4, Windsor Terrace, Malahide, Co. Dublin. 4 August, 1881.

Dear Sir John Lubbock,

I got your proof here, which was forwarded from Armagh. I expect to be going there tomorrow. I saw Miss Stokes the day before yesterday, and gave her your message.

I have read your proof, and have made some reference marks, in the margin, numbers enclosed in circles. I also corrected a few misprints which I happened to see. It is no trouble to correct them, and they might be overlooked, especially by the author, who is apt to read a proof as it was meant to be.

In what follows, the numbers refer to the reference marks.

1. A few of the more conspicuous of the fixed lines were discovered by Wollaston near the beginning of the century, by viewing a slit through a prism applied to the naked eye. This observation however remained but little noticed.

2. Long ago, but I have not got the date, and have not reference books here, Fox Talbot showed that the red given to a flame by strontium and the red due to a salt of lithium might be at once distinguished by the prism. I think too, but I am not sure, that he dwelt on the delicacy of this test for the detection of lithium. I do not recollect whether this was before or after 1835 [Wheatstone's experiments]. It is to Kirchhoff and Bunsen that we owe the great impetus that has been given to spectrum analysis, and perhaps it would be proper to mention their names in this connexion; it rather looks as if they had merely applied what had been done by their predecessors.