To accomplish this seemingly incredible act requires the following preparation: You must take an egg and soak it in strong vinegar, and in process of time its shell will become quite soft so that it may be extended lengthways without breaking; then insert it into the neck of a small bottle, and by pouring cold water upon it, it will reassume its former figure and hardness. This is really a complete curiosity, and baffles those who are not in the secret to find out how it is accomplished. If the vinegar used to saturate the egg is not sufficiently strong to produce the required softness of shell, add one teaspoonful of strong acetic acid to every two tablespoonfuls of vinegar. This will render the egg perfectly flexible, and of easy insertion into the bottle, which must then be filled with cold water.