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| William Crookes |
One of the most surprising scientific figures of
the second half of the 19th century in England was William Crookes (1832-1919),
whose scientific career was spectacular, although his activities related to
spiritualism, which was then in vogue in England, were also widely known.
Here's a list of Crookes's scientific achievements:
· An expert in spectroscopy, in 1861 he discovered a new chemical element, thallium, number 81 on the periodic table, located in the same column as boron, aluminum, gallium, and indium, whose chemical properties it resembles. Thallium was discovered simultaneously and independently by the French chemist Claude-Auguste Lamy, who is considered a co-discoverer, although it was Crookes who named it, from the Greek word θαλλός, meaning green twig, in reference to the green line in its spectrum that helped him discover it. This discovery led to his appointment as a Fellow of the Royal Society in 1863.
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| Crookes Radiometer |
·
In
1873, he invented the radiometer,
a partially evacuated glass bulb containing four plates, painted black on one
side and white on the other, suspended from an axis. When light hits them, they
rotate at a speed that depends on the intensity of the light they receive. It
is, therefore, a detector and meter of electromagnetic radiation.
·
Around
1875, he invented the Crookes tube, the precursor to the cathode ray tube, although it did not occur to
him that cathode rays were made up of particles smaller than atoms (electrons),
and he tried to explain them as a new state of matter.
·
Crookes
studied the fourth state of matter, plasma, which he called radiant matter and was the first
to describe in 1879.
·
In
1894, when William Ramsay and Lord Raleigh discovered the new element argon,
the first noble gas, Ramsay asked Crookes to study its spectrum. Crookes
pointed out that the sample they had given him contained a mixture of two
different chemical elements, the other being helium, whose existence had been
discovered by spectroscopy in sunlight in 1868. For this reason, Crookes is
considered the discoverer of terrestrial helium.
·
In
1903, he invented the spinthariscope, the first device that made it possible to detect and measure
radioactive particles by the flashes produced when alpha particles
collided with a fluorescent screen.
·
Finally,
in 1913, at the age of 80, he conducted an exhaustive search for chemicals
that, used to make lenses, would protect workers' eyes from ultraviolet light.
Of the more than 300 substances he tested, number 246, based on the element
cerium, proved to be
the most effective and was used commercially to make protective eyewear.
As a result of these discoveries, Crookes was
awarded the Davy Medal in 1888, a peerage in 1897, and in 1898 was appointed
President of the BAAS (British Association for the Advancement of Science). In
1913, Crookes became President of the Royal Society.
Crookes's second activity, which also brought him
fame but proved controversial, involved his research into spiritualism. It all began in 1867, when his younger brother,
Philip, died of yellow fever at the age of 21 while working on the laying of
the submarine telegraph cable between Cuba and Florida. The engineer Cromwell
Varley, who was involved in laying the transatlantic cable, suggested that
Crookes try to communicate with his brother and took him to a séance. From then
on, Crookes became deeply involved, supporting these "investigations"
with his scientific prestige.
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| Crookes with Katie King |
The most spectacular case he participated in, in
1873-74, was that of the medium Florence Cook, who put him in contact with the
ghost of Katie King,
supposedly the daughter of the pirate Morgan. Crookes took more than 40
photographs of her, which he refused to publish, showing them only to closest people.
He later claimed that they had been accidentally burned in a chemical fire.
However, four of the photographs surfaced in 1934 after the death of a Crookes
associate. In two of the photographs, Crookes appears with the ghost. In one,
the two are arm in arm.
There has been intense controversy over whether
Crookes was an accomplice of the mediums with whom he collaborated, or whether
he was deceived by them. Some say Crookes was very nearsighted, but refused to
wear glasses until the 1990s, which undermines the credibility of what he
claims he saw in the seances. In any case, he was not the only scientist to be
seduced by spiritualism. Other famous names included Alfred Russell Wallace,
co-discoverer with Darwin of the theory of evolution by natural selection; Augustus
De Morgan, mathematician; and Alfred, Lord Tennyson, poet.
In this capacity, Crookes published a famous
article in 1870, Spiritualism in the Light of Modern Science. He formulated the theory that telepathy could be
based on waves traveling through the ether. He was a member of the Society for
Psychical Research (SPR), founded in 1882 and dedicated to the scientific study
of paranormal phenomena. Many other scientists of the time also belonged to the
Society, where he served as president from 1892 to 1896.
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