such constant rubbing as will wear away the surface of the japan. But
japan coats applied with a priming coat crack and fly off in flakes at
the slightest concussion, at any knock or fall, more especially at the
edges. Those Birmingham manufacturers who were the first to practise
japanning only on metals on which there was no need for a priming coat
did not of course adopt such a practice. Moreover, they found it
equally unnecessary in the case of papier-mâché and some other goods.
Hence Birmingham japanned goods wear better than those goods which
receive a priming previous to japanning.


PRIMING or PREPARING THE SURFACE TO BE JAPANNED.

The usual priming, where one is applied, consists of Paris white
(levigated whiting) made into a thin paste with size. The size should
be of a consistency between the common double size and glue, and mixed
with as much Paris white as will give it a good body so that it will
hide the surface on which it is applied. But in particular work
glovers' or parchment size instead of common size is used, and this is
still further improved by the addition of one-third of isinglass, and
if the coat be not applied too thickly it will be much less liable to
peel or crack. The surface should be previously prepared for this
priming by being well cleaned and by being brushed over with hot size
diluted with two-thirds of water, that is provided the size be of the
usual strength. The priming is then evenly and uniformly applied with
a brush and left to dry. On a fairly even surface two coats of priming
properly applied should suffice. But if it will not take a proper
water polish, owing to the uneven surface not being effectually filled
up, one or more additional coats must be applied. Previous to the last
coat being applied, the surface should be smoothed by fine glass