Herschel's career as an observing astronomer came to a virtual end with his departure from the Cape. He was then forty-six, two years younger than his father when he began his course of prodigious activity at Slough. Sir William's craving to see and to know was insatiable; Sir John's was appeased by the accomplishment of one grand enterprise. His was a many-sided mind; dormant interests of sundry kinds revived on the first opportunity; new ones sprang up; and curiosity to interrogate the skies ceased to “prick the sides of his intent.” So the instruments taken down at Feldhausen in 1838 were not remounted in England; and their owner is never again recorded to have used a telescope. One cannot but regret that, in the plenitude of his powers, and instructed by rare experience, he should have put by his weapons of discovery. The immense stock of observations with which they had furnished him remained, it is true, in their primitive, rough-hewn state; and he may have considered that wise husbandry required him to save one harvest before planting another. This, at any rate, was the course that he pursued.

But it was often and in many ways interrupted. The demands on his time and thoughts were innumerable.