Olveston | 9 Oct. 1856.
My dear Sir,
My report on the last exam.1 for the Engineers has been printed and I trust that you will in a few days receive a copy of it, if you have not already done so.
I am very glad that your examination of the glaciers is favourable to my theory2 on some of the points to which Prof. Forbes takes objection. I have given such consideration to it lately as my other occupations have permitted and prepare [propose?] to put my thoughts on paper3 when I can find a few days leisure. Will you permit me to ask your opinion on one point. Prof. Forbes describes an experiment in which a thermometer was placed in a hole in the glacier made on purpose, and another (I think) in which it was let down into a ‘crevasse’, and showed in both cases a temperature of zero, and he concludes that the whole mass of the glacier is therefore of that temperature.4 Is this to be relied upon? Does not the presence of the air in the crevasse (or in any other hole he might make) when the external temperature is above zero imply a thawing condition of the surface ice of the crevasse and therefore a temperature of zero in the thermometer brought in contact with it?
Might not the solid depths of the glacier be of a temperature below zero notwithstanding that the walls of the crevasse (or of a hole made artificially) showed that temperature? Would not – in point of fact – a mass of ice 200 or 300 feet thick and as wide as the Mer de Glace5 – of necessity be of various temperatures from its surface to the parts furthest removed from it; supposing it originally to have been formed (or at any time to have existed) at a lower temperature? Does not the heating of a mass take place under conditions analogous – in this respect – to its cooling? and may the glacier not keep far into the summer in the abysses of the solid ice some of the cold of winter? May there not be depths in it to which the summer heat scarcely reaches – or rather layers in it which that heat reaches in succession, and to which it is communicated in different degrees – raising none however above zero – and thus expanding each differently and causing that ‘striated’ appearance on which Forbes so much insists?
Pardon me for troubling you with this.
Yours truly | H. Moseley.
P.S. Do you know of any facts bearing upon the question of the distribution of temperature at different depths of a solid body in the process of cooling and heating? I never can too much lament my own imperfect knowledge of these things. Is there not something analogous in the temperature of earth’s surface itself?
RI MS JT/3/897
LT Transcript Only
My report on the last exam: report not found.
my theory: Moseley had published an explanation in ‘On the Descent of Glaciers’, Roy. Soc. Proc., 7 (1854–5), pp. 333–42.
to put my thoughts on paper: Moseley did not do this until 1860: ‘On the Cause of the Descent of Glaciers’, Brit. Assoc. Rep., 1860, pp. 48–50. This was subsequently incorporated into ‘On the Motion of a Plate of Metal on an Inclined Plane, when Dilated and Contracted; and on the Descent of Glaciers’, Roy. Soc. Proc., 11 (1860–2), pp. 168–77.
Prof. Forbes describes … of that temperature: No such experiments were described in J. D. Forbes, Travels Through the Alps of Savoy ad Other Parts of the Pennine Chain (Edinburgh: Adam & Black, 1843) – though see, pp. 36, 358. Moseley must have been referring to one of Forbes’s many papers on glaciers.
Mer de Glace: A valley glacier in the Chamonix valley of France. At the time of Tyndall’s visit (and until 1860), it was part of the kingdom of Sardinia.
Please cite as “Tyndall1285,” in Ɛpsilon: The John Tyndall Collection accessed on