D. CALDWELL, Clerk of the District of Pennsylvania. [Illustration: Autograph notes] PREFACE. Agreeably to the plan on which the following memoirs have been conducted, it will be perceived, that they contain a great variety of matter; of which, some particulars have a remote, others merely an incidental connexion, with the chief object of the work. There may perhaps be some readers, to whom the introduction of such matters as the _University of Pennsylvania_ and the _Medical School_ connected with it, the _Pennsylvania Hospital_, the _Philadelphia Library_, and the like, into the _Life of Rittenhouse_, will, on a cursory view, seem to have little or no affinity to that object. But when it is considered, that this work is designed to comprehend Memoirs, not only of Rittenhouse personally, but of several literary, scientific, and other public institutions, as well as of many eminent men, with which his individual history and the annals of his time were in various ways associated, it is presumed, that the slight sketches which have been taken of those matters, in passing along, will neither prove foreign to the nature of the present undertaking, nor uninteresting in themselves. As a citizen of Pennsylvania; as an inestimable public and private character; as a distinguished son of science, of great probity and extensive usefulness in society; in all these points of view, the History of Dr. Rittenhouse may be contemplated, as holding a relationship with almost every object connected with science and the arts, in his day, that could in any wise contribute to the well being of mankind in general, and his native country in particular. Conspicuous and eminently meritorious as he was, yet an insulated account of his talents, his virtues, and his personal services,—a bare specification of such qualities and merits as he possessed, abstracted from a due consideration of the state of society and circumstances resulting from it, taken in connexion with them, during the same period,—would not be equally intelligible and instructive; and, consequently, must prove less useful. For these reasons, the Memorialist has pursued that course which he conceives to be perfectly congenial with the main design of his work; as best calculated to promote its general usefulness, and most suitably adapted to render it interesting, even to those who read for amusement solely.