CLOUD 



1438 



CLOUD 



with respect to utility and comparative values. 

 Some details of manufacture are also included. 



CLOUD, klowd. Some clouds assume the 

 shape of great, fleecy masses, some are feathery 

 formations far in the upper air, and some are 

 dull gray or black sheets which darken the 

 earth and give promise of rain; but whatever 

 their appearance, the formation is always the 

 same. They are merely atmospheric moisture, 

 condensed until it has become visible; in other 

 words, they are upper-air fogs. That this is 

 true the mountain-climber can bear witness. 

 From below he may see clouds high above as 

 rolling masses, veiling the summit of the moun- 

 tain; as he ascends he loses sight of cloudlike 

 forms but finds himself gradually enveloped 

 in a heavy mist; and when at last he comes 

 out upon the sun-bathed peak he can turn and 



within and around the cloud masses, the names 

 ought to be known by all who like to "discern 

 the face of the sky." Though they are Latin, 

 most of thorn can be easily remembered by 

 their resemblance to English words. 



Cirrus to a Roman meant a ringlet of hair, 

 and so the name was given to the curly white 

 cloudlets of ice crystals which form high above 

 all other clouds, five to ten miles above the 

 earth's surface. The word cirrus may be re- 

 called because it is similar to circle. 



Stratus, which in Latin means spread out, 

 is like the word stratum, the geological term 

 for a layer. Stratus clouds are the most fog- 

 like, and are generally very close to the earth. 

 They are oftenest seen at morning and even- 

 ing, when the still air contains no currents to 

 break them up. 



(l) 



CLOUD FORMATION 

 Cirrus, cirro-stratus and stratus ; ( 2 ) cumulus ; ( 3 ) 



see the mist again as heaving billows of cloud 

 below him. 



When the sun warms the surface of the earth, 

 water reached by its heat loses its liquid form 

 and is transformed into gaseous vapor. This 

 vapor rises, and as it cools by expansion in the 

 light upper air 'it is condensed again into the 

 tiny particles of water or snow or ice which 

 form the clouds. As their weight causes them 

 to sink, these liquid particles come again to 

 the warmer layers of air and are once more 

 vaporized and become invisible. So goes on the 

 ceaseless change that we can nearly always ob- 

 serve in cloud shapes as they float past us, and 

 that makes them, as Emerson has said, "always 

 and never the same." Clouds or banks of fog 

 are also formed when winds carry warm atmos- 

 phere into a cold region or cold air into warmer 

 lands, for the result is exactly the same as when 

 we "see our breath" on wintry mornings. 



Every Cloud Has a Name. Because of the 

 indication they give of weather conditions 

 present and to come, clouds have been closely 

 studied by men of science. To each shape of 

 cloud has been given a name descriptive of it, 

 and as the shapes depend upon the conditions 



strato-cumulus ; ( 4 ) nimbus. 



Cumulus means a heap (as we see in our 

 word accumulate, which is to pile up) and 

 cumulus clouds are the beautiful heaped-up 

 masses of white that float across the sky on 

 lovely summer days, casting swiftly-moving 

 shadows on the earth. It must have been a 

 cumulus that inspired the conversation between 

 Hamlet and old Polonius: 



Do you see yonder cloud that's almost in shape 

 of a camel? 



By the mass, and 'tis like a camel indeed. 



Methinks it is like a weasel. 



It is backed like a weasel. 



Or like a whale? 



Very like a whale. 



Cumulus clouds travel at a height of perhaps 

 a mile. In midafternoon, when the sun's rays 

 are the warmest, the heaps increase in number 

 and in size as more and more water is drawn 

 up by evaporation, but when comes 



The evening beam that smiles the clouds away, 

 they lose their beautiful dream-like shapes in 

 the flat monotony of stratus clouds. A great 

 number of heavy cumulus clouds often por- 

 tends rain, which comes when the atmosphere 

 contains more moisture than it can support. 



Nimbus is the very word which the Romans 



