In his walk along the beach, the nature of the air contained in the bladders of sea-weed was a constant subject of speculation with him; and he used to sigh over the limited laboratory at his command, which prevented him from thoroughly investigating the matter. But one day, as good luck would have it, the waves threw up a case of surgical instruments from some wrecked vessel, somewhat rusty and sand clogged, but in Davy's ingenious hands capable of being turned to good account. Out of an old syringe, which was contained in the case, he managed to construct a very tolerable air pump; and with an old shade lamp, and a couple of small metal tubes, he set himself to work to discover the causes of the diffusion of heat. At first sight the want of proper instruments for carrying on his researches might appear rather a hindrance to his progress in the paths of scientific discovery; but, in truth, his subsequent success as an experimentalist has been very properly attributed, in no small degree, to that necessity which is the parent of invention, and which forced him to exercise his skill and ingenuity in making the most of the scanty materials at his command. "Had he," says one of his biographers, "in the commencement of his career been furnished with all those appliances which he enjoyed at a later period, it is more than probable that he might never have acquired that wonderful tact of manipulation, that ability of suggesting expedients, and of contriving apparatus, so as to meet and surmount the difficulties which must constantly arise during the progress of the philosopher through the unbeaten track and unexplored regions of science!" While Davy was thus busily engaged qualifying himself for the distinguished career that awaited him, Gregory Watt, the son of the celebrated James Watt, being in delicate health, came to Penzance for change of air, and lodged with Mrs. Davy. At first he and Humphrey did not get on very well together, for the latter had just been reading some metaphysical works, and was very fond of indulging in crude and flippant speculations on such subjects, which rather displeased the shy invalid. But one day some chance remark of Davy's gave token of his extensive knowledge of natural history and chemistry, and thenceforth a close intimacy sprang up between them, greatly to the lad's advantage, for Watt's scientific knowledge set him in a more systematic groove of study, and encouraged him to concentrate his energies on his favourite pursuit. Another useful friend Davy also found in Mr. Gilbert, afterwards President of the Royal Society. Passing along one day, Mr. Gilbert observed a youth making strange contortions of face as he hung over the hutch gate of Borlase's house; and being told by a companion that he was "the son of Davy the carver," and very fond of making chemical experiments, he had a talk with the lad, and discovering his talents, was ever afterwards his staunch friend and patron.