Notwithstanding the stormy times of the French Revolution and the stirring events going on all round him in Paris, Haüy continued to study his crystals in order to complete his observations; and then he embodied his investigations and his theories in his famous "Treatise on Crystallography." This attracted attention not only on account of the evident novelty of the subject, but more especially because of the very thorough method with which Haüy had accomplished his work. His style, says the historian of crystallography, was "perspicuous and elegant. The volume itself was noteworthy for its clear arrangement and full illustration by figures." In spite of its deficiencies, then deficiencies which must exist in any ground-breaking work--this monograph has had an enduring influence. Some of the most serious flaws in his theory were soon brought to light because of the very stimulus afforded by his investigations. {187} As to the real value of his treatise, perhaps no better estimate can be formed than that given by Cuvier in his collection of historical eulogies (Vol. III, p. 155): "In possession of a large collection, to which there flowed from all sides the most varied minerals, arranged with the assistance of young, enthusiastic, and progressive students, it was not long before there was given back to Haüy the time which he had apparently wasted over other things. In a few years he raised up a wondrous monument, which brought as much glory to France as it did somewhat later to himself. After centuries of neglect, his country at one bound found itself in the first rank in this department of natural science. In Haüy's book are united in the highest degree two qualities which are seldom associated. One of these is that it was founded on an original discovery which had sprung entirely from the genius of its author; and the other is that this discovery is pursued and developed with almost unheard-of persistence down even to the least important mineral variety. Everything in the work is great, both as regards conception and detail. It is as complete as the theory it announces." It was not surprising, then, that, after the death of Professor Dolomieu, Haüy should be raised to the chair of mineralogy and made director of that department in the Paris Museum of Natural History. Here he was to have new triumphs. We have already said that his book was noted for the elegance of its style and its perspicuity. {188} As the result of this absolute clearness of ideas, and completeness and simplicity of expression, Haüy attracted to him a large number of pupils. Moreover, all those interested in the science, when they came in contact with him, were so charmed by his grace and simplicity of manner that they were very glad to attend his lectures and to be considered as his personal friends. Among his listeners were often such men as La Place, Berthollet, Fourcroy, Lagrange and Lavoisier.