PROCEEDINGS 



OF 



THE ROYAL SOCIETY. 



1846. No. 67. 



November 19, 1846. 

 Sir W. BURNETT, M.D., in the Chaii". 



" On tlie Automatic Registration of Magnetometers and other 

 Meteorological Instruments, by Photography," By Charles Brooke, 

 M.B., F.R.C.S.E. Communicated by G/B. Airy, Esq., F.R.S., 

 Astronomer Royal. 



The author enters into fuller details than he had done in his 

 former communication to the Society, which was read on the 18th 

 of June, respecting the construction of the instrument, the prepa- 

 ration of the highly sensitive photographic paper employed in the 

 process, and the minute adjustments necessary for ensuring accuracy 

 in registering the results. 



In a supplement to the above paper, the author describes the 

 methods he has contrived for obtaining a similar automatic registra- 

 tion of the heights of the barometer and thermometer, by suitable 

 additions to the same apparatus which registers the magnetic varia- 

 tions. 



November 26, 1846. 

 The MARQUIS OF NORTHAMPTON, President, in the Chair. 



W. R. Grove, Esq., M.A., F.R.S., delivered the Bakerian Lecture 

 . — " On certain Phenomena of Voltaic Ignition, and on the Decompo- 

 sition of Water into its constituent Gases by heat." 



The author refers to an eudiometer, an account of which v/as 

 published by him in the ' Philosophical Magazine' for 1840, formed 

 of a glass tube, into the closed extremity of which a loop of plati- 

 num wire was sealed. The gases to be analysed were mixed in this 

 tube with a given volume of oxygen and hydrogen, and detonated 

 or slowly combined by the voltaic ignition of the platinum wire. 

 He was thence led to try a further set of experiments on the analysis, 

 by this instrument, of such gases and vapours as are decomposable 



