On the 20th of October in the preceding year, after the close of
the subscription, the president of the Gun Club had credited the
Observatory of Cambridge with the necessary sums for the
construction of a gigantic optical instrument. This instrument
was designed for the purpose of rendering visible on the surface
of the moon any object exceeding nine feet in diameter.
At the period when the Gun Club essayed their great experiment,
such instruments had reached a high degree of perfection,
and produced some magnificent results. Two telescopes in
particular, at this time, were possessed of remarkable power
and of gigantic dimensions. The first, constructed by Herschel,
was thirty-six feet in length, and had an object-glass of four
feet six inches; it possessed a magnifying power of 6,000.
The second was raised in Ireland, in Parsonstown Park, and belongs
to Lord Rosse. The length of this tube is forty-eight feet, and
the diameter of its object-glass six feet; it magnifies 6,400
times, and required an immense erection of brick work and
masonry for the purpose of working it, its weight being twelve
and a half tons.
Still, despite these colossal dimensions, the actual
enlargements scarcely exceeded 6,000 times in round numbers;
consequently, the moon was brought within no nearer an apparent
distance than thirty-nine miles; and objects of less than sixty
feet in diameter, unless they were of very considerable length,
were still imperceptible.
In the present case, dealing with a projectile nine feet in
diameter and fifteen feet long, it became necessary to bring the
moon within an apparent distance of five miles at most; and for
that purpose to establish a magnifying power of 48,000 times.
Such was the question proposed to the Observatory of Cambridge,
There was no lack of funds; the difficulty was purely one
of construction.
After considerable discussion as to the best form and principle
of the proposed instrument the work was finally commenced.
According to the calculations of the Observatory of Cambridge,
the tube of the new reflector would require to be 280 feet in
length, and the object-glass sixteen feet in diameter.
Colossal as these dimensions may appear, they were diminutive
in comparison with the 10,000 foot telescope proposed by the
astronomer Hooke only a few years ago!
Regarding the choice of locality, that matter was
promptly determined. The object was to select some lofty
mountain, and there are not many of these in the United States.
In fact there are but two chains of moderate elevation, between
which runs the magnificent Mississippi, the "king of rivers"
as these Republican Yankees delight to call it.
Eastwards rise the Appalachians, the very highest point of
which, in New Hampshire, does not exceed the very moderate
altitude of 5,600 feet.
On the west, however, rise the Rocky Mountains, that immense
range which, commencing at the Straights of Magellan, follows
the western coast of Southern America under the name of the
Andes or the Cordilleras, until it crosses the Isthmus of
Panama, and runs up the whole of North America to the very
borders of the Polar Sea. The highest elevation of this range
still does not exceed 10,700 feet. With this elevation,
nevertheless, the Gun Club were compelled to be content,
inasmuch as they had determined that both telescope and
Columbiad should be erected within the limits of the Union.
All the necessary apparatus was consequently sent on to the
summit of Long's Peak, in the territory of Missouri.
Neither pen nor language can describe the difficulties of all
kinds which the American engineers had to surmount, of the
prodigies of daring and skill which they accomplished. They had
to raise enormous stones, massive pieces of wrought iron, heavy
corner-clamps and huge portions of cylinder, with an
object-glass weighing nearly 30,000 pounds, above the line of
perpetual snow for more than 10,000 feet in height, after
crossing desert prairies, impenetrable forests, fearful rapids,
far from all centers of population, and in the midst of savage
regions, in which every detail of life becomes an almost
insoluble problem. And yet, notwithstanding these innumerable
obstacles, American genius triumphed. In less than a year after
the commencement of the works, toward the close of September,
the gigantic reflector rose into the air to a height of 280 feet.
It was raised by means of an enormous iron crane; an ingenious
mechanism allowed it to be easily worked toward all the points
of the heavens, and to follow the stars from the one horizon to
the other during their journey through the heavens.
It had cost $400,000. The first time it was directed toward the
moon the observers evinced both curiosity and anxiety. What were
they about to discover in the field of this telescope which
magnified objects 48,000 times? Would they perceive peoples,
herds of lunar animals, towns, lakes, seas? No! there was
nothing which science had not already discovered! and on all the
points of its disc the volcanic nature of the moon became
determinable with the utmost precision.
But the telescope of the Rocky Mountains, before doing its duty
to the Gun Club, rendered immense services to astronomy. Thanks to
its penetrative power, the depths of the heavens were sounded to
the utmost extent; the apparent diameter of a great number of stars
was accurately measured; and Mr. Clark, of the Cambridge staff,
resolved the Crab nebula in Taurus, which the reflector of Lord
Rosse had never been able to decompose.
