324 THE POPULAR SCIENCE MONTHLY 



as one writer has said, " as comparable as stations can be made." 

 These Nancy results showed, for a period of about twenty-five years, 

 and for the best pair of stations, somewhat more rainfall (about one 

 half inch to one inch in the yearly average) in the forest. In the case 

 of the other pair the excess was much greater. This series of compara- 

 tive observations was unfortunately discontinued a few years since, and 

 although the available data have been widely used, they are, in the 

 opinion of the leading official meteorologist of France, as expressed in 

 private correspondence with the present writer, inadequate to serve as 

 the basis of a serious study. 



The Indian Case 



The two cases just cited are in the temperate zone. The other two 

 cases are found within the tropics. There is, first, the case of a dis- 

 trict in the central provinces of India, where forest protection and 

 reforestation began in 1875, and where the rainfall, as compared with 

 the rainfall of all India, showed an increase of about 12 per cent, in a 

 comparatively few years. This, again, seemed an unanswerable argu- 

 ment in favor of a forest influence upon rainfall. But the complica- 

 tion due to periodic oscillations of climate, various uncertainties and 

 the possibilities of error in the observations, together with the difficulty 

 of " correcting " the catch, acknowledged by the Indian authorities 

 themselves, have led to a feeling that we ought at least to suspend 

 judgment in this case. Nevertheless, because the effect of wind upon 

 the rainfall catch is less in the tropics than in our own latitudes, and 

 therefore the error arising from the increasing protection afforded by 

 the growing forest is greatly lessened, von Hann (1908), the acknowl- 

 edged authority in climatological matters, is ready to accept the gen- 

 eral result of these Indian observations as evidence in favor of an influ- 

 ence of forests in increasing the amount of precipitation at least in 

 the tropics. Dr. G. T. Walker, however, the present director of the 

 Meteorological Service of India, in a recent study of supposed changes 

 of climate in India (1910), does not find evidence of an effect of forests 

 in increasing rainfall. 



The Java Case 



Finally, we may cite the Java case, which is without question the 

 most striking of all. This case was studied and first discussed a good 

 many years ago by Professor Alexander Woeikof, of St. Petersburg. 

 The facts as given by him are these : There are extensive dense forests 

 in the south of Java, while the north coast has been largely deforested. 

 A station, Tjilatjap, on the south coast, distant from the mountains, 

 has a mean annual rainfall almost twice as large as that of three sta- 

 tions (Batavia, Tegal, Samarang) on the north coast. The difference 

 is, in round numbers, about 150 inches against 75 inches. The north 

 side is the windward side for the northwest monsoon, and during the 



