TRANSAOTIONS OF THE SECTIONS. 21 
__ The points g q' therefore are calculable as to position and distance, and they are 
found to recede further and further from the surface as the distance between the 
nearest points of the spheres increases; it is only at an infinite distance that they 
can coincide with the centres of the spheres. 
Taking the force of the attraction to vary in the inverse duplicate ratio of the 
squares of the distances, it is not difficult to determine the force in the points of dis- 
charge from column d of the last table, supposing that column to represent the force 
in the points qq’ at the instant of discharge. 
With this view, the author was led to the results given in Table II., in which is 
given, as before,—distance between the nearest points (a) ; measures equal to a force 
of 1 grain (b) ; measures to produce discharge (c) ; attractive. force in points g q' at 
the instant of discharge (d). To which is now added, distance of points g g! within 
the hemisphere (e) ; distance of points gq! from each other (f); calculated force at 
the nearest points given in column a and taken at the instant of discharge (9) ; this 
last column being deduced from columns (a) and (f). 
Table IT. 
. Dist: f | Calcul; 
vote, |forstore of|,Memures, | Forcin the | pointea a! | aitane of |, 
near points. 1 grain. for discharge.| points q q’. ps get points qq’. red iees 
0-1 6 26 18 to 19 0179 0-458 383 
0-2 8to9 52 33 to 37 0-231 0'663 385 
03 11 78 50 0:265 0°830 382 
0-4 13 104 64 0-290 0-980 384 
0-5 15— 130 76 0:3 1-111 380 
0:8 20 208 108 0:348 1-497 379 
1-0 23 260 127 0:365 173 381 
15 30 to 31 390 162 0°395 2:29 378 
2-0 37 to 38 520 190 0-419 2°83 380 
a b e d e f g 
ren cn res aS a ae Se EE ey BEL cL Se i 
What the author wishes to call attention to in this table is, that the force in the 
nearest points at the instant of discharge, as represented in the last column g, is at 
all distances a constant quantity, the numbers in column g not differing more than 
may be conceived to arise from the differences incidental to such experiments, a 
result quite in accordance with certain deductions arrived at by the author in former 
researches and printed in the Royal Society’s. Transactions for the year 1834,- 
p- 227, and since confirmed by Faraday in the course of his admirable Electrical 
Researches, p. 449, § 1410. 
The author concluded this communication by observing that he does not value 
these results, however interesting the experiments from which they have been de- 
rived, further than in proportion to their importance in tending to elucidate an in- 
teresting department of science, and afford us some further insight into the nature 
and mode of operation of a most wonderful agency. 
_ With respect to the first. object of these experiments, namely the verification of 
certain series employed by Professor Thomson, he leaves that, in the absence of 
Professor Thomson, to a future Meeting of the Association; he would merely ob- 
serve, that the deductions from these new experimental inquiries correspond very 
fairly with the general formula he has given for such forces in electricity. 
— 
On the Mechanical Equivalent of Heat and on the Constitution of Elastic 
Fluids. By J. P. Jove. 
At the last meeting of the Association the author exhibited an apparatus which 
by the agitation of fluids produced heat in exact proportion to the mechanical power 
expended. Experiments were made with this apparatus on the heat evolved by the 
friction of three totally dissimilar fluids—water, mercury and oil; and in all three 
cases the remarkable result appeared, that the mechanical power represented by the 
ree necessary to raise 782 lbs. one foot high produced the quantity of heat equal 
to raise the temperature of a pound of water one degree. 
