THE FARM AND METEOROLOGY. 437 



ALTITUDE. Wheat refuses to ripen in Britain when grown at elevations 

 of from 1000 to 1200 feet, a fact which proves the influence of altitude. 

 An elevation of 1500 feet is sufficient to seriously impair the fertility of 

 fields for even the hardier crops. On the other hand the same, and a 

 much higher altitude, on the American continent grows wheat to perfec- 

 tion. 



LONGITUDE. Climate varies considerably in the matter of rainfall from 

 east to west. The effect on the agriculture of the two sides of an island 

 country is also easily seen in the prevalence of grazing on the west, and 

 the leaning towards the cultivation of cereals on the east. The Gulf 

 Stream also acts beneficially on climate, receiving additional warmth from 

 its presence. 



PROXIMITY TO THE SEA usually gives a more uniform temperature than 

 1 1 joyed far inland, and this is attributed to the uniform temperature of 

 the adjacent mass of water. 



LAKES AND MARSHES influence climate. The latter especially often give 

 rise to night fogs, which chill the ground and render the air unwholesome. 

 An ordinary result is the prevalence of ague, and, it may be, certain forms 

 of fever among the human population, and even the live stock of the farm 

 are apt to suffer from allied ailments. 



9, The leaves of trees condense the atmospheric vapour, and 

 precipitat<> it to the ground, as may often be noticed in a humid atmos- 

 pheiv. It is many years since Humboldt pointed out the effect of forests 

 upon the supply of springs, and the consequent injury that may follow 

 from their destruction. Hills clothed with wood offer a barrier to the 

 ent of cold currents of air, and are also directly a shelter from the 

 wind. The difference in temperature between a bare mountain and one 

 which carries a forest oji its higher slopes has been often remarked. 



EOT i< an exceedingly important element in intlm-iK-ini; the climate. 



Who doea nut know tin- value of a southern aspect for wall-fruit, or of a 



B dairy ? Such cases at once show that aspect exerts 



a decided intlm-nce Attention has been drawn to the effect of slope or 



inclination upon climate, and ^uch effect mi^ht have been included under 



the pre-.-nt heading. Aspect is, ho wever, a wider term, and might include, 

 as it certainly ^oes beyond, slope. The aspect of a house or a bedroom is 



tier <>< importance, and so aN,, is t lie aspect of a field. 



LTBR I or shelter muM also !>< enumerate. 1 as a regulator 



of climate. An 1 situation is airy, breezy, or windy, ace,.rding to 



the speed of aerial currents, Iti^oi't.-n int. -n-.eiy cold, because the n 

 idly a cold wind parses over any object, the .pucker du-s it al-stract it- 



