] (150.) 
value of 
his obser- 
vations at 
Greenwich. 
‘remained in manuscript. 
Cuap. III., § 1.] 
were both distinguished by modesty, simplicity, and 
love of truth, Of all their contemporaries of emi- 
nence, few escaped so happily from the unprofitable 
strife of rivalry and personal disputes, and none ex- 
hibited a more impartial desire for the advancement 
of the science to which they were devotedly attached. 
Perhaps neither was a man of lofty talent, yet they 
did not fail to secure deserved respect in their own 
day, and far more gratitude from the posterity whom 
they essentially benefited than falls commonly to 
the share of men of higher pretensions in this re- 
spect. Both their names are important links in the 
history of astronomy. 
Nevin Masxetyne, born in 1732, and educated at 
Maskelyne; Cambridge, was early attached to astronomical pur- 
suits, After various minor services connected chiefly 
with navigation and the discovery of the longitude, he 
attained the honourable post of Astronomer Royal, 
which he filled from 1765 till 1811 with distinguished 
success, His immediate predecessor was Dr Bliss, who 
held the office for but three years and without dis- 
tinction. Practically, Maskelyne may be said to have 
succeeded Bradley, probably the greatest astronomer 
whom England has yet seen, whose discoveries have 
been recorded in the last Dissertation, and whose 
observations, through a variety of circumstances, were 
destined rather for the benefit of the nineteenth cen- 
tury than for his own, Maskelyne wisely recollected 
that the observatory was mainly founded for -the 
improvement of navigation,! and one of his earliest 
labours was the establishment in 1767 of the “ Nau- 
tical Almanac,” a work based on the best astronomi- 
cal observations and of the highest service to seamen. 
“ During Maskelyne’s long tenure of office he was 
entirely devoted to its duties, making himself all the 
most delicate observations, particularly those of the 
moon, and rarely quitting the observatory except to 
attend the meetings of the Royal Society. The per- 
fect method and continuity of his observations give 
to them a great value, especially for the correction 
of the Lunar Tables, in which respect they are indeed 
without a parallel. But the regularity of their 
publication was not their least merit. Four large 
folio volumes include the patient labours of a life 
(for he had but one assistant). Delambre in his 
character of Maskelyne says, that if through some 
catastrophe the whole materials of science should be 
lost, except these volumes, they would suffice to re- 
construct entirely the edifice of modern astronomy.’ 
In fact, on Maskelyne’s accession, the only methodi- 
cal publication which had issued from Greenwich 
Observatory was the “ Historia Celestis’? of Flam- 
steed; Halley’s, Bradley’s, and Bliss’s observations 
A like fate attended most 
ASTRONOMY.—MASKELYNE—DELAMBRE. 
833 
of the foreign astronomical observations; labours 
the most irksome and conscientious lie buried in 
piles of MS. useless to science, and which therefore 
might almost as well have never been made, This 
is particularly the case with the Parisian observa- 
tions (as the impartial Delambre records with pain), 
commenced even before the time of Flamsteed; but 
which, owing to this cause principally, have remained 
even to the present day (and it is forty years since 
Delambre wrote his patriotic protest) without con- 
tributing materially to advance astronomy. Let it 
then be recorded to the honour of Maskelyne, that 
this important step of regular and full publication 
at the public expense was entirely due to him. His 
places of the sun, moon, and planets, were the founda- 
tion of the improved theories of physical astronomy, 
then more ably cultivated on the Continent than in 
Britain, and of the tables also chiefly furnished by 
German and French computers. 
Maskelyne’s more important contributions to 
science may be briefly stated under these two heads ; 
—The determination of the Lunar orbit from observa- 
tion, and its application to navigation ; and the de- 
termination of the local attraction of Schehallien and 
of the density of the earth. 
I. The determination of the Lunar Orbit from Ob- 
servation and its application to Navigation.—Though 
astronomy owes (as we have already said) much to 
Maskelyne in the exact determination of the places 
of the sun, planets, and the most conspicuous fixed 
stars, the comparison of the Lunar place with the 
tables was by far the most arduous and the most im- 
portant of his undertakings, It was the most ardu- 
ous, because, from the extreme complexity of the 
moon’s motions, every part of its orbit must be nar- 
rowly watched, requiring the astronomer’s presence 
at his instruments at all possible hours during the 
course of a lunation, these motions being subject to 
important changes which recur every nineteen years, 
besides others of yet far longer duration. It was 
Maskelyne’s good fortune, and at the same time the 
reward of his perseverance, to watch three revolu- 
tions of the lunar nodes, He did not content him- 
self, however, with making observations ; he contri- 
buted in every possible way to the improvement of 
the tables of the moon’s motion, He was in con- 
stant communication with Mayer, one of the ablest 
astronomers of his day, and he directed the calcula- 
tion of Bradley’s observations by Mason, for the far- 
ther improvement of Mayer’s Tables. Maskelyne’s 
own observations, to the number of at least 5000, 
were used by Biirg in his excellent tables of the moon 
which have even yet been hardly surpassed; but 
their full value has only beén tested recently by the 
1 In the warrant appointing Flamsteed to be the Royal “ Astronomical Observator,” his duty is declared to be “ to rectify the 
tables of the motions of the heavens and the fixed stars, so as to find out the so much desired longitude at sea, for perfecting the 
art of navigation.” 
2 From an article on 
VOL. I. 
eiamwioh Observatory in the Edinburgh Review, written by the author of this Dissertation. 
5N 
(151.) 
(152.) 
Lunar-ob- 
servations. 
