1811.] made during the Year 1813. 3 



observations require so much nicety, and such perfect and expensive 

 instruments, that for many years tliey have been almost confined to 

 national observatories; among which that at Greenwich has hitherto 

 held the first place, both on account of the importance of the 

 observations, and their being the only ones regularly ])ublished. 

 The following are the only astronomical facts, which, to my know- 

 ledge, have been published in the course of the year. 



1. Mr, Pond has made observations on the summer and winter 

 solstice of 1812, in order to determine the obliquity of the ecliptic. 

 He found it, by the summer solstice, 23° 27' 51'50": by the 

 winter solstice, 23° 27' 47*35''', This small difference, he con- 

 ceives, may probably be owing to a small error in Bradley's table 

 of refractions, which astronomers have been in the habit of using. 

 He is at present employed in endeavouring to determine that point. 



2. Mr. Pond has likewise published a table of the north polar 

 distances of 14 of the principal fixed stars. He conceives his table 

 to be much more accurate than any hitherto offered to astronomers. 

 The maximum of error he thinks seldom exceeds half a second, and 

 only in four cases amounts to one second : for example, the pole 

 star in summer is 1° 41' 22-07", and in winter 1° 41' 21-47", from 

 tiie north pole of the heavens. 



3. It is well known that the measurement of three degrees of 

 latitude l)y Col. Mudge, in 17^3, in the southern extremity of 

 Great Britain, does not correspond with the measurements made in 

 other countries to represent the earth as flattened at the poles. la 

 Col. Mudge's measurement tiie length of each degree diminishes as 

 we advance northward, instead of increasing, as had been found in 

 other countries. Various conjectures had been thrown out to 

 account for tiiis anomaly ; and Mr. Playfair's opinion, that it might 

 depend upon the vicinity of the sea and the nature of the rocks 

 under the suiface of the earth, was considered as very probable : 

 but, in the Philosophical Transactions for 1 812, a paper was published 

 by Don Joseph llodriguez, in which he endeavours to show that the 

 apparent anomaly was owing to errors in tlie astronomical observa- 

 tions, which occasioned corresponding mistakes in the latitude; and 

 that when these errors are corrected, the apparent anomaly disap- 

 pears. The paper is remarkal)le for its modeiation and apparent 

 candour; and certainly tiie suggestion which it contains is well 

 entitled to attention. Unless too it can be shown in the clearest 

 manner tli;it the alleged errors iiavc not been committed, one 

 would naturally (.ujipose that the true mode of settling tlie point 

 would be again to repeat the astronomical observations. 



But Dr. bliiithus Gregory, of the Military Academy, Woolwich, 

 ha^ jjublislied a letter on tlu; subject, in a style quite new to astro- 

 nomical discussions. He atVuins tliat the sole object of Don Rod- 

 riguez was to elevate the Frcneii astronomers, and depress the 

 I'^iiglish ; and he iiwinuafes pretty })lainly lliat the Koyal Society 

 coiiciMTed in the same design. He then shows that an insular 

 ■situation is peculiarly ill adapted for such miasurements, that the 



