5o8 



THE POPULAR SCIEXCE MONTHLY. 



hind 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 sus- 

 pended. The peculiai'ity 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 -5^- to ^^^ of an inch 

 in diameter ; another peculiarity was its 

 lumbering mode of rolling, in which it re- 

 sembled dust. The author found that the 

 particles were perfectly spherical, and not 

 hollow, but concrete throughout. 



Foad-Ratlons of the French People. A 



Tery curious calculation has been made by M. 

 Herve Mangon to determine the average ra- 

 tion per kilogramme of live weight consumed 

 by the rural population of France. He esti- 

 mates the " live weight " of the French peo- 

 ple 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 re- 

 quired. 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 terras 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-con- 

 sumption, 2,112,978,201 kilogrammes (4,- 

 648,552,042 lb.), and from the point of view 

 of carbon-consumption 2,095,886,031 kilo- 

 grammes (4,610,949,268 lb.). The food an- 

 nually 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 (21- 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 kilo- 

 gramme" contums 5.675 grammes of carbon, 

 and 0.332 gramme of nitrogen. Supposing, 



now, that the daily consumption per kilo- 

 gramme is the same in Paris, Lyons, Mar- 

 seilles, and the six other cities whose popu- 

 lation exceeds 100,000 souls, the mean daily 

 ration per kilogramme of weight for the 

 country districts is found to contain, of car- 

 bon 5.808 grammes, and of nitrogen 0.275 

 gramme. This ration M. Mangon considers 

 to be sufficient to fit the body for a moder- 

 ate 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 coun- 

 try people he regards as the natural result 

 of insufficient food. 



Relations of Meteorology to Life. At 



a recent meeting of the British Meteoro- 

 logical Society a communication from the 

 Council was read, entitled "Suggestions of 

 the Observation of Periodic Natural Phe- 

 nomena," the object being to call attention 

 to those phenomena manifested by organized 

 beings of the vegetable and animal king- 

 doms dependent on the progression of the 

 seasons, such as the budding, leafing, flower- 

 ing, 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 pas- 

 sage ; the periods of hibernation of reptiles 

 and small animals, as frogs, dormice, etc. 

 All these phenomena being closely con- 

 nected 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 in- 

 dication of instruments. Plants are very 

 susceptible of atmospheric influences, and 

 a close correlation exists between the de- 

 velopment 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 influ- 

 ence of marriage of first cousins on the men- 

 tal constitution of the offspring is almost uni- 

 versally 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 



