“At Practical Mechanics I have been turning Devils of sorts. For private studies I have been reading Young’s ‘Lectures,’ Willis’s ‘Principles of Mechanism,’ Moseley’s ‘Engineering and Mechanics,’ Dixon on ‘Heat,’ and Moigno’s ‘Répertoire d’Optique.’ This last is a very complete analysis of all that has been done in the optical way from Fresnel to the end of 1849, and there is another volume a-coming which will complete the work. There is in it, besides common optics, all about the other things which accompany light, as heat, chemical action, photographic rays, action on vegetables, etc. “My notions are rather few, as I do not _entertain_ them just now. I have a notion for the torsion of wires and rods, not to be made till the vacation; of experiments on the action of compression on glass, jelly, etc., numerically done up; of papers for the Physico-Mathematical Society (which is to revive in earnest next session!); on the relations of optical and mechanical constants, their desirableness, etc.; and suspension bridges, and catenaries, and elastic curves. Alex. Campbell, Agnew, and I are appointed to read up the subject of periodical shooting stars, and to prepare a list of the phenomena to be observed on the 9th August and 13th November. The society’s barometer is to be taken up Arthur’s Seat at the end of the session, when Forbes goes up, and All students are invited to attend, so that the existence of the society may be recognised.” It was at last settled that he was to go up to Cambridge. Tait had been at Peterhouse for two years, while Allan Stewart had joined him there in 1849, and after much discussion it was arranged that Maxwell should enter at the same college. Of this period of his life Tait writes as follows:--