PREFACE.

...a well-known astrological writer who died in 1623, which fixes the date of this manuscript at the end of the sixteenth or beginning of the seventeenth century. A glance at the manuscript shows that the figures were drawn at the same time as the text, as room was left on each page for their insertion. The style of the handwriting corresponds perfectly with this date. This version is referred to in this edition as manuscript D.

In 1825, another manuscript of the Greater Work Latin: "Opus Majus." was purchased for the Bodleian Library The primary research library of the University of Oxford.. It belonged at one time to Thomas Allen, the astrologer of Gloucester Hall, who early in the seventeenth century gave twenty manuscripts to the Bodleian. This one, however, passed into the possession of Sir Kenelm Digby A seventeenth-century diplomat, scientist, and philosopher., whose well-known signature and motto are inscribed on the first page. It is now numbered 235 of the Digby Manuscripts. The greater part of it dates to the fifteenth century. But a portion of it (pages 249–295) is written in an older and more beautiful hand, considered by Mr. Coxe Henry Coxe, a prominent nineteenth-century librarian and expert in ancient handwriting. to be of the fourteenth century. This section includes a considerable portion of the Optics Latin: "Perspectiva.".

These two manuscripts have been carefully collated A scholarly term for comparing different versions of a text to identify variations or errors. for the present edition. In the course of the comparison, unmistakable proof was found that the Dublin manuscript was a copy of the one in the Bodleian. At the close of page 470, column 2, of this latter volume, the sentence breaks off midway and is continued on the first line of page 487, column 1. An error of this kind, similar to that caused by the shuffling of sheets while binding a modern book, is easily explained. In the Dublin manuscript, the same rupture of the sentence occurs, but in the middle of a column (folio 224, column a, line 12), with the sentence being eventually continued on folio 229, column d, line 14. It may be added that these two manuscripts exhibit through—