Page:Popular Science Monthly Volume 7.djvu/524

508 the town, and rolling into the streets very slowly. A similar fog rose from the sea, and rolled, also, into the town. Hence it appeared that the wind had nothing to do with the matter, but that both fogs rolled because they were too heavy to remain suspended. The peculiarity of the fog was in the size of its particles, larger than any the author had ever before seen, and which he estimated at from $1/40$ to $1/300$ of an inch in diameter; another peculiarity was its lumbering mode of rolling, in which it resembled dust. The author found that the particles were perfectly spherical, and not hollow, but concrete throughout.

Food-Rations of the French People.—A Very curious calculation has been made by M. Hervé Mangon to determine the average ration per kilogramme of live weight consumed by the rural population of France. He estimates the "live weight" of the French people in 1861 at 1,771,142,951 kilogrammes (say 3,896,514,492 lb.). But these figures, though they represent fairly enough the total weight of the population, cannot serve as a basis for estimating the amount of food required. Children consume more food, in proportion to their weight, than adults. Hence, the author was obliged to express the weight of children, not as it actually was, but in terms corresponding to their consumption of food. In this way he finds the total weight of the French population to be, from the point of view of nitrogen-consumption, 2,112,978,201 kilogrammes (4,648,552,042 lb.), and from the point of view of carbon-consumption 2,095,886,031 kilogrammes (4,610,949,268 lb.). The food annually consumed in France contains carbon 4,434,716,270 kilogrammes (9,756,375,794 lb.); nitrogen 215,724,211 kilogrammes (474,593,264 lb.). If, now, we divide the sum of the carbon and nitrogen by 365 days and then divide the quotient by the total weight of the population, we find the mean daily rations per kilogramme (2$1/2$ lb.) of live weight to be, carbon, 5.1797 grammes (77.7533 grains); nitrogen, 0.280 gramme, (4.3212 grains). This is the daily ration per kilogramme for the whole population.

In Paris the daily ration per "live kilogramme" contains 5.675 grammes of carbon, and 0.332 gramme of nitrogen. Supposing, now, that the daily consumption per kilogramme is the same in Paris, Lyons, Marseilles, and the six other cities whose population exceeds 100,000 souls, the mean daily ration per kilogramme of weight for the country districts is found to contain, of carbon 5.808 grammes, and of nitrogen 0.275 gramme. This ration M. Mangon considers to be sufficient to fit the body for a moderate amount of labor; but it would be good economy, he holds, for employers to give their servants and workmen more abundant food. The dullness and slowness of country people he regards as the natural result of insufficient food.

Relations of Meteorology to Life.—At a recent meeting of the British Meteorological Society a communication from the Council was read, entitled "Suggestions of the Observation of Periodic Natural Phenomena," the object being to call attention to those phenomena manifested by organized beings of the vegetable and animal kingdoms dependent on the progression of the seasons, such as the budding, leafing, flowering, fruiting, and the shedding of leaves of trees, shrubs, and herbaceous plants; the earliest and latest appearance of insects; the times at which birds pair and build, and of the arrival and departure of birds of passage; the periods of hibernation of reptiles and small animals, as frogs, dormice, etc. All these phenomena being closely connected with the annual progression of the meteorological elements, are calculated to afford information of the progression of the seasons, of a much more interesting character than that derived from the indication of instruments. Plants are very susceptible of atmospheric influences, and a close correlation exists between the development of plant and animal life as the sun advances in his yearly course, each season being marked by its characteristic phenomena.

The Marriage of Cousins.—The influence of marriage of first cousins on the mental constitution of the offspring is almost universally pronounced to be deleterious. This subject has been treated by Mr. George H. Darwin in a paper read at a meeting of the London Statistical Society. Mr. Darwin's