PROCEEDINGS 



OF 



THE ROYAL SOCIETY. 



1840. No. 44. 



May 21, 1840. 



The MARQUIS of NORTHAMPTON, President, in the Chair. 



William Burge, Esq., Walter Ewer, Esq., Thomas Tassell Grant, 

 Esq., and Henry Lawson, Esq., were balloted for, and duly elected 

 into the Society. 



The following papers were read, viz. : 



1. " Remarks on the Meteorological Observations made at Alten, 

 Finmarken, by Mr. S. H. Thomas in the years 1837, 1838, and 

 1839." By Major Sabine, R.A., V.P.R.S., and Lieut .Col. Sykes, 

 F.R.S. ; being a Report from the Committee of Physics, including 

 Meteorology, to the Council, and communicated by the Council to 

 the Royal Society. 



These observations, made at Alten in lat. 69° 58' 3" N., and 

 23° 43' 10" east of Paris, would seem to have a claim to the atten- 

 tion of the Royal Society, as they offer the experimentum crucis of 

 Professor Forbes's empirical formula respecting the gradual diminu- 

 tion of the daily oscillations of the barometer, within certain limit 

 hours, from the equator to the poles. Professor Forbes has laid 

 down an assumed curve, in which the diurnal oscillation amounts 

 to '1190 at the equator and in lat. 64° 8' N., and beyond that lati- 

 tude the tide should occui with a contrary sign, plus becoming minus. 

 Now Alten being nearly in lat. 70°, if Professor Forbes's law hold 

 good, the maxima of the diurnal oscillations should occur at the 

 hour for the minima at the equator, and a similar inversion should 

 take place with respect to the minima. Mr. Thomas has himself 

 however modified the value his observations would otherwise have 

 had, by adopting 2 p.m., instead of 3 p.m., for the hour of his ob- 

 servations for the fall; and he has adapted his barometrical ob- 

 servations to a mean temperature of 50° Fahr., instead of 32°. 

 The first year's observations commence on the 1st October, 1837, 

 and terminate on the 30th September, 1838. The barometer stood 

 66 feet 5 inches above low- water mark, and the thermometer hung 

 at 6 feet above the ground ; but care was not always taken to pre- 

 vent the sun shining on it. The mean height of the barometer 

 for the year was 29°'771, and the mean of the thermometer al- 

 most coincident with the freezing point, viz., 32°'017. The 



