The following year he was apprenticed to Mr. Bingham Borlase, practising surgeon and apothecary in Penzance. Young Davy now seemed destined to become a physician, but his note-books show that he intended to know other things besides medicine. He laid out a plan for study: theology, logic, astronomy, mathematics, Latin, Greek, Italian, Spanish, and Hebrew.
He said later, "Almost all great deeds arise from a plenitude of hope or desire. No man ever had genius who did not aim to execute more than he was able." And all his life he planned to do twice as much as he was ever able to do. And yet he knew that he must bind himself to a few things, if he would succeed. He said, "In minds of great power, there is usually a disposition to variety of pursuits, and they often attempt all branches of letters and science, and even the imitative arts; but if they become truly eminent, it is by devotion to one object at a time, or at most two objects. This sort of general power is like a profusion of blossoms on a fruit tree, a symptom of health and strength; but if all are suffered to become fruit, all are feeble and bad; if the greater portion is destroyed by accident or art, the remainder, being properly nourished, become healthy, large, and good." In these early note-books, he began to show an unusual and mature mind. He wrote essays: "On the Immortality and the Immateriality of the Soul," "On Governments," "On Moral Obligation," and the like. Of Friendship, he wrote at seventeen: "It is a composition of the noblest passions of the mind; a just taste and love of virtue, good-sense, a thorough candor and benignity of heart, and a generous sympathy of sentiment and affections, are the essential ingredients of this nobler passion. When it originates from love and esteem, is strengthened by habit, and mellowed by time, it yields infinite pleasure, ever new and ever growing. It is the best support amongst the numerous trials and vicissitudes of life, and gives a relish to most of our enjoyments. What can be imagined more comfortable than to have a friend to console us in afflictions, to advise with us in doubtful cases, and share our felicity?... It exalts our nobler passions, and weakens our evil inclinations; it assists us to run the race of virtue with a steady and undeviating course. From loving, esteeming, and endeavoring to felicitate particular people, a more general passion will arise for the whole of mankind."
He finishes this essay with an allegory. God is described as deliberating with the angels on the propriety of creating woman. Justice, Peace, and Virtue plead against her creation, as through her Adam will be driven out of Paradise. Then Divine Love stands before Jehovah, her countenance covered with smiles. "Create her," she says, "for Paradise itself will afford no delight to man without woman. She will be the cause of his misery, but she will likewise be the cause of all his happiness. She will console him in affliction; she will comfort and harmonize his soul; she will wipe the tears from his eyes, and compose the fury of his passions. Her friendship shall make him virtuous, and her love shall make him happy; and, lastly, the tree of their transgression, and the plant of immortality, nourished by the blood of her son, shall flourish, and grow out of Paradise, and overspread the earth: man shall eat of their fruit, and be immortal and happy."
All through these early note-books are scattered his poems, showing a passion for the blue sea at Penzance, and an unbounded love of nature.
Just as he was entering his nineteenth year, young Davy began the study of chemistry, as a branch of his profession. He read "Lavoisier's Elements of Chemistry," and "Nicholson's Dictionary of Chemistry." Suddenly a new world seemed to open before him. He began to think for himself, and to make experiments. As his means were limited, his apparatus consisted of vials, wine-glasses, tea-cups, tobacco-pipes, and earthen crucibles.
His first experiments were the effects of acids and alkalies on vegetable colors, the kind of air in the vesicles of common seaweed, and the solution and precipitation of metals. These were made in his bedroom in Mr. Tonkin's house, or in the kitchen, when he required fire. This old gentleman had brought up his mother and her two orphan sisters, and now was like a father to Humphrey. He said, "This boy, Humphrey, is incorrigible. Was there ever so idle a dog! He will blow us all into the air." He was at this time probably making a detonating composition, which he called "thunder power," his sister Kitty being his assistant.
At this time, a young man came to board at the house of Mrs. Davy, Gregory Watt, the only child of James Watt, the inventor of the steam-engine. He was the idol of his parents; possessed of a mind so unusual in its passionate love for knowledge, and a nature so companionable, that everybody loved him. He was twenty-one, and Humphrey nineteen.
Between these two young men there grew a most ardent and lasting friendship; lasting because it had the only sure foundation, moral and mental worth. They were always together. They visited the neighboring mines and mountains, and came home with their pockets filled with minerals.
The brilliant Gregory died at twenty-eight, but Davy lived to show the fruits of one of the most beautiful things in life, the affinity of two noble and intellectual souls, with similar tastes and aspirations. This death was a great loss to Humphrey. He wrote to a friend: "Poor Watt! He ought not to have died. I could not persuade myself that he would die: and until the very moment when I was assured of his fate, I would not believe he was in any danger.
"His letters to me only three or four months ago were full of spirit, and spoke not of any infirmity of body, but of an increased strength of mind. Why is this in the order of nature, that there is such a difference in the duration and destruction of her works? If the mere stone decays, it is to produce a soil which is capable of nourishing the moss and the lichen; when the moss and the lichen die, and decompose, they produce a mould, which becomes the bed of life to grasses, and to more exalted species of vegetables. Vegetables are the food of animals; the less perfect animals of the more perfect; but in man the faculties and intellect are perfected. He rises, exists for a little while in disease and misery; and then would seem to disappear, without an end, and without producing any effect.