428 
TIic Water Economy of France 
throughout the whole of its course a rapid current, an unsettled 
flow, and a bluish turgidity, which at once reveal its mountain 
birth and connexion ; the other, the tranquil Saone, having its 
source amongst low hills, and pursuing its sluggish course 
through a wide exj)anse of level plains, slowly nio\ es, as if loth 
to leave its grassy banks, until it encounters the swift Rhone, and 
is hurried along together with the fretful current of its mighty 
invader. It is worthy of special remark that the overflow of 
these two rivers, arising in each case from a different, if not an 
antagonistic cause, never occurs at the same time — -a provi- 
dential circumstance for the great city, below which they meet. 
The waters of the Saone and of its principal affluents are 
directly affected by the rainfall ; those of the Rhone and all 
its mountain tributaries, on the contrary, are furnished by the 
sudden melting of the snow that caps the mountain-tops, the 
result of sunshine and genial temperature ; so that in winter the 
Rhone is at its lowest ebb and the Saone at its fullest tide, whilst 
in summer the contrary takes place. 
II. Tlir Gcolom/ and tJic Chemistri/ of the Riinninf/ IVnters 
of France. 
We now come to a branch of hydrography most important to 
agriculture, although it has been hitherto much overlooked. At 
a time when the happy results of irrigation are so generally recog- 
nised, and so many efforts are being made to utilize the available 
streams that flow within the reach of waste lands and barren hill- 
sides, it is obvioi^gly important to investigate by chemical 
research the characteristic constituents of our rivers. It is with 
this view that I will now introduce in a condensed form the inter- 
esting results of the investigations made in that direction by 
French savants in regard to the principal rivers of France. 
The physical condition of water, whether it be rain, spring, or 
river water, is by no means homogeneous, but varies a great deal, 
according to the very many local and diversified circumstances 
presented by the surface of the globe. Even with respect to the 
laws which regulate the supply of rain, though some influences, 
such as proximity to the sea or to mountain chains, have been 
recognised and explained, still other peculiarities, though re- 
marked, remain among nature's mysteries. It has been demon- 
strated to satisfaction on the other hand, that of two rain-gauges 
placed in the same district, but at different elevations, the lower 
gauge registers more rain than the upper one. That the mean 
temperature of a district, the intensity of solar action, the phy- 
sical constitution of the soil, as well as its state of cultivation, 
exercise a most powerful influence on the distribution and 
