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.
In the spring of 1790, he left Göttingen, and, with Foster and Van Genns, took a journey to the Lower Rhine, Holland, Belgium, England, and France, studying docks, mines, botanic gardens, manufactures, and churches, and visiting literary celebrities. Still the new friends did not take the place of the old, for he writes to Wegener: "I beseech you, dearest Wegener, by all the affection which you know I bear you, never to forget our brotherly love and friendship. You are infinitely more to me than I can ever be to you. I have now seen the most celebrated places in Germany, Holland, and England--but, believe me, I have in seeing them never been so happy as while sitting in Steinbart's arm-chair."
The influence of this journey was never lost. Sixty-eight years afterward, Humboldt said: "For the space of thirty years I have never known leisure but of an evening, and the half-century that I have spent in this ceaseless activity has been occupied in telling myself and others how much I owe my teacher and friend George Foster in the generalization of my views on nature, and in the strengthening and development of that which had already dawned in me, before those happy days of intimate friendship."