247 



had lost by evaporation the preceding week. These hitter, therefore, 

 show us the niaxinmni elt'ect that water can have on vegetation in the 

 climate of Paris. The proportion of water that is consumed is 

 exaggerated, but the crop increases at the same time, but less ra^iidly 

 than the consumption of water. We may, therefore, say that to 

 a ccKtain extent, water can with the aid of the sunshine supplement 

 the fertilizers, although we can not say that a deficiency of fertilizer 

 is a good thing. 



In general, all the observations recorded in France, Switzerland, 

 and England show that the total annual evaporation from cultivated 

 soils is TO to 80 per cent of the total annual rainfall. A large part 

 of the rain falls in the autumn and winter w^hen vegetation has 

 ceased. The rains of these seasons j^artly filter into the earth and 

 feed the subterranean springs, but they must first return to the soil its 

 own water supply. Xow the more the soil is impoverished by cutting 

 the crops the more it will take up of the autumn rains and the less 

 will be received by the subterranean water beds. It is then easy to 

 understand that in cultivated lands the mean flow in the water 

 courses diminishes in proportion to the progress of the cultivation. 

 It seems certain that in France, and especially in the central portions, 

 the grains do not find in the soil all the water that they could 

 profitably use to the advantage of the crop and that irrigation would 

 be advantageous in these and many other crops wherever there is a 

 good soil and an abundance of sunshine. 



Notwithstanding this necessity for water, the rainy years are 

 frequently bad for cereals. Rainy summers are deficient in light 

 and dry summers have too much. It is the relative distribution of 

 heat, sunshine, and moisture from day to day throughout the whole 

 season that is important. 



From a meteorological point of view we should say that from the 

 sowing to the formation of the embryo grain sunlight is indis- 

 pensable, but from the formation to the maturity it is far less 

 important. 



In his Annuaire for 1878 (p. 468) Marie-Davy gives a summary 

 of the meteorological data, month by month, for several years, as a 

 sample of what may be done by way of explaining the general rela- 

 tions between meteorology, as hitherto pursued, and the crops of the 

 agriculturist. He says: 



Meteorology, as seen from the agricultural point of view, has for 

 its ultimate object to enable the farmer to anticipate the future of 

 his current crop. This explains why we think it necessary to study 

 the influence that each of the meteorological elements has on the 

 progress of the development of the plants in the successive phases 



