1814: Spectral lines - The book of science

Spectral lines
Breakthrough
Spectral analysis
Commentary

Spectral lines

In the gaseous atmosphere of the sun
each element absorbed
a different combination of wavelengths leaving
its own pattern of dark lines visible
in the spectroscope
that Joseph von Fraunhofer in Bavaria built
using his famous achromatic lenses.
Peering through a small scope
mounted to calibrate a circular scale
von Fraunhofer counted 574
and measured the wavelengths of 324
spectral lines.
A pure scientific observation
began a sequence of inspirations
resulting in a practical tool
for chemical and astronomical
analysis.

Breakthrough

Isaac Newton didn’t get it.
William Hyde didn’t get it.
But after Joseph von Fraunhofer
everyone got it.
Robert Bunsen got it.
Gustav Kirchhoff got it.
William Huggins got it.
That each element
has its own absorption pattern,
that the chemical composition of laboratory samples
can be identified by their spectral lines,
that helium, caesium, rubidium,
neon, and argon exist,
and that the sun, the stars, and the nebulae
are composed of the same elements as the earth.

Spectral analysis

The humanist believes
each human being is unique
including human beings like me
—like each snowflake
—each piece of popcorn.
But convert those flakes or kernels to a gas
and get their spectral signatures—
anyone can see
they’re all the same.

Joseph von Fraunhofer was an orphan apprentised to a glassmaker. His workhouse collapsed and he was buried in the rubble, but he was rescued by Prince Maximilian Joseph, who subsequently ensured that Joseph was treated better and could continue his education.

Early opticians ground their own lenses; von Fraunhofer constructed his own furnace, invented and made his own glass, designed and built machines for grinding and polishing lenses, and designed his own optical instruments. He designed and built telescopes and microscopes, and he invented the spectroscope.

Like the other glassmakers of his time, he was poisoned by heavy metal vapors and died young.

The absorption lines in the solar spectrum are still named Fraunhafer lines.