624 THE POPULAR SCIENCE MONTHLY. 



the end of tliis period he became for a tune Captain Moorsxim's engi- 

 neering secretary, and during this time he devised the little instru- 

 ment which he called the velocimeter, and described in the Civil 

 Engineer's Journal. It was for the purpose of calculating, by me- 

 chanical means, the speeds of locomotive engines from given frac- 

 tional distances and times, which otherwise required much trouble in 

 estimating the velocity. Then followed a period of some six months 

 occupied in out-door works, partly in superintending the completion 

 of constructions, and partly in testing the performances of engines. 



During this period he was led, by collecting fossils, into the study 

 of geology, and read Sir Charles Lyell's " Principles," then recently 

 published. The noteworthy fact respecting this is, that in it the 

 doctrine of Lamarck respecting the develoi^ment of species is there set 

 forth, combated and rejected. Mr. Spencer cannot say whether he 

 was before familiar with this doctrine, but he remembers that Lyell's 

 arguments failed to disprove it to him, and he became, thereafter, a 

 firm believer in the general idea that all organized beings had arisen 

 by development (1839). He had so profound a belief in natural cau- 

 sation, in general so strong a tendency to see a unity of processes in 

 things, that an hypothesis of this kind, which suggested that the gen- 

 esis of organisms had arisen from physical actions, was one that he 

 was prepared to accept as congruous with the system of things known 

 by experience. Such a notion as that of miracle, utterly inharmonious 

 with the ideas of cause and law and order which had become ingrained 

 in him, was inadmissible, and hence the only alternative view pre- 

 sented itself to his mind as obviously necessary. Nothing ever after- 

 ward shook this belief. There naturally went along with this a gradual 

 dropping of the current theology, although Mr. Spencer cannot say 

 when it began or when it ended. The conception of the natural gene- 

 sis of things gradually replaced the conception of the supernatural 

 genesis, and belief in the prevailing creed gradually faded away. 



In April, 1841, having declined the offer of an engineering appoint- 

 ment, Mr. Spencer returned home, intending to carry further his 

 mathematical studies. Very little came of this intention, however, 

 and some two years were spent at home in a miscellaneous and seem- 

 ingly futile manner. Botany occupied his attention for some months. 

 He made a botanical press and an herbarium. He- practised drawing 

 to some extent, and made pencil-portraits of various friends. Phre- 

 nology, of which he did not at that time see the fallacies, occupied 

 some attention. All the time, however, he had in progress one or 

 other scheme of invention. Improvements in watch-making, machines 

 for making type by compression of the metal instead of casting, a 

 printing-press of a new form, the application of the electrotype for 

 engraving, afterward known as the glyptograph, occupied his atten- 

 tion. The great flood in Derby, in 1842, caused by the sudden over- 

 flow of a tributary of the Derwent, having occurred, Mr. Spencer wrote 



