80 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



ed from the upper strata of air downward to the earth. 

 Therefore every stratum communicates to the next lower a 

 certain quantity of vapor and receives a new share from 

 above; but the new share is not fully equivalent to the loss, 

 as is seen from the fact that an incessant diminution takes 

 place in all the strata, although the precipitation occurs only 

 at the earth's surface itself. The diminution of the humid- 

 ity which corresponds to the difference between the quan- 

 tity of moisture in the descending and ascending air strata 

 begins subsequently in the upper air strata, which is a nat- 

 ural consequence of the fact that the diminution has its spe- 

 cial cause at the surface of the earth. For the same reason 

 it is also less the greater the altitude is, provided that the 

 comparison between the different air strata is made at the 

 same hour. Moreover, the diminution of humidity tends to- 

 wards a limit or maximum value which, as the observations 

 seem to show, is greatest at the earth's surface, where it oc- 

 curs at the time of greatest diminution of temperature, and 

 diminishes as we ascend. 



STORMS. 



Among the general treatises on meteorology lately pub- 

 lished, we notice Scott's "Weather Charts and Storm Warn- 

 ings," and especially Rosser's " Law of Storms," which latter 

 is an impartial summary of the views of prominent meteorol- 

 ogists as to the rotation of winds about storm-centres. 



Professor Loomis's seventh contribution to meteorology 

 treats of rain areas, and shows that they have an elliptical 

 form: they exist under the influence of (or within the lim- 

 its of) areas of high pressure as well as of low ; that rain is 

 not a necessary attendant of an area of low pressure; that 

 the depression at a storm-centre is, as first demonstrated by 

 Ferrel, and now widely accepted, a result of the centrifugal 

 force due to the wind. The heat liberated by condensation 

 into rain does, however, exert a decided influence upon the 

 development and progress of low areas. The eighth paper 

 by the same author was read before the National Academy 

 in October, but was not printed until after the 31st of De- 

 cember. 



During a portion of December, 187G, and January, 1877, 

 "both Great Britain and the eastern portion of the United 



