86 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



this altitude ; such as the depth of the annual fall of snow 

 and the dryness of the atmosphere, the direction of the winds, 

 and the amount of the cloudiness. Grad finds the altitude 

 of tlie lowest limit of permanent snow to be less within the 

 tropics than under the latitudes of twenty to thirty-five de- 

 crees, Avhence asrain it diminishes to three thousand feet in 

 the latitudes sixty degrees south and sixty-five degrees north. 

 For no known part of the globe does the belt of perpetual 

 snow descend to the level of the sea, nor to within less than 

 a thousand feet of altitude; not even in the region where 

 the average temperature of the cold half of the'year is below 

 freezing, as in Greenland and Spitzbergen. 



It is only the glaciers that descend to the sea-level in the 

 countries south of forty-five degrees south latitude, and north 

 of sixty degrees north latitude, by reason of the excessive 

 falls of snow accompanying moist winds. 6 j5, 1813, 780. 



poey's classification of clouds. 



Poey has presented his classification of clouds to the Paris 

 Academy of Science for their approval. In doing so he says 

 that the honor of classifying the clouds by their types be- 

 longs to the naturalist Lamarck (1801), and especially to the 

 English meteorologist Luke Howard (1802). Later writers, 

 in followins: the classification of Howard, have made some 

 mistakes, which Poey now proposes to explain. He states 

 that the stratus of Howard is confounded with his mist or 

 hoar-frost, his original description of stratus having been 

 first published in 1803 in Tllloch's Magazine. The nimbus, 

 as defined by Kiimtz, and after him by all meteorologists, 

 has no actual existence. In the definitions of cumulus, cu- 

 mulo-stratus, and strato- cumulus there is a great confusion. 

 Having, for good reasons, omitted the stratus, nimbus, and 

 cumulo-stratus of Howard, and the strato-cumulus of Kamtz, 

 Poey preserves only the two types, cirrus and cumulus, and 

 the two derivatives, cirro-stratus and cirro-cumulus, and re- 

 places the four rejected orders of clouds by the following 

 three derivatives : pallio-cirrus, pallio-cumulus, and fracto-cu- 

 mulus. The pallium is the sheet cloud, of which two strata 

 *are generally present during rain, hail, or snow; the upper 

 cloud (the pallium) is electro-negative ; the lower (the pallio- 

 cumulus) is electro-positive. The term nimbus indicates the 



