S$ ■THE NATURAL HISTORY OF CLOUBf. 



and electricity, wliicli continually occur in the atmosphere) 

 our knowledge of its constitution and properties has been 

 considerably advanced. It is nevertheless true, that the phi- 

 losopher of the present duy is not more weather-wise than 

 his predecessors in ancient times. He is still obliged to yield 

 the palm in the science of prognostics to the shepherd, the 

 ploughman, or the mariner; who, without troublinghis head 

 about the reasons of things, has learned, by tradition and 

 experience, to connect certain appearances of the sky with 

 certain approaching changes; of which those appearances 

 are, in fact, a commencement or continuation, discoverable 

 while the cause is yet at a distance. Undoubtedly the union 

 of these two kinds of knowledge would best deserve to be 

 « entitled the science of meteorology; and it ihust tend, 



equally with the invention or perfection of philosophical in- 

 struments, to the improvement of t'lis science, could w* re- 

 store to its place the ancient and popular branch of it, now 

 too much neglected by philosophers, which is founded wholly 

 on natural phenomena. If we except the changes of the 

 wind, some indications of moisture and dryness, and a few 

 others of less importance, the whole of these may be traced 

 to one common origin in the product resulting from the de- 

 composition of vapour; whif-h remains, during a certain in- 

 terval, in a state of simple diffusion or suspension in the at» 

 mosphere. To give to the extensive collectipn of facts, 

 whtch it is easy to make on this subject, a communicable 

 ind useful form ; to render that attainable in a short time, 

 ■which has been hitherto the exclusive treasure of the adepts 

 of long experience, is the object of the writer of the fol- 

 lowing systematic nomenclature and natural history of 

 clouds. 



Modifications Clouds are suscentible of various modifications. 



o ou s. j^y, ji^jg term is intended the structure or manner of aggre- 



gation, in which the influence of certain constant laws is suf- 

 ficiently evident iimidst the infinite less diversities result- 

 ing frona occasional causes. 



Hence the principal modifications are as distinguishable 

 from each other, as a tree from a hill, or the latter from a 

 lake ; although clouds, in the same modification, compared 



with 



