798 ME. G. GOEE ON THE PEOPEETEES OP ELECTEO-DEPOSITED ANTDIONY. 
62. And as a final settlement of this question, I took a bar weighing 277-16 grains, 
and the same weight of very finely powdered active antimony formed at the same period, 
and made two more experiments, the weight of water in each instance being 401-11 
grains, and the specific heat-value of the thermometer and tube being =14-6 grains of 
water. With the har, the water rose in temperatm-e from 59°- 3 to 78°-4Fahe., and 
with the jpotvder it rose from 58°-9 to 78°-0Fahe., equal in each case to a rise of 19-1 
Fahr. degrees. The loss of weight in the bar was 9-42 grains, or 3-39 per cent., and the 
amount of condensed vapour found in the tube was 9 26 grains. 
63. After making a small deduction for loss of heat by particles which may have 
undergone the change during the process of grinding, it is evident that the amount of 
heat set free by the powdered substance is not sensibly difierent from that evolved by 
the substance in the coherent massive state, and therefore the force exercised in the 
peculiar change of antimony is not that of cohesion. 
64. The only method by which I have yet been able approximately to determine the 
amount of changed antimony contained in the powder, or the extent to which the 
powder has lost its peculiar thermic power, has been to measure the amount of heat 
evolved by the discharge of a given weight of it in a calorimeter. 
b. Heat of discharge not due to alteration of specific heat. 
65. It may readily be supposed that a portion of the evolved heat may be due to 
diminution of specific heat attendant upon the increase of specific gravity which occui-s 
during the sudden change (46.) ; I therefore made several determinations of the specific 
heat of unchanged and changed specimens in an apparatus similar to that used by 
Fegnault for specific heats. The specimen to be examined was placed in a small 
copper wire basket, suspended by a horsehair, and raised by means of small pulleys 
into a vertical cylindrical air-chamber, surrounded by a vessel of hot water, and retained 
there in contact with the bulb of a thermometer mitil it had acquired a perfectly unifoi-m 
and stationary temperature (generally about 160° or 180°Fahe.) by careful regulation 
of the heat. Meanwhile a known quantity of distilled water (usually an equal weight 
to the antimony) in a thin glass vessel covered externally with cotton-wool, and con- 
taining a thermometer, was brought to a uniform and stationary’- temper atuie (generally 
about 60°Fahe.) by surrounding it by non-conducting screens. At that moment the 
vessel of wnter was placed close beneath the air-chamber, and the basket lowered in an 
instant into the water by means of the horsehair arrd pulley’s. The vessel of water was 
immediately removed and closed, and the basket agitated continually by means of a 
hooked glass rod passing through a hole in the cover until the ther-morneter indicated a 
maximum temperature, which occurred in about two minutes. Corrections in the 
calculation were made in each instance for the amouirt of heat evolved by the basket, 
and for that absorbed by the immersed portion of the thermometer. 
66. Seven determinations were made of the specific heat of twm imchanged bars, 
each weighing upwards of 250 grains, and the following numbers were obtained, in the 
