and have chosen such as were likely to instruct and enlighten.
In
Parts iv. and v. it was necessary to introduce some of the elements of
crystallography, without which those two important chapters would have
lost a great part of their value. We have treated the subject, however,
as briefly as possible, but, at the same time, in a strictly scientific
manner. To attempt to popularize science, by stripping it, as is so
often done, of that which constitutes its very essence, is not to
popularize, but to disfigure and travesty it.
The
part devoted to counterfeit precious stones will not be "one of the
least useful. The facts which it contains will carry their own
teaching with them, and of this the purchasers of precious stones will
know how to avail themselves.
In
another part the methods are explained, by means of which modern
savants have succeeded in producing the majority of the precious
stones. These methods, and the remarkable results obtained by the
employment of them, have hitherto remained locked up in collections of
scientific papers, or in special treatises. We are glad to have had the
opportunity of first making them known to the public at large.
The
illustrations interspersed through the book all reproduce as
accurately as possible by engraving the objects they profess to
represent, and none of them are fancy sketches. The utmost care has
been bestowed on this department: for, if the engraver's art is one of
the
