242 Astronomical Society. 



ductlon of (I work now on the table, too remarkable to escape our 

 notice, whether we consider what it contains, or by whom it was writ- 

 ten. We allude to the " Mechanism of the Heavens" by Mrs. Somer- 

 ville. This lady has added to our stock the most complete account 

 of the discoveries of continental mathematicians in physical astronomy 

 which exists in our language. Following closely in the steps of 

 Laplace, but diverging to take notice of the discoveries of Lagrange, 

 Poisson, and others, she has produced a treatise, which, while it paves 

 the way to a complete understanding of the Mecanique Celeste, may 

 be substituted for it by all who do not re()uire, we will not say the 

 most profound, but the most widely extended knowled.n;e of the hea- 

 venly phenomena. Commencing with a general exposition of the 

 laws of mechanics, as in the Mecanique Celeste, the authoress proceeds 

 to the proofs of fhe general theory of gravitation, the elliptic motions 

 of the planets, their perturbations and secular inequalities ; generally, 

 though not universally, adopting the methods of Laplace. She then 

 considers the lunar theory, and that of the satellites of Jupiter. At 

 the end of each part the numerical values of the perturbations are 

 deduced ; and any particular cause, which might produce a perturbing 

 effect, such as the resistance of a medium, or tlie attraction of the 

 fixed stars, is inquired into. In a preliminary dissertation a popular 

 account of the results is given, the whole thus forming a complete 

 system of physical astronomy. In concluding this slight notice, your 

 Council cannot forbear their expression of delight and admiration at 

 the achievement of our countrywoman ; or of hope, that the example 

 thus set may stimulate others to exertion in a field which, they lament 

 to say, has been too much neglected in England. 



The vacancy occasioned by the death of Mr. Fallows, has been sup- 

 plied, as already noticed, by the appointment of Mr. Henderson : and 

 the Council cannot omit this opportunity of again* bringing before 

 the Society the very able assistance which has been, from time to 

 time, afforded them by the voluntary labours of this gentleman. 

 Bound to the Society by no conventional engagement (for Mr. Hen- 

 derson has but very recently become a Fellow of the Society), he was 

 always ready to aid and assist in any investigations that might be 

 required. And although the Council cannot but lament, in common 

 with the Society, the partial separation of so active a member, yet 

 they are well aware that the powerful resources of his mind will be 

 more efficiently called into action, and will reflect more honour on 

 his name and nation in the new sphere in which he is about to engage. 



Previous to his departure for the Cape, Mr. Henderson made ar- 

 rangements for observing Mars at his opposition in November next : 

 and requested Mr. Daily to select the stars proper to be observed with 

 that planet. This has been done; and the Council have directed that 

 the same shall be ])rinted and circulated amongst different observers, 

 in order that the greatest advantage may be taken of the favourable 

 opportunities now afforded for determining the parallax of that planet. 



* At the anniversiry in 18i?0, the Society presentcfl Mr. Henderson with 

 a copy of its Memoirs, as a small token of their sense of iiis services. 



