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tigated by Stokes. 1 I do not mean any immediate likeness,but distant connexion. He has been rendering the invisible,chemically acting rays, visible 2 — that is to say he has beenConverting them into visible rays. — You, by giving a givencondition to a substance, make it, when in Compounds, send oneray to the eye — and then by giving it another conditioncause it to send other rays to the eye, the body being chemi-cally the samc. Both thcse are phenomena of radiation, andboth are connected with chemical agencies or forces. If theycould be connected, what a heap of harvests would spring upbetween the two. - - I do not know enough yet of Stokes'phenomona to form any thing but a crude idea and I knownothing of yours yet, so that you will think nie very absurdto write such stuff; but then it is oniy to a friend.

You are very amusing with your criticisms on Organicchemistry. B I hope that in due time the chemists will justify

1 George Gabriel Stokes, professor of Mathematics at Cambridge was bornin 1819 at Skreen, Co. Sligo, Ireland.

2 "On the change of refrangibility of iight," Roy. Soc. Proc. 1850—1854.p. 195 and 333. "On the change of refrangibility of light and the exhibitionthereby of the chemical rays," Roy. Soc. Proc 1850—1854. p. 259.

3 He seems to have expressed similar criticisms to Grove, for in a letterdated Jan. 5. 1845 the latter writes: "I quite agree with the remarks at the close.I think chemistry is being frittered away by the hairsplitting of the organic chemists ;we have new Compounds discovered, which scarcely differ from the known onesand when discovered are valueless — very illustrations perhaps of their refinementsin analysis, but very little aiding the progress of true science." On the otherhand he writes, after commenting on Becquerels process for extracting metalsby voltaic means: "Who would not have been laughed at if he had Said in 1800that metals could be extracted from their ores by electricity or that portraits couldbe drawn by chemistry." (Aug. 20. 1847.)

We rnight also quote Graham's views, which are contained in a letter toSchcenbein, dated Jan. 9. 1862: "Your very kind letter acknowledging receiptof my paper has afforded me much gratification ; the more so, that the stand-point from which you have always surveyed chemistry, is high and philoso-phical .... The various modifications of oxygen (an element) which you haveestablished, with the Compounds into which they carry their properties are dis-coveries of a fundamental character, leading into new regions of science, quiteaside from the routine chemistry of the day."O

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