Page:Popular Science Monthly Volume 10.djvu/395

Rh illustrations of the supposed necessity of insect fertilization. In one plant experimented with in this way (Baptisia), seeds were not formed. This plant, in the author's opinion, may possibly require insect agency for its fertilization. He does not deny that flowers are sometimes fertilized by the aid of insects; but he does not admit that this mode of fertilization is very common. His conclusions may be stated as follows: 1. That cross-fertilization by insect agency does not exist nearly to the extent claimed for it; 2. That, where it does exist, there is no evidence that it is of any material benefit to the race, but contrariwise; 3. That difficulties in self-fertilization result from physiological disturbances that have no relation to the general welfare of plants as species.

Proposed International Geological Congress.—A committee appointed by the American Association has issued a circular addressed to geologists, announcing the proposed convocation of an International Geological Congress, to be held at Paris some time during the Exposition of 1878. It is proposed to make the Congress an occasion for considering many disputed points in geology, and to this end it is desirable that the Geological Department of the Exhibition should embrace—1. Collections of crystalline rocks, both crystalline schists and massive or eruptive rocks, including the so-called contact-formations and the results of the local alteration of uncrystalline sediments by eruptive masses. In this connection are to be desired all examples of organic remains found in crystalline rocks, including Eozoon and related forms. These collections should, moreover, comprehend all rare and unusual rocks of special lithological, mineralogical, and chemical interest, examples of ore-deposits and of vein-stones of all kinds, with their incasing rocks. As far as possible these collections should be limited to specimens of a size convenient for examination, and be accompanied with sections prepared for microscopic study.

2. Collections illustrating the fauna and the flora of the Palæozoic and more recent periods, particularly of such horizons as present a more critical interest to paleontologists from the first appearance or the disappearance of important groups of organic forms. It has appeared to the committee that the organic remains of the Cambrian, Taconic, or so-called Primordial strata merit especial attention in this connection.

These various collections should be explained as fully as possible by labels, catalogues, monographs, and maps.

3. Collections of geological maps, and also of sections and models, especially such as serve to illustrate the laws of mountain-structure. In the geological maps, regard should be had to various questions which deserve the special consideration of the Congress, such as the scales best adapted for different purposes, the colors and symbols to be used, and the proper mode of representing superficial deposits conjointly with the underlying formations. The secretary of the committee is Dr. T. Sterry Hunt, of Boston.

Comparative Dietetic Value of Meat and Eggs.—A writer in the Scientific Farmer estimates the food-value of one pound of eggs as a producer of force, i. e., the amount of work the pound oxidized in the body is theoretically capable of producing, at 1,584 foot-tons, and the value of one pound of lean beef, from the same point of view, at 990 foot-tons. As a flesh-producer, one pound of eggs is about equal to one pound of beef, as is shown by the following analysis quoted by the author:

The author hereupon remarks as follows:

"A hen may be calculated to consume 1 bushel of corn yearly, and to lay 12 dozen or 18 pounds of eggs. This is equivalent to saying that 3.1 pounds of corn will produce, when fed to this hen, 1 pound of eggs. A