“If mercury has often ministered to vanity and folly,” said the Thimble, “I remember hearing of one curious instance where it served to mortify them both. A dashing lady, who was absurd enough to try to increase her beauty by covering her yellow complexion with a delicate coating of white paint, once visited a quicksilver mine. She must have felt it strange to find herself in that gloomy place, where the sickly miners, by the glare of torch-light, pursue their unwholesome occupation.”
“Why should it be unwholesome?” I asked.
“Because mercury is of that poisonous nature, that it is said that those employed to procure it seldom live longer than two years in the mine.”
“I should think that after learning that,” observed I, “the dashing lady would have a feeling of pain when next she looked in a mirror.”
“Probably she had,” replied the Thimble, “but from a different cause. While she had been examining the mine, she little thought of the strange effect which the mercury would have on the paint which covered her face. She entered the place white like a lily; she left it black like a negro!”
The idea of the poor lady with her black face mightily tickled the fancy of the Scissors, who wished that she had been there to see her. But my curiosity about the strange metal mercury was not quite satisfied yet.
“What was the use of that instrument hung on the wall, where the quicksilver lay in its little glass ball, till Master Eddy broke its prison and set it free?”
“That instrument is called a thermometer. It is employed to measure the heat of the weather.”
“I cannot imagine how it can do that.”
“It is the nature of mercury to expand—that is, grow bigger—whenever it is exposed to heat. At the top of the glass ball there is a slender glass tube. When the weather is warm, the mercury swells; and the ball being too small to hold it, it is forced up the tube to a greater or less height, according to the amount of the heat.”