The custom is said to have originated among the Spanish nobility several centuries ago, when the first bug was educated and worn by a princess. The bug became greatly attached to the maiden, and partook of her moods and dispositions. When she was sad or disheartened the bug became sluggish; and when she was joyous and vivacious the bug was likewise lively in its movements. At her death, the bug pined away and died, too. Miss Nelson is very happy and justly very proud of her present. The insect is about the size of an ordinary black beetle. Around the body is firmly fastened a gold band. A gold strap is riveted to this and passes down the back around and under the body, and is welded upon the under side to the gold belt. Upon the back are tiny jewels set in gold and fastened into the shell. The coloring of the shell is a brilliant Nile green, edged with black. The movement of the bug gives flashes of variegated colors. Upon the under side is fastened a delicate gold chain which in turn is attached to a brooch. It is educated to eat from the lips. It understands various whistles and calls, and appears and disappears at the word of command.--_Globe_. RUSTLESS IRON is being manufactured in New York by a new process which, it is claimed, converts the surface of the metal into magnetic oxide of iron. This is done by subjecting it successively to the action of highly heated air and carbonic acid gas from coal fires. The process can be applied with most satisfactory results to water-pipes and architectural work. WEIGHING THE EARTH.--Prof. Proctor proposes to repeat in Florida an experiment to determine the weight of the earth, and mentions the results of the methods heretofore tried. Newton first estimated the weight of the earth to be between five and six times as great as that of water. Such a weight it would have if it were one half iron and the other half limestone, or half copper and half clay. Evidently the metallic weight preponderates. Weighing the earth is accomplished by comparing the effect of its attraction with that of much smaller bodies. One method is to compare, by balancing the weight of two balls, one above a globe of lead, as large as practicable, and the other below it, so as to have the attraction of the leaden globe pulling up and counteracting the gravitation to the earth. The effect is very slight and requires delicate apparatus.