GRISCOM ON METEOROLOGICAL OBSERVATIONS. 349 



" The Cirro-Cumulus. A connected system of small roundish 

 clouds, placed in close order, or contact. 



" The Cirro-Stratus. A horizontal, or slightly inclined, sheet, atten- 

 uated at its circumference, concave downward, or undulated. Groups 

 Or patches having these characters. 



" Lastly, there are two modifications which exhibit a compound 

 structure, viz. 



" The Cumulo-Stratus. A cloud in which the structure of the cu- 

 mulus is mixed with that of the cirro-stratus, or cirro-cumulus. The 

 cumulus flattened at top, and overhanging its base ; and 



" The Nimbus. A dense cloud, spreading out into a crown of cir- 

 rus, and passing beneath into a shower." 



These modifications are defined with such further precision and 

 minuteness as to enable a person, of common intelligence, by the aid of 

 a little observation, to understand and to apply the terms. And to 

 render the daily insertion of these characteristic traits of weather more 

 easy, each modification may be represented by a short mark, or charac- 

 ter, which may be arranged in a column under the head of clouds. 

 Considering the facility with which such a list may be kept, the com- 

 mittee would recommend its adoption. They observe, that among the 

 numerous diaries of the weather which are published in the foreign 

 journals, that which is kept by the author of the essay on the clouds 

 appears to be one of the most instructive. 



In mountainous countries, the figure, position, and motion of the 

 clouds, afford, to the experienced observer, the means of prognosticat- 

 ing, with very considerable accuracy, the approaching state of weather, 

 although their appearances are very deceptive to persons accustomed 

 to view them only as suspended over a widely extended horizon. A 

 course of judicious observations on the atmosphere in a number of such 



