CONTINENTAL NOTES — FRANCE. 6 1 



deforestation have been terrible {^.g-, in Persia and in Macedonia), 

 holds that the effects of deforestation are felt at great distances. 

 He draws attention to the heat waves that have latterly affected 

 various places. He states that the intensity of the sun's rays 

 does not vary, taking the statements of astronomers as his 

 authority, and that therefore the lieat waves are due to 

 circumstances on the earth itself. Thus bare spaces become 

 very much heated by the sun, and communicate heat to the air 

 in contact with them, and the hot air rises in great columns to 

 the upper atmosphere. To fill the void so caused cool air 

 from better protected places f^ows in, moving tangentially to the 

 earth's surface. But it appears that the hot air currents above 

 mentioned, on reaching the rarer atmosphere above, are curved 

 over and, still heated, come down to the earth again. Naturally, 

 there are numerous variations, but, broadly speaking, this is how 

 heat waves come about — so that the evil done in the way of 

 deforestation in one country may affect even distant countries. 



On the other hand, M. Lafond states that there is an 

 astronomic law, called the law of the " Undecennial cycle," 

 which lays down that every eleven years the intensity of the 

 sun's rays reaches a maximum. This, he says, causes excessive 

 evaporation and subsequent increased precipitation. 1906 was 

 a year of maximum solar intensity, to be followed by wet years, 

 decreasing, however, till about 1913, when a dry period will set 

 in. 



At Pontvallain (Sarthe) a M. Marion owns a piece of land of 

 120 acres, which formerly was very marshy and did not brino- 

 in more than 3s. an acre, insufficient to pay the taxes. It was 

 the worst land on his property ; now it is the best, and brings in 

 ^6 per acre for hay and ^6 to ;^8 for wood. This transforma- 

 tion has been brought about by draining with large open drains, 

 and planting poplars 4 metres apart, and at i^ to 2 metres 

 distance from the ditches. The planting consisted in cutting 

 poplar sticks, like peasticks, and driving them into the ground 

 about half a metre deep in holes made with an iron bar. This 

 very successful experiment might, it is thought, be of use to 

 others in places where poplar has a value, while if poplar has 

 no direct value it will nevertheless greatly improve the land by 

 its power of absorbing water. Moreover, other species of local 

 value, and possessing the quality of absorbing water in quantity, 

 might possibly be found. 



