386 HEINIUCH WILHELM DOVE. 



was given by lectures on physics and meteorology. For the experi- 

 mental illustration of these lectures he spared no time or labor. He 

 was a familiar sight in the streets of Berlin, as he carried such 

 apparatus as belonged to him from his house, or from one audience to 

 another, in his hand or in a market-basket. But familiarity only 

 deepened the universal respect which his presence always inspired. 

 For a hundred semesters there sat at his feet a succession of inter- 

 ested students, many of whom afterwards, by their own fame, magni- 

 fied his renown. In the city which had hung with delight upon the lips 

 of Humboldt in 1827-28. the seats and aisles of the largest auditorium 

 were crowded by all ranks of society, to listen to Dove's lectures on 

 meteorology. Germany could not boast of a more clear and eloquent 

 expounder of science, or of a teacher gifted with greater power of 

 infusing his own scientific spirit into those who heard him. Dove was 

 indeed the Faraday and Arago of the scientific and fashionable circles 

 of Berlin. 



This learned, laborious, and successful teacher was none the less an 

 original investigator. Two hundred and thirty-six contributions to 

 science between the years 1827 and 1876, published principally in 

 the Abhandlungen or the Monatsbericlde of the Berlin Academy, or in 

 the Zeitsehrift of the Prussian Statistical Bureau, bear witness to the 

 fertility and originality of his mind. He has left his impress on all 

 the physical sciences, — on electricity and magnetism, on the metric 

 system, acoustics, optics, and optical crystallography. Coronas, sub- 

 jective colors, binocular vision, and binaural hearing interested him 

 greatly ; and whatever he touched he enriched, not only by his original 

 ideas, but by new instruments of his own happy invention. A differ- 

 ential inductor, a polyphonic siren, a variety of new stereoscopes, a 

 pseudoscope, a photometer, a stephanoscope, his rotating disks for 

 optical deceptions, his complete polarizing apparatus, his rotating po- 

 larizer, his new polarizer of Iceland spar, his new analyzer of arra- 

 gonite, his prisms to produce circular polarization in place of Fresnel's 

 rhombs, his adaptation of the kaleidoscope to the chromatic effects of 

 polarized light, all these ingenious instruments and appliances have 

 made the name of Dove a household word in every well-equipped 

 physical cabinet on both continents. His application of the stereo- 

 scope to distinguish a bank-note from its counterfeit, and thereby to 

 detect forgery, is used in many of the banks and offices of Germany. 



But it is a greater work to create a new science, especially if it 

 intimately concerns the comfort and safety of mankind, than to extend 

 and illustrate old ones. What, then, are Dove's claims to be called, 



