469 
Group III. Gases whose cooling power is greater :— 
olefiant gas, ammonia, vapours of alcohol and ether. 
Group IV. Hydrogen. 
Dr. Apjohn next drew the attention of the Academy to 
a metallic ore recently found at the Kilbricken Lead 
Mine, County of Clare, which he had received through a 
friend from Mr. M. Taylor, the gentleman who conducts the 
mining operations in that district. It occurs in amorphous 
masses of a bJuish grey colour; has a metallic lustre, and 
something between a compact earthy and close foliated struc- 
ture. Specific gravity =6°407 ; hardness intermediate be- 
tween that of galena and sulphuret of antimony. Subjected 
to the action of the blowpipe sulphur is burned off; white 
oxide of antimony is deposited upon the charcoal; and a 
metallic globule is produced, brittle at first, but which be- 
comes malleable lead after having been submitted for some 
time to the action of the oxidating flame. In muriatic acid 
the ore dissolves, though slowly, with the evolution of sul- 
phuretted hydrogen; and the solution, when poured into a 
large quantity of boiling water, gives a white precipitate 
(oxichloride of antimony.) When this precipitate has sub- 
sided, the solution is found to contain nothing but chloride 
of lead, with traces of antimony and iron. From these ex- 
periments the mineral was concluded to be a combination of 
sulphur, lead, and antimony ; and to determine the proportions 
in which they were associated, the following analytic process 
was adopted. 
44°52 grains of the ore, previously reduced to a fine 
powder, were introduced into a ball, blown upon a tube of 
Bohemian glass; and through this a current of dry chlorine 
was made to pass, the arrangement of the apparatus being 
such, that by a rectangular bend in the portion of the tube 
beyond the ball, the chlorine was made to bubble through a 
