Take the butt end of a quill, A, from a chicken, goose or turkey feather—­the latter preferred as it will hold more ink—­and clean out the membrane in it thoroughly with a wire or hatpin.  Then make a hole in the tapered end of the quill just large enough to pull through a piece of cotton string.  Tie a knot in one end of this string, B, and pull it through the small end of the quill until the knot chokes within, then cut off the string so that only 1/4 in. projects.  Shave out a small stopper from a bottle cork for the large end

[Illustration:  Fountain Attachment]

of the quill.  This completes the ink reservoir.

Place the quill on top of the penholder C, so that its small end rests against the pen immediately above its eye.  Pull the string through this eye.  Securely bind the quill to the pen and holder with a thread, as shown, first placing under it a wedge-shaped support of cork or wood, D, hollowed on both sides to fit the curved surfaces of the quill and holder.  The illustration shows the detail clearly.

To fill the reservoir place the pen upright on its point and dip a small camel’s-hair brush or cloth-bound toothpick into the ink bottle and “scrape” off the ink it will hold on the inner edge of the quill.  Cork tightly, and the device is ready for use.  When not in use place the holder at an angle with the pen uppermost.  —­Contributed by Chelsea C. Fraser, Saginaw, Michigan.

** How to Construct a Small Thermostat [455] By R. A. McCLURE

It is a well known fact, that there is a change in the dimensions of a piece of metal, due to a change in its temperature.  This change in dimensions is not the same for all materials; it being much greater in some

[Illustration:  Simple Thermostat; Couple and Mounting Strip]

materials than in others, while in some there is practically no change.

If two thin, narrow strips of different metals, that contract or expand at different ratio due to a variation in temperature, be rigidly fastened together at their ends, and the combination then heated or cooled, the combined piece will have its shape changed.  One of the pieces will increase in length more than the other, due to a rise in temperature, and this same piece will decrease in length more than the other when subjected to a decrease in temperature.

If one end of this combined piece be rigidly clamped to a support, as shown in Fig. 1, and the combination then have its temperature changed, the free end will move to the right or left of its original position, depending upon which of the pieces changes in length the more.  If there is a rise in temperature and the right-hand piece B increases in length faster than the left-hand piece A, the free end of the combined piece win move to the left of its original position.  If, on the other hand, there is a decrease in temperature, the right-hand piece will decrease in length more than the left-hand piece, and the upper or free end will move to the right of its original position.