280 Address of Sir William Thompson. 
hardness or indivisibility of atoms by virtually assuming them to 
be infinitely small and infinitely numerous. We must now no 
longer look upon the atom, with Boscovich, as a mystic point 
endowed with inertia and the attribute of attracting or repelling 
with those who have attributed to the atom occupation of space 
with infinite hardness and strength (incredible in any finite 
body); but we must realize it as a piece of matter of meas- 
urable dimensions, with shape, motion, and laws of action, in- 
telligible subjects of scientific investigation. 
Spectrum Analysis. 
The prismatic analysis of light discovered by Newton was 
estimated by himself as being “the oddest, if not the most con- 
siderable, detection which had hitherto been made in the opera- 
7 
who first showed how through it the old “ blowpipe test,” 
fro olors W 
they give to flames, can be prosecuted with an accuracy and @ 
minati the color 
the summer of 1852. The observational and experimental 
as obs a by Fraunhofer of a det 
Couble dark line D of the solar spectrum and a double brig 
line which he o sae tie gee lige artificial 
a 
