Divide one of its extremities to a length of about half an inch in four, five or six parts, which separate slightly, so as to form a truncated cone.
After having thus prepared the straw, take a dry pea, with a larger diameter than that of the tube, and place it in the cone. Hold the tube upwards, and blow into it at the opposite end.
The pea will be forced upward by the air column which you blow into the tube. It will remain suspended in the air as long as the interior pressure continues, then fall back into the arms of the cone.
To vary that experiment pass a long pin through the pea, the point of which is turned into the tube. When well thrown up, the pea can be maintained at a distance of two or three inches from the mouth of the straw. According to the stronger or weaker blast of breath, the pea will go up or down.
To Acquire a True Eye.
Here is a peculiar and clever recreation, easily performed, though at first sight it may appear difficult.
Put a tumbler upside down. By means of bread crumbs, fix a match vertically on the top. On the edge of the table place another match, partly raised on a piece of cork or wood.
Stoop down and aim at the vertical match on the glass, so that the one on the table is in the exact line of fire.