224 



Royal Astronomical Society. 



These bodies are semicircular, very thin, slightly concave plates, 

 usually corneous, sometimes more or less calcareous. Mr. Strickland 

 regards them as having formed laminar appendages to the animals 

 of the Ammonites, adapted to discharge some unascertained function. 

 They resemble the two expanded valves of Aptychus, soldered toge- 

 ther ; and the author considers them as allied to that fossil, to which 

 he attributes a similar origin. 



ROYAL ASTRONOMICAL SOCIETY. 

 [Continued from p. 73.] 

 March 8, 1844 {continued). — II. Elements of the Comet of Faye. 

 By Professor Henderson. 



From obsen'ations made at Cambridge on December 16 and Ja- 

 nuary 15, and at Greenwich on February 8, the following elements 

 of the comet's orbit have been obtained, which are likely to be more 

 correct than those formerly given : — 



Epoch of mean anomaly for December 31, 1843,1 o ; „ 



mean noon at Greenwich J 11 32 14 



Longitude of perihelion 43 39 46 



Eccentricity sin. 34 38 



Log. of semi-axis major 0"56533 



Mean daily motion 503"-52 



Time of revolution 7'0468 sidereal years. 



Longitude of ascending node 211 59 12 



Inclination 11 28 48 



Motion direct. 



Ephemeris for 8^ Mean Greenwich Time. 



Edinburgh, Feb. 14, 1844. T. Henderson. 



III. Elements of the Comet of Faye. By J. R. Hind, Esq. Com- 

 municated by the Rev. R. Main. Inserted in the Monthly Notices, 

 vol. vi. No. 5. 



IV. Letter from Professor Encke (translated), dated Berlin, Feb. 

 18, 1844. Communicated by G. B. Airy, Esq., Astronomer-Royal. 



" The comparison of the Berlin observations of the Comet of Pons, 

 made in the year 1842, with the elements which were derived from 

 the observations up to the year 1838 and from the mass of Mercury 

 thence deduced, and with the total disturbances up to 1842, has 

 shown that the remaining errors are quite insignificant ; and I find, 

 in fact, for the less accurate observations at the commencement, 

 when the comet was very faint, — 



