s able to estimate the lustre of the _natural_ stars
examined by the distances at which the artificial object appeared equal
respectively to each. He thus constructed a table of 191 of the
principal stars,[127] both in the northern and southern hemispheres,
setting forth the numerical values of their apparent brightness
relatively to that of Alpha Centauri, which he selected as a unit
of measurement. Further, the light of the full moon being found by him
to exceed that of his standard star 27,408 times, and Dr. Wollaston
having shown that the light of the full moon is to that of the sun as
1:801,072[128] (Zoellner made the ratio 1:618,000), it became possible to
compare stellar with solar radiance. Hence was derived, in the case of
the few stars at ascertained distances, a knowledge of real lustre.
Alpha Centauri, for example, emits less than twice, Capella one hundred
times as much light as our sun; while Arcturus, at its enormous
distance, must display the splendour of 1,300 such luminaries.

Herschel returned to England in the spring of 1838, bringing with him a
wealth of observation and discovery such as had perhaps never before
been amassed in so short a time. Deserved honours awaited him. He was
created a baronet on the occasion of the Queen's coronation (he had been
knighted in 1831); universities and learned societies vied with each
other in showering distinctions upon him; and the success of an
enterprise in which scientific zeal was tinctured with an attractive
flavour of adventurous romance, was justly regarded as a matter of
national pride. His career as an observing astronomer was now virtually
closed, and he devoted his leisure to the collection and arrangement of
the abundant trophies of his father's and his own activity. The
resulting great catalogue of 5,079 nebulae (including all then certainly
known), published in the _Philosophical Transactions_ for 1864, is, and
will probably long remain, the fundamental source of information on the
subject;[129] but he unfortunately did not live to finish the companion
work on double stars, for which he had accumulated a vast store of
materials.[130] He died at Collingwood in Kent, May 11, 1871, in the
eightieth year of his age, and was buried in Westminster Abbey, close
beside the grave of Sir Isaac Newton.

The consideration of Sir John Herschel's Cape observations brings us to
the close of the period we are just now engaged in studying. They were
given to the w