HISTORY OF rilYSICAL ASTRONOMY.
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to tlie consideration of the theorist. It is thus that the recent determi-nations of the places of the stars at that observatory, have served toconfirm beyond all doubt the interesting conclusion arrived at by variousastronomers in modern times relative to the motion of the solar system inspace *.
In the department of practical astronomy, which relates to the de-termination of the figure of the earth and the promotion of objects con-nected with geographical science, England, although not the first inthe field, has in recent times assumed a distinguished position. Thegeodetical operations which have been carried on in the present cen-tury, both in the British Isles and in India , may fairly challenge compa-rison with the most unexceptionable undertakings of a similar kind thathave been executed on the Continent. The Indian arc of the meridianis, moreover, especially remarkable for being the longest that lia3 yetbeen measured upon the surface of the earth. With respect to thoseoperations which have for their object the determination of the terrestrialellipticity by means of experiments with the pendulum, it may be assertedwith confidence, that no country has achieved so much as Britain has done.The experiments of the lamented Captain Foster, for completeness anddelicacy of execution, may be said to leave nothing further to be desired.
It is impossible, within the limits of this work, to give an account ofthe numerous establishments that have been founded, in different parts ofthe British empire, for the promotion of practical astronomy. To the in-lluence of the Astronomical Society is attributable in a great degree theactivity which thus generally prevails. This society was founded in theyear 1820, and was finally incorporated by Royal Charter in 1830. Thefirst President of the Society was Sir William Herschel .
In France , practical astronomy continued to make slow progress duringthe whole of the eighteenth century; a circumstance mainly attributableto the imperfect organization of the Royal Observatory of Paris. Somebrilliant exceptions, indeed, must be made to this remark. We haveseen Lacaille, in spite of unfavourable circumstances, raise himself, bythe mere force of his talents, to a high position among contemporary as-tronomers. It has been remarked, also, that France took the initiative inthose important operations which relate to the determination of the mag-nitude and figure of the earth. In this department of practical astro-nomy, she still continued to maintain her pre-eminence. The measure-ment of the arc of the meridian comprehended between Dunkirk andBarcelona, was one of the most splendid scientific operations of theeighteenth century f. This magnificent undertaking was executed underthe joint superintendence of Delambre and Mechain . Delambre, moreespecially, by his labours on this occasion, proved himself worthy to be as-sociated with Picard, Bouguer, and Lacaille. The main peculiarity of theoperation consisted in the observations having been made exclusively withthe repeating circle. It has been already mentioned that Mayer first sug-
* Iti recent years attention has been devoted at the Greenwich Observatory to the phe-nomena of Meteorology and Magnetism, and the observations relative to these departmentsof physical science are now published with the same regularity as the astronomical obser-vations.
f It may be remarked that the object of this operation was, not to determine the figureof the earth, but to obtain an invariable standard of measurement, by adopting as thefundamental linear unit, the ten millionth part of a degree of the meridian. MM. Aragoand Biot subsequently extended the arc beyond Barcelona to Formentera, one of the Bale-aric Isles .