pe had not suffered deterioration.
These doubts were strengthened in the following way: When hundreds of
curious objects were being discovered in the heavens here and there,
observers with small instruments naturally sought to find them.
The result was several discoveries belonging to the same class
as that of the satellite of Procyon. They were found with very
insignificant instruments, but could not be seen in the large ones.
Professor Hall published a letter in a European journal, remarking
upon the curious fact that several objects were being discovered
with very small instruments, which were invisible in the Washington
telescope. This met the eye of Professor Wolf, a professor at the
Sorbonne in Paris, as well as astronomer at the Paris Observatory.
In a public lecture, which he delivered shortly afterward, he lamented
the fact that the deterioration of the Washington telescope had gone
so far as that, and quoted Professor Hall as his authority.

The success of the Washington telescope excited such interest the
world over as to give a new impetus to the construction of such
instruments. Its glass showed not the slightest drawbacks from its
great size. It had been feared that, after a certain limit, the
slight bending of the glass under its own weight would be injurious
to its performance. Nothing of the kind being seen, the Clarks were
quite ready to undertake much larger instruments. A 30-inch telescope
for the Pulkova Observatory in Russia, the 36-inch telescope of the
Lick Observatory in California, and, finally, the 40-inch of the
Yerkes Observatory in Chicago, were the outcome of the movement.

Of most interest to us in the present connection is the history
of the 30-inch telescope of the Pulkova Observatory, the object
glass of which was made by Alvan Clark & Sons. It was, I think,
sometime in 1878 that I received a letter from Otto Struve, [2]
director of the Pulkova Observatory, stating that he was arranging
with his government for a grant of money to build one of the largest
refracting telescopes. In answering him I called his attention to
the ability of Alvan Clark & Sons to make at least the object glass,
the most delicate and difficult part of the instrument. The result
was that, after fruitless negotiations with European artists, Struve
himself came to America in the summer of 1879 to see what the American
firm could do. He first went to Washington and carefully examined
the telescope there