Category Archives: Experiments

Phosphorus

Hennig Brand, (flourished 1670, Hamburg [Germany]), German chemist who, through his discovery of phosphorus, became the first known discoverer of an element.

A military officer and self-styled physician, Brand has often received the undeserved title “last of the alchemists” because of his continual search for the philosopher’s stone, which reputedly could change base metals into gold. About 1669 he isolated from urine a white, waxy material and named it phosphorus (“light bearer”), because it glowed in the dark. Although Brand kept his process a secret, phosphorus was discovered independently in 1680 by an English chemist, Robert Boyle.

Arabian alchemists of the 12th century may have isolated elemental phosphorus by accident, but the records are unclear. Phosphorus appears to have been discovered in 1669 by Hennig Brand, a German merchant whose hobby was alchemy. Brand allowed 50 buckets of urine to stand until they putrified and “bred worms.” He then boiled the urine down to a paste and heated it with sand, thereby distilling elemental phosphorus from the mixture. Brand reported his discovery in a letter to Gottfried Wilhelm Leibniz, and, thereafter, demonstrations of this element and its ability to glow in the dark, or “phosphoresce,” excited public interest. Phosphorus, however, remained a chemical curiosity until about a century later when it proved to be a component of bones. Digestion of bones with nitric or sulfuric acid formed phosphoric acid, from which phosphorus could be distilled by heating with charcoal. In the late 1800s James Burgess Readman of Edinburgh developed an electric furnace method for producing the element from phosphate rock, which is essentially the method employed today.

The Obedient Coin

Take an ordinary wooden matchbox, and remove the drawer holding the matches. In the center place a small coin, a cent will be the best for the experiment, the object of which is to make the coin fall into the interior without touching it. Tap lightly on that side of the box to which you desire the coin to come, until it rests upon the edge.

Then slightly raise the end of the box whereon the coin rests, and lightly tap with the finger once more. At once the coin will fall into the box. The secret of the experiment is this: the taps on the box only move the box, while the coin retains its position by reason of its own inertia, until the edge of the box reaches it. The last tap knocks away the support, and the coin, obedient to the law of gravity, falls vertically into the interior of the box. This little experiment is easily performed, and extremely interesting when done neatly.

The experiment

[T]ake a fresh egg and wrap it round with this divine Pantagruelion. Thus wrapped up, put it in a brasier, as large and hot as you like. Leave it there as long as you like. At last you will take out the egg cooked, hard, and burnt, without alteration, change or over-heating of the sacred Pantagruelion. For less than fifty thousand Bordeaux crowns, reduced to the twelfth part of a mite, you may make the experiment.

– Rabelais, The Third Book of Pantagruel, chapter 52