292 Royal Society. 



the two first experiments, or whether reduced from the pre- 

 cipitates afforded by the adulterated oils submitted to ex- 

 amination, produces precisely the same quantity of metallic 

 lead, viz. 27 per cent. Both these precipitates also, when 

 exposed to a moderate heat, fuse, affording a brown transpa- 

 rent substance very much resembling common colophony, 

 but which seems to be harder and more brittle than rosin is. 

 Pure linseed oil, when mixed with the same quantity of rosin 

 as analysis indicated in one of the samples of adulterated oil 

 marked " Raw oil," that containing 44' 1 per cent., was ex- 

 actly of the same density as the sample in question, both being 

 982, whilst pure linseed oil was considerably lighter, its den- 

 sity being '9518 ; thus corroborating not merely the fact of 

 adulteration, but also the close approximation to correct re- 

 sults afforded by the mode of analysis adopted. 



I remain, my dear Sir, yours very truly, 

 Duke-Street, Liverpool, J. DENHAM SMITH. 



Sept. 3, 1840. 



XLIV. Proceedings of Learned Societies. 



ROYAL SOCIETY. 

 [Continued from p. 149.] 



April 30, HpHE following communications were read : 

 1840. A 



1. A Letter from Sir John Barrow, Bart., V.P., addressed to the 

 President, accompanying a series of Magnetic Observations made on 

 shore, and on board Her Majesty's ships ' Erebus' and ' Terror,' 

 under the direction of Captain James Clark Ross, R.N., together 

 with a Series of Observations made on the temperature and specific 

 gravity of the ocean at various depths, and at the surface, namely, 



" Observations of the magnetic intensity on shore, and on board 

 H.M.S. Erebus, with needle F. 1. 



" Magnetic dip observations on shore, and on board H.M.S. Ere- 

 bus, with needle F. 1 . 



" Observations for the magnetic dip on shore, and on board H.M.S. 

 Terror. 



" Observations of the magnetic dip by needle F. C. 5. on shore, 

 and on board H.M.S. Terror. 



" Observations in magnetic intensity by needle F. C. 5. on shore, 

 and on board H.M.S. Terror." 



The whole of these observations are up to the 31st December, 

 1839. They are transmitted to the Royal Society from the Lords 

 Commissioners of the Admiralty. 



2. Postscript to Major Sabine's paper, entitled " Contributions to 

 Terrestrial Magnetism," which was read at the meeting of March 

 19th; (see p. 144), containing an extract from a letter from Capt. 

 James Clark Ross, commanding the Antarctic expedition, dated from 

 St. Helena, February 9th, 1840; noticing the success which had 



