120 FRAGMENTS OF SCIENCE. 



the natural one, as regards the exhibition of a number 

 of wholly unexpected phenomena. By a continuous 

 process of growth, moreover, we are able to connect 

 sky-matter, if I may use the term, with molecular mat- 

 ter on the one side, and with molar matter, or matter 

 in sensible masses, on the other. In illustration of 

 this, I will take an experiment suggested by some of 

 my own researches, and described by M. Morren of 

 Marseilles at the Exeter meeting of the British Asso- 

 ciation. Sulphur and oxygen combine to form sul- 

 phurous acid gas, two atoms of oxygen and one of sul- 

 phur constituting the molecule of sulphurous acid. It 

 has been recently shown that waves of ether issuing 

 from a strong source, such as the sun or the electric 

 light, are competent to shake asunder the atoms of 

 gaseous molecules.* A chemist would call this, * de- 

 composition ' by light; but it behoves us, who are ex- 

 amining the power and function of the imagination, to 

 keep constantly before us the physical images which 

 underlie our terms. Therefore I say, sharply and 

 definitely, that the components of the molecules of 

 sulphurous acid are shaken asunder by the ether-waves. 

 Enclosing sulphurous acid in a suitable vessel, placing 

 it in a dark room, and sending through it a powerful 

 beam of light, we at first see nothing: the vessel con- 

 taining the gas seems as empty as a vacuum. Soon, 

 however, along the track of the beam a beautiful sky- 

 blue colour is observed, which is due to light scattered 

 by the liberated particles of sulphur. For a time the 

 blue grows more intense; it then becomes whitish; 

 and ends in a more or less perfect white. When the 

 action is continued long enough, the tube is filled with 

 a dense cloud of sulphur particles, which by the appli- 



* See ' New Chemical Reactions produced by Light,' vol. i. 



