176 



SCIENCE 



[Vol. V., No. 108. 



and the strata are estimated to end at 4,000 feet in 

 depth. Even if they do extend deeper, mining would 

 he impracticable because of the expense; and, be- 

 sides, the temperature would be 116 c F. The deep- 

 est coal-pit in England is 2,448 feet, but one in Bel- 

 gium extends 3,490 feet. 



In 1831, 154,000,000 tons were extracted, — enough 

 to build fifty-five great pyramids, or rebuild the great 

 wall of China and add one-quarter to its length. 

 The total amount of coal mined since 1854, would 

 build a column 9 feet 4 inches in diameter, a distance 

 of 240,000 miles, i.e., to the moon. The output 

 shows considerable fluctuation from year to year, — 

 as might be expected from the variety of accidental 

 circumstances, such as new inventions, the mean 

 annual temperature, and the state of trade, — but, on 

 the whole, a very rapid increase ; the output for 1875 

 being double of that for 1854, and that for- 1883 

 double of that for 1862; and, if the amount ex- 

 tracted increases at this rate (3,000,000 tons annu- 

 ally), the supply will be exhausted in the year 2145 

 A.D. The exhaustion will be theoretical only; for 

 in a comparatively short time the price of coal will 

 increase, and the demand necessarily lessen, so that 

 coal will never be exhausted. One of four things 

 must then happen, — either some new source of en- 

 ergy must be supplied, or a larger per cent of the 

 coal must be utilized, or coal must be imported, or 

 England must give up her manufactories. It is 

 doubtful if any new source of energy on a large scale 

 will be discovered, unless some explosive be used for 

 the purpose. According to Sir William Thomson, 

 energy in the form of electricity can be transferred 

 three hundred miles through a copper rod, with a 

 loss of only twenty per cent: so in this way water- 

 falls may be utilized in the future. 



While it is hardly possible to use less coal, we may 

 get more energy out of it; for at present, out of a 

 theoretical 10,000,000 foot-pounds of work which one 

 pound of coal can supply, we only get 1,000,000 foot- 

 pounds. But instead of a decrease in the waste, 

 there is likely, on the contrary, to be an increase; 

 for each year faster speed is demanded by rail, and 

 steamships are rapidly replacing sailing-vessels. It 

 might be possible to prevent the annual exporta- 

 tion of 22,880,000 tons by export duties; but that 

 does not seem expedient. The idea of importation 

 is hardly practicable, for the nearest coal-mines of 

 any extent are in Canada and the United States. 

 The former are not easy of access, but are almost 

 unlimited; and those in the United States contain at 

 least thirty-eight times as much coal as those in 

 England. To supply England with the necessary 

 coal, 2,100 ships as large as the Faraday, each carry- 

 ing 6,000 tons and making thirteen trips a year, would 

 be required. The cost would be necessarily greatly 

 increased. In former times, England produced its 

 own breadstuffs: now the greater part is imported. 

 If coal becomes scarce, there will be no way of pay- 

 ing for food, emigration will begin, the death-rate 

 will increase, the birth-rate decrease, and England 

 will change once more to an open, cultivated country, 

 devoid of all other industries. 



PREHISTORIC AMERICA. 



This translation of Nadaillac's ' Prehistoric 

 America,' we are told, is made with the au- 

 thor's sanction ; and it is also by his permis- 

 sion that certain portions of the work have 

 been so ' modified and revised ' as to bring 

 them " into harmony with the results of recent 

 investigation, and the conclusions of the best 

 authorities on the archaeology of the United 

 States." Speaking in a general wa} T , these 

 changes and additions may be said to be con- 

 fined almost entirely to the chapters that re- 

 late to North America, and to consist, not in 

 the discovery of new truths, although some 

 additional facts are offered, but in the adop- 

 tion of certain theories, as positive conclusions, 

 which, in the original publication, are given as 

 explanations, more or less probable, of the 

 points at issue. Thus, for instance, in that 

 portion of the work wbich refers to the origin 

 and antiquit}' of man in America, we are given 

 to understand that he is probably of Asiatic 

 descent, all other theories being practically 

 ignored. To this explanation, considered sim- 

 ply as such, we do not object. Appearances 

 certainly favor it ; and as it is the most satis- 

 factory way of accounting for his presence here, 

 and for certain peculiar features in his civiliza- 

 tion, we do not see any reason why it should 

 not be accepted, at least until something bet- 

 ter is offered. That his ancestors arrived here 

 at a period so remote that it can only be meas- 

 ured by geological epochs and phases of civili- 

 zation, is conclusively proved ; and though it 

 is not equally susceptible of demonstration, 

 3'et we think it highly probable that these im- 

 migrants may have started from different cen- 

 tres, and gradually pushing their way westward 

 across Bering Strait, and by way of the Poly- 

 nesian Islands, ma} r have landed at different 

 times, and at different places, on the shores of 

 both North and South America. That the} 7 

 belonged to different races, and were in differ- 

 ent stages of development, is possible ; and 

 whilst we are willing to admit that " the cul- 

 ture which can be traced from the shell-heap to 

 the mound, from the mound to the pueblo, and 

 from the pueblo to the structures of Mexico, 

 Central America, and Peru, is distinctively 

 American," we ma}' be pardoned for suggest- 

 ing that it is possible, in view of what is. said 

 of the facilities of intercourse, not only between 

 our tribes but between the continents, that this 

 culture ma} 7 have been colored by Asiatic influ- 

 ences of a comparatively recent date. 



Prehistoric America. By the Marquis de Nadaillac. 

 Translated by N. D'Anvers. Edited by W. H. Dall. New 

 York, G. P. Putnam's sons, 1884. 566 p., illustr. 8°. 





