Vermont phÅ“nix. [volume] (Brattleboro, Vt.) 1834-1955, 1871-08-11

ions, or the dincrential aud integral calcu-
lus, which, accordingly, he was led TO in
vent. Supposing the earth and planets to
fall towards the sun by their weight, the
amount of that fall could be determined in
each case by series Of calculations de-
pending on the size and shape Of the orbit
and the mean velocity of the revolution.
Those calculations Newton made and on
comparing them with the distances of the
planets from the sun, as determined by
triangulation, the important result was ar
rived at that the fall invariably decreased
as the square of the distance increased. lie
then calculated the moons fall in the same
way, and found that it was much smaller
than this principle would give. Hence,
other things being equal, bodies do not fall
towards the earth as rapidly as towards the
sun. The decrease, as far as he could
judge Gt has been more fully verified since)
was in proportion as the earth contained
loss matter than the sun. The final prob
lem then arose: all this is due TO weight,
.aa fIl! =. the moon, and that Of an apple to
the earth, must follow the planetary law,
and be inversely proportional to the
squares of their distances from the earth's
centre. lie tried them, and found them
not 50. There was an error of about one
sixth orthe whole, which remained through
all rcpetitions of the calculations. Here
was a powerful temptation to save his
theory by framing another that would in
some way account for this variation. lie
did not yield to it, how ever, but laid
his calculations aside, and kept the
subject still before his mind, waiting for
more light. Several years after, Il new
and accurate measurement was made
of degree of the earth's great circles. 1t
was found to be siXty-nine and one-half
English miles, instead of sixty, as prev-
ously supposed. Newton at once perceived
the bearing of this fact ON his speculations.
The earths radius was different from what
it had hitherto been taken to be--was
nearly one-sixth greater. lie went home
with these new data, and repeated his for
mer work. The figures seemed to come
out as the theory demanded 1t is said that
as he proceeded, and perceived each figure
bringing him nearer to the object Of his
hopes, his agitation actually prevented him
from continuing the calculation, and he
was Obliged to request "A friend to conclude
it for him.
1t must not be supposed that the method
we have described is peculiar to astronomy
and optics it is universal. Every man
who interrogates nature must be guided by
an hypothesis, just as lawyer examining
witness must have some preliminary no.
ton of the truth he wants to get at. Sir
Humphry Davy did not anayze the alkals
| by chance; nor did Faraday construct his
| little globe beted with wires, as model
of the earth heated by the sun, without
| having previously formed vivid mental
| pictures of the magnetic currents which he
afterwards found. SO, too, in geology,
| known facts suggest visions of the past
earth. and Imagination crowds them with
details which guide to further research.
| Turning to natural history, we find its pro-
gress made in the same way. SO much for
the physical and natural sciences but in
the most speculative one the procedure is
| precisely the same. Thus the more we in
! quire into the manner in which science has
been advanced by the labor of its votaries,
the more strongly is the conviction forced
upon us that it mainly consists in the free
use of the imagination. BY continually
| forming theories and comparing them with
facts, the Investigator learns just what to
| look for: he creates for hmselfa system
| of the world in which new discoveries find
their appropriate place he trains his mind
TO such a habit of specializing in accord
ance with known laws, that, as was said of
Sir William Hercshel, "he cannot touch
anything without making discoveries
about it,"
y practical lesson may be learned from
| this 1t is in favor of freedom. When DR..
Franklin was asked the use Of his clcctri-
cal researches, he replied: "What is the
use Of an infant? 1t may become man;
and the electric telegraph now justihcs his
answer. John Hunter was supposed by
many Of his cotemporarics to be only vast
ing his time and thought in studying as
carefully as he did the growth of deer's
horn; but he learned by it how arteries ac-
commodato themselves to circumstances
and enlarge rs occasion requires, SO that he
was emboldened in case of aneurism to
| tie the main trunk where no surgeon had
dared to tic il before, and the life of his pa
| tient was saved. The true explorer of ma
| ture loves knowledge. lie who does not
do so, makes little progress in it. Sir Isaac
| Newton compared himself to ~ child
| gathering pebbles on the sea-shore." The
| illustration was intended to show the low
estimate which he set on his own discover
les, in comparison with the possible extern
sion of our acquaintance with the universe.
| II may scryc, however, for another pur-
! pose. 1t may show how chld-like is the
highest and best pursuit of truth. The
child picks up the pebbles for their own
sake, not TO pave his fathers garden walk I;
and IL You do not present knowledge to
him rs task he will leave food rest, or
sport in order to learn some new fact, or,
still better, some explanation of it. So the
man of science, if you let him choose his
course freely, will exhibit an ardor which
finds no labor too great. When the spec
troscope revealed to Bunsen certain lines,
from which he inferred that minerals
hitherto unknown existed in water he
boiled down water to dryness till he had
used up forty-one tons before his labors
were rewarded by the discovery Of cesium
and rubidium.
The sole motive here is the desire to dis
cover truth. If ii is of any use, as it pro-
badly will be, let that reveal itself. In the
singleminded pursuit of truth as an ulti
mate end, the devotee of science considers
wealth IA trlhe. 81 have no iime," says
Prof. Agassiz, "to waste in making money"
Faraday might e6sily have secured for
himself an immense fortune by occupying
his time in analyzing minerals, etc, TAX
ing the duration of his life into account"
says Prof Tyndall, ''this son of black
smith, and apprentice to to a bookbinder,
had to decide between fortune of el5O,-
900 on the one side, and his uncovered
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