Royal Astronomical Society. 303 



are very favourable as regards the breadth of the pencil of rays where 

 it meets each lens, and which leave the focal length of the first lens 

 perfectly arbitrary, so that the power of the eye-piece may be changed, 

 preserving all its properties undisturbed, by merely changing the first 

 lens. This is the "new construction" proposed as the object of the 

 paper. 



The algebraic investigation is then given in detail ; and the author, 

 after the reading of the paper was concluded, gave an oral explana- 

 tion, illustrated by diagrams, of the construction and the theory upon 

 which it depends, 



June 13. — The following communications were read : — 



I. On the Ephemerides of Jarchi, the Chaldean Months, and the 

 derivation of Orion and his Dogs. By S. M. Drach, Esq. 



The author suggests, on the authority of Weidler's Historia As- 

 tronomice, that the first astronomical tables and ephemerides published 

 in Europe are those of Rabbi Solomon Jarchi, although still inedited. 

 Jarchi is supposed by Dr. Jost to have lived from the years 1040 to 

 1105 (Gesch. der Israel,, vol. vi. p. 243). 



The author then proceeds to the consideration of the passage of 

 the book of Job, contained in the thirty-first and thirty-second verses 

 of the thirty-eighth chapter : " Canst thou bind the sweet influences 

 of Pleiades, or loose the bands of Orion ? Canst thou bring forth 

 Mazzaroth in his season ? or canst thou guide Arcturus with his 

 sons ? " And he cites the opinion of the Rabbinical commentators 

 for the meaning of each of the astronomical words contained in it. 



He then gives from Buxtorf 's Lexicon the meanings of the names 

 of the Jewish months, and concludes that their calendar is founded 

 on the agricultural occupations of the Chaldean shepherds, who were 

 employed during winter in preparing the fleeces of their flocks f^ 

 clothing, &c. 



He thinks it not impossible that the numerical values of the names 

 of the months indicate the number of days wherein celestial phaeno- 

 mena recur, mystically decomposed for priestly purposes ; and he 

 gives instances in which certain combinations of their values repre- 

 sent pretty nearly the synodical periods of some of the planets. ^■ 



There is some reason for supposing that Orion, Sirius, and Pro-. 

 cyon, may be regarded as Hellenized Egyptian names by dropping 

 the final syllables, and that they may thus be referred to the Chal- 

 dean dialect. 



H. Extracts from a Letter to the President, dated Picket Berg, 

 Cape of Good Hope, January 1, 1845, from C. Piazzi Smyth, Esq. 

 Communicated by Captain Smyth. 



Great Comet of 1844-45. 



" Another splendid comet is at this moment astounding the south- 

 ern hemisphere and displaying the most interesting series of phaeno- 

 mena, which are passing away unrecorded, because the Institution is 

 still without sufiicient means, 



" The apparition of this comet, 1844-45, is just such an opportu- 

 nity, such a crucial test of his theory, as Bessel is so ardently desi- 



