structures of snowflakes and plants and introduced the public to the widespread
occurrence of fleas and lice and their detailed appearance. Hooke’s study of the bark
of the cork tree revealed its microscopic structure and resulted in the discovery of the
cell, which proved to be the building block of all life forms. He also used his
microscope to show that ancient cells were present in fossilised wood. He concluded
that fossils had once been living creatures whose cells had become mineralised. He
also concluded that some species that had once existed must have become extinct.
He thereby started a process which was to lead to Darwin’s theory of evolution in
1865. In 1665 at the age of 30, Hooke published Micrographia, the first ever
scientific bestseller, which illustrated his understanding of nature and light, his
highly developed skills in designing and constructing scientific instruments and
his skills as an artist. Antonie van Leeuwenhoek, who used a microscope with one
lens to observe insects and other specimens, was the first to observe bacteria. Despite
many innovative developments, it did not prove possible in the subsequent two
centuries to use the increased power of microscopes to examine the structures at the
atomic level of metals, nonmetals and the compounds they formed when they
combined. The discovery of X-rays at the end of the nineteenth century did not
immediately enable scientists to look directly at the structures of molecules. Nevertheless, the diffraction patterns produced on photographic plates when crystals were
exposed to X-rays enabled scientists to mathematically manipulate the data and
calculate the three-dimensional arrangements of atoms in crystals for the first time.
This procedure now described as X-ray crystallography has had an enormous impact
on physics, chemistry, biology and medicine during the last century [5–14].
Röntgen’s discovery occurred accidentally in his laboratory in Wurzburg, Germany, where he was trying to establish whether cathode rays could pass through
glass [15]. Cathode rays observed in discharge tubes were first discovered in 1867
and were shown to be streams of electrons by J.J. Thomson in 1897 [16] and led to
his determination of the e/m ratio of the electron particle. In the darkened room,
Röntgen observed a glow coming from a nearby chemically coated screen. He
attributed this glow to a novel but not previously studied form of radiation, which
he described as X-rays, and he set about to define their true nature by further
scientific studies. These established that X-rays unlike cathode rays are electromagnetic energy waves that act similar to light rays but have wavelengths approximately
1,000 times shorter than those of visible light. The absence of a charge and their
higher energies meant that they could penetrate human flesh and muscles but not
higher-density substances such as bone. The significance of this observation was
rapidly recognised by the medical profession and has proved to be the most
important application of his discovery for humanity ever since. The X-rays were
unable to penetrate heavier metals such as lead, and this property was used to
develop effective protection procedures for doctors and physicists who subsequently
developed the medical and scientific applications.
In 1912 Max von Laue, at the Institute of Theoretical Physics in Munich, became
aware of his colleague’s Paul Ewald’s theoretical research on the optical properties
of a solid containing a regular arrangement of resonators and argued that a crystalline
solid consists of a three-dimensional arrangement of atoms and molecules whose
4
D. M. P. Mingos
occurrence of fleas and lice and their detailed appearance. Hooke’s study of the bark
of the cork tree revealed its microscopic structure and resulted in the discovery of the
cell, which proved to be the building block of all life forms. He also used his
microscope to show that ancient cells were present in fossilised wood. He concluded
that fossils had once been living creatures whose cells had become mineralised. He
also concluded that some species that had once existed must have become extinct.
He thereby started a process which was to lead to Darwin’s theory of evolution in
1865. In 1665 at the age of 30, Hooke published Micrographia, the first ever
scientific bestseller, which illustrated his understanding of nature and light, his
highly developed skills in designing and constructing scientific instruments and
his skills as an artist. Antonie van Leeuwenhoek, who used a microscope with one
lens to observe insects and other specimens, was the first to observe bacteria. Despite
many innovative developments, it did not prove possible in the subsequent two
centuries to use the increased power of microscopes to examine the structures at the
atomic level of metals, nonmetals and the compounds they formed when they
combined. The discovery of X-rays at the end of the nineteenth century did not
immediately enable scientists to look directly at the structures of molecules. Nevertheless, the diffraction patterns produced on photographic plates when crystals were
exposed to X-rays enabled scientists to mathematically manipulate the data and
calculate the three-dimensional arrangements of atoms in crystals for the first time.
This procedure now described as X-ray crystallography has had an enormous impact
on physics, chemistry, biology and medicine during the last century [5–14].
Röntgen’s discovery occurred accidentally in his laboratory in Wurzburg, Germany, where he was trying to establish whether cathode rays could pass through
glass [15]. Cathode rays observed in discharge tubes were first discovered in 1867
and were shown to be streams of electrons by J.J. Thomson in 1897 [16] and led to
his determination of the e/m ratio of the electron particle. In the darkened room,
Röntgen observed a glow coming from a nearby chemically coated screen. He
attributed this glow to a novel but not previously studied form of radiation, which
he described as X-rays, and he set about to define their true nature by further
scientific studies. These established that X-rays unlike cathode rays are electromagnetic energy waves that act similar to light rays but have wavelengths approximately
1,000 times shorter than those of visible light. The absence of a charge and their
higher energies meant that they could penetrate human flesh and muscles but not
higher-density substances such as bone. The significance of this observation was
rapidly recognised by the medical profession and has proved to be the most
important application of his discovery for humanity ever since. The X-rays were
unable to penetrate heavier metals such as lead, and this property was used to
develop effective protection procedures for doctors and physicists who subsequently
developed the medical and scientific applications.
In 1912 Max von Laue, at the Institute of Theoretical Physics in Munich, became
aware of his colleague’s Paul Ewald’s theoretical research on the optical properties
of a solid containing a regular arrangement of resonators and argued that a crystalline
solid consists of a three-dimensional arrangement of atoms and molecules whose
4
D. M. P. Mingos