820 



May 3, 1849. 



The EARL OF ROSSE, President, in the Chair. 



In accordance with the Statutes the President read the following 

 list of Candidates recommended by the Council for election into the 

 Society : — 



John Couch Adams, Esq. 

 Thomas Andrews, M.D. 

 Robert Alfred Cloyne Ansten, 

 Esq. 



Charles Barry, Esq. 

 Benjamin ColHns Brodie, Esq. 

 John Dalrymple, Esq. 

 James Glaisher, Esq. 



Sir Robert Kane, M.D. 

 William Lassell, Esq. 

 Henry Beaumont Leeson, M.D. 

 Andrew Crombie Ramsay, Esq. 

 John Scott Russell, Esq. 

 Francis Sibson, M.D. 

 Robert Stephenson, Esq. 

 Lieut.-Col. Philip Yorke, 



A paper was read, entitled " On the Reduction of the Thermo- 

 metrical Observations made at the Apartments of the Royal Society 

 from the year 1774 to 1781, and from the year 1787 to 1843." By 

 James Glaisher, Esq. of the Royal Observatory, Greenwich. Com- 

 municated by John Lee, Esq., LL-D., F.R.S. &c. 



In this paper, the author states that he has examined all the ther- 

 mometrical observations which have been made at the Apartments of 

 the Royal Society, with the view of ascertaining whether the diurnal 

 variations at different epochs were in accordance with those which 

 he had determined from the Greenwich observations, and which are 

 contained in his paper published in the Philosophical Transactions 

 for 1848. The result of this investigation was, that the corrections 

 contained in the tables in his former paper were applicable to the 

 observations of all the years since 1774. 



The author is led from these examinations to the conclusion, — 

 1st, that the instruments used have been uniformly good; 2ndly, 

 that the observations have been faithfully recorded as read from the 

 instruments ; Srdly, that the readings have been taken with great care 

 with respect to the times stated ; and lastly, that the observations 

 were well-worth the necessary labour of reduction. He finds, how- 

 ever, that some of the more recent observations of the self-register- 

 ing instruments are liable to some uncertainty. 



Having satisfied himself that the observations were well-worth 

 any amount of labour that might be bestowed on them, the author 

 was anxious to reduce them to a useful form, but, in consequence of 

 the great amount of work that would be required for the reduction 

 of so extensive a series, he for some time hesitated to enter upon 

 this labour. Finding however that there was a demand for the re- 

 sults of trustworthy observations extending backwards many years, 

 and having, besides, the hope of connecting the*Greenwich series of 

 observations with these, he determined to perform the work. He 

 states that the mean temperature of every month was determined in 

 the first instance from the observations which had been made during 

 the day, and secondly, from the observations of the self- registering 



