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Ordinary Meeting, December 15, 1863. 
J. P. Joule, LL.D., F.R.S., Vice-President, in the Chair. 
Mr. Robert Leake rvas elected an Ordinary Member of the 
Society. 
J. C. Dyer, V.P., read a Paper entitled “Notes on some 
recent Discoveries in Elemental Physics.” 
He stated that the discoveries in question related to the 
nature of heat and force. From the earliest times the nature 
of heat had been treated upon opposite theories ; the one 
maintaining heat to be a material element sui generis, per- 
vading space and bodies, but in itself imperceptible except 
by the effects it produces in connection with bodies : the other 
theory considering heat to be the result of mechanical force 
exciting the particles or molecules of bodies, and producing 
the effects of sensible heat in them. Boerliaave was among 
the most able expounders of the former theory, Bacon and 
Boyle of the latter. 
In later times the materiality of heat has been forcibly 
sustained by the discoveries of the existence of latent or 
specific heat in bodies, by the experiments of Drs. Black, 
Irvine, Crawford, and others ; whilst the mechanical origin 
of heat has been sustained by the experiments of Count 
Rumford and of Dr. Joule. 
Upon these conflicting views many able treatises have 
been written on both sides ; yet the question as to the nature 
of heat remains involved in such obscurity as lo require far 
more decisive evidence than has yet appeared for settling 
either of them upon a sound and immovable basis. 
Proceedings— Lit. & PeTil. Society— No. 8.— Session, 1863-64. 
