The Abbé's recreation consisted in botanizing expeditions; and Haüy, who had chosen the kindly old priest as his spiritual director, was his most frequent companion. Occasionally, when M. Lhomond was ailing, and unable to take his usual walks, Haüy spent the time with him. He rather regretted the fact that he did not know enough about botany to be able to make collections of certain plants to bring to the professor at such times, in order that the latter might not entirely miss his favorite recreation. Accordingly, one summer when he was on his vacation at his country home, he asked one of the Premonstratensian monks, who was very much interested in botany, to teach him the principles of the science, so as to enable him to recognize various plants. Of course his request was granted. He expected to have a pleasant surprise for Abbé Lhomond on his return, and to draw even closer in his friendly relations with him, because of their mutual interest in what the old Abbé called his _scientia amabilis_ (lovely science). His little plan worked to perfection, and there was won for the study of physical science a new recruit, who was to do as much as probably any one of his generation to extend scientific knowledge in one department, though that department was rather distant from botany. Haüy's interest in botany, however, was to {177} prove only temporary. It brought him in contact with other departments of natural history, and it was not long before he found that his favorite study was that of minerals, and especially of the various forms of crystals. So absorbed did he become in this subject that nothing pleased him better than the opportunity to spend long days in the investigation of the comparative size and shape of the crystals in the museum at Paris. A friend has said of him that, whether they were the most precious stones and gems or the most worthless specimens of ordinary minerals, it was always only their crystalline shape that interested Haüy. Diamonds he studied, but only in order to determine their angles; and apparently they had no more attraction for him than any other well-defined crystal--much less, indeed, than some of the more complex crystalline varieties, which attracted his interest because of the difficulty of the problems they presented.