising certain terrestrial elements, and their 
simpler compounds; as to the contents of space we know that 
there are very numerous solid masses, some of considerable size, 
others minute, and possibly ranging through many degrees from 
the largest to the minutest. Yet these really occupy but an 
inconsiderable portion of space, and apparently originated in 
solar or planetary orbs. 
Such is, briefly stated, the state of knowledge and of hypo- 
thesis concerning the substantial contents of space. We need 
but add the uncertain reasons for arguing the presence of a 
resisting medium in space, and the necessity of a highly elastic 
condition of the light-conducting substance, to exhaust the 
subject so far as yet pursued. 
It is held by some that the gravitation energy of the suns and 
planets is sufficiently great to sweep space of all contiguous 
material particles, except those solid masses which are saved 
from this fate by the vigour of their orbital motions. The 
atmospheres of suns and planets are retained with an energy 
very greatly in excess of their reverse energy of molecular 
motion, and therefore it is quite impossible that any of this 
material should escape into space, or that fany similarly-con- 
ditioned material should exist contiguous to the spheres without 
being forced to become atmospheric matter. The centrifugal 
energy of the earth’s atmosphere at the equator is only ,'7 of 
that necessary to overcome gravity. The molecules of the 
atmosphere have also a vigour of heat vibration about equal to 
their centrifugal energy. Hence the resisting energy of these 
molecules is far below the gravitative energy, and they are 
vigorously held. 
The question of the possible existence of gravitating matter in 
interspheral space depends strictly upon that of its mctor energy. 
If the momentum of any particle, or of the whole sum of 
particles, be insufficient to constitute a centrifugal energy equal 
or superior to the centripetal energy of gravitation, then the 
material contents of space must inevitably be drawn into the 
attracting spheres, as atmospheric substance, and space be 
denuded of matter. If, on the contrary, the centrifugal energy 
of these particles be sufficient to resist gravitation, they will 
remain free, and space continue peopled by matter. 
Such gravitative particles, wherever existing in space, could 
not be for an instant free from the influence of spheral attraction 
whatever their energy of motion. . If this energy be too small, 
they must be related to the spheres as falling bodies, and must 
become atmospheric matter. If the two opposite energies be 
equal, they must be related to the spheres as planetary bodies, 
and circle in fixed orbits around the centre of attraction. If 
the centrifugal energy be in excess they must assume the con- 
dition of independent cometary bodies, temporarily influenced 
but not permanently controlled by any sun, and wandering 
eternally through space. 
Such are the three possible conditions of the material contents 
of space. If the first obtain, space must be denuded of matter ; 
if the second obtain, it will permanently contain matter in a 
partially elastic state; if the third obtain, it will permanently 
contain matter in a highly elastic state, since the pressure upon 
each other of the vigorously centrifugal particles must be great, 
and may be extreme. Of course no single particle could long 
retain its direction of motion, as related to any sphere. Con- 
stant impacts must constantly vary the directions of molecular 
motion, But the motion of each particle is successively trans- 
ferred to a long series of particles, and thus is virtually continued 
in force and direction, Each motion pursues its course 
independently, though not as affecting any fixed particle of 
matter, and each particle aids in the progression of a vast 
network of motions, proceeding in every direction throughout 
the universe. Thus each particle, though not actually changing 
its place, may have motor relations which extend in every 
direction to the utmost extremes of space. It is a node in an 
interminable network of motions, and its incessant leaps through- 
out the limits of its narrow space are each part of a long motor 
line, which affects successively myriads of particles. So far as 
the energy of gravitation is concerned the effect upon this 
incessantly transferred motion is precisely the same as if the 
motion was confined to a single particle. If it lack energy the 
motion will be a falling one; if it equal the gravitative energy 
it will form a closed orbit. If it exceed the gravitative energy 
it will form an open curve, and be only temporarily controlled 
by any sphere. 
In this interchange of motor energy certain particles may 
continually decrease in vigour of motion, and if near solar orbs 
may be drawn in as atmospheric matter. But they can only lose 
motion by transferring it to others, which would in consequence 
become more independent of gravity. The sum of motor 
energies in the universe must persist unchanged, and the aggre- 
gation of atmospheric substance around any planet must cause 
an outflow of motor energy which will increase the motor vigour 
of exterior particles. In such a case the height of atmosphere 
in any sphere will depend, partly on the attractive vigour of the 
sphere, and partly on the average motor vigour of the whole sum 
of matter. Every contraction and loss of motor energy by any 
portion of matter will increase the motor energy of remaining 
matter, and a fixed limit to the atmospheric control of every 
sphere must result, since in the outer layers of its atmosphere 
the centrifugal energy of molecular motion must increase until 
it equals the energy of gravitation. 
Can we arrive at any conclusion as to which of the three 
possible conditions above considered really exists ? If so we can 
answer the question as to the existence of matter as a constant 
tenant of space, and also reach some conclusions as to the 
character of its motor conditions. 
