838 
His impar- Mathematical Sciences, he had to make frequent re- 
tiality— 
his death. 
(172.) 
Sir Wm. 
Herschel ; 
(173.) 
his exten- 
sive works; 
(174) 
early his- 
tory. 
ports on the progress of those progressive branches 
of knowledge, and to contribute memoirs of the most 
eminent academicians, both native and foreign. Both 
these duties he executed with his customary labour 
and fidelity. His private character was as amiable 
as his public career was distinguished. The tendency 
of his writings was constantly to enforce the histori- 
ASTRONOMY.—SIR WILLIAM HERSCHEL. 
[Diss. VI. 
cal credibility of the Scriptures, especially with regard 
to the most ancient astronomical records.. The value 
of his testimony is increased by his unusual skill in 
philology. He died 19th August 1822, aged 73. 
We reserve some farther remarks on the geodetic 
results of this period, and especially on the pendujum 
observations with which they were accompanied, for 
the fourth section of this chapter. 
§ 2. Sir WILLIAM HEerscuEeL.—History of Sidereal and Telescopic Astronomy to 1820. Her- 
schel as an Optician.—Planet Uranus—Solar Spots—Orbits of Double Stars—Nebule—The 
Milky Way—Sun’s Motion in Space. 
The eighteenth century was not, generally speak- 
ing, distinguished by original observations. The ex- 
ceptions stand out with all the brighter lustre. 
Amongst these, the discoveries of Sir William Her- 
schel occupy perhaps the foremost place. Arago has 
affirmed that Slough is the spot on the earth’s sur- 
face signalized by the most numerous discoveries, 
and in a certain sense this is strictly true. No one, 
before or since (with possibly the exception of Mr 
Hind) has added so many new bodies to the known 
planetary system, and this at a time when such 
discoveries were rarer, more unexpected, and more 
difficult than now. His researches on the fixed 
stars are not of a nature to have their importance 
numerically estimated. 
Sir William Herschel’s career was one of the 
longest and of the most sustained labour in the history 
of science. T’o have contributed papers—often several 
in one year—to the Philosophical Transactions for 
thirty-nine consecutive years, from 1780 to 1818, 
with but two exceptions, is a feat of astonishing per- 
severance ; but if we recollect that many of these 
papers contain announcements of capital discoveries, 
that every one of them is stored with original matter, 
and that the author had already passed his fortieth 
year when he commenced the production of this as- 
tronomical library, we cannot withhold a tribute of 
the warmest admiration. 
England cannot claim Herschel as her own, except 
by adoption. He was born at Hanover in 1738, and 
was one of a numerous family who supported them- 
selves chiefly by their musical talents. William 
Herschel, the third son, came to England in 1759 
with his elder brother, and after struggling with many 
difficulties, found himself in comparatively comfort- 
able circumstances as an organist at Bath. In 1774 
he had executed a reflecting telescope. with his own 
hands, and soon acquired so much dexterity as to 
construct instruments of ten and twenty feet in focal 
length. In 1780 he contributed his first paper on 
the variable star in Cetus to the Royal Society, and 
the following year (13th March 1781) discovered the 
erratic body, which he at first took for a comet, but 
which proved to be a planet exterior to Saturn; the 
first addition therefore to the number of the primary 
planets since a period of an immemorial antiquity. 
So fortunate a success made the name of Herschel 
speedily famous, and he was effectively befriended by 
George III., who brought him to live near Windsor, 
and gave him a pension.4 
From this brief sketch it will appear how great 
were the obstacles which Herschel had to vanquish 
before he became a man of science, and that, besides 
the claims to distinction already enumerated, his 
knowledge and his skill were acquired in spite of 
every disadvantage. 
Practical Astronomy naturally divides itself into 
two great branches, that which depends upon the 
use of the telescope merely; on the telescope and 
micrometer ; and that which determines the absolute 
places of the heavenly bodies, and requires the aids 
of divided instruments and a well furnished obser- 
vatory. In the century to which he belonged Her- 
schel is the type of the telescopic observer, Bradley 
of the instrumental. The discoveries of Aberra- 
tion and of Nutation by the latter may stand a com- 
parison with any in the history of science, but the 
resolution of Nebula and the proof of the mutual 
connection of stars in binary systems are not less 
distinguished and original. Herschel would have 
gained a great reputation as an optician, merely by 
the wonderful improvement which he effected in the 
dimensions and magnifying power of telescopes, and 
by the skill with which he applied them to celestial 
observations. He would have stood still higher as 
an astronomer had he been merely the first observer 
of a new planet and of eight secondary ones, as well 
as of several comets, and the author of many nice 
1 It may be doubted whether any other similar annuity was given at that period on scientific grounds alone, and it is difficult 
to estimate the amount of benefit thus conferred on astronomy, for nothing short of the entire devotion of a lifetime could have 
produced such results as we owe to Herschel, His proposal to name his planet after the Sovereign was a very natural expression 
of his gratitude at a period when no rule whatever existed on the subject. 
See an interesting letter from Herschel to Sir 
Joseph Banks (who was also a warm friend) in Weld’s History of the Royal Society, ii, 146, note. Herschel was elected into the 
Royal Society 6th Dec. 1781. 
a71) 
(175.) 
(176.) 
Division of 
Practical 
Astronomy 
into Tele- 
scopic and 
Instru- 
mental, 
