. Mechanical appliances, mechanical movements and novelties of construction; a complete work and a continuation, as a second volume, of the author's book entitled "Mechanical movements, powers and devices" ... including an explanatory chapter on the leading conceptions of perpetual motion existing during the past three centuries. i8o ELECTRIC POWER AND 434. WIR P: L E S S TELEGRAPHY. Marconi coherer. Themost important part of the receiver is the coherer, which consists of a small glass tube about two and a half milHmeters ininternal diameter and some four centimeters in si
. Mechanical appliances, mechanical movements and novelties of construction; a complete work and a continuation, as a second volume, of the author's book entitled "Mechanical movements, powers and devices" ... including an explanatory chapter on the leading conceptions of perpetual motion existing during the past three centuries. i8o ELECTRIC POWER AND 434. WIR P: L E S S TELEGRAPHY. Marconi coherer. Themost important part of the receiver is the coherer, which consists of a small glass tube about two and a half milHmeters ininternal diameter and some four centimeters in silver pole pieces are lightly fitted into this tube,separated by a gap of about a miUimeter, containing amixture of 96 parts of nickel and 4 parts of silver, nottoo finely granulated, and worked up with the meresttrace of mercury. This powder must not be packedtoo tight, or the action will be irregular and oversensi-tive to slight outside disturbances, while if too loose itwill not be sufi&ciently sensitive. It is found that thebest adjustment is obtained when the coherer workswell under the actions of the sparks from a small electrictrembler placed at a distance of about a meter. Thetube is then exhausted on a mercury pump until thepressure falls to about a millimeter, when the tubulureleft for exhausting it is sealed off. The tubes are testedover a
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Keywords: ., bookauthorhiscoxgardnerdexter18, bookcentury1900, bookdecade1910
