_Fol. 142^a_, COLOPHON: EXPLICIT LIBER ETHIMOLOGIARVM ISIDORI
HISPALENSIS EPISCOPI.

Folio. Quires [1-13^{10}, 14^{12}], 142 leaves, the first blank, 2
columns, 51 lines to the column, without signatures, catchwords,
pagination, printer's name, place or date. Gothic lower-case type,
roman capitals. Book and chapter headings printed wholly in
majuscules. Large woodcut diagrams. Three-to nine-line spaces left
for chapter and book initials, also spaces for occasional Greek
words (mostly left unsupplied) and for small diagrams. Two
pinholes, which in Mentelin's use point to a date not later than
1473. Hain *9270. Brit. Mus. 15th cent., I, p. 57 (IC. 586). Burger
pl. 170.

On the first page large illuminated initial with floral border ornament,
and similar initials at the head of the several books. Chapter initials
supplied in red or blue; initial-strokes in red throughout the volume.
Blank first leaf wanting.

Incorporated with the present edition of the Etymologiae by way of
supplement, though not named in the table of contents, is an earlier
treatise of Isidore's entitled _De natura rerum_, written at the request
of Sisebut, king of the Visigoths, 612-621, and dedicated to him. It
contains the sum of the physical philosophy of his time, and, being
largely astronomical, is sometimes found in the MSS. under the title
_Liber de astronomia_. In order to bring it into immediate connection
with the corresponding section of the Etymologiae, it is placed
immediately after the third book (devoted to the _quadrivium_, the last
division of which is astronomy) and given irregularly the heading "Liber
quartus," the regular _Liber quartus (De medicina)_ beginning twenty