'_15 June._--As her husband had invited me to do, I called this morning on Lady Davy. I found her in her parlour, working on a dress, the contents of her basket strewed about the table, and looking more like home than anything since I left it. She is small, with black eyes and hair and a very pleasant face, an uncommonly sweet smile; and when she speaks, has much spirit and expression in her countenance. Her conversation is agreeable, particularly in the choice and variety of her phraseology, and has more the air of eloquence than I have ever heard before from a lady. But, then, it has something of the appearance of formality and display, which injures conversation. Her manner is gracious and elegant; and though I should not think of comparing her to Corinne, yet I think she has uncommon powers.' The honeymoon, the greater part of which was spent in Scotland, was scarcely over, before, in the month of June, he dedicated to his wife his 'Elements of Chemical Philosophy,' as a pledge of his continued ardour for science, as well as of his love for her; and Davy returned to his scientific pursuits. In the following November he nearly lost his eyesight, whilst performing the dangerous experiment of effecting the combination of azote, as nitrogen was then called, and chlorine. He soon, however, completely recovered the use of his eyes, and took a trip into his native county; fishing and geologizing on the way. It was about this time also that Davy made the first experiments in electric lighting, by producing the voltaic arc by the use of carbon; the discovery was improved by Foucault, who substituted retort-carbon for wood-charcoal. (Comte du Moncel's 'L'Eclairage Electrique,' Paris, 1880.) With reference to this, now highly important, subject, a writer in the _Times_ for 22nd October, 1881, points out that 'Sir Humphry Davy showed that when a powerful current passes across the point of contact of two carbon rods, their points become heated; and on separating them to a short distance, an arc of light shoots between them, and the carbons are raised to a white heat.' The writer adds, that 'all lamps (until lately) had this point chiefly in view; namely, to introduce an arrangement which should keep the carbon-points at the fixed distance found to be the most advantageous.' Surely here was the germ of that discovery which is now becoming so rapidly developed.