I was very much pleased with your paragraph on page 310, of the October Magazine, regarding "Trees, Rain-fall and the Lakes." Writers on these subjects often run away rapidly with what appears a good and new theory. But has it been proved by lengthened observation, carefully carried out, that cutting down the trees prevents rain-fall? I observe in some recent foreign publications that it is doubted, and they bring, in confutation, observations on the summer drying up of the Arno, to show that Florence has always suffered, though it is but lately that the mountains which feed the river have been in the course of destruction, or the denudation of their trees.

Let us try. Have the Falls of Niagara decreased in volume, or has the flow of the Mississippi diminished in any material degree? What is wanted is " observation with extensive view," and facts that science can recognize.

[It is a great pleasure to have this brief but pithy note from so intelligent a source as this. The Editor of this magazine has had to stand almost alone in opposition to the deductions of the celebrated author of "Man and Nature," and these too backed up by the full force of the influential American Association, which adopted a report of one of its committees in favor of Mr. Marsh's views. We do not say Marsh's theories are not true, but we do say that the reasoning ought not to satisfy a truly logical and scientific mind. - Ed. G. M.]