290 Ahsfract of a Memoir on the Limits 



1690 metres, the latitude being about 61°. This height is less 

 (oulv 1597 metres) in the chain nearest the sea, which is called 

 Folge-Fonden-Fipld. Finally, the Melderskin, still nearer the 

 ocean, constantly retains the snow, and yet its peak is 209 me- 

 tres below the limit at which we observe the same phienomenoii 

 on the Great Chain. 



In order to account for this gradual lowering of the limit of 

 snow in proportion as we approach the ocean, M. de Buch re- 

 marks that the prevailing winds on the coasts of Norway are al- 

 ways south-west and south ; northerly and easterly winds are there 

 infinitely less frequent, and feebler. Now the former come from 

 the warm regions : in passing over the sea they are saturated with 

 humidity ; but being soon cooled by the continents, a part of 

 the dissolved water is precipitated in the form of mists, clouds, 

 and, finallv, of those torrents of rain which inundate the islands si- 

 tuated along the shore*: the sun j)enetrates but rarely this almost 

 perpetual bed of clouds, and its rays warm theground but slightly; 

 the temperature of the wannest months ought consequently to be 

 less near the shores than in the interior, where the sun during 

 the long days of summer exercises a great influence. There is 

 therefore every ^•ear less snow melted on the mountains which are 

 near the sea; and the limit at which it keeps unmelted ought to 

 be lowered much. 



Another cause, of which Saussure had already perceived the in- 

 fluence, is the mass of mountains. If the snow occupies a great 

 extent, it lowers considerably the temperature around, and thereby 

 prevents the lower snows from melting at elevations at which it 

 would melt on isolated peaks. M. de Buch finds in the form and 

 situation of the c'iiain of Fonden Field, something on which to 

 found a fortunate application of those considerations to the re- 

 markable phaenomenon which he wished to explain. 



If we quit the countries just mentioned, and proceed 10 de- 

 grees further northward, i. e. to the extremities of the European 

 continent, we expect to meet with the snow limit almost at the 

 surface of the ground ; but the general aspect of the country soou 



* Tliere never falls at Bergen in the space of a year, less than 68 inches 

 of rain, and iVequently 92 have been known to fall : w hercas at Upsal, in the 

 same latitude, but inthc interior, the annual quantity of rain does notexcecd 

 li inches. The oni-ents of heated and humid air whicli produce these 

 ^reat diftcrencfes also exercise a remarkable influence in the ijravity of the 

 atmosphere. M. Ilcrtzbcru; of Kynserviif, by usint; excellent syphon baro- 

 meters, never saw, for ton years, the mean annual height of the barometer 

 exceed 23 inches and half a line (0-7.592'"). Tliis result is eontirnied by the 

 observations of M. .Stroem, undt r the 03d degree, and by those of M. 

 Schytte in the 63th : «nd ii will appear still more curious to learn that at I'e- 

 terbburg, Abo, and .Stockholm, in the Baltic, the mean annual l>vis;;ht of the 

 barometer frequently rises to 28 inch, 3 iin. = 7Gd6"'. — AJ, dc Btali. 



shows 



