NATURE 
4.4 ed ae a pr Sa ed 
137 
. THURSDAY, DECEMBER 26, 1872 
THE PROGRESS OF NATURAL SCIENCE 
_ DURING THE LAST TWENTY-FIVE YEARS 
iG 
N the occasion of the celebration at Breslau of the 
twenty-fifth anniversary of Prof. Goeppert’s presi- 
_ dency of the Silesian Society for National Culture, Prof. 
_ Ferdinand Cohn delivered an address characterised by 
eloquence of the highestk ind on the above subject. As the 
wanderer, he said, who is climbing towards a high 
mountain peak, feels from time to time the desire to stand 
_ still a little, and look back on the way over which he has 
_ passed, to enjoy the wider outlook which he gains from his 
higher stand-point; so he thinks there are moments in 
the uninterrupted progress of science, when we long in 
some measure to strike a balance, and see how much 
_ acquired property the present puts aside as useless, how 
much it uses only for temporary purposes, and how 
_ many enduring acquisitions have been made. 
Dr. Cohn refers, no doubt with justice and some pardon- 
able pride, to the foremost place held by Germany during 
the last quarter of a century, in the march of science. 
_ At the same time he awards due praise to other European 
states, and above all to England, which, during that time 
and more pirticularly at present, he thinks, abounds in 
“men of the highest eminence, whose scientific achieve- 
_™ents stand prominently out on account of their as- 
tonishing energy, clearness, depth, and independence of 
thought. Still, we cannot but admit that Dr. Cohn is 
‘right in asserting that Germany is free from the dilettan- 
_tism which abounds in this country, and that asa rule 
Science in Germany is both far more widespread, and 
far more thorough than it is among ourselves, and that 
the Opportunities furnished there to all classes for scientific 
study at the ordinary educational establishments have 
until recently left us almost nowhere. But happily, signs 
of the beginning of the end of this state of things among 
us are becoming rife. 
After briefly referring to the intellectual awakening of 
Germany along with the rest of Europe at the time of 
the Reformation, and showing how this start forward was, 
especially in the case of Germany, in a great measure 
ustrated by the Thirty Years’ War, Dr. Cohn pays a 
high and justly-merited tribute to France, and especially 
to Paris, on account of the supreme place she took during 
the first thirty or forty years of the present century in 
early allthe sciences. The glory of France in this direc- 
ion has however, he thinks, departed, and Germany is 
coming daily more and more the intellectual centre of 
‘the world. Had Dr. Cohn written his lecture now, he 
might have somewhat modified his language ; for within 
the last few months, the signs have been many, that in 
the direction of science the French are determined to try 
to hold their own with the foremost in Europe. Their 
professors are prosecuting an amount of research which 
puts our own to shame, while they are at the same time 
forming a school of investigators. We do not grudge to 
Germany all the praise she well deserves, and the in- 
fluence which the results of German research exercise 
‘ Vo. vi.—No, 165, 
Hy 
on other nations, is likely to urge them to such vigorous 
and determined efforts, that, sooner or later, science and 
every other progressive influence shall be “ great gainers.” 
Meantime, however, Germany is doubtless in the ascendant. 
In the year 1845 appeared the first volume, and in 
1846 the second of Humboldt’s Cosmos. As comprising 
|a view ef the whole created universe depicted with the 
most wonderful sympathy, the book is as it were a canon 
forming a key to everything that was known of nature at 
the time. No man was then more suited for such work 
| than was in the highest degree A.von Humboldt. A Divina 
‘Commedia of science, the Cosmos embraced the whole 
universe in its two spheres, heaven and earth, Under th> 
leadership of the great searcher of Nature, as Dante once 
by the hand of Virgil, we climb from the depths of the 
universe, with its furthest nebula and double stars, down 
through the star depths to which belongs our solar system, 
to the air and sea-enveloped earth, where form, tempera- 
ture and magnetic condition are unveiled to us; then to 
the wealth of organic life, which, stimulated by the light, 
unfolds itself on its surface. It is an overwhelming pic- 
ture of nature, of surpassing beauty of outline, abounding 
in grand perspective, with the most careful execution of 
the smallest detail. 
But we cannot conceal from ourselves that the 
Cosmos, published twenty-five years ago, is in many of 
its parts now antiquated, not merely because it is wanting 
in many facts which have since been discovered, but most 
particularly because Humboldt was ignorant of some 
highly important questions which have since taken their 
place in the foreground of scientific discussion, while our 
scheme of the universe during the last ten years has been 
considerably modified by the introduction of new and 
influential ideas. Any one who to-day would attempt to 
recast the Cosmos, must proceed like the Italian archi- 
tect who took the pillars and blocks of the broken temples 
of antiquity, added new ones, and rebuilt the whole after 
a new plan. 
There are three discoveries which during the last 
quarter of a century have entirely changed the position of 
natural science :—the mechanical equivalent of heat, spec- 
trum analysis, and the Darwinian theories. 
Since, in the year1842, an unknown physician in a 
Swabian country town, Dr. Mayer of Heilbronn, pointed 
out that a hammer 424 kilograms in weight, which falls 
from the height of a metre on an anvil, raises the heat of 
the latter by one degree centigrade, and that by this pro- 
cess of bringing a falling motion to a stand-still it is con- 
verted into a fixed quantity of heat—since then has science 
gained a new conception of the conditions of matter and 
of the powers of nature. This new doctrine appears in 
the mechanical theory of heat announced by Joule, 
Kr6énig, Maxwell, and Clausius, in the doctrine of the con- 
servation of energy of Helmholtz and Thomson, and by 
means of the brilliant writings of Tyndall it has become 
the common property of the educated world, Electricity 
and magnetism, heat and light, muscular energy and 
chemical attraction, motion and mechanical work—all 
forces in the universe are only different forms of one and 
the same power, which has dwelt from the first in matter 
in invariable quantity, neither increased nor diminished. 
not the least trifle of it can be annihilated or created 
Only the phenomenal forms of power are changeable ; 
I 
ir a ea Saal Se ve 
