Humboldt was also fond of Greek. He said, "The more I know of the Greek language, the more am I confirmed in my preconceived opinion, that it is the true foundation for all the higher branches of learning." With some friends, he soon founded the Philosophical Society, which, with the admirable libraries and museums at hand, became of great assistance to the students. The next year, 1790, he had become so interested in science, that he wrote Wegener: "I was away from Göttingen for two months, spending the vacation in making a scientific tour with a Herr van Genns, a Dutchman with whom I became acquainted through his writings on botanical subjects.... Amid the numberless distractions of the journey, which was made sometimes on foot and sometimes by carriage, and with the incessant occupation of packing up minerals and plants, I was not very well able to write to you." The result of this tour was a pamphlet, "Mineralogical Observations on some Basalts of the Rhine." His next works were two small treatises, "The Aqueous Origin of Basalt," and "The Metallic Seams in the Basalt at Unkel." And this youth of twenty-one was self-taught both in mineralogy and geology! The wonder was not so great, perhaps, that a young man of his age should have written these sketches, as that, being wealthy and of the best social position, the temptations to ease and enjoyment did not draw him away from such subjects. Poverty may not be a delight, but the larger part of the world's work has been done under its stimulus. Wealth should be an incentive, because it gives leisure for careful study, but this is not always the case. At Göttingen, Humboldt found a friend among the eight hundred. At the house of Heyne he made the acquaintance of George Foster, Heyne's son-in-law, a man who exerted a remarkable and lasting influence over him. Foster was thirty-six; Humboldt, fifteen years his junior. He had been around the world with Captain Cook in his second voyage, and had published an able book upon the subject. He was skilled in chemistry, philosophy, literature, and politics, understood Latin, Greek, French, English, Dutch, and Italian, and was somewhat conversant with the Swedish, Spanish, Portuguese, Russian, and Polish languages. The influence of such a man can well be imagined. He became a guiding star to the young Göttingen student. If we could but estimate the value of right friendships in life! We flatter ourselves that we are too strong to be influenced, and yet we are greatly influenced for good or for evil by those with whom we associate. Humboldt always chose intellectual friends, and the natural result followed.