17th Jan. 1859
My dear Sir
I have been reading with pleasure and interest your lectures at Ipswich1—would you kindly inform me whether any models similar to those you used in the lectures are to [be]2 borrowed, or then loan purchased, at any place in London?
In one of your lectures at the R.I.3 you had a model of the experiment of Cavendish4—is it to be found in London?
I have a course of lectures5 which commence on the 27th. and I must talk a little of the gravity & motion of the planets—as you know very well our audience requires illustration.
Have you ever tried the experiment of Cavendish with a fine torsion balance and Gauss’s reflector?6 I almost think the attraction would manifest only with much smaller masses than those used by Cavendish.
Most truly yours | John Tyndall
I am hard at work upon a glacier paper7 which I hope will interest you.
RGO MS.RGO 6/408.378–9
lectures at Ipswich: G. B. Airy, Six lectures on astronomy: delivered at the meetings of the friends of the Ipswich Museum, at the Temperance Hall, Ipswich, in the month of March 1848 (London, 1849). The Ipswich Museum in the English town of Ipswich in the county of Suffolk, was founded in 1846 and devoted largely to natural history collections.
[be]: the word ‘be’ was missing from the letter.
one of your lectures at the R.I.: on 2 February 1855, Airy delivered a lecture at the RI entitled ‘On the Pendulum-experiments lately made in the Harton Colliery, for ascertaining the mean Density of the Earth’ (for an abstract, see Roy. Inst. Proc., 2 (1854–8), pp. 17–22).
experiment of Cavendish: Henry Cavendish’s (1731–1810) torsion balance experiment in the late nineteenth century that measured the force of gravity between two masses, and yielded an estimated mass density of the Earth.
course of lectures: Tyndall delivered ‘Twelve Lectures on the Force of Gravity’ at the RI in 1859, on Thursday afternoons from 27 January to 14 April (Roy. Inst. Proc., 2 (1854–8), p. 4). See RI Guard Book, vol. 2, p. 110–1.
Gauss’s reflector: heliotrope, invented by Carl Friedrich Gauss (1777–1855), the German astronomer and mathematician (CDSB).
glacier paper: J. Tyndall, ‘On the Veined Structure of Glaciers; with observations upon White Ice-seams, Air-bubbles and Dirt-bands, and remarks upon Glacier Theories’, Phil. Trans., 149 (1859), pp. 279–307. Read for the RS on 24 February 1859.
Please cite as “Tyndall1582,” in Ɛpsilon: The John Tyndall Collection accessed on