XIV 



place and with that appearance the planet was found. The predic- 

 tions of Adams and Leverrier differed by only one degree of longi- 

 tude. The controversy which has arisen on this discovery cannot be 

 briefly discussed, and must be omitted in a sketch as short as the 

 present one. 



In the years 1850, 1851, Mr. Airy turned his attention to anti- 

 quarian researches. There are several papers in the ' Athenaeum ' on 

 the Exodus of the Israelites, and some more on the place of the land- 

 ing of Caesar. The hrst of these lines of enquiry led gradually to the 

 " Notes on the earlier Hebrew Scriptures" (1876), and the latter to the 

 f ' Treatise on the Roman Invasion of Britain " (1865). Halley, reason- 

 ing on the phenomena of the tides as described by Caesar, and com- 

 paring these with the Channel tides as then known, had concluded 

 that Deal was the landing place. Mr. Airy, however, showed that, 

 with fuller knowledge of the local tides, this line of reasoning would 

 prove that Pevensey was the actual landing place. He also con- 

 tended that this result was confirmed by a study of Caesar's move- 

 ments in Gaul before the crossing, and his transactions in the interior 

 of Britain after the passage of the straits. Mr. Airy was also inter- 

 ested in several other antiquarian questions. Thus in the ' Phil., 

 Trans.' for 1853 there is a paper on the eclipses of Agathocles, 

 Thales, and Xerxes, in which he arrived at some new dates for these 

 events. After the publication of Professor Adams' theory of a 

 diminished value of the acceleration of the Moon's mean motion, Mr, 

 Airy repeated his calculations, and somewhat modified his results. 

 He also compared the dates of thirty-six eclipses given in a Chinese 

 historical work called * Chun Tsew ' with those calculated by theory 

 by a French writer, and points out how generally accurate the 

 Chinese records are on these points. 



Mr. Airy had the pleasure of viewing three total eclipses of the Sun, the 

 first from the Superga, near Turin, in 1842, the second at Gothenburg, 

 in Sweden, in 1851, and the third at Herena, in Spain, in 1860. 

 In the many accounts which he has given of these eclipses, he con- 

 tinually dwells on the impressiveness and awfulness of the scene, 

 pointing out that no degree of partial eclipse gave the least idea of a 

 total eclipse. He mentions, on the authority of Arago, that the 

 officers of a French corvette who had been trained to observe the 

 eclipse of 1842 lost their discipline when the darkness came on, and 

 the observations were not made. The most remarkable of all the 

 appearances at the first eclipse were the red mountains or flames seen 

 round the Moon. It was afterwards discovered that these had been 

 seen in 1733 by a Swedish astronomer, but all the observers at Turin 

 were taken by surprise. It was difficult then to decide what they 

 were, or even whether they belonged to the Sun or to the Moon. In 

 the eclipse of 1851 special attention was given to these flames, and, 



