324 ME. G. GOEE ON THE PEOPEETIES OF ELECTEO-DEPO SITED ANTBIONY. 
single contact of the red-hot wire. Pieces i^th of an inch thick in a platinum dish 
upon a solution of chloride of calcium at 295° Fahr., did not discharge their heat by 
repeated scratching with a sharp steel pointer, but instantly discharged it by contact of 
a heated wire, and shattered themselves to pieces. 
97. On placing a small fragment upon melted fusible alloy, and gradually heating 
the latter, the fragment dischai’ged all its heat suddenly and powerfully, and shattered 
all to pieces, when the alloy obtained a temperature of 318° Fahr. A similar piece upon 
the surface of mercury discharged itself similarly when the mercury attained a tempera- 
ture of 322° Fahr. And another piece, -g^th of an inch thick, weighing 33 grains, immersed 
in a solution of chloride of calcium at 272° Fahr., suddenly discharged its heat and 
shattered to pieces at the end of four minutes, when the solution was at 275° Fahr. A 
fragment -iirth of an inch thick, formed three years and four months previously ("viz. in 
December 1858), was put in a platinum dish upon a solution of chloride of calcium at 
268° Fahr., and touched with red-hot wire ; it instantly discharged its heat with violence, 
scattering fragments of the metal in all directions. The temperature of sudden dis- 
charge appears from these circumstances to lie between 270° and 300° Fahr. ; but 
depends upon several conditions, especially upon the degree of rapidity with which the 
heat is carried away in relation to that with which it is generated. The fi-actured 
surface of pieces suddenly discharged is brighter than that of the unchanged substance. 
98. Thick pieces of the active substance maybe easily reduced to powder in a mortal' 
without causing them to discharge their heat. A small quantity of the powder formed 
into a train upon the surface of glass or metal at 60° Fahr., and touched by a red-hot 
wire, only exhibited the change near where it was touched ; but if the powder was pre- 
viously placed in a platinum dish upon a solution of chloride of calcium at 265° Fahr., 
and then touched at one end by the heated wire, it discharged its heat gradually, 
and the change, attended by evolution of fumes, was slowly propagated to the distant 
extremity. 
99. The active substance was gradually discharged of its heat in the following manner : 
— A piece barely l^th of an inch thick, and weighing 40'05 grains, was suspended during 
thirty minutes in a solution of chloride of calcium at 252° Fahr. ; when taken out, washed 
with water, dried at 240° Fahr., cooled and weighed, it had lost 2-45 grains =6'117 
per cent. It was then reheated in a platinum dish upon a solution of chloride of calcium 
at 250° Fahr., and touched six or eight times with a red-hot wire ; not the slightest sign 
of molecular change occurred, and its weight remained but slightly altered : on breaking, 
it was found to have become less brittle and of stronger cohesion ; its fractured surface 
was quite dull and earthy, and exhibited the appearance of a dark inner core surrounded 
by a layer of a lighter colour, as if an action or change had proceeded from the outer 
surface towards the centre. 
100. 20*3 grains of it, fused in an analysis-tube (82.), gave 17*20 grains in the form of 
a metallic button, =79*52 per cent, of metal, and 20*48 per cent, of volatile matter, in 
the original unchanged substance ; and there distilled into the bent part of the tube a 
