6 Windsor Villas | Plymouth | January 25th 1864
My dear Tyndall,
Allow me to place in your hands, a copy of my paper on Intensity1 lately printed in the last number of the Phil. Mag. which I trust may prove of some little interest to you. I am more than ever satisfied that very erroneous views have been entertained relative to Electrical Force, and in whatever that force consists, we have no evidence whatever of its being susceptible of change in its elementary state; thus gravity is the same in a feather, as in a lump of lead, it is not more intense in the one, than in the other.
I am more confirmed in my views since reading the interesting and instructive review of your lectures, on the “Dynamical Theory of Heat” printed in the last number of the Edinburgh review.2 If you have a few minutes at any time to spare I should like you to cast your eye over the little geometrical diagram I have given in my paper, in illustration of the operation of the Leyden Jar.
The advances in Philosophical research will soon oblige the Continental philosophers to abandon the idea of Electric fluids, susceptible of change in what they call Intensity, and such like
I am about to send another paper to the R. S.3
Believe me to be | My dear Tyndall | ever your sincere friend | W. Snow Harris
In a former letter when adverting to your little misunderstanding with Thomson relative to your exp. &c. concerning the development of heat by motion, I called attention to Rennie papers4 which I have since found and enclose in my paper on Intensity thinking it may be of interest to you.
W. S. H.
Should my life be spared5 I shall hope to see you this way in the course of the ensuing summer.
RI MS JT/1/TYP/2/481
LT Typescript Only
my paper on Intensity:. W. S. Harris, ‘On the Correct Interpretation of the Electrical Terms Intensity and Tension’, Phil. Mag., 26 (1863), pp. 504–15.
the “Dynamical Theory of Heat…the Edinburgh review: ‘Review of Tyndall’s Heat Considered as a Mode of Motion, Joule’s On the Mechanical Equivalent of Heat, Mayer On Celestial Dynamics’, Edinburgh Review, 119 (1864), pp. 1–13.
another paper to the R. S: possibly W. S. Harris, ‘Further inquiries concerning the laws and operation of electrical force’, Roy. Soc. Proc., 13 (1864), pp. 364–75 (received by the RS on 8 June 1864).
former letter when adverting… attention to Rennie papers: letter missing. There appears to be no other letter from Snow Harris in the Tyndall correspondence which referred to papers by Rennie. However, in both previous letters in this volume from Snow Harris (1984 and 1986), Thomson is discussed. The Rennie referred to is probably George Rennie (1791–1866), a British mechanical and civil engineer (ODNB).
Should my life be spared: Snow Harris survived until 1867.
Please cite as “Tyndall2066,” in Ɛpsilon: The John Tyndall Collection accessed on