The most resolute antigravitationist that ever lived might yet acknowledge his debt to Newton for the Method of Prime and Ultimate Ratios and the Principles of Fluxions by which Newton sought to establish gravitation. So let it be with Colenso. He has given me a power of tracing out truth to a certain extent which I never could have obtained without him. And for this I am very grateful. As to the further employment of this power, you know that he and I use it to totally different purposes. But not the less do I say that I owe to him a new intellectual power. I quite agree with you, that the sudden disruption of the old traditional view seems to have unhinged his mind, and to have sent him too far on the other side. I would not give a pin for his judgment. Nevertheless, I wish he would go over the three remaining books of the Tetrateuch. I know something of Myers, but I should not have thought him likely to produce anything sound on such things as the Hebrew Scriptures. I never saw his "Thoughts." I am, my dear Sir, Yours very truly, G.B. AIRY. _Professor Selwyn_. * * * * * The following letter has reference to Airy's proposal to introduce certain Physico-Mathematical subjects into the Senate-House Examination for B.A. Honors at Cambridge. On various occasions he sharply criticized the Papers set for the Senate-House Examination and the Smith's Prize Examination, and greatly lamented the growing importance of pure mathematics and the comparative exclusion of physical questions in those examinations. His proposal as finally submitted in the letter that follows was somewhat modified (as regards the mode of introducing the subjects) from his original draft, in deference to the opinions of Whewell, Adams, Routh, and other friends to whom he had submitted it. His proposal was favourably received by the Mathematical Board, and recommendations were made in the direction, though not to the extent, that he desired, and he subsequently submitted a Memorandum on those recommendations: ROYAL OBSERVATORY, GREENWICH, _1866, May 11_. MY DEAR SIR, You will perceive, from perusal of the enclosed paper, that I have acted on the permission which you kindly gave me, to transmit to you my proposal for extension of the mathematical education of the University in the Physical direction.