heen is produced by
polarization of the light in some manner, or whether it is at all
analogous to fluorescence, is yet to be decided. The impression of the
surface with fine microscopic lines might produce an iridescence, but
not separate and clearly defined hues. The ware was intended for
ornamental purposes, not for household use; and it was suspended
against the rich, dark tapestries of the period with which walls were
covered, thus aiding, as it were, in illuminating the apartment with
its exquisite radiance.

* * * * *

THE BLUE GLASS DECEPTION.

On September 26, 1871, General A.J. Pleasonton, of Philadelphia, Pa.,
obtained a patent for "utilizing the natural light of the sun
transmitted through clear glass, and the blue or electric(!) solar
rays transmitted through blue, purple, or violet colored glass, or its
equivalent, in the propagation and growth of plants and animals." In
his specification, of which the above constitutes one claim, he states
that he has discovered "special and specific efficacy in the use of
this combination of the caloric rays of the sun and the electric blue
light in stimulating the glands of the body, the nervous system
generally, and the secretive organs of man and animals." He also
states that he finds that vegetation is vastly improved by the
transmitted blue light. These alleged re-discoveries--for the General
only claims to have devised the method of utilizing them--were
extensively promulgated through the press early in 1871. Subsequently,
in 1876, General Pleasonton published a book on the subject, the
volume being appropriately bound in blue and printed in blue ink.
Recently public attention has again been called to the subject by a
New York daily journal. The peculiar kind of glass in question is
known as "pot metal blue," that is, it is stained a bluish violet
throughout, and is not clear glass covered with flashings of blue
glass. It is used in greenhouses, etc., in connection with clear
glass; and in General Pleasonton's grapery it appears that only every
eighth row of panes was blue. Some of the results alleged to have been
obtained by exposing animals and plants are as follows: Twenty grape
vines, in their second year, after being set out under the blue glass,
bore 1,200 lbs. of splendid fruit. A very weak Alderney bull calf was
in four months developed into a strong and vigorous bull. Heifers when
kept under blue glass may safely