1887.] H. F. Blanford — Lifluence of Indian Forests on the Rainfall. 3 



almost hopeless to seek for decisive evidence of the influence of forests 

 by any comparison of the rainfall of different provinces, or of areas suffi- 

 ciently large to display the contrasted effects in a striking and convin- 

 cing manner. The best and perhaps only satisfactory kind of evidence, 

 were it obtainable, would be the comparison of the rainfall of one and 

 the same tract (one of at least some hundreds of square miles in ex- 

 tent) for many years, first while covered with forest, and again for 

 many years after clearing. It is, however, not until a tract of virgin 

 forest has been brought under the destructive operation of civilizing 

 agencies, that, as a general rule, any attempt is made to record its rain- 

 fall ; and when, therefore, the conditions necessary to obtain one term of 

 the comparison are rapidly disappearing. The reversal of this order of 

 things, the conversion of bare or at least partially wasted tracts into 

 protected forest, is one, however, of which India already furnishes some 

 examples, and with the progress of forest protection may yet furnish 

 more ; and if due advantage be taken of these as they present themselves, 

 it may yet be possible to obtain rainfall data which may afford valuable 

 and indeed practically onclusive evidence on the point in question, 

 even if not fulfilling in all respects the rigorous conditions of the logical 

 method of differences. 



One instance of the kind, on a scale large enough for all reasonable 

 demand, has lately been brought to my notice by Mr. Ribbentrop, and 

 has been quoted in my Report on the Administration of the Meteorolo- 

 gical Department in 1885-86 ; and despite some shortcomings in the 

 due verification of the data it furnishes, shortcomings which it is now 

 impossible to make good, it will probably, in the course of some years, 

 as nearly fulfil the conditions of a test case as we are likely to attain to 

 in an experiment of such magnitude. In some respects, indeed, the 

 circumstances of this case are unusually favourable. The vicissitudes 

 of the rainfall of the Central Provinces are smaller, proportionally, than 

 those of any other province of an equally moderate average, and of the 

 22 stations, the rainfall registers of which will be brought in evidence, 

 not less than 10 are regular meteorological observatories, working under 

 the Meteorological Department of the Government of India. 



The region referred to in the 1st part of my Memoir on the Rainfall 

 of India as the Central Provinces south, has been described as a hilly 

 and jungle clad country, including some extensive fertile plains, especially 

 that which surrounds Raipur. The northern portion consists of the 

 range of broken tablelands and hills here spoken of as the Satpuras, 

 and these are largely clothed with forest. According to the most recent 

 report of the Officiating Inspector General of Forests, the area of forest 

 in the Central Provinces is estimated at 54,600 square miles, of which 



