and under his roof Harding and Bessel received
their training as practical astronomers.

But he was reserved to see evil days. Early in 1813 the French under
Vandamme occupied Bremen. On the night of April 20, the Vale of Lilies
was, by their wanton destructiveness, laid waste with fire; the
Government offices were destroyed, and with them the chief part of
Schroeter's property, including the whole stock of his books and
writings. There was worse behind. A few days later, his observatory,
which had escaped the conflagration, was broken into, pillaged, and
ruined. His life was wrecked with it. He survived the catastrophe three
years without the means to repair, or the power to forget it, and
gradually sank from disappointment into decay, terminated by death,
August 29, 1816. He had, indeed, done all the work he was capable of;
and though not of the first quality, it was far from contemptible. He
laid the foundation of the _comparative_ study of the moon's surface,
and the descriptive particulars of the planets laboriously collected by
him constituted a store of more or less reliable information hardly
added to during the ensuing half century. They rested, it is true, under
some shadow of doubt; but the most recent observations have tended on
several points to rehabilitate the discredited authority of the
Lilienthal astronomer. We may now briefly resume, and pursue in its
further progress, the course of his studies, taking the planets in the
order of their distances from the sun.

In April, 1792, Schroeter saw reason to conclude, from the gradual
degradation of light on its partially illuminated disc, that Mercury
possesses a tolerably dense atmosphere.[796] During the transit of May
7, 1799, he was, moreover, struck with the appearance of a ring of
softened luminosity encircling the planet to an apparent height of three
seconds, or about a quarter of its own diameter.[797] Although a "mere
thought" in texture, it remained persistently visible both with the
seven-foot and the thirteen-foot reflectors, armed with powers up to
288. It had a well-marked grayish boundary, and reminded him, though
indefinitely fainter, of the penumbra of a sun-spot. A similar appendage
had been noticed by De Plantade at Montpellier, November 11, 1736, and
again in 1786 and 1789 by Prosperin and Flaugergues; but Herschel, on
November 9, 1802, saw the preceding limb of the planet projected on the
sun cut the luminous solar clouds with the most