on satin books, and it is also found more commonly upon them; but as I
have put the canvas books first for the purpose of description, and the
'thread' occurs in one of them, this is the best place to put its
description. This thread I call 'Purl,' and a thread with this name is
mentioned in several places as having been used in England in the
seventeenth century; but there is no description of it, so that this
thread may not be the 'purl' mentioned by the seventeenth-century
writers, but if it is not, I do not know what purl is, neither do I know
any other special name for the thread. In order that there may be no
doubt as to what I mean by purl, I will shortly describe the thread as I
know it.

First there is a very fine copper wire; this is closely bound round with
coloured silk, also very fine, and in this state it looks simply like a
coloured thread. Then this coloured thread is itself closely coiled
round something like a fine knitting-needle--in fact I have made it on
one--and then pushed off in the form of a fine coiled tube. The thread
is always cut into short lengths for use, and on books these short
lengths are generally threaded and drawn together at their ends,
making, so to speak, little arches--so that although on the under side
of the material there is only a tiny thread, on the upper side there is
a strong arch, practically of copper. On boxes and other ornamental
productions of this same period, pieces of purl are not infrequently
found laid flat like little bricks; and houses, castles, etc., are often
represented by means of it; but on books the general use is either for
flowers, grounds, or (in very small pieces) to keep on spangles.
Obviously any coloured silk can be used in making this thread, so that
it may be said that for coloured silk work, where strength is required,
flowers worked in purl are the best. The colours used when roses are
represented are usually graduated,--yellow or white in the centre, then