But he could not succeed in shaking off the illness of which he had had more than one warning; and even his elastic spirits began to flag under its depressing influence. The spring of 1826 found him worse; he complained much of rheumatism, and of slight numbness in his limbs; and the death of his mother in the autumn still further affected his health. With great pain and effort he delivered what proved to be his last address to the Royal Society—a body whose mission was so like his own, 'ad inquisitionem et inventionem naturæ veræ et interioris rerum omnium'—on St. Andrew's Day, 1826; and shortly after he suffered a slight attack of paralysis, which, however, did not prevent his revising his discourses, nor even deter him from projecting new scientific treatises. During his recovery he liked nothing better than having novels and romances read to him,—partly I should think to divert his mind from the small worries which were inevitable to one occupying the post which he filled, but which at this juncture pressed upon him with increasing force, and indeed probably conduced to his determining upon another visit to the Continent in January, 1827, accompanied on this occasion only by his brother, Dr. John Davy, an army surgeon.
The winter journey was rough and dreary. Paris was avoided, on account of the too great excitement which it was feared its society might induce; and the roads along which the travellers drove, bad at the best, were now in their very worst condition from the snow. The scenes through which they passed were uninteresting, the occasional roadside churches being the only noteworthy objects; and these they rarely failed to enter, the sick philosopher generally dropping on his knees for a silent prayer.
So they passed on, notwithstanding the severe cold and the snow, over the Mont Cenis, into Italy, reaching Ravenna on the 27th February—Davy, strange to say, rather the better than the worse for his cold and cheerless expedition. Here he rested for some time, occupying himself chiefly in shooting, fishing, and reading Byron, whose acquaintance (with that of the accomplished Countess Guiccioli) he had previously made at this place. His note-book was kept up, and was filled with numerous acute observations on subjects connected with natural history and chemistry, interspersed with expressions of pious humility and of gratitude to 'the Great Cause of all being.' His health improved; and in March, 1827, Dr. Davy returned to Corfu, whilst Sir Humphry shortly afterwards started on a solitary expedition through the Eastern Alps and down the Rhine. But his health now declined; he frequently had to apply leeches and blisters, and he lived so abstemiously as to considerably reduce his strength and spirits. 'Valde miserabilis!' he often exclaimed in his note-book; and once he wrote, 'Dubito fortissime restaurationem meam.' It was no doubt whilst in this mood that he wrote to Mr. Davies Gilbert from Salzburg, on 30th June, 1827, announcing his retirement from the office of President of the Royal Society.[115] Whilst on one of his numerous fishing expeditions, a pursuit[116] which, as we have seen, he passionately followed all his life long, he wrote about this time, the following pensive lines, more suo, on contemplating a rapid river:
'E'en as I look upon thy mighty flood,
Absorb'd in thought, it seems that I become
A part of thee, and in thy thundering waves
My thoughts are lost, and pass to future time,
Seeking the infinite, and rolling on
Towards the eternal and unbounded sea
Of the All-Powerful, Omnipresent Mind.'
This was a favourite thought of his. He amplified it in a letter which he addressed from Rome in the following year to his friend Poole:
'I have this conviction full on my mind,' he wrote, 'that intellectual beings spring from the same breath of Infinite Intelligence, and return to it again, but by different courses. Like rivers born amid the clouds of heaven, and lost in the deep and eternal ocean—some in youth, rapid and short-lived torrents; some in manhood, powerful and copious rivers; and some in age, by a slow and winding course, half lost in their career, and making their exit by many sandy and shallow mouths.'
The current of his own life now carried him back in one of its eddies to London, which he reached on 6th October.
The winter was passed in town, but the state of his health prevented any great exertion, and did not permit his seeing much society; yet the world can scarcely be said to have been the loser; for in his retirement he composed (being now nearly fifty years of age), that delightful book, dear to every angler, 'Salmonia.'[117] Returning spring revived his desire to revisit what he considered the finest scenery in the world, namely, the Alpine valleys of Illyria and Styria; and at the end of March he left England, accompanied by a young medical gentleman (his godson), Mr. Tobin, the son of a much-valued old friend. His pursuits were much as usual, and, living somewhat more generously, he more than once entertained some faint hopes of his ultimate recovery; 'attaching,' as he himself put it, 'a loose fringe, of hope to his tattered garments.' His mind was fully active during this summer, as may be judged from his having now planned his well-known work, 'Consolations of Travel,' which he used to say 'contained the essence of his philosophical opinions;' and from his having sketched out a slight plan for his own memoirs. Stress of weather detained him a short time at Wurzen, and here he occupied the time of his detention by writing his little Irish romance, 'The Last of the O'Donoghues.' He also now sent to press the second edition of his 'Salmonia,' which he thought 'twice as good, as well as twice as big' as the first. At Trieste he resumed his experiments on the electric eel, and at length satisfied himself that under no conditions did the shock affect the magnet. This formed the subject of a paper—the last of a series which continued almost uninterruptedly for a period of twenty-eight years—published by the Royal Society. It was about this time that he made the noble and touching entry in his diary:
'Si moro, spero che ho fatto il mio dovere; e che mia vita non e stato vano ed inutile.'[118]