ALEXANDER DALLAS BACHE. 



441 



modification of Osier's anemometer and invented a thermo- 

 scope of contact, both of which avoided difficulties involved in 

 the use of previous instruments. 



The way in which a man conducts a controversy is always 

 a severe test of his character. Bache had one with Denison 

 Olmsted on the periodical recurrence of meteors. Prof. Gould, 

 in his American Association memoir, thus describes the occur- 

 rence : "^Mr. Bache maintained that there was no recurrence in 

 1834; Prof. Olmsted, on the other hand, maintained the re- 

 verse. Prof. Bache instituted special inquiries at the military 

 posts (where, of course, sentinels were on duty) along all the 

 frontiers of the United States, also among the night police of 

 various cities, and at the universities, and he found but one 

 exception to the statement that no unusual number of meteors 

 was seen. Of this controversy Bache wrote, in 1846 : 



" ' There is something yet to be found out on this subject 

 which may reconcile our opinions. Neither I nor any of those 

 watching with me, or for me, have seen an unusual number of 

 meteors on the night of the i2th of November in any year 

 since the great night at Philadelphia, and we have taken great 

 pains to be sure. Yet I can not doubt the testimony as given 

 for some other places. ... I had a complimentary letter from 

 the professor in regard to my manner of conducting the con- 

 troversy, which I valued more highly than if I had gained the 

 victory.' " 



The year after Prof. Bache resumed his old position at the 

 university he was called to the superintendency of the United 

 States Coast Survey, left vacant by the death of Mr. Hassler. 

 His appointment to this position was first suggested by mem- 

 bers of the American Philosophical Society, and the nomina- 

 tion was fully concurred in by the other principal scientific and 

 literary institutions of the country. For the successful prose- 

 cution of the work of the survey Dallas Bache was abundantly 

 well qualified by his training at West Point and subsequent 

 experience as an army engineer, by his attainments in pure 

 and applied science, by his knowledge of the world, by his 

 skill in research, his rare executive ability and consummate 

 tact. 



Although the Coast Survey had been founded a quarter of 

 a century, -the policy of Congress toward it had been change- 

 able and its appropriations limited. It had been suspended 

 29 



