New-York tribune., 1867-04-06

pleuOn 81 the Atlantic telegraph cable tho Cmcaeo 'un
mel uder Lake Michigan, and the progress oil the railway
OyCr Mt Cents improvements IN engineering nave ooon
Effected in the direction OF economy In fuei oJ hOueF
tons of furnaces and ues and the due supply OF air
for perfect combustion The substitution OF steel Tor IRON
In arioe narts NJ locomotives and for rails has greatly
diminished the wear and tear Of machinery ana ADDED 10
its permanence in remarkable degree The extensive
use OF steel in shipbuding has contributed much TO the
strength and safety Of eagong vessels The new gun
powdcr made from wood, bids fair to rival the old ex
plosiye for certain purposes. Nitro-glyoerine has
also been successfully introduced for blasting, and
eunpapcr for small arms. The important theory
of The correlation of forces has received fresh Il
lusratOn by the OF experimental research III
may considered proved that light, heat, chemlea
affinity electricity, and magnetism which are universal
attributes Of matter in all its FORMS are interchangeable
forces with each other and with motion Many points Of
great practical moment are connected with this subject
as whether we produce heat by the expenditure OF
other forces than those locked in our coal beds ana
forests, whether absorb and store mp 1or luue
use by chemical mechanical means the rays OF the
sun now wasted human purposes in the desert ana
the tropcs The remarkable results of spectrum analysis,
from the labors Of KrchhOn Bunsen, Huggns, and NIL
ler have thrown flood Of light upon the structure OF inc
heavenly bodies Physiology has made great progress,
mainly owing mcroscOpical and chemical lnVestsa
tions. The law Of uniformity in the development OF
cells as the foundation Of organic structures has been
fruitful in consequences II is now believed that the SIM
pie forms Of animal and vegetable life arc perfectly ake
that the tough oak plank the blade Of grass the non
claw the contracting muscle, and the thinking brain,
all emanate from similar The theory OF Darwin
that species have not been created at various umes
complete and unchangeable but that they nave
been gradually modified by external circumstances, mas
continually gained ground, and now numbers among us
advocates many Of the first naturas ot Europe ana
this country although the opponents of this theory IKE
Agassz and others, bring forward many strong points
On the whole the tendency to be 10 the belief tha
the divisions into species, genera and families arc not
founded in nature but merely convenient terms fOr
| subdivisions having a permanence which may onthve
many generations Of men, but which yet are not aoso
utely fixed Time the great element, both IN the de
veopment of vegetable and animal life, ana aiso III tno
progress barbaTism to civilizatlon ana s
must be held prominently in view In the consideration o
the theory Of Darwin In selecting the facts and autho
ties for the materials Of this volume DR. Kneeand has
evnced an experience TO which the conclusions OF science
are as familiar household words" and an excellent
Judgment in the arrangement Of details His work does
ample credit his accomplishments as naturalist, and
forms manual less valuable for practical reference
than as a historical record.