[ 442 ] 

 LXV. Proceedings of Learned Societies. 



ROYAL SOCIETY. 



A T a late meeting, a paper was read, entitled " Astronomical 

 -ti. Observations made in the Observatory at Paramatta," by 

 Charles L. Riimker, Esq., communicated by the President. — The 

 object of this memoir is the determination of the right ascension of 

 two circumpolar stars of the southern hemisphere, by a direct com- 

 parison with the sun, independent of the transit, and of the solar 

 tables. This comparison is made by deducing the superior and in- 

 ferior culminations of the stars from an uninterrupted series of equal 

 altitude, for the space of a month about the time of the equinox. 

 This gives the difference of right ascension between the sun and 

 stars. Finally, the distance of the sun from the equinoctial point 

 is derived from the observed declination of the sun on those days. 

 In an appendix, the author subjoins a list of the stars of which he 

 ascertained the right ascensions by equal and absolute altitudes. 



April 30. — Two papers were read : the first " On the respiration 

 of birds," by Messrs. Allen and Pepys; the second," On the spon- 

 taneous purification of Thames-water," by John Bostock, M.D. 

 F.R.S.&c. 



In the report which the author made of the result of his exami- 

 nation of Thames-water to the commissioners appointed by His 

 Majesty to inquire into the supply of water for the metropolis, one 

 of the specimens, taken near the King's Scholars' Pond sewer, was 

 described as in a state of extreme impurity. This water had re- 

 mained in the laboratory unattended to ; and after an interval of 

 some weeks, it was observed to have become clear, while nearly the 

 whole of the former sediment had risen to the surface, forming a 

 stratum of half an inch in thickness, and still emitting a very ofien- 

 sive odour. In process of time this scum separated into large masses 

 or flakes, with minute air-bubbles attached to them. At the end 

 of two months longer these masses again subsided, leaving the fluid 

 almost totally free from any visible and extraneous matter. On 

 analysis, the water was found to contain lime, sulphuric and mu- 

 riatic acids, and magnesia, in much larger quantities than in the 

 specimens of Thames-water previously examined ; the proportion of 

 saline matter being increased fourfold. The proportion of the mu- 

 riates is nearly twelve times greater ; that of carbonate of lime, 

 between two and three times; and that of sulphate of lime five and 

 a half times greater. The water, in its foul state, had given very 

 obvious indications of both sulphur and ammonia ; but neither of 

 these substances could be detected, after its spontaneous depura- 

 tion. The source of these new saline bodies is referable to the 

 organic substances, chiefly of an animal nature, which are so co- 

 piously deposited in the Thames. The depurating process may be 

 denominated a species of fermentation, in which the softer and more 

 soluble animal compounds act as the ferment, and are themselves 

 destroyed ; while the salts that are attached to them are left behind. 

 Hence, the more foul the water, the more complete the depuration ; 



and 



