Januabt 28, 1887.] 



scmj^GJr, 



91 



$1,056,406,208, which seems to show that the rev- 

 enue which went to reduce the national debt has 

 been diverted to local improvements, and has be- 

 come a wealth-producing power. 



Comparing, now, the average increase by decades 

 since 1850, we find population at about 30 per cent 

 per decade ; hay, except for 1883 and 1884, 36 per 

 cent ; cotton, 40 per cent ; grain, 42 per cent ; rail- 

 way mileage, 115 per cent ; improved land, 37 per 

 cent ; agricultural implements, 40 pev cent ; Irish 

 potatoes, 38 per cent ; butter, 26 per cent ; live- 

 stock, 47 per cent ; assessed valuation, 40 per 

 cent; while rice, sweet-potatoes, and cheese have 

 decreased 50 per cent, 14 per cent, 74 per cent, 

 tobacco is as in 1860, and our debts have simply 

 changed form. This statement of average increases 

 per decade shows how closely together the various 

 values have kept for thirty-five years. The great ad- 

 vance since 1865 has now about brought us up to the 

 place we should expect had the war not interrupted 

 our development. Production has advanced only a 

 little faster than population, and this is probably due 

 to improved implements, improved methods, greater 

 demand, and more facilities for handling the crops, 

 i.e., railways. 0. H. Leete. 



New York, Jan. 32. 



Professor Newberry on earthquakes. 



In his notice of my article on earthquakes, in 

 Science of Jan. 7, Mr. Everett Hayden intimates that 

 I am not warranted in my statements in reference to 

 the cause of earthquakes and the condition of the in- 

 terior of the earth, citing the diversity of opinion 

 which is on record, and the authority of great names 

 opposed to me, as a reason why I should exhibit 

 greater modesty. 



I am sorry that I cannot see the matter from Mr. 

 Hayden's stand-point. If he has any facts or argu- 

 ments to offer which militate against the statements 

 I have made, I shall be most happy to consider 

 them, and I shall be convinced by them if they are 

 convincing ; but, without facts or new arguments, 

 we may well be spared the appeal to authority. A 

 blind deference to the utterances of great men has 

 done geology much harm. Sir William Thomson 

 has no more sincere admirer than myself, both for 

 his genius and his nobility of character ; and yet I 

 do not hesitate to say, that by his unwarranted state- 

 ments in regard to the condition of the interior of the 

 earth, a matter in which his mathematical genius and 

 learning give him no fitness to speak authoritativelj'^, 

 he has seriously retarded the progress of geological 

 knowledge. From the phenomena of the tides and 

 the precession of the equinoxes, he has inferred and 

 asserted that the figure of the earth is as inflexible 

 as though it were composed of glass or steel. There 

 is, however, a doubt in the minds of many physicists 

 whether the tides and the precession of the equinoxes 

 afford such delicate and quantitative tests of the 

 constancy of the earth's figure as to warrant these 

 conclusions. Hennesy and Delaunay have shown 

 that the argument from the precession of the equi- 

 noxes, at least, is weak ; but, even if the fact of the 

 constancy of the earth's figure be conceded, the in- 

 ference that it is becaxxse of a rigidity of the earth's 

 material equal to that of glass or steel, is certainly 

 unwarranted. The argument proves too much : we 

 all know that the materials composing the earth's 



mass are not as rigid as steel. The facts connected 

 with earthquakes, volcanoes, mountain-chains, and 

 the oscillations of the level of coasts, which I briefly 

 cited in my article, show conclusively that the earth 

 is not an unyielding solid ; and I have suggested 

 that the want of homogeneity in the materials com- 

 posing it, — partly solid, partly viscous, partly fluid, 

 — under varying conditions of pressure, may neu- 

 tralize the tendency to distortion from the changing 

 attractions of the sun and moon. The facts cited by 

 geologists as disproving the absolute rigidity of the 

 earth are unquestionable, and their arguments are 

 cumulative and unanswerable. Hence astronomers 

 must find some other explanation of the constancy 

 of the figure of the earth — if that be proved — than 

 a solid interior. 



I am only exercising my inalienable right, am de- 

 fending my hearth and home, when I protest against 

 the invasion of our field of research by masters 

 in other departments of science, however gifted, 

 who, with imperfect knowledge, hurry to conclusions 

 incompatible with those which geologists have 

 reached by lifelong study. That Sir William Thom- 

 son did not give to the geological facts due considera- 

 tion when he uttered his dictum, is shown in his 

 original paper read before the Geological society of 

 Glasgow in 1879. Here in advocating the theory 

 that the earth is solid, and that the solidification 

 began at the centre, the result of the cooling and 

 sinking of an external crust, he states that most sub- 

 stances are denser when cooled to solidification than 

 when fused. In a footnote to p. 40 of the volume of 

 the Transactions of the geological society of Glas- 

 gow which contains Sir William Thomson's address, 

 is given a report of later experiments made to test 

 this question by Mr. Joseph Whitley of Leeds, Eng- 

 land, who found that iron, copper, brass, whinstone, 

 and granite, the only materials he tested, were all 

 less dense when solid than liquid. 



This is not the only instance where men of de- 

 served eminence in their own departments of science, 

 withotit taking pains to inform themselves in regard 

 to the facts of geology, have sought to teach geolo- 

 gists lessons which they have not themselves fullj^ 

 learned. 



Sir Robert Ball, astronomer royal of Ireland, an 

 able and distinguished man, whose merits have been 

 suitably recognized in the ofl&ce he holds, and the 

 title conferred upon him, in his eloqiient address 

 entitled ' Glimpses through the corridors of time,' 

 has proposed a theory, which, if accepted, would 

 not only revolutionize all geological history, but 

 would discredit the teachings of the most eminent 

 geologists. In the circumstances, I have felt called 

 upon to protest against this invasion of our domain, 

 and have shown that the geological record affords 

 conclusive evidence against this theory. 



So Mendelieif , one of the most eminent of chemists, 

 has proclaimed the inorganic origin of the Pennsyl- 

 vania petroleum from an inferred absence of organic 

 matter from which it could be generated. Here, 

 also, I have ventured to show that a better knowl- 

 edge of the geological structure of western Pennsyl- 

 vania would have revealed to him the true source of 

 the petroleum in enormous underlying organic de- 

 posits, and would have prevented the promulgation 

 of a geological heresy. 



Those only are capable of intelligently discussing 

 and deciding these difficult problems in geology, who, 

 with special tastes and abilities, have devoted lives 



