Friday, August 22, 2014

Paul Nipkow and the Picture Scanning Technology

Paul Nipkow (1860-1940)
On August 22, 1860, German engineer Paul Gottlieb Nipkow was born. He is best known for having conceived the idea of using a spiral-perforated disk (the Nipkow disk), to divide a picture into a matrix of points, and became an early television pioneer.

Nipkow was born on August 22, 1860, in Lauenberg (Lębork) in Pomerania, now in Poland. Inspired by the work of Guglielmo Marconi, Nipkow began thinking about the challenge of transmitting a visual image while still a student in Germany. While at school in Neustadt (Wejherowo), West Prussia, Nipkow began to experiment in telephony and the transmission of moving pictures. It was well known that any successful transmission device required three essential components: a device to translate the visual image into an electronic impulse, a second device to reassemble that impulse into an image again, and a third device by which to transmit the impulse from the first device to the second. In 1884, even before completing his degree, Nipkow had developed and patented a transmissions system that achieved all three requirements.[1]

While still a student Nipkow conceived the idea of using a spiral-perforated disk (Nipkow disk), to divide a picture into a matrix of points. Accounts of its invention state that the idea came to him while sitting alone at home with an oil lamp on Christmas Eve, 1883. Alexander Bain, a Scottish inventor who had patented the electric clock, had transmitted images telegraphically in the 1840s but the Nipkow disk improved the encoding process. The Nipkow disk was a metal or cardboard disk that was perforated with twenty square holes arranged in a spiral so that each hole was a little closer to the center than the last. As Nipkow spun the disk, he shined a strong light through the holes and onto the subject. Because each hole was slightly offset, the image was scanned in a series of twenty horizontal lines.[1]

Nipkow's Disk from his
1884 patent application
Another important component of his invention was a selenium photocell used to transform differences in the intensity of light into electric current. The current could be transmitted to a receiver, where the image was reproduced with an identical disk that was synchronized with the first in front of a lamp whose brightness changed according to the received signal. Nipkow once used his device to transmit a visual image from London to Paris, but the system was never developed for commercial use. Ironically, at the time, investors could not foresee a practical use for it, and therefore, Nipkow received little recognition during his lifetime for the feat.[3]

Nipkow applied for a patent in the imperial patent office in Berlin for his electric telescope. This was for the electric reproduction of illuminating objects, in the category "electric apparatuses". German patent No. 30105 was granted on 15th January 1885, retroactive to 6th January 1884, the 30 marks fee being lent by his future wife. It was allowed to lapse after 15 years. Nipkow had taken a position as a designer in the Berlin-Buchloh Institute and did not continue further development of the electric telescope.[2]

The first television broadcasts used an optical-mechanical picture scanning method, the method that Nipkow had helped create with his disk. The first inventor who used Nipkow's disc successfully, creating the first television pictures in his laboratory in October 1925, was John Logie Baird. From 1937, when the infant BBC television service chose it above Baird's mechanical system, total electronic picture scanning, based on the work of Manfred von Ardenne and the iconoscope invented by Vladimir Zworykin, became increasingly prevalent and Nipkow's invention was no longer essential to further development of television. Today, the Nipkow disk is used extensively in reflected light confocal scanning microscopy to produce images that can be viewed in real time through the microscope eyepieces.

At yovisto you can watch an RCA documentary on the history of television to learn more about the invention of television and its early days.

References and Further Reading:
Related Articles at yovisto Blog:

If you like the daily blog posts of yovisto about the history of science, please support us by clicking on the amazon links and making your next amazon purchase via our offered links. Nevertheless, please do also support your local (real world) bookstore at the corner of the street.

Thursday, August 21, 2014

William Murdock 'enlights' the 19th Century

William Murdock
(1754 – 1839)
On August 21, 1754, Scottish engineer and inventor William Murdock was born. He was the first to make extensive use of coal gas for illumination and a pioneer in the development of steam power.

William Murdock (sometimes also referred to as Murdoch) excelled in the field of math from early age and even studied the principles of mechanics and worked much with metal and wood while helping out in his fathers work. It is not quite clear, which achievements Murdock really made in these years. It is assumed that he built a wooden horse with his father that he was responsible for the construction of a bridge. Also, it is believed that the young Murdock performed several experiments with coal gas, but this is not really proven. He got to know James Watt around 1777 and was hired in Birmingham due to his extraordinary abilities.

Murdock was soon sent to Cornwall in order to erect and maintain Boulton & Watt engines, which he did perfectly, as Boulton later wrote. However, they were not the only company operating in the Cornwall area and it became soon clear that most of these companies started copying from each other. Murdock was appointed to undertake some inspections of their competitor's engines and was sometimes threatened for doing so. But Murdock also spent a lot of time improving the Boulton & Watt engines and it is known that he discussed some further inventions with his employers. Unfortunately, his contract stated that all inventions he made belonged to the company and therefore, it is not exactly clear, which improvements he made in this period. In 1799, he invented a steam wheel that was a lot more efficient than any of its kind and due to the fact that his contract was amended by then, he was able to file this patent in his own name.

To one of his most important inventions belongs the so called road locomotive in 1784. Nicolas-Joseph Cugnot was already known to have demonstrated a similar device even though it weighted more than 4 tonnes. Murdock built a working model on his own and on this day there are several accounts from witnesses who "saw the model steam carriage run around Murdock's living room in Redruth in 1784". This model had 3 wheels with the engine and boiler placed between the two larger back wheels. Murdock performed the first public demonstration in Great Britain, but he never really gained popularity for these achievements.

However, Murdock is best known for his gas light. Many historians believe that his first experiments with gas took place in a cave in the early 1790s and first, he had to develop a method for the production and the capture of gas. He returned to Birmingham in 1798 where he continued his experiments and four years later, he performed a public exhibition of his lighting by illuminating the exterior of the Soho Foundry. Soon, companies like Philips gained their interest in illuminated their factories. Still, it is believed that he never really made much money from his invention, even though soon most towns in Britain were lit by gas.

Murdock moved into a house in Birmingham, where he installed several of his inventions like the gas light, a doorbell that worked by compressed air and even a conditioning system. Around 1830, his partnership with Boulton & Watt came to an end. William Murdock passed away in 1839.

At yovisto, you can watch John Merriman's video lecture on the Industrial Revolution at Yale University.

References and Further Reading:
Related Articles in the Blog:

Wednesday, August 20, 2014

Jöns Jacob Berzelius - One of the Founders of Modern Chemistry

Jöns Jacob Berzelius
(1779 – 1848)
On August 20, 1779, Swedish chemist Jöns Jacob Berzelius was born. Berzelius is considered, along with Robert Boyle, John Dalton, and Antoine Lavoisier, to be one of the founders of modern chemistry. In Sweden, Berzelius Day is celebrated on 20 August in honor of him.

Jöns Jacob Berzelius was born in 1779 as the son of a teacher and was educated in Linköping, Sweden. His medical studies started in 1796 in Uppsala because this field of study was quite close to natural sciences and most likely provided a decent income. He studied under Anders Gustav Ekeberg, the chemist who discovered tantalum and after Berzelius left the university, his uncle organized him a job as a pharmacist. While in medical school at the University of Uppsala, he read about Alessandro Volta’s “electric pile” and while working at the Medevi mineral springs, a spa and health resort, Berzelius constructed one for himself from 60 zinc plates and 60 copper plates. His thesis for his medical degree was on the effect of electric shock on patients with various diseases, for instance paralysis. Even though he reported no improvement in his patients, his interest in electrochemical topics continued. In 1807 he was made a professor at the Medical College in Stockholm, which soon after became the Karolinsska Institute. A year later he began his long association with the Royal Swedish Academy of Sciences [1,3].

Berzelius intended to create a textbook for his medical students and performed a series of experiments which made him most famous. With these experiments, he managed to establish that the elements in inorganic substances are bound together in definite proportions by weight. His increasing interest in all kinds of compounds led to his discovery of numerous elements, such as cerium, selenium, and thorium. Selenium was named after the moon goddess selene by Berzelius [3]. Also, several students worked together with the scientist and discovered several elements as well, including lithium and vanadium. Berzelius was then able to determine the atomic weight of almost all elements and he was motivated to create a logical system of symbols (H, Cl, Ca ...) [1,2].

Jöns Jacob Berzelius received 12 royal orders and was member of almost 100 academies and scientific societies around the globe. He was elevated to the nobility in 1818 and awarded the baronetcy in 1835. The scientist, who is on this day considered as one of the founders of modern chemistry passed away on August 7, 1848 [3].

At yovisto, you may be interested in a short documentary on Jöns Jacob Berzelius.

References and Further Reading:
Related Articles in the Blog: