TO MRS. MAXWELL.

                                                                             20th March 1871.

     There are two parties about the professorship. One wants popular lectures, and the other cares more for    experimental work. I think there should be a gradation—popular lectures and rough experiments for the masses;    real experiments for real students; and laborious experiments for first-rate men like Trotter and Stuart and Strutt.

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TO MRS. MAXWELL.

                                                                   Athenæum, 22d March 1871.

I also got a first-rate letter from Monro about colour, and the Arab words for it (I suppose he studied them in Algeria). They call horses of a smutty yellow colour "green." The "pale" horse in Revelation is generally transcribed  green elsewhere, the word being applied to grass, etc. But the three green things in the Arabic dictionary are  "gold, wine, and meat," which is a very hard aying.