JAMES MITCHELL. 153 
nomical. Both were formed from hollow moulds. The 
pasteboard was first moistened, then laid on the mould. In 
making the one, a layer of fine sand was placed above it, 
and over that the weight intended to produce the impression. 
In making the other, the thin pasteboard was carefully forced 
into the hollow lines of the mould with a paper-folder ; small 
quantities of moist paper were then stuffed into the cavity to 
fill it, and over this the weight was laid till it was dried. A 
subsequent improvement has occurred, for which I am in- 
debted to the ingenuity of Mr Joun Rursven (the inventor 
of the Ruthven printing-press), who is now executing in brass 
a set of types adapted to this object. This consists in form- 
ing hollow moulds, of the size and shape of letter now fixed 
upon, and also letters in relief corresponding to them, by which 
the moistened paper or pasteboard may be forced into the 
moulds. This method produces an impression in a most cor- 
rect and speedy manner, and any word in one entire piece 
may be conveniently formed. The nature of these materials 
: is such as to enable any person, when in possession of sepa- 
rate letters, to fix them together extemporaneously, so as to 
form words which can either be kept in that state or taken to 
pieces at pleasure. The separate letters may be introduced in 
their proper order into a running case formed of paper or 
pasteboard, and the word will then have this appearance. 
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