An Alarm Clock with a Wood Covering Ornamented and Finished in Mission Style
The sketch shows a design which is neat and easily made. Accurate dimensions cannot be given as these will vary with the size of the clock. Quarter-sawed oak, 1/4 in. thick, is the best material to use. The front and back can be cut on a jigsaw, the opening for the clock face being cut slightly smaller than the metal of the clock so that only the face shows. An opening in the back piece should be cut a little smaller than the one in front, to provide a free opening for winding the clock. Fasten the parts together with small round-head brass brads or screws and finish to match the furniture. A small desk clock can be made in a similar manner, using a cheap watch instead of the alarm clock.—Contributed by C. E. Hamann, Somerville, Mass.
Mixing Sulphuric Acid
One of the first lessons given a student in chemistry is how to mix sulphuric acid with water. This would naturally be supposed to be very easy, yet, if it is not done right, it will surely result in injury to the person doing the mixing.
The specific gravity of sulphuric acid is 1.849 and, on account of its chemical attraction to water, great heat is set up or generated when the two are being mixed. If the acid is put into a jar and the water poured onto it, they will be temporarily separated, as the heavy acid will remain at the bottom, the chemical reaction taking place on the dividing line only. This soon generates heat which rapidly increases until steam is formed. Then the water boils over and finally becomes a bubbling volcano which readily ejects the contents of the jar. As the mixture at this moment is very hot, bad burns will be the result, which are aggravated by the biting of the acid; and clothing or anything that it comes in contact with will be ruined or badly damaged. Always remember this caution: add the acid to the water.
The following is the proper way to proceed in mixing sulphuric acid as well as other acids of lighter weight. Place the water in a jar and pour the acid in, a little at a time, stirring the mixture with a wooden stick. The mixing process will always heat the solution, which in many instances, must be allowed to cool before using.
A Chinese Pagoda
Fold the end of a long and narrow strip of paper over several times as shown in Fig. 1 and roll the entire length over a stick, then remove the roll and crease, or make it flat, as shown in Fig. 2. Make two cuts with a sharp knife centrally so that they reach to the several folds first made on the inner end of the paper, then cut the fold in the paper between the cuts as shown in Fig. 3, and bend the ends over to form the shape in Fig. 4. Insert the knife blade under the first fold and draw it out until the paper takes the form in Fig. 5.
Stages in Making the Strip of Paper into the Finished Pagoda (Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5)