My brother began his series of sweeps when the instrument was yet in a very unfinished state, and my feelings were not very comfortable when every moment I was alarmed by a crack or fall, knowing him to be elevated fifteen feet or more on a temporary cross-beam instead of a safe gallery. The ladders had not even their braces at the bottom; and one night, in a very high wind, he had hardly touched the ground before the whole apparatus came down. Some labouring men were called up to help in extricating the mirror, which was fortunately uninjured, but much work was cut out for carpenters next day. That my fears of danger and accidents were not wholly imaginary, I had an unlucky proof on the night of the 31st December. The evening had been cloudy, but about ten o’clock a few stars became visible, and in the greatest hurry all was got ready for observing. My brother, at the front of the telescope, directed me to make some 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 hanging their joints upon, and having to run in the dark on ground covered a foot deep with melting snow, I fell on one of these hooks, which entered my right leg above the knee. My brother’s call, “Make haste!” I could only answer by a pitiful cry, “I am hooked!” He and the workmen were instantly with me, but they could not lift me without leaving nearly two ounces of my flesh behind. The workman’s wife was called, but was afraid to do anything, and I was obliged to be my own surgeon by applying aquabusade and tying a kerchief about it for some days, till Dr. Lind, hearing of my accident, brought me ointment and lint, and told me how to use them. At the end of six weeks I began to have some fears about my poor limb, and asked again for Dr. Lind’s opinion: he said if a soldier had met with such a hurt he would have been entitled to six weeks’ nursing in a hospital. I had, however, the comfort to know that my brother was no loser through this accident, for the remainder of the night was cloudy, and several nights afterwards afforded only a few short intervals favourable for sweeping, and until the 16th January there was no necessity for my exposing myself for a whole night to the severity of the season. I could give a pretty long list of accidents which were near proving fatal to my brother as well as myself. To make observations with such large machinery, where all around is in darkness, is not unattended with danger, especially when personal safety is the last thing with which the mind is occupied; even poor Piazzi[10] did not go home without getting broken shins by falling over the rack-bar, which projects in high altitudes in front of the telescope, when in the hurry the cap had been forgotten to be put over it.