458 Reviews, and Notices respecting New Books. 



object is to determine the figure of the earth. IX. General history of phy- 

 sical theories. X. Comparison of the progress of Astronomy in England 

 with that in other countries. XI. Suggestion of points to which it seems 

 desirable that the attention of Astronomers should be directed." 



To give any account of so detailed a history of the recent pro- 

 gress of Astronomy as that contained in this Report, is impracti- 

 cable; but we shall extract a few passages which possess peculiar 

 interest. The Cambridge Observatory, it appears, is devoted espe- 

 cially to the observation of the planets: on this subject Prof. Airy 

 informs us, that 



" A vast number of observations of planets is to be found in the Trans- 

 actions, the Ephemerides, and the astronomical periodicals. Their object 

 however is generally rather confined. The inferior planets are little ob- 

 served : the superior, little except at opposition. At the regular observa- 

 tories they have been much neglected. In the Berliner Jahrbuch 1816, it 

 is remarked that in two years there were only six observations of planets at 

 Greenwich. The foreign observations are sometimes given without any 

 comparison : sometimes however (especially in the Milan Ephemeris,) they 

 are compared with the Tables, and even the equations of condition for cor- 

 recting the elements are formed (as in Milan Eph. 1822). In reflecting on 

 these circumstances, it appeared to me desirable that one set of good in- 

 struments should be devoted to the observation of planets : and when the 

 Cambridge Observatory was put under my care, I determined on making 

 the planets my principal object. I hope in a few years to collect a mass of 

 observations directed to this point that will possess great value. I have al- 

 ready obtained and compared with Tables about 1 100 right ascensions of 

 planets, besides numerous observations of the sun and moon." 



Of the Trigonometrical Survey of Ireland now in progress, we 

 have the following notice : 



" The survey of Ireland that has lately been and is now going forward, 

 is, I suppose, in accuracy and in excellence of arrangement, (I am not speak- 

 ing of the minutiae of the map, but of the principal triangles, by which the 

 great distances north and south or east and west are to be measured,) supe- 

 rior to every preceding survey. Little is now wanting for the measure of an 

 arc of meridian but the observation of zenith-distances of stars at its extre- 

 mities. The country is also favourable for the measuring an arc of parallel 

 of considerable extent : and a new method of producing intense light, intro- 

 duced into practice by one of the gentlemen employed on the survey, will 

 probably give the means of determining the differences of longitude on a long 

 arc without the errors produced by intermediate stations. It is also under- 

 stood that our Government have long contemplated the repetition or exten- 

 sion of Lacaille's measure at the Cape of Good Hope : and several circum- 

 stances lead me to hope that this undertaking, which would perhaps contri- 

 bute more than any other to our knowledge of the earth's figure, will ere long 

 be seriously taken up. The extension of Struve's arc is in contemplation." 



A considerable part of many volumes in the first series of the Phi- 

 losophical Magazine, and also of many in the second series, is occu- 

 pied by the records and discussions of the pendulum experiments, 

 which, since Capt. Kater's beautiful application of the convertible 

 pendulum, have been so assiduously and so extensively prosecuted. 

 On this subject, which has thus so often occupied our pages, we 

 have the following remarks by Professor Airy : 



