A very handy tack puller can be made of a round-head bolt. On one side of the head file a V-shaped notch and screw a wood handle on the threads. This makes a very powerful puller that will remove large tacks from hardwood easily.

The Shape of the Head Permits a Leverage Action That Lifts the Tack Easily How to Make a Radium Photograph

Ill: The Shape of the Head Permits a Leverage Action That Lifts the Tack Easily How to Make a Radium Photograph

The radium rays, like the X-rays, affect the photographic plate, as is well known, but it would naturally be supposed that the enormous cost of radium would prevent the making of such a photograph by the amateur.

It is a fact, however, that a radium photograph can be made at home at practically no cost at all, provided the amateur has patience enough to gather the necessary material, which is nothing else but broken incandescent gas mantles. These (especially Welsbach mantles) contain a salt of the rare metal thorium, which is slightly radioactive. The thing to do, then, is to collect a sufficient quantity of broken mantles to cover the bottom of a small cardboard box - a dryplate box, for instance - with a layer of powdered mantle substance. Upon this layer and pressed tightly against it is placed a piece of cardboard; then some metal objects, a button, hairpin, a buckle, or the like, are laid on the cardboard and covered with a sensitized paper. This is again covered with a piece of cardboard and the box filled with crumpled paper to the top. The cover is then put on, the box tied up with a piece of string and set in some place where it is sure to be left undisturbed.

The radium rays from the powdered mantles readily penetrate the cardboard and paper, but not the metal articles. Being very weak, the rays must be given four weeks to accomplish their work. After that time, however, if the sensitive paper is taken out, pictures of the metal objects in white on a dark background will be found on it. These pictures will not be so sharp as ordinary photographs, because the rays are not focused, but they fairly represent the originals and the experiment is an interesting one.

A good imitation mahogany stain consists of 1 part Venetian red and 2 parts yellow lead, mixed with thin glue size, and is laid on with a woolen cloth.