Sunday.
My dear Heins
It is long since I wrote to you—far too long. I have however for many weeks been fighting with great difficulties in my investigations and had no great heart to write to any body. I am happy to say that all are now substantially overcome, and that the progress of my work is in the highest degree satisfactory. The more I think and work on the subject the more I see its great extent and importance. If I mistake not before the year closes I shall be able to furnish a memoir which will exceed in interest all that has been published on the subject of radiant heat for many years. In a chemical point of view the results also promise to be of great interest and importance.
Among other things I believe I have discovered an allotropic condition of oxygen.2 I find that ozone presents most striking characteristics: but I wish you were near me so that we might talk over these matters—Will you kindly inform me of some of the ways by which ozone may be produced; and also by which it may be reduced to the condition of ordinary oxygen?
What is your belief regarding the substance? My experiments harmonise with the idea that it is a peroxide of hydrogen; but they do not yet prove it!
My health since I returned from the Alps has been excellent. I work hard every day and do not find my strength sensibly diminished. I am glad that the glaciers are off my hands,3 for if I mistake not I shall soon shew the world that I can produce something better. Forbes has written against me4 as I suppose you are aware, but he shall not make me swerve from my work at present. Besides his pamphlet has produced no effect in London. When a second edition of my book is published5 I shall make a few remarks upon his pamphlet, but not before.
I think you know a good deal about Brodie’s ideas of grouped elements.6 With regard to the nitrogen the element which I obtain from the nitrite of potassium, and which chemists state to be perfectly pure, is a totally different body from the nitrogen of the atmosphere—in all chemical tests they agree, but my physical test shews an enormous difference between them.
Does any impurity occur to your mind likely to mix itself with nitrogen obtained from the nitrite of potassium? I have prepared it on several occasions, but with the same unvarying result.
What amount of gaseous impurity do you think ordinary chemical means could detect in the atmosphere? I can readily measure the effect 0·008 per cent of certain gases mixed with air. I can also accurately determine the absorption of a gas possessing no more than 1/15th of a millimetre of tension.
Do not mention these things to any body Faraday has warned me against speaking of the subject at all:7 I would again express the wish that you were nearer to me so that I might have the benefit of your suggestions.
Believe me dear Heins | Most truly Yours | John Tyndall
RI MS JT/5/11/1365–6
LT Transcript Only
[28 October 1860]: letter 1734 is the reply to this letter, making the date Sunday 28 October 1860.
allotropic condition of oxygen: the typescript text reads ‘nitrogen’, but it can be assumed that Tyndall wrote, and certainly meant, ‘oxygen’. Though Tyndall incorrectly concluded at this point that oxygen was monatomic, he was correct to identify ozone as a form of oxygen, which was uncertain at the time. See also letter 1734, n. 2.
I am glad that the glaciers are off my hands: Glaciers of the Alps had been published on 6 July.
Forbes has written against me: see letter 1731, n. 4.
When a second edition of my book is published: a second edition was not published until 1896, after Tyndall’s death. Though the first edition was published by Murray, the second edition was published by Longmans: Glaciers of the Alps (London: Longmans, Green, & Co., 1896).
Brodie’s ideas of grouped elements: Benjamin Collins Brodie (1817–80), chemist. In the 1860s, Brodie rejected an atomic interpretation of chemistry, and proposed a new set of symbols for chemistry which took into account the laws of chemical combination. He gave a seminal exposition of his theory to the Chemical Society in 1867. See W. H. Brock (ed.), The Atomic Debates (Leicester: Leicester University Press, 1967), pp. 13–15.
Faraday has warned me against speaking of the subject at all: this indicates the importance of establishing Tyndall’s priority for the absorption of heat by gases, and indeed that Faraday was not unconcerned at such earthly reputation.
Please cite as “Tyndall1733,” in Ɛpsilon: The John Tyndall Collection accessed on