470 



NATURE 



[March i6, 1905 



plcnients of the orbits of those minor planets discovered 

 during 1904 of which the paths have been computed at the 

 Berlin Astronomischcn Recheninstitut. The lisl contains the 

 orbits of 28 minor planets, 24 (523-549) of which are 

 referred to the epoch 1904.0, and 4 (550-553) to 1905.0, 

 and is followed by a scries of remarks which name the 

 observations on which the computations were based, and the 

 corrections to some of the orbits as obtained from sub- 

 sequent observations. A note concerning (526) NQ savs 

 that that object is probably identical with 1901 HA. 



.An additional list of live asteroids discovered during- 

 November and December, 1904, and to which the per- 

 manent numbers 549-553 are now allotted, brings the total 

 number discovered during last year up to thirty-two. 



EFFECT OF AUTUMNAL RAINFALL UPON 

 WHEAT CROPS.' 

 g \' autumn, in this note, is to be understood the period 

 from the thirty-sixth to the forty-eighth week, 

 both inclusive, of the year, as represented in the 

 Weekly Weather Report of the Meteorological Office ; 

 it covers the months of September, October, and 

 November, approximately. The rainfall to be re- 

 ferred to is the average amount in inches, for the 



general consonance, with exceptions, more or less striking, 

 in a few of the years. In other words, the yield of wheat 

 in any year seems to depend mainly on the absence of 

 rainfall in the previous autumn, and but little on any other 

 factor. 



The obvious algebraical expression for such a condition 

 as the curves represent is a linear equation, and the equation 

 which represents the relation between yield of wheat for 

 England and the previous autumn rainfall is : — 



Yield =39.5 bushels per acre-s/4 (previous autumn rain- 

 fall in inches). 



H we call the yield obtained from the rainfall by this 

 equation the "computed yield," a comparison with the 

 actual yield for the twenty-one years shows that the com- 

 puted yield agrees with the actual yield within half a bushel 

 in seven years out of the twenty-one. In fourteen years 

 the agreement is within 2 bushels; in the remaining seven 

 years the difference between computed and actual yield ex- 

 ceeds 2 bushels. The extreme variation of yield in the 

 twenty-one years is 9 bushels, from 26 bushels per acre in 

 1892 and two other years to 35 bushels per acre in 1898. 



Of the seven years for which the formula gives yields 

 differing from the actual by upwards of 2 bushels, 1896 is 

 the most conspicuous ; its actual yield exceeds the computed 

 yield by 4.5 bushels. 



These seven years all show :momalous seasons. Taken 



{tJiK'erlci) tutye) 





" Principal Wheat Producing Districts," for the period 

 mentioned, in successive years. The amounts are taken 

 from the summaries of the Weekly Weather Report. 



The yield of wheat is that given for successive years in 

 the annual summaries of the Board of Agriculture and 

 Fisheries as the average yield in bushels per acre for 

 England, since 1884, or more strictly since 1885, as that 

 is the first year for which the figures for England are given 

 separately. In 1884 the figure for Great Britain, which 

 generally differs but little from that for England, is used. 



These are the only figures in the official publications which 

 are immediately available for the purposes of comparison. 

 The totals of rainfall for the thirteen weeks have been com- 

 piled from the weekly amounts, otherwise the figures are 

 taken as they stand in published returns. The areas referred 

 to are not exactly coterminous, but they are more nearly 

 so than if the rainfall values had been taken for the whole 

 of England, or the wheat yield for Great Britain. 



When the autumn rainfall and the yields of wheat for 

 successive years from 1884 to 1904, as thus defined, are 

 plotted, the rainfall curve being inverted, i.e. rainfall being 

 measured downward on the paper while yield is measured 

 upward, there is a very striking similarity between the 

 curves, so much so as to suggest that if the scales were 

 suitably chosen the two curves would superpose and show 



' "On a Relation between Autumnal Rainfall and Ihc Yield of Wheat of 

 the following Year.— Preliminary Note." By Dr. W. N. Shaw, F.R.S,, 

 Secretary of the Meteorological Council. Read liefore the Royal Society 

 on I-'ebruar>' 2. 



NO. 1846, VOL. 71] 



seriatim, thev are 1887, 1888, 1S93, 1S95, 1896, 1899, and 

 1903. 



In 1888 and 1903 the crops were washed away by in 

 inches of rain in the summer ; 1893 is the year of phenomenal 

 drought, and the crop was below the computed figure bv 

 2.5 bushels. The years 1892 and 1899 are interesting, 

 because though the amounts of rain were up to the average, 

 the former had eight dry weeks and the latter ten dry 

 weeks out of the thirteen included in the conventional 

 autumn. They were thus dry autumns, the average amount 

 of rainfall being made up by a few exceptionally wet weeks. 

 The yields correspond with dry autumn values. They are 

 above the average and above the computed figures by some 

 2 or 3 bushels per acre. , 



There remain 1895 and 1896. 1895 was the year of re- 

 markably cold weather, and in that year the yield fell short, 

 but in the following year the deficiency was made up by a 

 yield as much above the computed value as the previous 

 one fell short. It would appear that in this instance the 

 productive power not utilised in the year of the great cold 

 was not lost, but stored. On the other hand, it must be 

 remarked that 1896 had the advantage of a specially dry 

 winter. 



It appears from these considerations that the dryness of 

 autumn is the dominant element in the determination of the 

 yield of wheat of the following yeai". The averages of 

 yield and of rainfall are taken over very large areas, and it 

 may be taken for granted that the investigation of the 

 question for more restricted areas would introduce some 



