To Heinrich Debus   14th, Oct, 1861

Royal Institution | 14th, Oct, 1861.

My dear Heinrich

I was very glad to receive your letter,¹ which is some compensation for your absence from the Isle of Wight. However you were wise not to come, for in the first place we had to get from Southampton to Cowes in a storm, and secondly after we have arrived there we were compelled by the rain to keep within doors. You must indeed be hardly worked at present, and the pay of £20 for the additional lectures appears to me incomprehensibly small. But you are a man of a physical head and the pleasure which the subject gives is in part compensation. Nevertheless £20 for two whole days a week is less than any thing of the kind I ever heard of in England before. If Queenwood cannot give more, be content; if it can you ought to have it.

I continue to be exceedingly well in health, though I work in rather an unwholesome atmosphere. In fact I feel rather to be getting young than getting old. My hairs are beginning to turn gray, but my body is usually full of vigour. Indeed it is many years since I have been so strong. My work is going on daily—It is tremendously difficult and sometimes drives me to the brink of despair. In the laboratory where I work there are three classes of actions on Radiant Heat. The first due to the pure oxygen and nitrogen alone is expressed by the number 1; the second due to aqueous vapour is expressedly the number 40 and the third due to the remaining foreign constituents of the air is represented by the number 27. This will give you some idea of the delicacy of my apparatus, and of the immense difficulty of bringing it into such a condition. Our atmosphere is a practical vacuum to rays of heat: and all that has been hitherto ascribed to the air is mainly due to the aqueous vapours. It is at least 40 times more potent than the whole air itself. Don’t mention these results. I am daily fighting with difficulty and usually do not quit the laboratory from morning till night. My progress is exceedingly slow, but by constancy I hope to get something done. I was under the impression that Mr E.² had got a good man for lecturing; but I think you may congratulate yourself in getting rid of that ill conditioned individual to whom you allude. Tom³ and I had a glorious walk yesterday. We got through about 18 miles of the most beautiful country imaginable. If you desire to know Mr Harcourt’s⁴ address I can get it at once by writing to my friend Cook,⁵ the editor of the Saturday Review. If you want the address let me know and I will obtain it for you.

My mornings are occupied in writing out an account of my Swiss tour for publication:⁶ so that my days are as full as your own.

goodbye | always Yours sincerely | John Tyndall

RI MS JT/5/11/1333