NOTICE BY PROF. J. LOVERING. 437 



sympathy of the unscientific community. There are times when 

 sextants, chronometers, tables of the moon, and even light-houses, 

 are of no avail, and an impenetrable veil of darkness shuts out the 

 mariner from the lights of heaven and earth. But what is opaque 

 to light may be pierced by sound. The experiments which have 

 been made by Henry in this country and by Tyndall in England, in 

 their official capacity, on the fog-penetrating power of the fog-horn, 

 the fog-bell, the siren, the steam-whistle, and cannonading, have 

 raised interesting questions in science, to which different answers 

 have been given ; but the facts remain, above controversy, to instruct 

 governments in the best way of supplementing optical signals by 

 acoustic signals. These last investigations of Professor Henry, to 

 which it is feared he was a willing martyr, will always have a 

 pathetic interest for those who knew and loved him. 



It has been the aim of this notice to place in strong relief a few 

 of the salient points in the intellectual life of Henry. Any state- 

 ment in detail of the accumulations of his long life, in the way of 

 experiment or deduction, must be very voluminous or very meagre. 

 For he was not a concentrated specialist. His expanded thought 

 swept the whole vast horizon 'of the physical sciences ; not to specu- 

 late, but to discover. The severe discipline of science did not 

 harden him against the fascinations of literature, poetry, and art. 



It would be a delicate task, and premature, to attempt to assign 

 to Henry his exact rank among those who have legislated for science 

 in this and former centuries. There are laws of perspective in 

 time as well as in space, whereby a small eminence seems to out- 

 climb the distant Alps, and the present generation dwarfs apparently 

 all its predecessors. Foreign countries and posterity will pronounce 

 their irreversible verdict in this as in other cases. In his own 

 country, and among his contemporaries, Mr. Henry was long and 

 easily the acknowledged chief of experimental philosophers. If the 

 earlier science of the country is passed in review, only a few names 

 shine so brightly across the intervening years as to deserve any 

 comparison with him who has recently departed. Winthrop and 

 Rittenhouse in astronomy, Franklin in electricity, Rumford in 

 thermotics, and Bowditch in mathematics, exhaust the catalogue of 

 possible rivals. Of these, all but Winthrop were self-instructed, 



