Oct. 20, 1870] 
NATURE 
499 
THE RECENT DEVELOPMENTS OF COSMICAL 
PHYSICS* 
"] HERE are two conflicting theories with regard to education. 
The extreme partisans of one of these would have us believe 
that the great object of education is not so much to inform as to 
discipline the min1—the subject taught in a seminary may not 
in itself increase th: student’s real knowledge, yet if it tend to 
discipline his mind, it has proved its value in their eyes as a 
branch of education. 
According to the upholders of this theory, our object in going 
to school is to leave it with a mind enlarged in its capacity for 
acquiring knowledge rather than stored with knowledge itself— 
having trained the soldier well, they would send him without 
scruple into the enemy’s country, not only to fight his own way 
but to find his own weapons. 
But there is another and opposite class of theorists who re- 
gard education not as an agent for training the mind so much 
as a means of storing it with knowledge. The extreme parti- 
sans of this theory would teach the student nothing but what is 
of apparent and immediate use; above all things they would 
teach him the sciences, both in their principles and also in the 
various details of their applications to the industrial arts of life. 
The mind of the student who has undergone a training of 
this kind carried to its extreme, resembles the inmate of a house 
which is not so much well-furnished as filled full of furniture. 
In the accumulation of mere material, anything like plan or 
principle has been forgotten. It ought to be remembered that 
the value of a fact lies not in its existence somewhere in the 
mental storehouse, but in the readiness with which the mind can 
find it when required. i 
Now between these two extreme theories it is surely possible 
to steer a middle course—it is possible to avoid grounding on 
Scylla without being swallowed up in the vortex of Charybdis. 
In the material world, what would be said to a man who insisted 
upon developing bodily strength by a course of gymnastics with- 
out reference to food, or of another who insisted upon doing 
the same by a course of diet without reference to exercise ? 
But is the separation more natural in the mental world? Is 
not that mind most perfectly disciplined which is at the same 
time most perfectly informed? ‘The student who has been dis- 
ciplined by only one branch of knowledge is, I venture to 
think, the possessor of a mind only partially disciplined, as it is 
only partially informed. He may not easily perceive his defi- 
cient discipline, but in after life he must often have cause to 
regret his deficient information. Nor is he whose mind is 
inordinately stored with sc entific details one whit better off. 
Facts in education ought to be strictly subordinated to 
principles. A sound principle of science clearly understood 
will embrace a great multitude of facts, just as a simple rule of 
arithmetic wil! enable us to obtain a thousand products, each of 
which we should have to remember were it not for the rule. 
And in other branches of scietice, if the triumph of principle be 
not so apparent, it is only because we have a less accurate know- 
ledge o! iis fundamental laws. It would be difficult indeed to 
say how many of the failures in the various walks of life are 
due to the neglect or ignorance of some principle. which has 
been either omitted or dismissed from our calculations. From 
our leaders downwards-we are a nation systematically ignoring 
principles, and in the minds of many a high esteem for fact is 
held to be quite consistent witha contempt for theory. A theory 
is not regarded as the very sap and life-blood of the tree of 
knowledge, but rather as the mildew that blights its leaves, or 
the worm that gnaws its root. Facts and theories.are esteemed 
by this class of men to be sworn foes to each other, and the 
philosopher is supposed.to live in a world of his own, rather 
hostile than otherwise to the world around him, 
The existence of the two extreme educational theories to 
which I have alluded would thus seem to indicate the wisdom 
of a middle course. We ought to start from a platform as com- 
prehensive as possible. Literature and science ought to go hand 
in hand in producing the well-trained and well-informed disciple. 
And while there ought to be a broad basis of instruction com- 
mon to all, there sh uld be raised upon this common basis 
several distinct departments, so that the student may have the 
opportunity of attaining proficiency in that of his choice, 
Professor Stewart next touched upon the subject of energy. 
*Extracted from a Lecture delivered at Owens College, Manchester, 
introductory to the Session 1870-71, by Professor Balfour Stewart, LL.D., 
If an egg be allowed to rest on its shorter axis, it will remain 
stationary, and any attempt to alter its position will be resisted 
by the egg. But the case will be different if we succeed, as 
perhaps we may, in causing it to stand on its longer axis, for in 
this position the slightest force will cause it to topple over. In 
the first case the egg is in stable, but in the second case it is in 
unstable, equilibrium. 
If it stand upon its longer axis at the very edge of a table, we 
cannot tell whether the first slight breath of air will cause it to 
fall inwards upon the table or outwards over the table, to be 
dashed to pieces on the floor. It is a case where a very slight 
cause may determine a very considerable issue as far as energy is 
concerned. Whether the-egg will retain its energy of position 
by falling on the table, or whether it will convert this into the 
energy of motion, and ultimately into heat, by falling upon the 
floor, is an issue that depends upon a cause too minute to come 
within the scope of our calculations. 
Now we have two types of machines, and in one of these we 
take advantage of the principle of stability, while in the other 
we use the principle of instability. A clock is a very good 
instance of a machine of the first kind. When a good clock 
has been wound up, we are perfectly sure that at noon to- 
morrow both its hands will stand at twelve, and-that its weight 
will have fallen through a distance which we can calculate with 
the utmost exactness, if we take the trouble, all its movements 
being capable of the most rigorous calculation, On the other 
hand, a mine that is about to be fired by means of an electric 
battery is a machine or combination in-which advantage is taken 
of nature’s unstable arrangements. The powder which is about 
to explode represents chemical instability, just as the egg on its 
longer axis represents mechanical instability. The slightest per- 
cussion, the smallest spark will rouse the imprisoned giant which 
it contains into volcanic energy. This spark has to be sent 
from a distance by the galvanic battery, and to do this we must 
complete the circuit. We cause the two wires to approach 
each other until they are only a very small fraction of an inch 
apart, but the contact is not yet complete—another touch, so 
slight as to be imperceptible, and the current passes, the powder 
is ignited, the mine explodes, and the fortress is hurled into the 
air. Insuch machines, great results, great transmission of energy, 
are due to the most trivial disposing causes. It depends at last 
upon the smallest conceivable movement of the wires conveying 
the current whether or not the fortress is to perish. 
Nature also employs these two varieties of mechanism. In 
the solar system we have a clock on a large scale, only very much 
more accurate than any time-piece we can produce. The move- 
ments of every planet ‘in the solar system are susceptible of the 
most rigorous calculation, and we have only to point our tele- 
scope properly in order to tell to the fraction of a second when a 
given planet will cross the field of view. 
But in the living forms with which this world is so plentifully_ 
endowed, we have machines, which, viewed in their relation te 
matter, belong to the second order we have described. The 
object here is not regularity, but rather freedom of action. 
motion of an animal is not like that of a planet—thelatter yields 
to calculation, but the former defies it. Now it is probably 
somewhere in the mysterious brain chamber that the delicate 
directive touch is-given which determines our movements, just 
as the slightest possible touch to the wire in the battery chamber 
explodes the distant mine. That mysterious thing we call life 
is not a bully who swaggers out into the open universe, up- 
setting the laws of energy in all directions, but rather a consumi- 
mate strategist, who, sitting in his chamber before his wires, 
directs the movements of a great army. 
While we are thus led to confine the directive action of life to 
the very boundary of the universe of energy, it must not, however, 
be supposed that we have solved the problem as to the nature of 
life. We have only driven the difficulty into a border land of 
thick darkness, into which the light of knowledge has not yet 
been able to penetrate. If there be truth in these statements, 
and if we see in a living being a machine in which great results 
are produced by an exceedingly small primeval impulse, are we 
not led to expect that the unstable forms of nature will here be 
largely made use of? We must not therefore be surprised that 
the materials of our bodily frames are eminently liable to decay, 
or that the very intensity of our life is to be measured by the 
rate of change taking place in the tissues of our bodies, so that 
possibly those parts which have during life the noblest and most 
delicate offices to perform are.the very first to perish when lile +s 
extinct. 
But this unstable matter, which is so wonderfully worked into 
The: 
