69 
established by such a test, — as unreasonable, I humbly think, 
as it was in the other case to dispense with such a test. 
I therefore pass over the test of possibility as applied to 
Darwinism, to apply the other tests of harmoniousness, con- 
sistency and adequacy. And again, I must revert to the ana- 
logy of what Mr. Warington thinks established the adequacy 
of gravitation, — the discovery of the planet Nejptune, — and 
which I will venture to say is strictly analogous to what was 
supposed to be the discovery of the missing link between man 
and apes” in the famous Neanderthal skull, appealed to so con- 
fidently in the Antiquity of Man by Sir Charles Lyell, and in 
Man’s Place in Nature by Professor Huxley. Again, I think 
the analogy will be found to run admirably on all fours. I am 
glad to follow Mr. Warington in his chosen analogies, and I 
am doing my best to complete them in thorough detail. Mr. 
Warington appears to have taken his view of the discovery of 
Neptune from Sir John Herschel's Outlines of Astronomy . 
But he ought to know that Messrs. Peirce and Gould, the 
American astronomers, have written also on the subject. 
From Mr. Gould's Report on the History of the Discovery, 
published in Washington in 1850, it appears that the tables 
used for the computations of the places of Uranus were cal- 
culated by M. Bouvard in 1821, and are now known not to 
represent the places of that planet, which was observed twenty 
times between 1690 and 1771, but was then mistaken for a fixed 
star. I cannot, however, here pursue the whole history of the 
discovery of Neptune. It is enough to say that certain irre- 
gularities or perturbations in the observed motions of Uranus 
led to the idea (which was shared by M. Bouvard himself) 
that these were caused by the influence of some exterior 
planet. Without going into the question of priority of dis- 
covery between Mr. Adams and M. Le Yerrier, I shall here 
give you their respective computations of the mass, eccentri- 
city, mean distance, period of revolution, and longitude of 
perihelion, of the supposed exterior planet, in a tabular form, 
alongside the figures deduced by Messrs. Walker and Peirce 
from actual observation of the planet Neptune after it was 
discovered. Thus : — 
Theoretical. 
Actual. 
Adams. 
Lk Verrier. 
Walker 
and Peirce. 
Mass of Neptune . . 
1 
1 
1 
Eccentricity 
Mean distance from Sun 
Period of revolution 
| Longitude of perihelion . . . 
6,666 
0T2062 
37-247 
299°-2 
9,322 
0-10761 
36-154 
217-378 yrs. 
284°-7 
19,840 
0-00872 
30*037 
164-618 yrs. 
47°-2 
