[Footnote 1:  Afterwards Sir John Herschel.]

From this dangerous attack Sir William recovered, but thenceforth it was clear to his friends that his strength gradually decreased, though not his enthusiasm or his industry.  He persevered in his life-long labours with all his old intellectual force.  What failed him was neither his tender affections nor his mental powers; but his body refused to answer all the demands made upon it by the resolute will,—­the sword was slowly but surely wearing out the scabbard.  Under the date of April 2, 1819, we meet with an ominous entry in his loving and faithful sister’s diary:—­

“My brother left Slough, accompanied by Lady Herschel, for Bath, he being very unwell; and the constant complaint of giddiness in the head so much increased, that they were obliged to be four nights on the road both going and coming.  The last moments before he stepped into the carriage were spent in walking with me through his library and workrooms, pointing with anxious looks to every shelf and drawer, desiring me to examine all, and to make memorandums of them as well as I could.  He was hardly able to support himself; and his spirits were so low, that I found difficulty in commanding my voice so far as to give him the assurance he should find on his return that my time had not been misspent.

“When I was left alone, I found that I had no easy task to perform, for there were packets of writings to be examined which had not been looked at for the last forty years.  But I did not pass a single day without working in the library as long as I could read a letter without candlelight, and taking with me papers to copy, which employed me for best part of the night; and thus I was enabled to give my brother a clear account of what had been done at his return.  But (May 1) he returned home much worse than he went, and for several days hardly noticed my handiwork.”

To this same year of decay and decline (1819) belongs a small slip of yellow paper, inscribed with the following lines in a tremulous and feeble handwriting, which is jealously preserved by the illustrious astronomer’s descendants:—­

“LINA,—­There is a great comet.  I want you to assist me.  Come to dine, and spend the day here.  If you can come soon after one o’clock, we shall have time to prepare maps and telescopes.  I saw its situation last night,—­it has a long tail.

     “July 4, 1819.”

Then follows:—­

     “I keep this as a relic!  Every line now traced by the hand of
     my dear brother becomes a treasure to me.

     “C.  HERSCHEL.”

We know of nothing more touching in literary history than this noble, self-sacrificing, generous affection of the sister towards her eminent brother.  Such instances of absolute self-denial and all-absorbing love elevate our opinion of human nature generally, and prove that something of the Divine image lingers in it still.