CORRELATION OF FORCES CORRfcZE 381 changed, and the heat-producing elements be- come as five or six to one. This proportion is not far from that arrived at by the measure- ment of the force produced from these two sources. Dr. Samuel Houghton, the eminent physiologist of Dublin, calculated, from a course of experiments on himself, that the heat gene- rated in the system, if converted into work, would be sufficient in 24 hours to raise his body to a height of six miles ; and he estimates that the daily external muscular work of a man is about one sixth of this, or sufficient to raise him with his clothes and travelling knapsack to the height of about one mile. The ^results of more numerous experiments upon different men give a larger result; and while Houghton gives 353-Y5 foot tons as the equivalent of daily labor, Prof. Huxley states the average to be 450 foot tons. Dr. Houghton makes the inter- nal vital work of the system to be very nearly the same as the external muscular work. Con- sidering the body in the light of a vital en- gine for the development of power by transfor- mation of matter, the problem must be solved on the basis of the physiological constants which are given by Prof. Huxley in his " Elementary Physiology " as follows. The average weight of the human body being taken at 154 Ibs., "it would lose in 24 hours of water, about 40,000 grains, or 6 Ibs.; of other matters about 14,500 grains, or over 2 Ibs. ; among which of carbon 4,000 grains; of nitrogen 300 grains; of min- eral matters 400 grains ; and would part, per diem, with as much heat as would raise 8,700 Ibs. of water from to 1 F., which is equiva- lent to 3,000 foot tons. The losses would occur through various organs ; thus by the Water, grs. Other mat- ter, grg. Nitrogen, grs. Carbon, grs. Lungs 5,000 12,000 8,300 Kidneys 23000 1000 250 140 Skin 10000 700 10 100 Fasces 2,000 800 40 460 Total 40,000 14,500 800 4,000 The gains and losses of the body would be as follows : Or. Grg. Solid dry food 8,000 Oxygen 10,000 Water.... Total 54,500 Dr. Grg. Water 40,000 Other matters 14,500 Total..., .. 54,500 Such a body would require for daily food, car- bon 4,000 grains, nitrogen 300 grains, which, with the other necessary elements, would be most conveniently disposed in Grs. Proteids 2.000 Amyloids 4,400 Fats 1,200 Minerals 400 Water 86,500 Total 44,500 which, in turn, might be obtained, for instance, by means of ' Gn. Lean beefsteaks 5,000 Bread 6,000 Milk 7,000 Potatoes 8,000 Butter, dripping, &c 600 Water 22,900 Total 44,500." Physiologists include nervous force in the cor- related series, although a quantitative estima- tion of intellectual and emotional effects has hardly been attempted. It is perfectly well known that the intense and prolonged action of the brain draws powerfully upon the bodily energies ; and it may be inferred from the large amount of blood sent to the brain, to sustain the physical processes, that a very considera- ble portion of the force of nutriment is spent in this way, although physiologists are cautious about tabulating this item of expenditure. From what has been said, we cannot suppose that Faraday or Helmholtz over-estimated the import of the law of conservation, for it cer- tainly opens a new epoch in the progress of science, and gives a new aspect and a new in- terest to almost the whole range of its ques- tions. If the amount of power in nature and in all parts of nature, including the domain of life, be thus inexorably limited, this fact be- comes a fundamental condition, under which all research is to be pursued. When force ap- parently disappears, wherever it is exercised, science demands that it shall be traced and its equivalent effects stated. This enforces the view of dynamic causation and the derivation of one state of things from another. (See EVO- LUTION.) If the principle be universal, it must apply to the activities of human society, which are but phenomenal effects of vital and men- tal forces ; and the law thus becomes a funda- mental doctrine of the science of society. It has been stated above that the modern ex- perimental investigation of this subject was initiated by an American; other American scientists have also contributed to the inves- tigation. Prof. Joseph Henry has published valuable original papers in the "Smithsonian Contributions;" and Prof. Joseph Le Conte, of the university of California, printed an able and ingenious essay on the correlation of the physical and vital forces in the "American Journal of Science " for 1859. Prof. Benjamin N. Martin, of the university of the city of New York, has also recently published two acute and valuable papers on the limits and meta- physical bearings of the doctrine. CORR^ZE, a southern department of France, bordering on the departments of Haute- Vienne, Creuse, Puy-de-D6me, Cantal, Lot, and Dor- dogne; area, 2,265 sq. m. ; pop. in 1872, 302,- 746. It was formed from the ancient province of Limousin, and takes its name from the river Correze, a branch of the Vezere, which has its whole course in this department. The surface is hilly, and in the north (Montagne) there are mountains 4,000 ft. high and covered with snow most of the year. This district is stony
