THE FARMER'S MAGAZINE. 



237 



of wind ; but when the gauges were placed on posts 

 of different heights, removed from any disturbing 

 causes, similar results were obtained. Mr. Phillips 

 placed live gauges at different heights from the 

 surface; they all collected different amounts of 

 rain, on an average of two years that placed at 



24 feet collected 24.158 inches. 



12 

 6 

 3 



u 



26.039 

 2G.109 



26.298 

 26.559 



On the sides of mountains a different result is 

 obtained; for there, up to a certain elevation, the 

 amount of water collected by the rain gauge in- 

 creases with its elevation above the level of the sea. 

 From Mr. Miller's observations, we find that in 

 Cumberland the amount of rain increases as we 

 ascend the mountain side, until it attains its maxi- 

 mum at about 2,000 feet. In 1848 it was at 



Whitehaven 



78 feet 36.334 inches. 



47.342 



46.700 



109.19 



138.72 



148.39 



91.32 



64.73 



.... 90 „ . 



480 „ . 



Bruntrigg 500 „ . 



Styehead 1290 „ . 



Sprinkling Tarn ..1900 „ . 



GreatGable 2928 ,, , 



Scafell Pike, the highest 



point in England 3166 „ , 



On the west coast of India the line of maximum 

 fall would appear to be about 2,500 feet higher than 

 with us. Colonel Sykes {Trans. Roy. Soc, 1850, 

 p. 362) has given the fall at different stations : — 



At sea level, west coast 8 1.70 inches. 



1 50 feet, Rutnaghery 1 14.55 „ 



900 „ Dapoolee 134.96 „ 



1740 „ Kundalla 141.59 „ 



4500 „ Mahabuleshwur. . . . 254.05 „ 

 4500 „ UttrayMullayinTra- 



vancore 263.21 ,, 



6100 ,, Kotergherry, on the 



Neilgherries 81.70 „ 



8640 „ Dodabella, the highest 

 point of Western 



India 101.24 „ 



It is not only the elevation above the level of the 

 sea, or above the surface of the land, which in- 

 fluences the amount of rain collected by the rain- 

 gauge : the size of the gauge appears, for some 

 unexplained reason, to vary the quantity collected. 

 Mr. T. 11. Lawes found, at Rothamsted, in Hert- 

 fordshire, that where a small rain-gauge collected 

 an annual fall of 22.23 inches, a large gauge (equal 

 to l-l,000th of an acre) placed by its side collected 

 29.30 inches. 



Rain-water, thus collected at a distance from 

 populous places, was once supposed to be pure 

 water. The fact that a variety of impurities, so- 

 luble and insoluble, were constantly exhaling from 

 the surface of the earth, or raised by the winds, 

 and mingling with the atmosphere, was quite dis 

 regarded : what became of them there, no one 

 paused to inquire. The celebrated Swedish che- 

 mist, Bergman, however, towards the close of the 

 last century, discovered in rain-water traces of 

 nitric acid. Then Liebig, in our time, found in it 



ammonia. The proportions of these substances 

 present in an imperial gallon were not long since 

 determined by M.l?aral,an eminent French chemist. 

 He found in an im])erial gallon of water — 



Grains. 

 Of ammonia (the mean of five months, 



from August to December) .■ . . . 0*240 



Of nitric acid 1-350 



The mechanically-suspended matters in rain- 

 water vary according to the locality in which it is 

 collected. In the neighbourhood of populous 

 places, there is a deposit of finely-divided soot. 

 This has been detectei in places to the leeward of 

 London, more than twenty miles distant from the 

 city. Rain of different colours has been recorded. 

 Minute snails, and even larger animals, such as 

 small fish and frogs, have mingled with other 

 shovvers. There are, probably, minute proportions 

 of other matters occasionally united with rain. 

 There is a particular scent discernible in some 

 showers, such as those falling near the sea, or in 

 the neighbourhood of manufacturing districts, 

 which must arise from the presence of pecuhar 

 foreign substances. 



The deposition of the aqueous portion of our 

 atmosphere is not always in the liquid state, as in 

 rain : it descends upon us in the solid form, in 

 snow, and in ice or hail. If we inquire into the 

 origin of these, the answers we receive are but im- 

 perfect. We believe that snow descends from the 

 clouds ; but we have no reasonable certainty that 

 it exists in the state of watery vesicles in those 

 clouds, which are frozen and enlarge as they de- 

 scend ; or that it exists as clouds of fine flakes, 

 supported by the force of under-currents of air. 

 Snov/ appears to us in crystals of varying shapes 

 and beauty. When under the microscope, they 

 appear as modifications of stelliform and hexagonal 

 crystals. Often they consist of stais of six rays, 

 composed of prisms united at angles of 60 deg. : 

 from these other prisms shoot, at similar angles. 

 But there are numerous beautiful variations in the 

 shape of the crystals of snow, produced most pro- 

 bably by different states of the atmosphere. The 

 density of snow is much less than that of ice. Ice 

 is only about one-ninth larger in bulk than the 

 water of which it is congealed; but the bulk of 

 snow is more than ten times greater than the 

 water of which it is formed. A depth of about 10 

 inches of snow, when melted, hardly produces one 

 inch of water. 



As the temperature of the atmosphere decreases, 

 as we ascend mountains, by pretty regular degrees, 

 it would follow that at certain elevations we should 

 reach the point where the thermometer is always 

 below the freezing point of water, and that conse- 

 quently, at such point, the snow should never melt. 

 Now this is found to be the case in most portions 

 of the earth. In considerable elevations, we arrive 

 at the point where the snow remains during the 

 whole year. These altitudes, as might be expected, 

 are the most considerable under the Torrid Zone, 

 the perpetual-snow line gradually descending to- 

 wards the level of the sea, as we approach the 

 poles of the earth. The following table gives, in 

 feet, the line of continued congelation above the 



