| Feb. 8, 1883] 
NATURE 
351 
_ pressing influence upon interspheral matter, and thus produce 
an elasticity, sufficient perhaps for the requirements of light 
radiation. 
The lines of motion thus transferred through space cannot be 
unvarying in their orbital directions. Nature knows no great or 
small in her processes, and each movirg particle of the free 
matter of space is controlled by the same principles which 
control the motions of a planet. It is subject to perturbations 
from lateral atiractions, similar to those which draw planets 
and comets out of their orbits, and completely change the 
orbit of the latter. And its impacts with other particles yield 
effects such as would arise in impacts between planets of 
oppositely moving systems, Action and reaction are equal, in 
this as in every case. The orbit and the speed of a line of 
motion may be changed through impact or attractive resistance, 
but only by its causing an opposite change in some other line. 
Thus the lines of motor energy referred to are not unvarying in 
speed and direction, but are unvarying in their sum of corre- 
lated speeds and directions. The variations which take place 
in the orbits of spheres and comets through attractive pertur- 
bation, and the greater variations which would take place did 
spheres come frequently into contact, are precisely similar to 
those which must occur in the case of interspheral particles, and 
any change in the direction of one orb t is balanced by an equal 
opposite change in the direction of another orbit, the balance of 
motor direction and energy in nature being exactly preserved. 
If such a line of motion pursues a cometary ellipse and enters 
the atmosphere of a globe, it must be affected by friction pre- 
cisely as if the line of moving particles were a single particle, or 
a niinute comet. It might be obliterated by friction or resistance, 
as the orbital motion of a falling body is obliterated, But this 
obliteration is really caused by the opposing energy of opposite 
lines of molecular motion. The single line of motion may be 
gistributed into a thousand lines differing in direction, but the 
pe ronent of these thousand lines must agree with the original 
ine. 
The transfer of motion from particle to particle here indicated 
may take place through attractive resistance as well as through im- 
pact resistance. The original disintegration of the matter of space 
must have increased, as spheral condensation denuded space of 
much of its material, and as radiation from the spheres increased 
its motor energy. If matter thus divided up into smaller and 
smaller particles, these may have continued as closely contiguous 
in space as are the molecules of spheral atmospheres. In such 
a case they may present the conditions of excessive rarity so far 
as weight of matter is concerned ; of close contiguity of particles, 
sufficient to permit the exercise of attractive energy ; of great 
compression, through their vigour of centrifugal motion, and of 
intense elastic resistance to compre-sion. These are the con- 
ditions necessary for the transfer of the radiations of light and 
heat. In these radiatures motion is conveyed through space by 
transfer of vibratory motions, not of impacts. The vibrating 
particle swings between lateral chains of attraction, and causes a 
like transverse swing in successive particles with which it is 
attractively connected. Greater energy here causes only greater 
width of vibration, not greater rapidity of transfer. The latter 
depends only on the elasticity of the matter concerned. Impact 
transfer of motion, on the contrary, must differ in speed with 
every difference in vigour. It is transferred by the motions of 
what we know as local heat, similar to the incessantly varied 
heat motions of gaseous matter. As the particles are unvarying 
in weight, increased momentum can be gained only by increased 
rapidity of motion, and the lines of motion thus transferred 
through space vary in speed with every variation in vigour. 
Every motion, of every particle of matter, is really a minute 
portion of an orbit, which represents that of a falling body, of 
a-planet, or of a comet, according to its rapidity. Though the 
momentum affects successive particles of matter the orbit is con- 
tinous, except to the extent that it is varied by perturbations 
through attraction and impact. 
Wherever any influence aids a translation of interspheral matter 
—causes a wind to blow through space—the lines of motion con- 
tinue to be conveyed by the same particles. The orbital motions 
of the spheres are such winds through space ; minor aggregations 
of moving matter may enter the . tmosphere of the sun or other 
globes. But no atmosphere can become permanently increased 
in this manner ; such masses, checked by friction, must yield 
motion, which flows outward. The centrifugal energy of the 
molecules of the external atmosphere is thereby increased, and 
the gain of matter must be balanced by an equal escape of 
matter at that critical atmospheric limit where centrifugal and 
centripetal energies are in balance. But any such fall of inter- 
spheral matter must aid the radiant emissions of the sun. Its loss 
of proper motion, its high degree of absolute heat, its increased 
temperature through condensation, and its consequent radiation, 
would make it a source of solar heat. Any such cometary 
matter must form part of ‘‘ Phe Fuel of the Sun.” 
Philadelphia, U.S. CHARLES Morris 
THE INSTITUTION OF MECHANICAL 
ENGINEERS 
THE Annual General Meeting of this Institution was held on 
January 25 and 26, at the Institution of Civil Engineers, 
Great George Street ; and the papers read were of unusual 
interest, from a scientific point of view, for a society whose 
aims are so distinctly practical. As it was pointed out by the 
president, Mr. Westmacott, three out of the five papers on the 
list were contributed by professors of science, and dealt with 
aspects more or less theoretical of the subjects treated upon. 
This forms, in fact, an additional instance of the way in which 
the old barriers between theory and practice are breaking down, 
and it is everywhere bec ming recognised that neither can flourish 
without the aid of the other. 
The first two papers, though quite independent, were both 
evolved, as it were, out of the same subject, namely, the research 
which the Institution has for some time been carrying on into the 
properties of hardened and unhardened steel. The first of these 
is an inéevim report by Prof. Abel, C.B., F.R.S., on the present 
stage of his experiments relating to the condition in which car- 
bon exists in steel. Preliminary trials had shown that the treat- 
ment of steel and iron by a chromic acid solution (produced by 
mixing a solution of potassium bichromate, saturated in the 
cold, with one-twentieth of its volume of pure concentrated sul- 
phuric acid) gave great promise of success in detecting the 
chemical differences existing in the same steel, according to the 
treatment to which it has been subjected. When cold—rolled, 
and annealed steel was thus treated, it yielded considerable 
amounts of an insoluble residue, consisting of black spangly 
particles, strongly attracted by the magnet, and presenting the 
characteristics of a true carbide, to which was assigned provision- 
ally the formula Fe,C;. With hardened steel, on the other 
hand, but a small quantity of such particles were obtained, 
mixed with a lighter sediment; and the total residue contained 
only about one-sixth the carbon in the original steel, whereas in the 
annealed samples nearly all the original carbon was detected in the 
residue. The theory to which this points clearly is that in soft 
steel the carbon exi-ts in a state of chemical combination, forming 
a carbide which is disseminated as a separate body through the 
mass of the iron ; but that in hard steel this combination is dis- 
solved, and the carbon exists in its pure form, either merely in 
mechanical admixture, as in the case of grey cast-iron, or in that 
peculiar and not very well understood form of association 
which metallurgists term an alloy. It would follow that the 
process of tempering, or rapid cooling, does not leave time for 
the complete formation of the carbide, and that in tempered 
steel all or some of the carbon still survives in its free or alloyed 
condition, : 
The fresh experiments described by Prof. Abel give, on the 
whole, great support to this theory. Four preparations were 
made of steel dissolved in chromic acid solution made as above, 
but of difterent degrees of strength. In the last only, where the 
strength was very high, were the re-ults different, showing that 
the carbide had not been able to resist the oxidising effects of 
the solution. In the others, a considerable deposit was found, 
which, after being kept for several days, first in the original and 
afterwards in a fresh solution, was washed and dried, and then 
analysed. Another portion of the same was treated with chlor- 
hydric acid, in order to ascertain what proportion would be 
converted into hydrocarbon. When this proportion was de- 
ducted from the whole, the remainder showed a most remarkable 
uniformity of composition, the percentages of carbon in three 
experiments being 5°93, 5°94, and 6°00 respectively. It seems 
evident that we have here a definite compound, to which Prof. 
Abel gives the formula Fe,C. The deviations from this exact 
composition he accounts for by the presence of a certain amount 
of water, indicating that a carbo-hydrate had been formed, pro- 
bably as a result of the action on the carbide first separated. 
Prof. Hughes’s paper, which was illustrated by a series of very 
