The Phenomena of Fluorescence. lOdtober, 
miniferous ether, originate rays of higher refrangibihty, the 
analogy to which might be, for example, as a higher odtave 
in musical sounds. But this is considered by another 
authority as amounting to negative fluorescence. 
M. W. Eisenlohr is of opinion that the phenomena are 
caused by the interference of the bluish violet and the ultra 
violet rays, which, it is argued, would give rise to rays of 
lesser refrangibihty, in the same way as “combination 
tones ” are of a lower pitch than the tones taken separately. 
But Prof. Bohn considers that according to this opinion 
fluorescence could never be seen in a speftrum that was 
pure, because “ there rays of only one degree of refrangibihty 
are to be found at the same place.” 
Prof. Lommel combines the theories of Stokes and bisen- 
lohr, but is of opinion that he has discovered a series of 
substances (anthracen-blue among others) which do not obey 
Stokes’s law, — i.e., that a body in the aft of fluorescence 
never emits rays which exceed the refrangibihty of the inci- 
dent or exciting rays. 
The results of Lommel’s researches, it was reported, were 
coroborated by Brunner (of Prague) and Lubasch (of Berlin). 
But Hagenbach, the author of some very accurate studies 
of the phenomena, could not arrive at Lommel s results. 
M. Lamansky, however, after repeating the experimental 
work of his contemporaries, announced last year that, not- 
withstanding the fadts and arguments adduced by Eisenlohr 
and others, he had nevertheless fully confirmed the validity 
of Stokes’s law. This he accomplished by devising a means 
of measuring the difference between the incident or exciting 
rays and those simultaneously emitted by the substance 
under excitation, — i. e. 9 the fluorescent rays. This he inge- 
niously effected in the following way Refledting the solar 
rays by a heliostat, and concentrating them upon a narrow 
slit by the aid of an achromatic lens, he then placed two 
flint glass prisms behind the slit and another achromatic 
lens, the latter being put at twice its focal distance from the 
slit/ By this arrangement he obtained a spedtrum^ of such 
purity that the chief lines were rendered visible. The 
spedtrum was then thrown on the side of a box provided 
with a movable slit capable of adjustment to the several 
parts of the spedtrum, and also provided with a means of 
widening or narrowing as might be required. Through this 
slit certain rays of the spedtrum, which had been previously 
made to pass through a flint glass prism, entered the box, 
within which was a vessel full of fluorescent liquid : then 
by the aid of a refledting prism these perfedtly homogeneous 
