This telescope consists of a series of square wooden tubes, with an inside diameter of about five inches, so carefully joined together that no ray of light can find its way in through the crevices. The oblique lines are pieces of looking-glass, with their faces turned toward each other. Now, by placing the eye at E, of course it would seem that anything at H could be seen directly through the tubes A B, while if a book or other opaque object be interposed, as shown in Fig. 2, it would seem equally a matter of course that the view would be obstructed; this, however, is not the case, as the mirrors reflect the object through the tube and it appears as plainly as when the book is removed.
To those unfamiliar with its construction this magic telescope, by which you apparently see through a solid substance, is an unfailing source of wonder.
The object at H should be quite brilliantly lighted, as some of the rays are absorbed in the passage of the reflection through the tube; especial care should also be taken to place the mirrors at a slant, exactly midway between the horizontal and the upright, or, to speak more scientifically, at an angle of 45 degrees to the line of the tubes.
The tubes A and B should not be so far apart at the place where the book is inserted as to permit the backs of the mirrors to be easily seen.
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TO CRYSTALLIZE GRASSES, SEED-VESSELS, Etc.
Take a large-sized piece of alum, and pour over it a pint of boiling water, letting it stand until the water has taken up or dissolved all the alum it will. If at the end of a few hours any alum remains undissolved, you may be sure the water contains all the alum it can hold in a liquid state, and the solution is called a “saturated solution of alum.”
During the summer, while the grasses are in their most perfect state, select such as you think will look well crystallized, and put them into a vase or wide-mouthed bottle to dry, being careful to spread them well apart, so that they may retain their perfect shape in drying. If the season of grasses should pass before you have a chance to collect them, the season of weeds is always at hand. Any boy, in his wanderings over marsh or mountain, through woods or our quiet village street, during even the coldest winter months, could not fail to see some beautiful sprays of seed-pods crowning many of our most common weeds, which if crystallized, would make a very pretty and acceptable present to mother for the corner bracket, or the shelf which seemed just a little bare before. Having secured your grasses or weeds, both together if you like, and having your saturated solution of alum at hand, lay as many tops of the grasses in a flat dish as will fill it without crowding, then pour the liquid over them, being careful that the parts you wish crystallized are under the surface. Let them lie in this position until well coated with the alum. When finished remove them and put in others. Continue in this manner until all are treated. If only a few crystals are desired they may be obtained by dipping the heads one at a time in the solution and slightly shaking them after each immersion. When all have been dipped, commence with the first and repeat the process. Do this until the crystals formed are as large as you wish them to be.
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