Manuscript text, by William Salmon, on Vitruvian principles of architecture. The volume includes 84 leaves of illustrations, all in pen and brown ink, with gray wash. It is likely that the entire manuscript is in Salmon's hand. The work was almost certainly intended for publication, but never actually published. The text and illustrations are clean, with minor revisions and additions; it is probably a late draft. All leaves of text are ruled in graphite. Illustrations also show the use of working lines made in graphite. The preliminary unnumbered plate is a drawing for an added engraved title page. Pages and "plates" are numbered in separate sequences.
As in Salmon's successful published works, the present manuscript endeavors to appeal to a wide audience. The preface (pages 1-10) offers a brief summary of architectural history up through Inigo Jones, with an emphasis on the Greeks and Romans. Salmon notes that his work on Vitruvian principles will be especially useful to an English audience because Vitruvius's "works are writ in the French toung, scarce, and hard to come at, and of a great price." In his preface, Salmon states his intention to simplify certain concepts: "And as Vitruvius hath proportioned his orders of columns in a very intricket manner, I have reduced his proportions to modules and minutes, as being the best and most easiest method for the practis of the leaner ..."
The illustrations are the core of the manuscript. The text describes each illustration, one plate at a time, with notes on the techniques used in each design. Many of the illustrations show the geometric shapes underpinning the proportions of various designs, with frequent use of a compass. Some of the designs include measurements; others are keyed with letters or numbers, to facilitate description in the text. Plates 1-29, and pages 1-50, describe the five classical orders: Tuscan, Doric, Ionic, Corinthian, and composite. The middle portion of the manuscript shows elaborations on these orders, incorporating the ideas and designs of the likes of Palladio, Serlio, Le-Clerc, Inigo Jones, and James Gibbs. Plates 67-84 depict designs for vases, described in pages 82-91 of the text. A final unnumbered illustration, "Two different designs for book cases", was probably not intended for publication.