12 



SCIENCE. 



[N. S. Vol. III. No. 53. 



locality, but to have arrived opportunely at 

 the critical epoch. 



Still another contribution to the subject, 

 while it does not increase the number of 

 hypotheses, is nevertheless important in 

 that it tends to diminish the weight of the 

 magnetic evidence and thus to reopen the 

 question which Mr. Baker and I supposed 

 we had settled. Our fellow-member, Mr. 

 Edwin E. Howell, through whose hands 

 much of the meteoric iron has passed, 



Fig. 5. — Iron meteorite found near the crater. Weighs 

 161J pouuds. Property o£ Mr. Edwin E. Ho\YelI, 

 . o£ Washington, D. C. 



points out that each of the iron masses, 

 great and small, is in itself a complete in- 

 dividual. Thej' have none of the charac- 

 ters that would be found if they had been 

 broken one from another, and yet, as they 

 are all of one type and all reached the earth 

 within a small district, it must be supposed 

 that they were originally connected in some 

 way. Reasoning by analogy from the char- 

 acters of other meteoric bodies, he infers 

 that the irons were all included in a large 

 mass of some different material, either 

 crj'stalline rock, such as constitutes the 

 class of meteorites called ' stony,' or else a 

 compound of iron and sulphur, similar to 

 certain nodules discovered inside the iron 

 masses when sawn in two. Neither of 

 these materials is so enduring as the iron, 

 and the fact that they are not now found 

 on the plain does not prove their original 



absence. Moreover, the plain is strewn 

 in the vicinity of the crater with bits 

 of limonite, a mineral frequently produced 

 by the action of air and water on iron 

 sulphide, and this material is much more 

 abundant than the iron. If it be true that 

 the iron masses were thus imbedded, like 

 plums, in an astral pudding, the hypothetic 

 buried star might have great size and yet 

 only small power to attract the magnetic 

 needle. Mr. Howell also proposes a quali- 

 fication of the test by volumes, suggesting 

 that some of the rocks beneath the buried 

 star might have been condensed by the 

 shock so as to occupy less space. * These 

 considerations are eminently pertinent to 

 the study of the crater and will find ap- 

 propriate place in any comprehensive dis- 

 cussion of its origin ; but the fact which is 

 peculiarlj' worthj"^ of note at the present 

 time is their abilitj' to unsettle a conclusion 

 that was beginning to feel itself secure. 

 This illustrates the tentative nature, not 

 only of the hypotheses of Science, but of 

 what Science calls its results. The method 

 of hypotheses, and that method is the 

 method of Science, founds its explanations 

 of Nature wholly on observed facts, and its 

 results are ever subject to the limitations 

 imposed hy imperfect observation. How- 

 ever grand, however widely accepted, how- 

 ever useful its conclusion, none is so sure 

 that it can not be called in qu^estion by a 

 newly discovered fact. In the domain of 

 the world's knowledge there is no infal- 

 libility. 



And now let us return for a moment from 

 the illustrative investigation to the hypoth- 

 esis of hypotheses. If my idea is correct 

 — ^if it be true that tentative explanations 

 are always founded on accepted explana- 

 tions of similar phenomena — then fertility 

 of invention implies a wide and varied 

 knowledge of the causes of things, and the 



* Mr. Howell's suggestions -were communicated 

 orally and are here published by permission. 



