Cultural First Principles. 317 



With regard to climate, the forester requires to know merely the 

 rudimentary facts and principles of meteorology ; but it M'ould be well 

 if a thorough weather chart were kept on every large estate. Tlie 

 apparatus necessary is neither extensive nor costly ; a rain gau^e, a 

 barometer, a thermometer, an hygrometer, and a weathercock being 

 obtainable for a total outlay of but a few pounds, and the method of 

 recording observations easily learnt by any intelligent man. The 

 elevation above sea level, proximit)- to the ocean, or to a mountain- 

 range, aspects, slope, and mechanical composition of the soil of a 

 forest, large or small, are all important. The fundamental fact — 

 groupings as to climate — is so admirably set fortli in the " Manual of 

 Sjdviculturc " of Professor Bagneris, of Nancy, which has been pub- 

 lished in English at Madras, that as the book is not commonly seen 

 in this country, no excuse is necessary, for the following abstract 

 of this portion of it : — 



"The cHmatc of any spot may be defined as the state of the surround- 

 ing atmosphere as regards (i.) temperature, (ii.) the intensity of light, 

 (iii.) the degree of moisture, and (iv.) the prevailing winds. These four 

 factors, which go to make up climate, are determined by various causes, 

 of which some are general or geographical, but the more important are 

 special or local disturbing causes. Geographically, climate depends 

 on latitude ; but the disturbing causes are so numerous that, practi- 

 cally, latitude has but little to do with its determination. These 

 disturbing causes constitute 'local climate,' which depends mainly 

 on two things, ' situation ' and ' aspect.' 



" The situation of a place is its position with regard to the sea, 

 including its distance from it and its height above it. 



"The aspect of a tiact of land is its inclination towards one of the 

 points of the compass. Tlius the distance from the sea in the direc- 

 tion of prevailing winds is one of the determining causes of rainfall, 

 more evaporation taking place from the sea than from the laud, and 

 more rain, therefore, falling near the coast-line. The rainfall at 

 Bristol, for example, is nearly twice that at London. So, a'-ain the 

 irregular shape of oceans and continents has a vast effect on the tem- 

 perature of various places, i. c, on the distribution of heat over the 

 globe. Places having the same mean annual temperature, as is o-ene- 

 rally known, are termed 'isothermal,' and lines connecting them 

 "isotherms." A warm current in the Atlantic Ocean deflects the 

 isotherm of 62^ P. mean July temperature more than 1 5° of latitude 

 north of its course, so that Xew York, in the latitude of Madrid, has 

 the same mean annual temperature as London. 



" The climate of lyJains is generally milder and more uniform than 

 that of mountains. It varies with the elevation of the plain as 

 regards temperature, the proximity of the ocean and of mountain- 



