Wilhelm Conrad Röntgen: The Discoverer of X-Rays

Wilhelm Conrad Röntgen was born on March 27, 1845, at Lennep in the Lower Rhine Province of Germany, as the only child of Friedrich Conrad Röntgen and Charlotte Constanze. His family relocated to Apeldoorn in The Netherlands when he was three years old, and he attended the Institute of Martinus Herman van Doorn, a boarding school. Röntgen loved nature and enjoyed exploring the vast land and forests. He was highly skilled at devising mechanical devices, which he retained throughout his life. In 1862, he enrolled in a technical school in Utrecht, where he was wrongly expelled for producing a caricature of one of the lecturers, which was actually done by someone else.

In 1865, he enrolled at the University of Utrecht to study physics. He did not have the credentials required for a regular student, but after hearing that he could enter the Polytechnic in Zurich by passing its examination, he did so. He began his studies there as a mechanical engineering student. Röntgen attended Clausius' lectures and also worked in Kundt's laboratory. Both Kundt and Clausius had a significant impact on his development. In 1869, he received his PhD from the University of Zurich and was appointed Kundt's assistant, accompanying him to Würzburg the following year and Strasbourg three years later.

In 1874, he was appointed Lecturer at Strasbourg University, and in 1875, Professor at the Württemberg Academy of Agriculture in Hohenheim. He returned to Strasbourg as a Professor of Physics in 1876, but three years later took the Chair of Physics at the University of Giessen. Röntgen's first study on the specific temperatures of gases was published in 1870, followed by a paper on the thermal conductivity of crystals a few years later. Among the other issues he investigated were the electrical and other properties of quartz, the effect of pressure on the refractive indices of various fluids, the modification of the planes of polarised light by electromagnetic influences, the variations in the functions of temperature and compressibility of water and other fluids, and the phenomena associated with the spreading of oil drops on water.

However, Röntgen's name is most closely connected with his discovery of the radiation known as X-rays. In 1895, he was researching the phenomena associated with the passage of an electric current through a highly low-pressure gas. Röntgen's research on cathode rays led him to the discovery of a new and different kind of rays.

On November 8, 1895, he discovered that if the discharge tube is enclosed in a sealed, thick black carton to exclude all light, a paper plate covered on one side with barium platinocyanide and placed in the path of the rays becomes fluorescent even when it was two metres away from the discharge tube. During further experiments, he discovered that objects of varying thicknesses placed in the path of the rays revealed changing transparency when captured on a photographic plate.

When he temporarily immobilised his wife's hand in the path of the rays over a photographic plate, he saw an image of his wife's hand that showed the shadows thrown by the bones of her hand and that of a ring she was wearing, surrounded by the penumbra of the flesh, which was more permeable to the rays and thus threw a fainter shadow. This was the very first "röntgenogram" ever performed. Furthermore, Röntgen demonstrated that the new rays are formed by the impact of cathode rays on a material object in subsequent experiments. Röntgen named them X-rays because their nature was unclear at the time. Later, Max von Laue and his students demonstrated that they had the same electromagnetic nature as light and only differed in the greater frequency of their vibration.

Several honours were bestowed upon Röntgen following his groundbreaking discovery. He was awarded the first-ever Nobel Prize for Physics in 1901. Streets were named after him in various towns. In addition, he was awarded an uncountable number of Prizes, Medals, honorary doctorates, honorary and corresponding memberships in learned organisations in Germany and abroad, and other honours.

Despite all of this, Röntgen remained a startlingly modest and quiet man. He maintained his love of nature and outdoor activities throughout his life. Many of his vacations were spent in his summer house in Weilheim, near the Bavarian Alps, where he hosted his friends and embarked on many mountain trips. He was an excellent mountaineer who frequently found himself in hazardous situations. However, by nature, he was friendly and courteous and always accepting of people's points of view and issues. He was usually hesitant to work with others and preferred to work alone. He created much of the apparatus he used himself with tremendous inventiveness and experimental competence.

Wilhelm Röntgen, unlike other scientists, never tried to attain credit for his work, and he never took out any patents on X-rays. Instead, he ensured that the world could freely benefit from his work. He rejected a title that would have given him entry into the German nobility and donated his Nobel Prize money to his university. At the time of his death in 1923, Röntgen was nearly bankrupt from the inflation following World War I.

Röntgen married Anna Bertha Ludwig in 1872. They had no children but adopted Josephine Bertha Ludwig, then six years old, from Mrs Röntgen's sole brother in 1887. On February 10, 1923, four years after his wife, Röntgen, died in Munich of intestinal cancer.