THE CORRELATIONS OF AREAS OF MATURED CROP AND THE RAINFALL. 351 



PART I. 



THE CORRELATION OF THE MATURED AREAS OF CROPS AND 



THE RAINFALL. 



i. The data considered in this part of the paper refer on the one hand to the 

 total areas of crops which come to maturity and contain an ' average ' amount of 

 grain, and straw, variously spoken of as ' cropped/ ' matured ' or ( harvested ' areas ; 

 and on the other to the rainfall recorded at or near the places where the crops in 

 question have grown. 



The accuracy of the latter or rainfall data may for the most part be assumed to 

 be fair, and where the guages are directly under the supervision of the Meterological 

 Department, to be good. In cases where the rainfall is measured by the dis- 

 trict authorities an accuracy of more than i or 2 per cent, is hardly to be expect- 

 ed/ though, on the whole, the records even here are at any rate approximately 

 correct. 



In respect of the matured areas of crops the data are less satisfactory. In the 

 Punjab these data are based on a rough estimate of the relative amount of the grain 

 and straw-bearing crop in each field examined by a local official, and compared men- 

 tally with what he believes to be a normal outturn for the particular locality and the 

 class of crop. In many cases, too, it is to be feared that the estimate is made without 

 seeing the field, merely from hearsay and by a judgment of the probabilities of the 

 case. The area of each field is quite accurately known, and it is only in this mental 

 comparison of the produce of a unit of area for the harvest considered with the ' average ' 

 or ' normal ' produce of a unit of area that serious errors arise. The ' average ' or 

 'normal' is solely the estimating official's conception of what a ' normal' harvest 

 should be. Though, of course, persons of long experience will agree to some extent 

 in their conception of the 'normal' or 'average' harvest, yet, so far as I know, it 

 has never been quantitatively defined. Whether the total yield should be measured by 

 weight or by volume, what proportions of grain, chaff and straw it should contain, 

 what percentage of moisture should be deducted, and so forth are all questions which 

 would have to be answered if an accurate standard is to be set up ; and the need for 

 some such standard appears to be very great. 



Yet, in spite of indefiniteness in these respects a certain tradition as to what 

 constitutes an average crop, made more precise by experiments on the yield of 

 certain crops, exists, and as a unit of measurement is not quite the inadequate in- 

 strument that it might appear to be at first sight. 



When the ratio of the actual yield to the assumed average has been determined, 

 to be, for instance three-quarters, then a field of an area of 1 acre of this kind of crop 



1 I have found a guage which should have had an opening of a circular shape and 5" in diameter, to have an 

 opening approximately elliptical with axes of 5"*io and 4"'96. This alone, apart from inaccurate measurement, 

 would introduce an error of over 1%. 



