Chemistry and Physics. 273 
ored engravings upon metallic plates, as had already been accomplished 
more brilliant of the dark colors. The most difficult color to obtain 
’ the others, is the green of foliage, the green rays being almost as 
inert as the black ones; clear green colors, particularly if brilliant, as 
glazed green paper, were, however, reproduced in a satisfactory 
manner. In all cases, the colors produced were transitory, and no 
. Method of permanently fixing them has yet been devised, but 
antimony to fluorine and has found that but a single compound of these 
elements, namely, the terfluorid, exists. When an aqueous solution of 
fluohydrie acid is poured upon oxyd of antimony, a solution immedi- 
ately takes place accompanied by the evolution of great heat. By 
transpa- 
ammonium, the fluorid of-antimony forms salts represented by the 
formulas Sb F's .3NaF, SbF .2LF, SbFe.2NHsF. From these re- 
Pohl the general formula SbFs.(1.2.3) RF. Flickiger adopts 
ue views of Bonsdorff, Boullay, Thomson and Hare, in regard to the 
Sonstitution of the so-called fluorids, and considers them as perfectly 
gous to oxygen salts of corresponding constitution. [This 
View, lon arnestly maintai in this country by Dr. Hare, is 
Ene gaining ground at the present day, though but a few years 
