92 FOREST INFLUENCES. 



peratiire in latitudes 20° to 30° N, seems to fall slowly from Western 

 India to China and Tonqnin, but Dr. Woeikoff finds tliat it rises in tlie 

 east, in tlie hot season, where there are extensive treeless regions, and 

 instances Hanoi, in 21° N., where the annual temperature is 75^.6, May 

 830.8, June 88o.2, July 8Co.9. 



Dr. Woeikoff also gives series of temperatures near jiarallels of lati- 

 tudes across Europe and into Asia. A correction of 0o.9 is made for 

 each degree of latitude, and of 1°.3 for each 100 meters of elevation. 

 All temperatures are reduced to a uniform elevation of 200 meters (656 

 feet). The order is always from west to east. 



Mean temperaiiires for Jnhj on the parallel of 52° N. 



Degrees. Degrees. 



Valentia 57.6 Orel and Kursk 67.6 



Leipsic 62. 6 Poljiiulii 65.7 



Warsaw 64. 7 Orenburg 69. 1 



Tscheniigow 65.1 Akmollinsk 70 



The mean temperature is lowest on the Atlantic coast. It rises up 

 to Poland by seven degrees, then remains steady over the forests of 

 the Bug and Dneiper, then rises over the black-earth region of Central 

 Russia with extensive cultivation (Orel and Kursk), falls again in the 

 forests over the sources of the Sura (Poljiinki), to become again higher 

 over the Kirghiz steppes. 



July mean iemperature along 50° K. 



Degrees. Degrees. 



Guernsey 59. 5 Troppau 68 



Brussels 62. 6 Arvavarallja (Cariiatbians) 64. 2 



Wiirzburg 68 Lirow (Lemberg) 65. 5 



Promenbof (N. W. Bohemia) 64.4 Kieft 66.2 



Prague 68 Cbarkow 68.4 



Hochwald 63.9 Seniipalatinsk 72.7 



The temperature increases rapidly to the Main valley, then rises and 

 falls over the forests of Bohemia and the Carpathians, becoming hardly 

 higher at Charkow, where there remains some forest, than at Wiirz- 

 burg. Eastward from here it rises rapidly. 



July mean temperaturea along 48° N. 



Degrees. Degrees. 



Brest 62.2 Bistnitz (Transylvania) 68 



Versailles 65.5 Czeniowitz 68.9 



Carlsruhe 66.6 Ekaterinoslaff 71.6 



Vienna 67.8 Lngau 72.5 



Debreczin (Hungary) 70.7 Irgis (steppes) 75.6 



Rosenau (Hungary) 68. 9 



Here the rise is about eight degrees from the Atlantic to the prairies 

 of Hungary (Debreczin). It is cooler in Eastern Hungary and in 

 Transylvania, where there is yet much forest. Czernowitz is near the 



