The companions of Pallas had suffered still more severely; scarcely one of them lived long enough to draw up an account of his travels; and it was therefore left to him to render this piece of justice to their memory. For himself, the splendid objects which he had beheld had made too profound an impression on his mind to allow of his being satisfied with the accounts of them which he had hastily traced in his journal. He therefore determined upon the publication of several separate works, which should contain the natural history of the most celebrated quadrupeds of Siberia; and these he actually laid before the public, together with descriptions of a great number of birds, reptiles, and fishes. In addition to all these, he even projected a natural history of all the animals and plants in the Russian empire; in which design, though it was never completed, he made a very considerable progress. The empress herself, worthless and profligate as she was, was possessed by the ambition of being regarded as the patron of the sciences, and in order to facilitate the execution of our traveller’s project, communicated to him the herbariums of several other botanists, who had studied the flora of the empire. To secure the completion of the undertaking, Catherine moreover engaged to furnish the expense of the engraving and printing of the work; but the end was not answerable to this magnificent beginning; projects of more vulgar ambition, or vile and despicable amours, too fully occupied the imperial mind to allow so unimportant a thing as the science of botany to command a thought, and Pallas was constrained to rely upon his own resources for making known his botanical discoveries to the world. The same fate attended his works on the natural history of the animals and insects of the empire. M. Cuvier, whose capacity to appreciate the labours of a scientific man can scarcely be called in question, observes, that it is seldom that very laborious men possess sufficient tranquillity of mind to conceive those root-ideas which produce a revolution in the sciences; but Pallas formed an exception to this rule. He nearly succeeded in changing the whole aspect of the science of zoology; and most certainly did operate a complete change in that of the theory of the earth. An attentive consideration of the two great chains of mountains of Siberia enabled him to discover this general rule, which has been everywhere found to hold good, that there exist three primitive orders of mountains, the granitic in the centre, the schistous next in succession, and the calcareous on the outside. It may be said that this great discovery, distinctly announced in a memoir read before the academy in 1777, gave birth to the modern science of geology: from this point the Saussures, the Delues, and the Werners proceeded to the discovery of the real structure of the earth, which is so exceedingly at variance with the fantastic ideas of preceding writers.