181 
OP GOLD (AND OTHEE METALS) TO LIGHT. 
the magnetic field, parallel to the magnetic axis, and then placed portions of the ruby 
and violet fluids, also of their deposits wet and dry, also portions of the gold films, of 
gold-leaf, the results of deflagrations, &c., in the course of the ray ; but on exciting the 
magnet could not obtain any effect beyond that due to the water or glass, which in any 
case accompanied the substance into the magnetic field. In some cases very dense prepa- 
rations of the ruby and blue deposits were employed, the intense electric lamplight being 
required to penetrate them. 
I passed the coloured rays of the solar beam through the various gold fluids and films 
that have been described. For this purpose a beam of sunlight entering a dark room 
through an aperture -g^th of an inch in width, was sent through two of Bontemps’s flint- 
glass prisms, and its rays either separated, or at once thrown on to a pure white screen ; 
the different objects were then interposed in the course of the ray, but I could not per- 
ceive when any portion of a ray passed (and that was generally the case) that it differed 
sensibly in colour or quality from the ray passing into the preparation. In like manner, 
the objects were put into the differently coloured rays and observed by the reflected light, 
a lens being sometimes employed to concentrate the light; but I could not find any 
marked difference between the colour or character of the ray reflected and the impinging 
ray, except in quantity. 
