an
elaborate (and the first systematically conducted) investigation of
their relative brightness. He was as careful and patient as he was
rapid; spared no time and omitted no precaution to secure accuracy in
his observations; yet in one night he would examine, singly and
attentively, up to 400 separate objects.

The discovery of Uranus was a mere incident of the scheme he had marked
out for himself--a fruit, gathered as it were by the way. It formed,
nevertheless, the turning-point in his career. From a star-gazing
musician he was at once transformed into an eminent astronomer; he was
relieved from the drudgery of a toilsome profession, and installed as
Royal Astronomer, with a modest salary of L200 a year; funds were
provided for the construction of the forty-foot reflector, from the
great space-penetrating power of which he expected unheard-of
revelations; in fine, his future work was not only rendered possible,
but it was stamped as authoritative.[13] On Whit-Sunday 1782, William
and Caroline Herschel played and sang in public for the last time in St.
Margaret's Chapel, Bath; in August of the same year the household was
moved to Datchet, near Windsor, and on April 3, 1786, to Slough. Here
happiness and honours crowded on the fortunate discoverer. In 1788 he
married Mary, only child of James Baldwin, a merchant of the city of
London, and widow of Mr. John Pitt--a lady whose domestic virtues were
enhanced by the possession of a large jointure. The fruit of their union
was one son, of whose work--the worthy sequel of his father's--we shall
have to speak further on. Herschel was created a Knight of the
Hanoverian Guelphic Order in 1816, and in 1821 he became the first
President of the Royal Astronomical Society, his son being its first
Foreign Secretary. But his health had now for some years been failing,
and on August 25, 1822, he died at Slough, in the eighty-fourth year of
his age, and was buried in Upton churchyard.

His epitaph claims for him the lofty praise of having "burst the
barriers of heaven." Let us see in what sense this is true.

The first to form any definite idea as to the constitution of the
stellar system was Thomas Wright, the son of a carpenter living at
Byer's Green, near Durham. With him originated what has been called the
"Grindstone Theory" of the universe, which regarded the Milky Way as the
projection on the sphere of a stratum or disc of stars (our sun
occupying a position near the centre)