A curious effect may be obtained by a magic lantern slide made as follows:—Tint vaseline with cochineal and place some between glasses of the magic lantern slide size, making a kind of vaseline sandwich. Put this slide in the lantern and focus it, and then insert a knife point a little way between the two pieces of glass and so let them be alternately forced asunder and drawn together. The effect upon the vaseline as seen upon the sheet is very peculiar.
Three Ways of Making a Hectograph.—It happens often that a boy, especially if he be the secretary of a cricket or football club, needs to send away many letters or notices, all alike; and few things are so wearisome as this writing of the same thing over and over again. If he will make for himself a hectograph he need write his notice no more than once and yet he may have more copies than he is likely to need. Here is the mixture that will prove so useful: gelatine, 4 ounces; glycerine, 15 fluid ounces; carbolic acid, ½ fluid ounce; water, 15 fluid ounces. First add the water to the gelatine and let it stand until the gelatine is quite soft. Now place all this in the glycerine and heat it over the fire until the gelatine has been dissolved, and then until the water has passed away in steam. The carbolic acid is to keep the mixture from turning sour, and it must be added gradually now, before cooling begins. Pour the whole into some shallow tray like the lid of one of those square tin boxes in which grocers keep biscuits. When the mixture has become firm and cold it is ready to be used.
Get a bottle of aniline ink and write or sketch whatever you desire to multiply. When the ink is dry place your letter or drawing face downwards upon the pad you have made with the gelatine. Rub the back of the paper with your hand to force the ink upon the gelatine. When the paper has been upon the hectograph for some time strip it off and you will find that your drawing or writing has been transferred to the gelatine. If you now press clean paper upon this drawing or writing it will be printed upon the paper, and so you may have copy after copy.
When you have as many as you need clean the surface of the hectograph for the next time you wish to use it. This may be done with a soft sponge and tepid water, but this process being rather tedious, most boys will be pleased to hear of an easier method, though it causes the hectograph in time to lose its clean appearance. Put it in the oven and let it melt, and when it is cold again it will be ready for the next letter or drawing.
The following is another way to make a hectograph: Take of pure glycerine, 9 parts; water, 6 parts; barium sulphate, 3 parts; sugar, 1½ parts; gelatine, 1½ parts. Mix well together, and allow all to stand for twenty-four hours; then heat gently over a slow fire until the whole is melted, stirring continuously until the various ingredients are thoroughly amalgamated. It may now be poured into the shallow tin or dish prepared to receive it, and allowed to stand for a day where it will be free from dust. It should not be used until absolutely cold and firm.
Here is another method we have found very successful. Take 2 ounces of fine Russian glue and 4 fluid ounces of cold water. Let the glue steep in the water until the water has been absorbed, or nearly so. Now place the glue and water in a vessel upon the fire until the glue melts. It need not boil. Add eight fluid ounces of common glycerine and six drops of carbolic acid, and also as much Paris white as will make the solution milky. Stir well and then pour the mixture into a shallow tray. In about twelve hours it will have set. For ink Judson’s purple dye will serve.
How to Make a Filter.—You should procure a common flower-pot, nine or ten inches deep. Put in a layer of animal charcoal two inches thick. Wood charcoal may be used, but animal charcoal—that is charcoal made from bones—is best. On this put a layer of well washed sand. For the way to wash sand see page 132. The layer is two inches thick. Then comes a two-inch layer of small pebbles, each about as large as a pea. At the hole at the bottom of the flower-pot should be a fragment of brick which fits the hole loosely. Put the filter on a stool or on a shelf. There should be a hole in the stool or shelf to correspond with the hole in the flower-pot, and under the hole a vessel to catch the filtered water. The first drops that come through the filter may not be clear, but in about a quarter of an hour clear water will commence to issue from the hole in the bottom of the flower-pot. Take out the sand and the pebbles and wash them thoroughly once in six weeks, and once in four months replace the vegetable charcoal.
The Syphon.—In aquarium work and in other occupations it is necessary sometimes to empty water from a vessel by means of a syphon. Suppose that we wish to empty a bucket. The simplest thing would be to take the bucket and turn it upside down. Suppose, however, the bucket were fast and could not be moved, or suppose there were some dregs or sediment in the bucket which we did not wish to disturb, then we should find a syphon useful. Suppose a bucket is on a table. One end of a pipe is in the water in the bucket and the other end is dangling down. Now if we can once induce the water to flow through the pipe the water will continue to run, although at first it has to run up-hill a little, a most unwaterlike proceeding. There are two ways of inducing the flow. If you take the lower end of the pipe and suck, water will be brought over the elbow. Or if before you put the pipe in position you fill it with water, it will flow, and in each case it will continue to flow until it has emptied the bucket; that is, if the pipe reaches to the bottom of the bucket.
How to Make a Fountain.—A fountain is based on the principle that water strives to find its own level. The water tries to rise as high as the reservoir which feeds it, and would succeed, but the pressure of the air prevents it. In a U tube the water keeps at the same level in each part of the tube, but if you were to cork one arm of the tube it would not come so high there, because the air would not allow it. The writer of this article when he was a boy made fountains for a fern rockery and for a garden aquarium in the following simple way:—Upon the garden wall he placed a bucket. At the bottom of the bucket he punched a hole and inserted one end of a length of india-rubber tube bought from a shop where they sell the appliances for the teaching of chemistry. At the same place he bought some pieces of glass tubing of such a size that it would fit inside the rubber tubing. Explain to the man in the shop, and he will know exactly what you need. Take a few inches of the tube and hold the middle of it in the gas flame, or in a Bunsen burner if you have one. When the glass is soft draw the ends asunder gently, and you will find you have two pieces of glass shaped like a fountain-pen filler. It may be that one end of each of these two pieces of tube may have been closed by this process, but all that needs to be done is to file the sharp point until you have come to where the tube is open again. This serves for the nozzle of the fountain. There were no fountain pens when the author made his fountain, and it has just occurred to him that perhaps the best thing would be to buy a fountain pen-filler at once and have your nozzle ready-made. If you make your own you may not get it right first time. It may be crooked or the opening too large or too small. However, there will be this advantage, you may make many nozzles, and so by changing them have a variety of sprays. The finer the opening the higher will be the jet. It is not difficult to apply the fountain to an aquarium. For a rockery it will be easy to arrange the pipe and nozzle, and to fix it in position with the stones.
Case for Shaving Papers.—Decide upon the size of paper you like best. Cut a piece of millboard, celluloid, or even thin wood the same size, and upon this paint an attractive design. Now cut a strip of the same material as wide as this piece, but only an inch, or less, deep. Arrange piece, paper and strip as in the sketch. A is the piece of millboard, B the sheets of paper, C the strip. At D E F bore holes and secure the whole with paper fasteners put through these. This pad may hang upon the wall with ribbon, but the design and not the strip should hang outwards. When all the pieces of paper have been used the paper fasteners may be unfastened, and a new set of papers introduced. The turned-down ends of the paper fasteners are ugly and are liable to scratch. Paste over them very neatly a strip of brown paper or other suitable material.