of the De Natura Deorum with the exception of the fragmentary Harleian no. 2622 (K), and is closely allied with the oldest of all the MSS, the Vienna Codex of the 10th century (v). I have inserted a full collation of the Merton Codex amongst Mr Swainson's Collations of English Mss, showing such a remarkable resemblance between it and v, that the one might easily be supposed to have been copied from the other.

As regards the Commentary I have again to thank Mr H. J. Roby and my brother, the Cambridge Professor of Latin, both for their careful criticisms of my own work and for the notes to which their initials are attached. I have also to thank Prof. W. G. Adams of King's College, and my kind neighbours Dr Woolley and Dr Henry Kane, for allowing me to consult them in regard to physical, astronomical or physiological difficulties. We are greatly in want of good books in English on the history of Ancient Science, especially of Astronomy, which occupies so large a space in this portion of Cicero's treatise. The best known English work on the subject, that by Sir G. C. Lewis, is utterly unmethodical, a mere collection of unconnected essays; while the famous French history of Delambre consists mainly of analyses of particular treatises, and is too technical for ordinary readers, not to mention its occasional carelessness in points of detail, of which an example may be seen in the account of Posidonius cited in my note on § 92 multis partibus. Schaubach's Geschichte der griechischen Astronomie is more

helpful to a scholar, but unfortunately it only comes down to Eratosthenes; and Rudolf Wolf in his excellent Geschichte der Astronomie is only able to allow a limited space to the Astronomy of the Ancients.

While I have been engaged in the study of the scientific writings of the Old World, it has often occurred to me to deplore the neglect into which they have fallen amongst ourselves. The early guesses of Greek science exhibit in a most interesting way the development of the human mind, and they are so closely connected with the philosophy of their time, that it is scarcely possible to form a right estimate of the one without knowing something of the other. Why might not Cambridge, which has now admitted into her final classical school the Art, Philosophy, History and Law of the Ancients, add to these also the Science of the Ancients as a new alternative subject? It would be easy to have examinations in Mathematical and Biological Science in alternate years; and, if in one year students were asked to bring up for examination specified treatises of such authors as Euclid, Archimedes, Geminus and Ptolemy, and in another year portions of Aristotle, Theophrastus, Pliny and Galen, particularly the De Usu Partium of the last, I think it would not only call attention to some very excellent and much neglected writings, but also provide a useful link between our literary and our scientific education.