taste. The worker who wishes to make the most of every slide will
do well to cut his own masks, not only because of the fact just
mentioned, but also because he can suit the size of the opening to
the requirements of each slide. Slides can be works of art just as
much as prints; so that masking a slide becomes just as important
as trimming a print, and equally worthy of individual treatment.
It is folly to give each slide a mask opening of uniform size and
shape.

When many slides are to be masked, it becomes tedious work to
treat each one separately, unless some special device is used. The
accompanying drawing shows a way to mark masks which is simple,
practical and costs nothing. The drawing is exactly lantern slide
size.

Lay the slide over such a guide and note the size of the opening
best suited to the picture. This will be determined by the
intersection of the ruled lines, which are numbered for
convenience in working. If the size wanted is No. 4 for width and
No. 2 for height, place the guide over a piece of black mask paper
and prick through the proper intersections with the point of a
pin. This outlines the desired

[Illustration: Form for Marking Out Rectangular Lantern Slide
Masks]

opening, which may then be cut out easily with a knife and
straight edge.

The black paper from plate boxes and film rolls is excellent for
making masks. It should be cut up in pieces 3-1/4 by 4 in. and
kept ready for use at any time.

** Relieving the Weight of a Talking Machine Reproducer [245]

Too loud reproduction from a record, the scratching noise
sometimes heard and the forcing of the needle into a soft record,
because the extension arm and reproducer are too heavy, can be
remedied in the following manner: Attach a small ring to the under
side of the horn and use a rubber band to lift the extending arm
slightly.
--Contributed by W. A. Jaquythe, Richmond, Cal.

** How to Make a Thermometer Back in Etched Copper [246]

Etching copper is not a very difficult process. Secure a sheet of
No. 16 gauge copper of the width and length

[Illustration: Copper Thermometer Holder]

wanted for the back of the thermometer. In the design shown the
extreme width is 3-1/2 in. and the extreme length 7 in.

Draw a design. The one shown is merely suggestive. The worker may
change the outline or proportions as desired. The decoration, too,
may be changed. The essential thing is to keep a space upon which
to place the