460 Astronomical Society. 



rarely met with in the gulf. For the weed swimming on the surface 

 of the Atlantic is withered, decayed, and incrusted with salt, which 

 proves the time it has been exposed to the sun, and is of a brownish- 

 yellow colour, whilst you rarely meet with a green bunch : that, 

 being heavier on account of its higher state of vegetation, swims seve- 

 ral feet below the surface. It is true that not with certainty can any 

 roots, thicker branches, or stems, be perceived, wherewith they 

 might have adhered to rocks or the ground : nevertheless, as these 

 weeds abound with animals that do not live upon the surface, but 

 inhabit the bottom of the sea, such as crabs, shrimps, barnacles, con- 

 chilias of all descriptions, and serpents, I have no doubt that they 

 originated in a shallow basin of water, out of which they were swept 

 by the force of a current along the bottom, until the heavier vegetable 

 fluid being exhausted, they rose to the surface. Moreover, they are 

 never seen near the European or African coast, but most plentifully 

 found about the entrance of the gulf." 



II. A letter from F. Hartmann, lieutenant of engineers, to J. F. W. 

 Herschel, Esq., describing an instrument constructed for him, accord- 

 ing to his own directions, by M. Hohnbaum, optician, of Hanover. 



III. On the rectification and use of the equatorial. By M.Kreih 

 This paper is intended to serve as a continuation and practical 



application of one by Professor Littrow on the same subject, pub- 

 lished in the Ast. Soc. Memoirs, vol. ii. p. 45. 



IV. On Barlow's new telescopes. By Professor Littrow. 



V. A letter by Mr. Hubert to the President, suggesting the possi- 

 bility that the discrepancies observed in pendulum experiments may 

 arise from the effect of magnetic attraction. He recommends the 

 pendulum to be swung, at the same place, in the magnetic meridian, 

 and at right angles to it, in order to ascertain the fact ; and that 

 observers should be careful to swing the pendulum in the magnetic 

 meridian for comparative observations. 



VI. On Mayer's celebrated Catalogue of Zodiacal Stars, by Fran- 

 cis Baily, Esq. 



Since the publication of the Astronomical Observations of Mayer, 

 by the late Board of Longitude, Mr. Baily has examined the position 

 of every star, by comparing each of them not only with the observa- 

 tions, but also with the catalogues of Bradley and Piazzi, by which 

 means he has been enabled to detect many inaccuracies in Mayer's 

 catalogue, which have hitherto puzzled the practical astronomer ; 

 and he has now given us a corrected catalogue, together with refe- 

 rences to every observation of every star, in a collateral column, as 

 well as the difference between the results of Mayer's observations 

 and those of Bradley, his contemporary, in another collateral column. 

 The corrections which Mr. Baily has actually introduced are those 

 only which are sanctioned by the observations themselves : at the 

 same time, he has pointed out other corrections, which, although 

 only conjectural, are highly probable ; but these are kept distinct 

 from the former. The author has subjoined a list of some other stars 

 observed by Mayer, but not contained in his catalogue, as well as a 

 list of several occultations. From the result of Mr, Baily's investiga- 

 tions, 



