8S8 Dr Brewster on the Phosphorescence tf Minerals. 
1. That the property of developing phosphoric light, when 
exposed to heat, is very common among mineral bodies. 
That when it does exist, it is most commonly found in 
coloured, or imperfectly transparent minerals. 
3. That the colour of the phosphoric light has no fixed rela- 
tion to the colour of the mineral. 
4. That this property may be entirely destroyed by the ap- 
plication of an intense heat. 
5. That in general light is not reabsorbed by phosphorescent 
minerals when exposed to its action. 
6. That the phosphoric light developed by heat is unconnect- 
ed with the light given out by attrition, as bodies deprived of 
the former still retain the power of giving out the latter. 
7. That this phosphoric light has the same properties as the 
direct light of the sun or any other luminous body. 
8. That as there are specimens of most of the substances 
contained in the preceding table, that are not phosphorescent by 
heat, it cannot be regarded as an essential character of those 
minerals that possess it. 
Esk-hill, August 81. 1819. 
Art. XXX. — Account of the new Binary Galvanic Pile^ in- 
vented hy M. Zamboni^. 
galvanic pile recently invented by M. Zamboni, and 
which he has called a Binary Pile^ is composed only of two ele- 
ments, namely, a metal and a fluid. The metallic elements of 
the pile are twenty-nine small squares of tin-foil, about half an 
inch long on each side, arid terminated by a very fine tail, from 
two to three inches in length ; and the fluid element is distill- 
ed water, placed in thirty watch glasses, arranged circularly on 
a table. The water in every two adjoining glasses is connect-^ 
ed with one of the elements of tin, by placing the square por- 
tion of the tin in one glass, and the tail in the adjoining one in 
such a manner that the square portion is wholly immersed, while 
the tail merely touches the fluid. When the metallic elements 
Published in Gilbert’s Annalen der Physilc, tom. lx. p. 141, 
