Joseph B ax end ell, F.R.S. 39 



mean. 3rd, A decrement of temperature above the mean 

 for the season is due to a cooling of the higher strata of the 

 atmosphere, and not to a heating of the lower strata. 4th, 

 The production of rain is attended with a diminution of the 

 general temperature of the atmosphere, the diminution 

 being greater in the higher than in the lower strata. It also 

 seems probable that one of the essential conditions in the 

 formation of a rotatory or cyclonic storm is a greater dif- 

 ference of temperature than usual between the successive 

 strata of the atmosphere at the point where the storm 

 originates. 



Sessio7i zc^^^-d-j.—" Remarkable Atmospheric Phenomena"; 

 " On a variable star." Notice of a variable star near the 

 nebula, discovered by Mr. Hind in 1852 in the constel- 

 lation Taurus, but which had now disappeared. " Oscillations 

 of Temperature at Greenwich"; "Iris Diaphragm"; On a 

 new Variable Star T Aquilee" ; "On a Periodic Change in the 

 magnetic condition of the earth and in the Distribution of 

 Temperature on its surface." The irregularities observed in 

 some of the variable stars led him to suppose as highly 

 probable that the light of the sun, and also its magnetic and 

 heating power, might be subjected to changes of a more 

 complicated nature than has been hitherto supposed, 

 and that beside the changes which are indicated by 

 the greater or less frequency of solar spots, other 

 changes of a minor character, and occurring in shorter 

 periods, might also take place. For magnetical observations 

 he selected those made at St. Petersburg, the most northern 

 station at which hourly magnetical observations have been 

 made for any lengthened period. An examination of the 

 magnetic declinations for 1848 indicated changes of activity 

 taking place in a period of 3 1 days. This period would not 

 apply to the observations of succeeding years, and he was 

 led to think that it might be variable in different years. 

 For 1856 he got a period of 23 days, for 1859 a period of 32 



