This dissertation is published in accordance with the conditions attached to the Hare Prize, and appears nearly in its original form. For many reasons, however, I should have desired to subject the work to a more searching revision than has been practicable under the circumstances. Indeed, error is especially difficult to avoid in dealing with a large body of scattered authorities, the majority of which can only be consulted in a public library.<br><br>The obligations, which require to be acknowledged for the present collection of the fragments of Zeno and Cleanthes, are both special and general. The former are soon disposed o£ In the Neue Jahrbucher fur Philologie for 1873, p. 430 foll., Wellmann published an article on Zeno of Citium, which was the first serious attempt to discriminate the teaching of Zeno from that of the Stoa in general. The omissions of Wellmann were supplied and the first complete collection of the fragments of Cleanthes was made by Wachsmuth in two Gottingen programs published in 1874 - 1875 (Commentationes I et II de Zenone citiensi et Ckanthe Assio). Mullach's collection of the fragments of Cleanthes in vol. I of the Fragments Philosophorum Graecorum is so inadequate as hardly to deserve mention.