a rock.

A most extraordinary blunder was made
in _Scientific American_ eight or ten years
ago. An engraving of a handsome Chelsea
china vase was presented with the
following description: ``In England no

regular hard porcelain is made, but a
soft porcelain of great beauty is produced
from kaolin, phosphate of lime,
and calcined silica. The principal works
are situated at Chelsea. The export of
these English porcelains is considerable,
and it is a curious fact that they are
largely imported into China, where they
are highly esteemed. Our engraving
shows a richly ornamented vase in soft
porcelain from the works at Chelsea.''
It could scarcely have been premised
that any one would be so ignorant as
to suppose that Chelsea china was still
manufactured, and this paragraph is a
good illustration of the evils of journalists
writing on subjects about which they know
nothing.

Critics who are supposed to be immaculate
often blunder when sitting in judgment
on the sins of authors. They are
frequently puzzled by reprints, and led into