London: The Royal Society, 1899. 1st Edition. FIRST EDITION IN ORIGINAL WRAPS (housed in a custom case) OF THE BOSE COHERER PAPER. Bose’s invention improved on Branly’s 1890 invention of the coherer. Note that we offer the Branly paper separately.
The coherer is the radio signal detector used in the first radio receivers at the beginning of the twentieth century. In 1890 and while studying the detection of electromagnetic waves, the French professor Édouard Eugène Désiré Branly discovered that “electromagnetic waves could be rectified by fine metal particles contained in a tube between metal conductors; the electrical energy would cause the particles to clump together and become conductive. The device was called a coherer because of the clumping action and was used as rectifiers in all the early practical wireless receivers, despite its operation being not well-understood” (Maloney, J.C. Bose and the Invention of Radio, 2016).
Branly’s coherer used iron particles as the spacing material that changed resistance. This worked well, but they were famously finicky because the filings remained in their new positions after the reception of a signal, thus requiring a “decoherer” mechanism -- a tiny electromagnetic tapping mechanism that jiggled the filings back into a non-conductive state before the next signal could be detected -- to shake the filings back to their original position. This had obvious and serious effects on bandwidth.
In 1899, Indian physicist Jagadish Chandra Bose developed an improved coherer that he termed an “iron-mercury-iron coherer with telephone detector" (now sometimes known as an “imperfect junction” coherer.) Bose’s coherer employed a pool of mercury in a small metal cup. A film of insulating oil shielded the mercury, and an iron disc dipped slightly into the oil but did not make contact with the liquid mercury. RF energy broke down the insulating oil and conduct, with the advantage of not needing a decoherer to reset the system; Bose’s invention provided much better performance.
Bose introduced this invention in a presentation to the Royal Society in London. Guglielmo Marconi attended Bose’s presentation to the Royal Society, later transmitting radio waves across the Atlantic using a coherer of Bose’s design to receive the signal. Marconi’s story about how he came up with the varied over time; as well, there were reports that Bose’s circuit designs were stolen from a London hotel room while he was presenting his work to the Royal Society. Regardless, Bose was not interested in commercializing his invention and Marconi would go on to patent it himself and win the 1909 Nobel Prize in Physics for this accomplishment. In 1998, Bose finally received recognition from the Institution of Electrical and Electronics Engineers (IEEE). Item #1266
CONDITION & DETAILS: Individual issue in original wrappers housed in a handsome custom clamshell box gilt-lettered on the front and spine. Professional repair to small section in lower part of front wrapper and on rear wrapper; slight flaking at the spine and some minor spotting (see photo; the light makes it darker in the picture than it is to the eye.) Bright and very clean throughout. Very good +.