There appear to be figures in your paper, and three of them are done in three sizes. We shall photograph, of course, from the largest size, but please say to which of the other two sizes you wish them reduced. The smallest is neatest: do you think it is sufficiently clear? The fourth figure, which has no number, I suppose I may call "Fig. 4"?
Asst. Sec. R.S. [Assistant Secretary, Royal Society]'.