Arizona weekly enterprise., 1888-01-07
CONCERNING OUDS.
Their Nature, Forms, 1omposltioD, vc
 locity, Height, Etc.

locity, Height, Etc.
 A oloud is a mass of visible vapor or water particles held in suspension in the atmosphere. If 1t rests upon the surface of the earth we call it fog
 We see mass of vapOr on the sum- init of a high mountain and we call it cloud, but if we climb to the top of the mountain and find ourselves in the cloud we sec it to be simply fog To our observation, clouds take on forms that are almost infinite in variety, yet they may be divided into six classes, each presenting quite distinct characteristics. These are known as cirrus. cumalus and stratus cloud, as simple div isions; auI cirro- cumulus, cirro-stratus and cumulo-stratus as compound divisions. The cirrus cloud consists of long. slender. fila ments. either parallel or diverging from each other. These clouds have the greatest elevation and the least dersity of all clouds. Even in fair weather tho sky is seldom free from small distant groups of cirrus clouds. They are thought 10 be mad e up of spicul@ of ice or flakes of snow, since at the great height at which they float, from five to eight miles above the earth, the temperature of the air is below freezing point even in midsummer The cumulus cloud is much densnr than the cirrus, and is formed nearer the earth. It usually has the form of hcmispherical or convex mass with horizontal base. This is the cloud of en seen in large masses near the horizon, looking like huge mountains of snow. The round- ed top of this cloud results from the mode of its formation. As the earth is heated by the suns rays, currents of warm air rise, carrying with them invisible vapor When they reach a certain height this vapor is condensed and forms cloud. and since the upward motion is greater under the center of the cloud, the vapor is then carried to its greatest height. The stratus cloud is widely horizontal sheet, often covering the entire sky, and and hanging SO low that it frequently touches the earth's surface in the form of-afag- For the compound notifications of cloud forms, the clr- ro-cumulus is seen in small rounded masses, often very near together. On account of their ficecy appearance. .hcse are often called ''woolly clouds.' This cloud is very frequent in summer. but seldom preccdes rain. The cirro- stratus consists of fibrous clouds spread out in strata, which are either horizontal or slightly in clined 10 the hor;zen. Sometimes the whole sky is mottled with the cloud, looking like tho back of a mackerel, and, therefore, is called a mackerel sky. This cloud always presages wind and rain. The cumulo-stratus is the large dark cloud formed by the mass ing of the fleecy cumulus in great heaps. Those clouds are to be seen in great magnificence on the approach of R thunderstorm, and are, therefore. often called thunder heads" Some meteoroIogists also classify with the above the nimbns cloud, which is a stratus cloud from which rain is fall ing, but others do not think it worth while to keep this division. The height of cloud is measured by trigonometrical rule by observing its direction simultaneously at two sta- tions. In mountainous countries it can be compared with the peaks near which it passes. Most accurate re- suits, however, are ob' aimed by ascend ing in balloon and nc. ing the height of the barometer when entering the cloud and again when emerging from it. the barometer giving the means of