The national era. [volume] (Washington [D.C.]) 1847-1860, 1858-08-26
Harvey to the discovery of the circulation Of

the blood.
remember that when asked our famous
harvey, 10 the only discourse | had with him,
which was but little while before he died
what were the things which induced him 10
think of circulation of the blood7 he answer
ed me, that when he took notice of the valves
Ia the veins of so many parts of the BODY were
80 placed that they gave free passage to the
blood towards the heart, but opposed the pas
sage of the venal blood the contrary way. be
was invited to think that 90 provident a cause
az nature bad not placed 30 many valves with
out design; and no design seemed more proba.
bic than that, since the blood could not we'll
because of the interposing valves be sent By
the veins to the limbs, it should be cent by the
arteries, and return through the veins, whose
valves did not oppose its course that way.
Inc reason here ascribed to Harvey seems
now 90 very natural and obvious, that some
have been disposed to question his claim TO the
high rank commonly assigned to him among
the improvers of science DR.. William Hunter
has said, that after the discovery of the valves
IN the veins, which Harvey learned, while in
Italy, from his master, Fsbricius alb Aquapen.
aense, the remaining step might easily have
been made by any person of common abilities
This discovery" he observes, set Harvey to
system in animals; and in the course of some
years, he was 80 happy as to discover, and to
prove beyond all possibility of doubt, the cir.
culation of the blood" He afterwards express.
ed his sstonishment that this discovery should
have been left for Harvey, though he acknowl.
edges it occupied "a course Of years; 4" add.
ing, that " Providence meant to reserve it for
htDs, and would not let men see what was be
tore them, nor understand what they read" 1t
is remarkable that, when great discoveries are
effected, their simplicity always seems to de.
tract from their originality on these occa.
sions, We are reminded of the egg of Colum.
bust
1t is said that recent discovery, which as
certains that the Niger empties itself into the
Atlantic Ocean, was really anticipated by the
geographical acumen of student at Glasgow
who arrived at the same conclusion BY q mosi
persevering investigation of the works of trsv
elers and geographers, ancient and modern
and by an examination of African captives, and
had actually constructed, for the inspection OF
Government, a map of Africa, on which he had
traced the entire course of the Niger from the
interior.
Franklin conjectured the identity of lightning
and of electricity, before he had realized it BY
decisive experiment. The kite being raised, a
considerable time elapsed before there was any
appearance of its being electrified. One very
promising cloud had passed over it, withou,
any effect. Just as he was beginning TO despair
of his continuance, he observed some loose
threads of the hempen string to stand erect
and to avoid one another, just as if they had
| been suspended on q common conductor
Struck with this promising appearance, he i'm
mediately presented his knuckle to the key
And let the reader judge of the exquisite pleas
ure he must have felt at that moment, wher
the discovery sods complete We owe t.
| PTiestley this admirable narrative-the stroul
sensation of delight which Franklin experi
enced as his knuckle touched the key, and a
the moment when he felt that q new world wal
opening, might have been equalled, but it wst
probably not surpassed, when the same hanC
signed the long disputed independence of hi
country
When Leibnitz was occupied in his philo
sophical reasonings on his Lao of Continuity
his singular sagacity enabled him to predict {
discovery, which afterwards was realized-ht
imagined the necessary existence Of the poly
pusl
1t has been remarked of Newton, that seyera
of his slight hints, some in the modest form O
queries, have been ascertained to be pre- ic
tiOns, and, among others, that of the il hamma
o'ny vi ING oiamouo anu many nave DeeI
seized upon as indsputable axioms. hint o,
the close of his optics, that If natural philos
ophy should be continued to be improved in IT'D
various branches, the bounds of moral philoso
ply would be enlarged ALSO" is perhaps among
the most important of human discoveries il
gave rise to Hartlsy's Philosophical Theory o,
the Mind. The queries, the hints, the conjec
lures of Newton, display the most creative ga
gacity, and demonstrate in what manner the
discoveries of retired men, while they bequeath
their legacies to the world, afford to themselves
frequent source of secret and silent tri
umphs.