Presently Caroline said, as she looked out:
"There is a chaise waiting at the end of the street, with post-horses."
But her brother's eyes were directed upwards, and he scarcely noticed her remark.
"Well," he said, "get the micrometer."
Caroline's feminine curiosity was roused, and presently she saw a figure muffled in a long cloak glide down the street to the opening where the carriage stood.
This was followed by another, and then, after some delay, the chariot drove off.
Alexander Herschel did not generally take part in these nightly vigils, although he lent his assistance in the daytime in the workshop, and in the correspondence about the music, which was very frequently necessary.
But about six o'clock Alexander appeared, and said:
"Did you hear carriage-wheels roll off not long ago?"
William Herschel did not answer. He had just brought a double star into the proper focus, and Caroline stood by with note-book and pencil, ready to write at his dictation.