! "I" im0050 COPYRIGHT (c) 1995, 2006 - Thomas B. Perera Ph. D.: 02-20-2006 >
(The instruments are in approximate chronological order: Oldest first.)
* = (Items no longer owned.) ** = (Items in other collections.)
10 * SINGLE-NEEDLE TELEGRAPH SET WITH GONG AND TELEGRAPH-LIKE KEY: (36KB) This old wooden instrument measures 24" high by 9" wide by 6" deep. It has a glass window through which the galvanometer needle can be viewed. The three positions of the needle are labeled: TRAIN ON LINE/LINE CLOSED/LINE CLEAR. The upper portion is supported by brass pedistals, exposing a large electrically operated gong. A telegraph key knob juts out forward from the right side of the instrument and doors open to reveal that the key lever bends upwards 90 degrees to make and break contacts. (Most needle telegraph sets use a right-to-left knob or 2 lever key to control the needle movement.) A hand written tag inside reads:p 6 76. needle 160. bell 45. No 8 22. This unit was used to control the movement of railroad trains on the British railroads. (Traded to the Samuel F. B. Morse Museum, Poughkeepsie, NY)
11 DOUBLE-NEEDLE TELEGRAPH SET WITH GONG, HANDLE, AND TELEGRAPH-LIKE KEY: (11KB) Similar to number 10 above but with an operating handle and a
2-needle dial: (17KB)
This view shows the internal mechanism: (16KB)
Another view of the internal mechanism: (16KB)
A view of the 2-needle set in scenic surroundings: (18KB)
Another view of the 2-needle set in scenic surroundings: (19KB)
12 EARLY SINGLE NEEDLE TELEGRAPH BY HARRIS: (21KB) This early telegraph set may have been used as a training set.
A close look at its dial (26KB) shows that it uses the international morse code with dots to the left and dashes to the right. The label reads: PHILIP HARRIS & Co. Ltd., Scientific Instrument Specialists, Birmingham and Dublin.
The back view shows the coils(22KB) which drive the needle and
a closeup shows the operating keys(27KB).
15 SINGLE NEEDLE TELEGRAPH INDICATOR: (28KB) Small 3" diameter table-top galvanometer mounted at an angle in a very old wooden case. Beveled glass. Large brass contact screws. Bottom of case stamped: GPO 4046.
16 * PORTABLE SINGLE NEEDLE TELEGRAPH INDICATOR: (16KB) This is a portable galvanometer indicator housed in a wooden case with a leather carrying handle.
16a A closer view showing the internal mechanism: (18KB)
16b A view of the case in the open position: (18KB)
19 * EARLY BRITISH RAILROAD TELEGRAPH SET:(15KB) This early railroad telegraph set used a series of bell rings to carry information about the trains which were operating. A wooden cover which I was not able to obtain protected the coils and contacts from dirt.
21 EARLY PORTABLE GALVANOMETER: * 2-1/4" diameter galvanometer in old
wooden box w/leather carry strap 70-0-70 scale. & room for dry battery.
24 TANGENT GALVANOMETER:(25KB) A large 4" diameter horizontally oriented compass indicator is located in the center of a 7" vertically oriented coil of wire all mounted on a wooden stand with leveling screws. The coil taps are marked 2,50,& 500. Made by Philip Harris Ltd,Birmingham, England.
30 * THOMPSON MIRROR GALVANOMETER:(47KB) Mirror galvanometers such as this were used to detect the weak signals from early submarine telegraph cables, and by Thomas Edison during his telegraph experiments. A kerosene light or candle was placed in front of the unit and, when the mirror moved in response to weak electrical signals, the reflected spot of light moved across a calibrated scale mounted on the wall of a darkened room. Due to the laws of optics, the spot of light moved over twice as large an angle as the mirror and this served to amplify the sensitivity of the instrument. This is an all brass mirror galvanometer standing on a brass tripod stand with overhead Earth's Magnetic Field compensating magnets. It was made by Elliot Brothers-London. Traded to Vince Thompson, K5VT.
31 ANOTHER STYLE OF MIRROR GALVANOMETER:(10KB) This small mirror galvanometer has a white paper scale integrated into its design. Light reflects from the moving mirror and onto the white scale allowing measurements to be made.
32++ * Many MIRROR GALVANOMETERS:(45KB) By several manufacturers, meter shunts, standard cells, standard resistors, used to measure the tiny electrical currents on telegraph lines and ground returns.
(For more details, See my SCIENTIFIC INSTRUMENT MUSEUM in a different part of this website.)
33 ** ABRAHAM RHEOGRAPH PRISM SYNCHROSCOPE: (32KB) The first dual-channel Prism Synchroscope. A horizontal rotating prism provides a time-base for twin high sensitivity, low mass mirror galvanometers. Projects dual-trace plus time-base information on a screen. Used to display telegraph cable voltages as a function of time. In original wooden box. Circa 1907.
35 * FARADAY PHILOSOPHICAL MOTOR: (35KB) Same as permanent exhibit at Smithsonian. Twin circular mercury pools with vertical rotating armiture. The first demonstration of the rotational forces of electric current. Used as a philosophical stimulus to early beard-scratching and thoughts about duplex telegraph and polar relays. Circa 1830s.(Traded to John Williams).
40 UNUSUAL NEEDLE TELEGRAPH TRAINING SET: (50KB This wooden set consists of a needle behind a glass window on one side. There is a GPO stamp and a complete description of the code alongside the meter as follows: A/\ B\/// C\/\/ D\// etc. Left deflections of the needle signaled dashes and right deflections signaled dots. Note that the code is NOT the morse code but the international code. As one well-known British key collector told me: "We didn't have much use for Sammy's code over here." Under this window there are two red up-down key knobs. Pushing down the left knob moves the needle left (dash). and the right knob moves it right (dot). The unusual aspect of this set is that there is an identical window on the back of the set so that an instructor can send on one side and a student seated on the other side can practice receiving.
43 ** EARLY BENJAMIN PIKE DIAL TELEGRAPH SET:(15KB) This is a very early dial telegraph sending and receiving set manufactured by Benjamin Pike Jr. of 291 Boradway, New York. The transmitting unit consists of a simple dial with the letters of the alphabet printed around the edge. The dial of the transmitting unit is first set at the top position marked Sign. Rotating this dial in a counterclockwise direction causes a metal brush to make a series of electrical contacts corresponding to how many letters have been passed. For instance, turning it to the letter ''C'' would produce 3 electrical pulses.
43a A closer view of the dial:(19KB)
43b The BENJAMIN PIKE DIAL TELEGRAPH RECEIVING UNIT:(15KB) consists of an identical dial to that on the transmitter with a pointer that is moved clockwise by an extremely early electrical coil-operated actuator. It steps clockwise exactly one letter every time an electrical pulse is received. The pointer is initially set at the center top of the dial and steps clockwise until the last pulse is received and it is pointing at the desired letter.
43c A closer view of the receiver dial:(18KB)
43d Another closer view of the receiver dial:(24KB)
43e A view of the back of the dial showing the actuator:(14KB)
43f A closer view of the actuator:(16KB)
43g A view of the actuator's early magnetic coils:(18KB)
43h A view of Pike name on the wooden base:(12KB)
(NOTE: This rare item is owned by collector Charles Crider who has given me permission to display it in my museum.)
45 MINIATURE FRENCH DIAL TELEGRAPH SET:(13KB) This tiny sending and receiving set is patterned after the British Wheatstone design. Rotating the sending dial to a letter causes an interrupter to send a string of pulses which step the receiving dial to the same letter. The lever on the side engages or disengages the bell which rings for each pulse received.
45a Another view of the set:(15KB)
45b A view of the rear of both units:(11KB)
45c A closer view of the back of the sending dial:(17KB)
45d A closer view of the back of the receiver:(10KB)
45e A closer view of the face of the sending dial:(21KB)
45f A closer view of the face of the receiving dial:(23KB)
46 UNUSUAL MINIATURE FRENCH DIAL TELEGRAPH SET:(13KB) This is an unusual and tiny sending and receiving set that is patterned after the British Wheatstone design. It is somewhat similar to the set described above however, a tiny telegraph key with an ivory knob is used to generate the pulses which rotate the dial of the receiving set to the appropriate letter. The unit is incomplete. It is missing the solenoid coils and other parts of its mechanism.
46a Closer view of the front of one dial unit:(14KB)
46b Closer view of the rear of one dial unit:(10KB)
48 * VERY UNUSUAL PORTABLE FRENCH DIAL TELEGRAPH TEST SET: This lovely set was sold at the 2005 Antique Wireless Association conference. The set allowed the telegraph lines to be tested at any location by simply throwing a wire over the telegraph line and inserting another wire into the ground. The set could be closed to protect the internal apparatus while transporting it.
NOTE: I AM ALWAYS LOOKING TO BUY OR TRADE TELEGRAPH KEYS !
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