256 



4. The wheat sown September 29 and October 6, 1880, which 

 headed out December oO and February 19, was injured as to the heads 

 by the subsequent frost. 



5. The seeds sown October 20, 27, and November 3, 1880, flowered 

 between the 4th and 8th of June, 1881, but at this time there was 

 experienced at Paris a spell of very cold weather, the minimum daily 

 temperature being 3.1° C, and even white frosts were reported, so 

 that wheat which was then in flower was badly injured. 



6. -In general, the dates November 10, 1880, to December 15, 1880, 

 are those indicated as most favorable for sowing wheat in that year, 

 and the crop of 1881 may be predicted as likely to be small, but of 

 excellent quality. 



The grape and loine crop. — In a short study on the relation between 

 the vine and the weather, Marie-Davy (1882, p. 290) states that, in 

 general, the annuals, such as the cereals, concentrate all their energy 

 in the formation of the ear and the seed or grain. Their work is then 

 finished and they die. The next year's crop of these annuals is 

 largely under the control of the husbandman, who can obtain seed 

 from more favored regions if his own crop was inferior. 



On the other hand, the work of the vine, like all perennials, is not 

 merely to ripen its fruit and seed, but to preserve its own individual 

 self for usefulness in future years. Therefore it elaborates out of its 

 own sap not merely leaves and fri^t and seed, but a store of woody 

 fiber. Corresponding to this more complex system of growth the 

 relations of the perennials to the climate are apparently more complex 

 1 han the relations of the annuals, and, it may also be added, the range 

 of geographical distribution, whether by nature or by cultivation, is 

 more restricted. 



Our studies will be confined to the data furnished by the observa- 

 tions at Epernay (1873-1881), to which Marie-Davy adds other data 

 computed from the observations made at Montsouris, in which latter 

 computation certain laws of growth of the vine as established by 

 Gasparin were adopted. 



In the neighborhood of Paris the leaf buds of the vine burst open 

 in May when the mean daily temperature has permanently passed 

 above 11° or 12° C. Assuming that the mean of twenty days, as 

 observed at Montsouris, will give this date (which was unfortunately 

 not observed at Epernay), we obtain the figures in the first three col- 

 umns of the following table. In some of these years the early leaf 

 buds were undoubtedly killed by nocturnal frosts, but they were soon 

 replaced by other buds, and the dates here given must be adopted in 

 the absence of actual observations, especially when we remember that 

 the quantity and quality of the final crop of grapes depend not only 



