would add this description of a case observed at "Harmon's Bottom," in Bedford County, Pennsylvania, twenty years ago. Two sugar-maples had been united by the natural grafting of the branch of one of them upon the trunk of the other, about six feet away, and at ten feet above the ground. The tree-trunks were both intact, with their roots, but the trunk of the second tree was strikingly smaller below the graft than above it, and one might consider this due to retardation of the circulation below, as well as increased flow of sap above. In your correspondent's illustration, the trunk below, being severed from its roots, became an appendage to the rest of the circulating system. It has been speculated that there is circulation downward in plants, the roots discharging to as well as eliminating from the soil, and that this action unfits a soil as much for repetition of crops as does exhaustion of nourishing constituents. The preference for change in kinds of trees that spring up after forest-clearing — a natural rotation of crops — has been very generally remarked.
F. Z. Schellenberg.
Irwin, Pennsylvania, September 3, 1887.
WHAT IS A BAYOU?
Editor Popular Science Monthly:
Sir: A friendly, well-meaning, and timely correction is never amiss. When the error to be rectified is such as is likely to arouse feelings of regretful remonstrance in a community, the correction is the more pardonable; when it is likely to color the opinion of a nation, the correction becomes imperative.
The correction which the writer, one of a "community" supposed above, would most humbly beg leave to make, is to an error that the writer of a most able and interesting article in the July issue of "The Popular Science Monthly," entitled "The North American Lakes," has doubtless unwittingly been guilty of. I do not presume to say that he was led to the commission of the error by any ignorance of his subject, but rather by a want of a sufficient knowledge of the local nomenclature of Louisiana.
To quote the author's words — "Lake Borgne and Lake Pontchartrain have been captured from the Gulf by the delta of the Mississippi, while numerous small lakes, called bayous," etc. We will say nothing of the derivation of the word, which, of itself, can not be construed to mean a lake, for, alas! local usages frequently defy all attempts at classification, and are by no means fair criteria for the true meaning and application of a terra; but, as a Louisianian, we will say that the term "bayou," in the article cited, has been used under some misapprehension.
If the author will procure for himself an authentic map of Louisiana, he will find the lower part of the State to be covered with almost a network of small water-courses, although they scarcely deserve the name, varying in size from the smallest "creek" to channels just navigable by small vessels, all exceedingly sinuous and very river-like. These are what, in Louisiana, are called "bayous." Whatever may be the geological origin and nature of these bodies, the fact still remains that the term "bayou," in Louisiana, is applied to nothing at all resembling a "lake." Respectfully yours,
C. M. Williams.
Carrollton. Louisiana, September 5, 1887.
SCIENCE IN HARNESS.
NO journal has upheld more steadily than "The Popular Science Monthly the principle that, as fast as they are established, the truths of science shall be applied to useful purposes, and, through popular education, be made as widely available as possible for the general guidance of life. And yet we can not look with favor upon what many persons doubtless regard as a very signal and happy example of the utilization of scientific conclusions — we mean the authoritative and dogmatic teaching as to the effects of alcohol, now provided for by the school laws of many States. It is only right, therefore, that we should assign our reasons for holding that this is not a case of the legitimate application of scientific truths to practical life.
In the first place, it is an abuse of power on the part of the majority. In the "temperance" controversy as a distinct social issue we have no wish to interfere; but we can not ignore the fact that there is such a controversy, nor can we consent to believe, with the advocates of prohibitory legislation, that their opponents are neces-