86 MEMORIAL OP JOSEPH HENRY. 



and conclusiveness in the development of an entirely new class of 

 phenomena, may, I think, be regarded as the most remarkable and 

 classical of his electrical researches. 



From this time forward, until his active scientific career was 

 interrupted, and in a measure terminated, by his removal to Wash- 

 ington to assume the great responsibility of the Smithsonian trust, 

 Henry continued his zealous investigations. Passing in succession 

 into new departments of physical inquiry, including questions in 

 atmospheric electricity, in heat and light, and in molecular physics, 

 and embracing theoretical generalizations on the origin of mechani- 

 cal power and the nature of vital force, he never failed to enrich 

 with new facts and new suggestions every subject to which his 

 philosophical genius was directed. Indeed, it may well be said of 

 him in connection with science, as once it was said of a literary 

 genius whom the world admires: "Nihil tetigit quod non omavit." 

 ■ Into the details of these researches and discoveries, so full of 

 interest to science and so replete with practical suggestions, I am 

 forbidden here to enter, and must leave them to other and abler 

 hands, and to a less popular occasion. Neither can I more than 

 passingly allude to those later labors of Henry, by which he initi- 

 ated a system of meteorological research on a uniform method and 

 of national comprehensiveness, nor to the great improvement which 

 he introduced in our light-house illumination and our fog-signals, 

 or in connection with the last, to the admirable series of observa- 

 tions undertaken to elucidate the acoustic phenomena due to varia- 

 tions of atmospheric movement and density, observations in which, 

 as we all know, he was zealously engaged until but a few months 

 before the time when the veteran philosopher was compelled by 

 failing health to retire from the field of his beneficent activity. 



On reviewing the long and fruitful career of Professor Henry 

 we are impressed by his ingenity and accuracy as an experimentalist 

 and by his clearness and breadth as a scientific thinker. Of the 



