his sister to make a certain alteration in the lateral motion, which was
done by machinery, on which the point of support of the tube and mirror
rested. At each end of the machine or trough was an iron hook, such as
butchers use for suspending their joints of meat; and having to run in
the dark across ground covered a foot deep with melting snow, Miss
Herschel fell on one of these hooks, which entered her right leg above
the knee. To her brother's injunction, "Make haste!" she could answer
only by a pitiful cry, "I am hooked!" He and the workmen hastened
immediately to her assistance, but they could not disentangle her
without leaving nearly two ounces of her flesh behind. For some weeks
she was an invalid, and at one time it was feared that amputation might
be necessary.

* * * * *

Not satisfied with the magnifying power of any of the instruments he
had hitherto constructed, Herschel resolved, in 1784, to attempt a
forty-foot telescope. Such a work, however, was far beyond his limited
private resources; and he did not venture to undertake it until promised
a royal bounty of £2000. Then he removed from Datchet to Clay Hall, Old
Windsor; and again, in 1786, to Slough, where he finally settled, and
succeeded in erecting a commodious and well-equipped observatory. "We
may confidently assert," says Arago, "relative to the little house and
garden of Slough, that it is the spot of all the world where the
greatest number of discoveries have been made. The name of that village
will never perish: science will transmit it religiously to our latest
posterity."

At Slough, as at Datchet, prevailed the most enthusiastic industry; and
the house was soon as full of well-ordered labour as a bee-hive. Smiths