WEATHER. 



WEATHER. 



The intermediate modifications which require 

 to be noticed are 4. Cirro-cumulus; small 

 well-defined, roundish masses, in close horizon' 

 tal arrangement. 5. Cirro-stratus; horizontal 

 or slightly inclined masses, attenuated towards 

 a part or the whole of their circumference, ben 

 downward, or undulated, separate or in groups 

 consisting of small clouds having these cha- 

 racters. 



The compound modifications are 6. Cumulo- 

 stratus ; the cirro-stratus blended with the cu- 

 mulus, and either appearing intermixed with 

 the heaps of the latter, or superadding a wide- 

 spread structure to its base. 



7. Cumulo-cirro-stratus, vel Nimbus the rain 

 cloud, a cloud or system of clouds from which 

 rain is falling ; it is a horizontal sheet, above 

 which the cirrus spreads, while the cumulus 

 enters it laterally and from beneath. 



The cirrus appears to have the least density, 

 the greater variety of extent and direction, and 

 to appear earliest, in serene weather, being in 

 dicated by a few threads pencilled in the sky. 

 Before storms they appear lower and denser, 

 and usually in the quarter opposite to that from 

 which the storm arises. Steady high winds 

 are also preceded and attended by cirrus streaks 

 running quite across the sky in the direction 

 they blow in. 



The cumulus has the densest structure, is 

 formed in the lowest atmosphere, and moves 

 along with the current next the earth ; a small 

 irregular spot first appears, and is as it were 

 the nucleus on which they increase. The lower 

 surface continues irregularly plain, while the 

 upper rises into conical or hemispherical heaps, 

 which may afterwards continue long nearly of 

 the same bulk, or rapidly rise into mountains: 

 they will begin in fair weather to form some 

 hours after sunrise, arrive at their maximum 

 in the hottest part of the afternoon, then go on 

 diminishing, and totally disperse about sunset. 

 Previous to rain the cumulus increases rapidly, 

 appears lower in the atmosphere, and with its 

 surface full of loose fleeces or protuberances. 

 The formation of la^ge cumuli to leeward in a 

 strong wind indicates the approach of a calm 

 with rain ; when they do not disappear or sub- 

 side about sunset, but continue to rise, thunder 

 is to be expected in the night. The stratus has 

 a mean degree of tensity, and is the lowest of 

 clouds, its inferior surface commonly resting 

 on the earth or water. This is properly the 

 cloud of night, appearing about sunset. It 

 comprehends all those creeping mists which in 

 calm weather ascend in spreading sheets (like 

 an inundation of water) from the bottom of 

 valleys and the surfaces of lakes and rivers. 

 On the return of the sun the level surface of 

 this cloud begins to put on the appearance of 

 cumulus, the whole at the same time separating 

 from the ground. The continuity is next de- 

 stroyed, and the cloud ascends and evaporates, 

 or passes off with the appearance of nascent 

 cumulus. This has long been experienced as 

 a prognostic of fair weather. 



The cirrus having continued for some time 

 increasing or stationary, usually passes either 

 to the cirro-cumulus or the cirro-stratus, at the 

 same time descending to a lower station in the 

 atmosphere. This modification forms a very 

 1104 



beautiful sky, and is frequent in summer, as 

 an attendant on warm and dry weather. The 

 cirro-stratus, when seen in the distance, fre- 

 quently gives the idea of shoals of fish (a 

 mackerel sky). It precedes wind arrd rain; is 

 seen in the intervals of storms, and sometimes 

 alternately with the cirro-cumulus in the same 

 cloud, when the different evolutions form a cu- 

 rious spectacle. A judgment maybe formed 

 of the weather likely to ensue, by observing 

 which modification prevails at last. The solar 

 and lunar halos, as well as the parhelion and 

 paraseline (mock sun and mock moon), prog- 

 nostics of foul weather, are occasioned by this 

 cloud. The cumulo-stratus precedes, and the 

 nimbus accompanies rain. 



When there are small round clouds, of a 

 dapple-gray colour, with a north wind, it may 

 be concluded that there will be fair weather for 

 2 or 3 days, but that large clouds like rocks 

 are a sign of great showers. And when small 

 clouds increase, it is a sign that there will be 

 much rain, but if the large clouds are seen to 

 lessen, there will be fair weather. 



In summer or harvest, when the wind has 

 been south 2 or 3 days, and it grows very hot, 

 and clouds are seen to rise with great white 

 tops like towers, as if one were on the top of 

 another, and joined together with black on the 

 lower side, it may be considered a sign that 

 there will be thunder and rain suddenly. When 

 two such clouds rise, one on each hand, it is 

 time to make haste to shelter. 



When a cloud is seen to rise against the 

 wind or side wind, it is a sure sign that when 

 the cloud comes up near you, the wind will 

 blow the way that the cloud came. It is the 

 same with the motion of a clear place, when, 

 all the sky is thick except one edge. 



At all times, when the clouds look black in 

 the west, it is sure to rain, or if raining, it is 

 sure to continue, whatever quarter the wind 

 may be in ; and, on the contrary, if it breaks 

 in the west, it is sure to be fair. 



It is often observed, on those clear sunny 

 mornings which occur in summer and autumn, 

 that it is very likely, if not certain, to rain be- 

 fore evening; and there is frequently much 

 truth in the remark. The reason is, that when 

 moisture accumulates in the air, before it be- 

 gins to be precipitated, it imparts to it a higher 

 refractive power; and it becomes, in conse- 

 quence, more bright and transparent. (British 

 Almanac, 1830.) 



The gradual diminution of clouds, till they 

 are no longer observable, is a sign also of fine 

 weather. So, likewise, is the continuance or 

 abundance of dew upon the grass, after a 

 serene day. 



During winter, fleecy clouds being thick and 

 close in the middle, and very white at the 

 edges, the surrounding sky being remarkably 



e, indicate hail or snow, or cold, chilling, 

 showers of rain. 



Where the clouds appear moving in two op- 

 Dosite currents, and the lowest is wafted rapidly 

 Defore the wind, it is a certain sign of rain ; 

 and if this occurs during summer, or generally 

 n hot weather, it announces a thunder-storm. 

 It may be a useful piece of information for 

 agriculturists, or those concerned in getting in 



