Notable Events of the Nineteenth Century / Great Deeds of Men and Nations and the Progress of the World

by Unknown

The history of the telescope-making in America properly begins with Alvan Clark, Sr., of Cambridgeport, Massachusetts. It was in 1846 that he produced his first telescope. Of this he made the lens, and such was the excellence of his work that he soon became famous, to the degree that the importation of foreign telescopes virtually ceased in the United States. Nor was it long until foreign orders began to arrive for the refracting lenses of Alvan Clark & Sons. The fame of this firm went out through all the world, and by the beginning of the last quarter of the century the Clark instruments were regarded as the finest ever produced.

We cannot here refer to more than a few of the principal products of Clark & Sons. Gradually they extended the width of their lenses, gaining with each increase of diameter a rapidly increasing power of penetration. At last they produced for the Royal Observatory of Pulkova a twenty-seven-inch objective, which was, down to the early eighties, the master work of its kind in the world. It was in the grinding and polishing of their lenses that the Clarks surpassed all men. In the production of the glass castings for the lenses, the French have remained the masters. At the glass foundry of Mantois, of Paris, the finest and largest discs ever produced in the world are cast. But after the castings are made they are sent to America, to be made into those wonderful objectives which constitute the glory of the apparatus upon which the New Astronomy relies for its achievements.

It was in the year 1887 that the Lick Observatory on Mount Hamilton, of the Coast Range in Southern California, was completed. The lens of this instrument is thirty-six inches in diameter. Nor will the reader without reflection readily realize the enormous stride which was made in telescopy when the makers advanced from the twenty-seven-inch to the thirty-six-inch objective. Lenses are to each other in their power of collecting light and penetrating apace as the squares of their diameters, and in the extent of space explored as the cubes of their diameters.

The objective of the Pulkova instrument is to that of the Lick Observatory as 3 is to 4. The squares are as 9 is to 16, and the cubes are as 27 is to 64. This signifies that the depth of space penetrated by the Lick instrument is to that of its predecessor as 16 is to 9, and that the astronomical sphere resolved by the former is to the sphere resolved by the latter as 64 is to 27—that is, the Lick instrument at one bound revealed a universe more than twice as great as all that was known before! The human mind at this one bound found opportunity to explore and to know a sidereal sphere more than twice as extensive as had ever been previously penetrated by the gaze of man.

Nor is this all. The ambition of American astronomers and American philanthropists has not been content with even the prodigious achievement of the Lick telescope. In recent years an observatory has been projected in connection with the University of Chicago, which has come almost to completion, and which will bear by far the largest telescopic instrument in the world. The site selected for the observatory is seventy-five miles from the city, on the northern shore of Lake Geneva. There is a high ground here, rising sufficiently into a clear atmosphere, nearly two hundred feet above the level of the lake.

The observatory and the great telescope which constitutes its central fact are to bear the name of the donor, Mr. Yerkes, of Chicago, who has contributed the means for rearing this magnificent adjunct of the University. The enterprise contemplated from the first the construction of the most powerful telescope ever known. The manufacture of the objective, upon which everything depends, was assigned to Mr. Alvan G. Clark, of Cambridgeport, Massachusetts, who is the only living representative of the old firm of Alvan Clark & Sons.

Alvan G. Clark has inherited much of the genius of his father, though it is said that in making the lens of the Lick Observatory the father had to be called from his retirement to superintend personally some of the more delicate parts of the finishing before which task his sons had quailed. But the younger Clark readily agreed to make the Geneva lens, under the order of Yerkes, and to produce a perfect objective forty inches in diameter! This important work, so critical—almost impossible—has been successfully accomplished.

The making and the mounting of the Yerkes telescope have been assigned to Warner & Swasey, of Cleveland, Ohio, who are recognized as the best telescope builders in America. The great observatory is approaching completion. The instrument itself has been finished, examined, accepted by a committee of experts, and declared to fulfill all of the conditions of the agreement between the founder and the makers. Thus, just north of the boundary line between Illinois and Wisconsin, the greatest telescope of the world has been lifted to its dome and pointed to the heavens.

The formal opening of the observatory is promised for the summer months of 1896. The human mind by this agency has made another stride into the depths of infinite space. Another universe is presently to be penetrated and revealed. A hollow sphere of space outside of the sphere already known is to be added to the already unthinkable universe which we inhabit. Every part of the immense observatory and of the telescope is of American production, with the single important exception of the cast glass disc from which the two principal lenses, the one double convex and the other plano-concave, are produced. These were cast by Mantois, of Paris, whose superiority to the American manufacturers of optical glass is recognized.

It is estimated that the Yerkes telescope will gather three times as much light as the twenty-three-inch instrument of the Princeton Observatory. It surpasses in the same respect the twenty-six-inch telescope at the National Observatory in the ratio of two and three-eighths to one. It is in the same particular one and four-fifth times as powerful as the instrument of the Royal Russian Observatory at Pulkova; and it surpasses the great Lick instrument by twenty-three per cent.