clxxv 



of years ago proves it, that man's action in cultivating the soil and clearing 

 the forests has important local effects on the annual quantity of rainfall, 

 which is less dependent on local causes than on the distribution of the rain- 

 fall throughout the season, and especially on the benefit the soil (and thus 

 the natural and cultivated vegetation) derives from the precipitated moist- 

 ure, and the stage of water in the smaller tributaries and larger streams. 



If the Mediterranean countries have become more arid, less fruitful, 

 than they were in the time of the Greeks and Romans, they owe it no 

 doubt in great part to the destruction of the forests of their hills and moun- 

 tains, and with it the denudation of the rocky soil, and not to a diminished 

 annual rainfall. But this rain is probably less evenly distributed, and is 

 certainly less beneficial to the soil, because not absorbed and retained; it 

 runs off over the arid surface, washes the soil more and more, swells the 

 streams rapidly, and disappears rapidly. We see the same effects in coun- 

 tries where the soil is naturally destitute of forests, e.g. in our southwest- 

 ern regions and Mexico. But in the United States territory' the artificial 

 destruction of forests is, compared with the vast extent of country, so lim- 

 ited that important general effects on the climate can not have resulted. 

 Whatever changes we may have observed within a few years, are, like the 

 changes of temperature spoken of above, evidently only of a temporary or 

 local character. 



The stage of the Mississippi River has not been recorded for more than 

 fifteen years, but we know of floods of the river at this point during ninety 

 years, an account of which I have published in our Transactions of 1868 

 (vol. 2, p. 423). In that period the river seems to have risen more than 40 

 feet above low-water mark twice, in 17S5 and (61 years later) in 1844; and 

 37 feet also twice, but at shorter intervals, 1851 and 1858; so that in four- 

 teen years we had three floods, and none as high in the last sixteen years. 

 But who can say that this coming season or next year will bring us a great 

 flood again ? There is not the least improbability in it. 



It is not the rains here about St. Louis or those in Missouri, nor the 

 melting of the snow in the mountains and northwestern regions, which 

 alone are the causes of the great floods ; it is the coincidence of many 

 causes, and especially contemporaneous high rises of the great rivers which 

 unite just north of us, which cause the highest floods, and there is no rea- 

 son why they might not occur again in any spring or summer. 



Judge Holmes announced to the Academy the death of a mem- 

 ber, Mr. C. C. Whittelsey, in a fitting speech, and offered the 

 following resolution : 



Resolved, That the Academy of Science has heard with regret of the 

 death of Charles C. Whittelsey, Esq., who had been for many years an 

 active and useful member to the Academy, and that we desire to give ex- 

 pression in this form of our high appreciation of his merits and services, 

 and of his excellent character and scholarly attainment?. 



