THE TELESCOPE OF THE ROCKY MOUNTAINS.
On the 20th 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 6000. 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 6400 times, and
required an immense erection of brickwork and masonry for the purpose of
working it, its weight being twelve tons and a half.
Still, despite these colossal dimensions, the actual enlargements
scarcely exceeded 6000 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 Apalachians, the very highest point of which, in New
Hampshire, does not exceed the very moderate altitude of 5600 feet.
On the west, however, rise the Rocky Mountains, that immense range which,
commencing at the Straits 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.
Illustration: THE TELESCOPE OF THE ROCKY MOUNTAINS.
Neither pen nor language can describe the difficulties of all kinds
which the American engineers had to surmount, or 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 lbs., 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 centres 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, towards 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 towards 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 dollars. The first time it was directed towards 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.