![]() ![]() Assisted by J.V.L.Parry, he commenced work in the spring of 1953 and by June 1955 the clock was working reliably, with an accuracy that was equivalent to one second in three hundred years. However, this device never realized the full potential of the concept, and after seeing it on a visit to the USA Essen was convinced that a more successful instrument could be built at Teddington. The idea of an atomic clock had been proposed by I.I.Rabbi in 1945, and an instrument was constructed shortly afterwards at the National Bureau of Standards in the USA. His expertise in these fields was to play a crucial role in the development of the caesium clock. He was also involved with radio frequency oscillators. At NPL he joined a team working on the development of frequency standards using quartz crystals and he designed a very successful quartz oscillator, which became known as the "Essen ring". He spent his whole working life at the NPL and retired in 1972 his research there was recognized by the award of a DSc in 1948. Louis Essen joined the National Physical Laboratory (NPL) at Teddington in 1927 after graduating from London University. And, of course, psychologists continue to study perception, memory, thought and action. ![]() These days one meets engineers who work on speech perception, biologists who investigate the mental representation of spatial relations, and physicists who want to understand consciousness. ![]() Anthropologists have examined the conceptual structure of cultural practices to advance hypotheses about the basic principles of the mind. Neurologists and neuropsychologists have used the pattern of competence and incompetence of their brain-damaged patients to elucidate the normal workings of the brain. Neurophysiologists have begun to relate the function of nerve cells to complex perceptual and motor processes. Ethologists have sought the innate roots of social behaviour. Linguists have struggled with the puzzle of how children acquire language. Computer scientists have tried to emulate its capacity for visual perception. Since the Second World War scientists from different disciplines have turned to the study of the human mind. We owe the notion of philosophy as a tribunal of pure reason, upholding or denying the claims of the rest of culture, to the eighteenth century and especially to Kant, but this Kantian notion presupposed general assent to Lockean notions of mental processes and Cartesian notions of mental substance. We owe the notion of "the mind" as a separate entity in which "processes" occur to the same period, and especially to Descartes. We owe the notion of a "theory of knowledge" based on an understanding of "mental processes" to the seventeenth century, and especially to Locke. To know is to represent accurately what is outside the mind, so to understand the possibility and nature of knowledge is to understand the way in which the mind is able to construct such representation. understands the foundations of knowledge and it finds these foundations in a study of man-as-knower, of the "mental processes" or the "activity of representation" which make knowledge possible. This was magneto-electric induction, the basis of the electric generator. ![]() Ten years later, after much thought and experiment, he achieved the converse of Oersted's effect, the production of an electric current from a magnet. This was the basis of the electric motor. After Oersted's announcement in 1820 that an electric current could affect a magnet, Faraday devised an arrangement in 1821 for producing continuous motion from an electric current and a magnet. Faraday was interested in electricity, which was then viewed as a branch of chemistry. The tour, and especially Davy's constant company and readiness to explain matters, was a scientific education for Faraday, who returned to the Royal Institution as a competent chemist in his own right. When a vacancy arose for a laboratory assistant at the Royal Institution, Davy remembered Faraday, who he took as his assistant on an 18- month tour of France, Italy and Switzerland (despite the fact that Britain and France were at war!). He made notes of the lectures, bound them and sent them to Davy, asking for scientific employment. A customer in the shop gave Faraday tickets to hear Sir Humphry Davy lecturing at the Royal Institution. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |