OCTOBKE 28, 1898.] 



SCIENCE. 



575 



Considerations like these must in the end 

 determine the range and avenues of com- 

 merce, perhaps the fate of continents. We 

 must develop and guide Nature's latent 

 energies ; we must utilize her inmost work- 

 shops ; we must call into commercial exist- 

 ence Central Africa and Brazil to redress 

 the balance of Odessa and Chicago. 



William Ceookes. 

 ( To le concluded. ) 



VABIA TIOmiNTHERATE OF AGRICOLTUBAL 

 PRODUCTION AND ONE OF THEIR CA USES* 

 The twenty years ending with 1897 wit- 

 nessed the harvesting in the United States 

 of crops of corn, oats and rye, the yield per 

 acre of which was from 50 to 60 per cent 

 greater than the corresponding yield in cer- 

 tain other years of the same period; of 

 crops of potatoes in which it was from 80 

 to 87 per cent greater than in other years 

 of the period under consideration, and of 

 crops of buckwheat in which it was from 80 

 to 130 per cent greater than in the case of 

 certain other crops of buckwheat grown 

 within this same period of twenty years. 

 On the other hand, the highest annual 

 yields per acre of wheat, cotton, hay, barley 

 and tobacco were only 50, 39, 39, 36 and 23 

 per cent, respectively, higher than the low- 

 est. This remarkable non- uniformity of 

 fluctuation has suggested to the author of 

 this paper the operation of some law not 

 hitherto generally recognized, and the ex- 

 amination of the statistics of a large num- 

 ber of crops for each separate state during 

 a period of twenty years shows that, en- 

 tirely independently of whether the aver- 

 age yield per acre be high or low, the 

 nearer the approach to the region to which 

 a product is indigenous the more uniform 

 will be the rate of production from year to 

 year, and the further the departure from 



* Abstract of paper read before Section I — Social 

 and Economic Science— of the American Association 

 for the Advancement of Science, August, 1898. 



such region the greater the liability to 

 fluctuation. 



For the purpose of this abstract, four 

 products only need be considered : oats, 

 barley, cotton and corn. The period cov- 

 ered is twenty years, 1878-97, and the com- 

 parison is based in each case — not upon the 

 two extreme deviations, but on the means 

 of the three highest and the three lowest 

 yields per acre in the twenty-year period 

 the figures given representing the per cent 

 of the deviation of these means from the 

 mean of the entire period. 



In the case of oats in 12 of the most 

 northerly states of the Union (the Transi- 

 tion zone * of the Merriam Life Zone Map) 

 the deviation from the twenty-year average 

 was only 34.23 per cent, only 2 states ex- 

 ceeding 40 per cent; in the Upper Austral 

 (from New Jersey, Delaware and Maryland 

 to Kansas and Nebraska) the deviation 

 was 53.95 per cent, only one state having 

 less than 40 per cent, and in the Lower 

 Austral (from Virginia, the Carolinas and 

 Georgia to Texas and Arkansas) it was 

 62.78 per cent, no state falling below 50 

 per cent. In the case of barley the devia- 

 tion in the Transition zone was 37.7 per 

 cent, in the Upper Austral 59.5 per cent, 

 and in the Lower Austral 69.9 per cent. 



On the other hand, in the case of corn 

 and cotton it is with the extension of their 

 cultivation northward that the range of 

 fluctuation in the average rate of produc- 

 tion is found to increase. In the case of 

 cotton this variation was 25.1 per cent of 

 the average yield per acre in Alabama, 26.3 

 per cent in Georgia, 35 per cent in Missis- 

 sippi, .37.9 per cent in South Carolina, 40.4 

 per cent in Louisiana, 41.3 per cent in 

 North Carolina, 42 per cent in Arkansas, 

 53 per cent in Texas,t 54 per cent in Vir- 



*The transcontinental belt in which Boreal and 

 Austral elements overlap. 



t The somewhat wide fluctuation in Texas is due 

 to the extension of cotton planting into regions of un. 

 certain rainfall. 



