300 



CLOUDBERRY 



CLOUDS 



at the Revolution to prevent their desecration. 

 See Life by Professor Kurth ( Eng. trans. 1899 ). 



Cloudberry (Bubus Chamcemorus), a plant 

 related to the bramble, although of very different 

 appearance, having a herbaceous single-flowered 

 stem destitute of prickles. The plant is of humble 

 growth, 8 to 10 inches in height ; the leaves few, 

 large, lobed, and kidney-shaped ; the flower large 

 and white ; the fruit orange red, equal in size to a 

 bramble-berry, and of an agreeable flavour. It is 

 a native of the northern parts of Europe, Asia, and 

 America. In Britain it is chiefly confined to 

 elevated moors ; in Norway and Sweden it is much 

 more abundant, and the fruit is highly valued and 

 made into excellent preserves. 



Clouds are masses of fog, consisting of minute 

 particles of water, often in a frozen state, floating 

 in the atmosphere. When air has its temperature 

 lowered below the saturation point, either by 

 ascending and becoming rarer, or by meeting a 

 colder current, a portion of the vapour loses its 

 gaseous form, and becomes condensed into minute 

 specks of water. It has been shown by Dr Aitken 

 that this condensation always takes place round a 

 small particle of dust. A cloud, therefore, does not 

 consist of vapour, in the proper sense of the word, 

 but of very small drops of water. How this water- 

 dust is suspended in the atmosphere why the 

 particles do not descend as soon as formed, has 

 never been thoroughly explained. Professor G. G. 

 Stokes holds that the rate of fall is rendered 

 exceedingly slow by the friction and drag of the 

 air-particles, just as fine powders remain suspended 

 for a long time in liquids of much less specific 

 gravity than themselves. Besides, as Sir J. 

 Herschel says, ascending air-currents also oppose 

 the fall of clouds, for the air may be ascending 

 faster than the particles of the cloud are falling 

 through it ; while at night, in the absence of 

 rising currents, clouds often descend to, and dis- 

 solve in lower and warmer levels. The conditions 

 under which clouds are formed, and afterwards 

 deposited in rain, are more fully considered under 

 EVAPORATION, DEW, RAIN, SNOW-LINE (under 

 article SNOW). The present article is confined to 

 a description of the various kinds of clouds and of 

 the weather they indicate. 



A general haze of precipitated vapour covering 

 the sky, and coming down to the earth, is termed a 

 Fog or Mist ; and the term cloud is usually con- 

 fined to masses of fog floating in the higher regions, 

 and not descending to the ground. They are mostly 

 within a mile of the earth's surface ; and few are 

 more than six miles above it. From observations 

 made at Upsala in Sweden, it has been found that 

 there are three principal cloud layers : the low 

 clouds at from 2000 to 6000 feet ; middle clouds, 

 12,000 to 15,000 feet ; and high clouds, 20,000 to 

 27,000 feet. These three layers are found at 

 apparently much the same heights all over the 

 earth. Clouds spread and move with the wind in 

 varied, often grand forms ; they are generally 

 disposed in beds parallel to the earth's surface ; 

 vertical clouds occur rarely, if at all. 



Mr Luke Howard's classification of clouds, pro- 

 posed in 1802, into three primary forms Cirrus 

 ( Cir. ), Cumulus ( Cum. ), and Stratus ( Str. ) ; three 

 intermediate Cirro-cumulus (Cir.-c. ), Cirro-stratus 

 (Cir.-s. ), and Cumulo-stratus (Cum.-s. ); and one 

 compound form, Nimbus (Nim. ) has been uni- 

 versally adopted, and has been shown by the Hon. 

 Ralph Abercromby and others to hold good in all 

 climates and atmospheric conditions. 



Cirrus, or curl cloud, consists of parallel, curling, 

 flexuous, diverging, and partly straight fibres, 

 increasing in any or in all directions by elongation, 

 branching, or addition of new fibres. It is the 



highest and least dense of clouds ; varies most in 

 extent, direction, and shape ; retains longest its- 

 varied outlines ; and is the longest illuminated 

 after sunset and before sunrise. It has been com- 

 pared to a mare's or cat's tail, a lock of hair, fine 



Cirrus. 



trellis-work, or thin silvery streaks, and it may 

 cover all the sky. Threads and groups of Cir., 

 during gentle wind after severe weather, presage- 

 serene settled weather. But after a long tract of 

 fair days, whitish filaments or parallel bands of Cir. 

 crossing the sky, with the ends converging by per- 

 spective in each horizon, foretell a change to wet ; 

 they move with the upper currents of the atmo- 

 sphere, and generally indicate by this motion a 

 change of wind long before it is felt on the earth's 

 surface. Cir., being so high, consists of minute ice 

 crystals, whose refractions and reflections produce 

 the halos, coronse, and mock suns and moons almost 

 restricted to this cloud and its derivatives the- 

 Cir.-s. and Cir.-c. Cir., especially with fine tails, 

 varying much in a few hours, presages rain or 

 snow, and windy variable weather. 



Cumulus, ball of cotton, day or summer cloud, 

 consists of dense, convex, hemispherical, or conical 

 heaps of small roundish clouds, piled or stacked 

 on each other. The heaps enlarge upwards from a. 



Cumulus. 



horizontal base, and have rounded or rocky tops ? 

 they sometimes unite into stupendous white-topped 

 mountains. It is formed by the condensation of 

 vapour in local ascending columns of air, and i& 

 generally at from 4000 to 6000 feet elevation. 

 Cumuli often begin after sunrise as a few scattered 

 specks in the clear sky ; these specks enlarge and 

 unite to form clouds, which nearly cover the sky in 

 the afternoon, and generally decrease and vanish 

 about sunset ; but rain follows if they increase in 

 number and darkness in the evening. Cum., of 



