The Foundations of Chemistry

CC The Development of Science

HEMISTRY IN USE

The Discovery of Phosphorus

Technology and its impact on society have always been

intriguing subjects for artists. This was particularly true dur-

ing the industrial revolution, when chemistry was on the

verge of transforming itself from alchemical “magic” into a

scientific discipline. It is easy to see how the scientist, toil-

ing away in a laboratory full of strange equipment and trying

to make sense of the natural world, held a certain heroic

appeal to artists.

One of the more romantic accounts of chemical activity

during that period is The Alchymist in Search of the Philoso-

phers’ Stone Discovers Phosphorus(1771) by the English painter

Joseph Wright of Derby (1734–1797). In Wright’s depiction,

a stately, bearded alchemist has just isolated a new element

by distillation. As the substance collects in the flask it begins

to glow in the dark, illuminating the laboratory with an eerie

white light and bringing the imaginary scientist to his knees

in wonder. The element phosphorus was in fact named for

this property—phosphorescence—with both words deriving

from the Greek phosphoros, or “giving light.”

The actual discovery of elemental phosphorus was prob-

ably not quite as dramatic as Joseph Wright envisioned. It

was first isolated from urine by the German chemist Hen-

ning Brand in 1669, by a much more laborious process than

the one represented by the tidy distillation apparatus in

Wright’s painting. The first step of the preparation, as

described in a 1726 treatise entitled “Phosphoros Elemen-

talis,” in fact involved steeping 50 or 60 pails of urine in tubs

for two weeks “... till it putrify and breed Worms”—hardly

a fitting subject for eighteenth century artwork!

The glowing material was of such novelty that two of

Brand’s scientific contemporaries offered to find a royal buyer

for his process. Expecting a bigger reward at a later date,

Brand gave the two the recipe for phosphorus in exchange

for some small gifts. However, one man instead claimed the

discovery for himself after repeating Brand’s work in his own

laboratory. Through the other, Brand did receive a contract

with the Duke of Hanover for the preparation of phospho-

rus; however, he was dissatisfied with his pay, and it was only

after writing a number of complaint letters (and enlisting his

wife to do the same) that he finally received what he felt was

fair compensation for his discovery.

A number of other eighteenth-century scientific tableaux

were immortalized by Wright. He was particularly fascinated

by light and shadow effects. This, combined with his inter-

est in technological subjects (the town of Derby played an

important part in the beginnings of the industrial revolution),

led him to use other unusual objects, such as glowing iron

ingots (Iron Forge, 1772) and laboratory candles (Experiment

on a Bird in an Air Pump, 1786), as focal points in paintings

of industrial or scientific scenes.

Lisa S. Boffa

Senior Chemist

Exxon Corporation

The Alchymist in Search of the Philosophers’ Stone Discovers

Phosphorus,by Joseph Wright (1771).

128 CHAPTER 4: Some Types of Chemical Reactions