Telegraph message, printed in Morse code, transcribed and signed by Samuel F. B. Morse. This message was transmitted from Baltimore, Maryland, to Washington, D.C., over the nation's first long-distance telegraph line.
In 1843, Congress allocated $30,000 for Morse (1791-1872) to build an electric telegraph line between Washington and Baltimore. Morse and his partner, Alfred Vail (1807-1859), completed the forty-mile line in May 1844. For the first transmissions, they used a quotation from the Bible, Numbers 23:23: "What hath God wrought," suggested by Annie G. Ellsworth (1826-1900), daughter of Patent Commissioner Henry L. Ellsworth (1791-1858) who was present at the event on 24 May. Morse, in the Capitol, sent the message to Vail at the B&O Railroad's Pratt Street Station in Baltimore. Vail then sent a return message confirming the message he had received.
The original message transmitted by Morse from Washington to Baltimore, dated 24 May 1844, is in the collections of the Library of Congress. The original confirmation message from Vail to Morse is in the collections of the Connecticut Historical Society.
This tape, dated 25 May, is a personal souvenir transmitted by Vail in Baltimore to Morse in Washington the day following the inaugural transmissions. The handwriting on the tape is that of Morse himself. Found in Morse’s papers after his death the tape was donated to the Smithsonian in 1900 by his son Edward, where it has been displayed in many exhibitions.
A model of a plow used for installing underground telegraph cables. The cable spool is mounted on top with channel down back of plow; rollers at upper part to permit operation of spool and cable without friction. A 23 November 1896 letter from Charles Selden, Superintendent of Telegraph, B&O Railroad states in part: "The models ... were gotten up under the supervision of Major J. G. Pangborn to be shown at, I think, the first New Orleans Exposition sometime between 1884 and 1886, .... The model of the Morse plow was made at the Mt. Clare shops under the supervision of a couple of men who said their recollection about it was quite clear. ... They are probably as near correct as could be gotten under the circumstances."
Insulated wire reel for electrostatic experiments. The experimental purpose of this device is uncertain. It may be for conducting charge from a kite string, or possibly for testing strength of charge over distances.
People from ancient times knew that rubbing certain materials and then touching something caused a spark. Studying what is called electrostatics laid the groundwork for understanding electricity and magnetism. Natural philosophers, scientists, and instrument makers created many ingenious devices to generate electrostatic charges starting in the 1600s. These machines varied in size and technique but all involved rotary motion to generate a charge, and a means of transferring the charge to a storage device for use.
Many early electrostatic machines generated a charge by friction. In the later 19th century several designs were introduced based on induction. Electrostatic induction occurs when one charged body (such as a glass disc) causes another body (another disc) that is close but not touching to become charged. The first glass disc is said to influence the second disc so these generators came to be called influence machines.
This influence machine has the design features of Wilhelm Holtz of Germany (1836-1913). There are two glass discs, one fixed and the other rotating. The fixed disc has two oblong holes called windows, each with a paper contact or “sector” held onto the glass with varnish. The slightly smaller rotating plate is turned by the user with a crank and spins close to the fixed plate, charging as it spins. Two brass combs mounted on the glass stands gather the charge and conducted it to a Leyden jar. When using the Holtz design one needed to “prime” the machine by putting a charge on one of the sectors and then connecting the electrodes to begin building up the charge. The brass bar attached to the axle is called the neutralizer bar and prevents the charging action from reversing at the wrong time and discharging the machine. The rubber disc under the fixed plate is stamped: "Ed Borchardt / Berlin / 400" and may be a maker’s mark.
This object was repaired in late 1958. The parts replaced included the rotating plate, the stationary plate clamp and screw, rotating plate drive handle, drive belt for rotating plate, and one Leyden jar.
People from ancient times knew that rubbing certain materials and then touching something caused a spark. Studying what is called electrostatics laid the groundwork for understanding electricity and magnetism. Natural philosophers, scientists, and instrument makers created many ingenious devices to generate electrostatic charges starting in the 1600s. These machines varied in size and technique but all involved rotary motion to generate a charge, and a means of transferring the charge to a storage device for use.
Many early electrostatic machines generated a charge by friction. In the later 19th century several designs were introduced based on induction. Electrostatic induction occurs when one charged body (such as a glass disc) causes another body (another disc) that is close but not touching to become charged. The first glass disc is said to influence the second disc so these generators came to be called influence machines.
This influence machine, made in New York City by the firm Hall & Harbeson, shows the design of Wilhelm Holtz (1836-1913) of Germany. Around 1865 Holtz’ new machine featured a fixed plate with two holes called windows, both of which had two contacts called sectors. The sectors were made of paper and on this machine each has a separate saw-toothed edge made of metal. The slightly smaller rotating plate is turned by the user with a crank and spins close to the fixed plate, charging as it spins. Two brass combs mounted on the glass stands gather the charge that is then conducted to a Leyden jar. When using the Holtz design one needed to prime the machine by putting a charge on one of the sectors and then connecting the electrodes to begin building up the charge. The brass bar attached to the axle is called the neutralizer bar and prevents the charging action from reversing at the wrong time and discharging the machine.
People from ancient times knew that rubbing certain materials and then touching something caused a spark. Studying what is called electrostatics laid the groundwork for understanding electricity and magnetism. Natural philosophers, scientists, and instrument makers created many ingenious devices to generate electrostatic charges starting in the 1600s. These machines varied in size and technique but all involved rotary motion to generate a charge, and a means of transferring the charge to a storage device for use.
Many early electrostatic machines generated a charge by friction. In the later 19th century several designs were introduced based on induction. Electrostatic induction occurs when one charged body (such as a glass disc) causes another body (another disc) that is close but not touching to become charged. The first glass disc is said to influence the second disc so these generators came to be called influence machines.
This small revolving doubler, developed by William Nicholson (1753-1815) in England, shows the basic principle of an influence machine. The user turns a crank that rotates a charged disc in front of the stationary discs. The rotating disc induces a charge on each stationary disc as it passes. The two stationary discs on this piece are connected briefly so both become charged. The charge is almost doubled each time the rotating disc passes a stationary disc and the effect repeats, building up a high voltage on the brass ball. This doubler was made in London by instrument makers William and Samuel Jones in the early 1800s. Since the charge is not quite doubled the term multiplier was later used for these types of devices.
People from ancient times knew that rubbing certain materials and then touching something caused a spark. Studying what is called electrostatics laid the groundwork for understanding electricity and magnetism. Natural philosophers, scientists, and instrument makers created many ingenious devices to generate electrostatic charges starting in the 1600s. These machines varied in size and technique but all involved rotary motion to generate a charge, and a means of transferring the charge to a storage device for use.
In the latter 1700s electrical researchers adopted improved electrostatic machines that replaced earlier glass cylinders with a flat glass plate. This increased the machines’ efficiency by passing the glass plate between leather rubbing pads that increased the contact area. Experience with plate machines brought many design variations with sizes ranging from small table-top units for laboratory use to large cabinets that powered early x-ray machines.
This plate machine was made in London in the years around 1810 by Robert Bancks (later spelled Banks). Bancks crafted scientific instruments of many types including microscopes and made devices for, among others, King George IV. This machine comes in a locking wooden case and includes a variety of accessories. A similar machine in the collections of the Science Museum in London is believed to have been used for medical electrotherapy experiments.
People from ancient times knew that rubbing certain materials and then touching something caused a spark. Studying what is called electrostatics laid the groundwork for understanding electricity and magnetism. Natural philosophers, scientists, and instrument makers created many ingenious devices to generate electrostatic charges starting in the 1600s. These machines varied in size and technique but all involved rotary motion to generate a charge, and a means of transferring the charge to a storage device for use.
In the latter 1700s electrical researchers adopted improved electrostatic machines that replaced earlier glass cylinders with a flat glass plate. This increased the machines’ efficiency by passing the glass plate between leather rubbing pads that increased the contact area. Experience with plate machines brought many design variations with sizes ranging from small table-top units for laboratory use to large cabinets that powered early x-ray machines.
This plate machine was made by Dutch physician and scientist Martinus van Marum (1750-1837) in 1791. Two glass plates are mounted parallel on a single crank-shaft although the handle is missing from this unit. Each plate has its own pair of leather pads set at top and at bottom that feed two shared prime conductors. The two primes are connected via a distinctive brass frame arching over the top of the unit and supported by three glass insulating rods.
The origin of this machine is uncertain but a paper tag marked “12 E” associates the machine with other electrical devices used in laboratory experiments. All of these devices have similar tags with a number and “E” written in ink in the same hand.
People from ancient times knew that rubbing certain materials and then touching something caused a spark. Studying what is called electrostatics laid the groundwork for understanding electricity and magnetism. Natural philosophers, scientists, and instrument makers created many ingenious devices to generate electrostatic charges starting in the 1600s. These machines varied in size and technique but all involved rotary motion to generate a charge, and a means of transferring the charge to a storage device for use.
In the latter 1700s electrical researchers adopted improved electrostatic machines that replaced earlier glass cylinders with a flat glass plate. This increased the machines’ efficiency by passing the glass plate between leather rubbing pads that increased the contact area. Experience with plate machines brought many design variations with sizes ranging from small table-top units for laboratory use to large cabinets that powered early x-ray machines.
This electrostatic machine was designed and made about 1880 in Paris by Eugène Ducretet (1844 -1915) based on a design by Ferdinand Carré (1824-1900). An unusual hybrid design, this machine operates by both friction and electrostatic induction. The lower glass plate rubs against a pair of leather pads, generating an electrostatic charge. The crank rotates both plates and the charged glass plate induces a charge on the upper plate which is made of ebonite.
Electrostatic induction occurs when a charged body (the glass disc, in this case) causes another body (the ebonite disc) that is close but not touching to become charged. The glass disc is said to influence the ebonite disc and some so-called influence machines, work solely on that principle. Points on the brass arms pick the charge off the ebonite plate and conduct the charge to the metal cylinder on top of the machine, called the prime conductor. The ring under the prime conductor can hold a Leyden jar or other experimental component. Ducretet also designed devices for radio work and received U.S. Patent 726413 in 1903 for a radio transmitter and receiver
One method that companies have long used to minimize production costs is to design products that use many of the same parts. In the early 1990s Duro-Test Lighting used this approach in a series of modular compact fluorescent lamps (CFLs).
Modular CFLs are designed so that specific parts can be replaced if they fail. This allows the reuse of expensive parts that still work. In this particular lamp, the fluorescent tube and the reflector enclosing it are made as one piece; the base-unit that houses the ballast and starter are another. In addition to allowing one to replace the tube assembly if it failed, one could swap different assemblies. The reflector lamp could be changed to a decorative lamp for example, without having to remove the base-unit.
Since the price of electronic components has dropped since this lamp was made, the economic reasoning behind this feature is less persuasive.
Lamp characteristics: Two-piece, modular compact fluorescent lamp including a base-unit and a tube assembly. The base-unit has a medium-screw base-shell with plastic insulator, and a plastic skirt that houses a ballast and a starter. A socket on top accepts a plug-in base. Tube assembly includes plastic plug-in base, a fluorescent tube with two electrodes, mercury, and a phosphor coating. A glass R-shaped envelope with silvered coating serves as a reflector and is glued to the tube assembly's base.
General Electric Corporate Research & Development Laboratory
inventor
Spellman High Voltage Electronics Corp.
ID Number
1998.0050.15
accession number
1998.0050
catalog number
1998.0050.15
Description
The energy crises of the 1970s inspired inventors to try novel ideas for new light bulbs. One of the more unusual designs emerged from the drawing board of Manhattan Project veteran Leo Gross. Supported by Merrill Skeist at Spellman High Voltage Electronics Corporation, Gross designed a compact fluorescent lamp that he called a "magnetic arc spreader" (MAS).
The design took advantage of a fundamental aspect of electro-magnetism known since the early 1800s. When a current flows through a coil of wire, it produces a magnetic field. The arc discharge that travels between the electrodes of a fluorescent lamp can be affected by the presence of such a field. In the center of the MAS lamp seen here there is a copper coil. Current moving through the coil creates a magnetic field that spreads out the electrical arc within the lamp. The expanded arc energizes phosphor throughout the lamp's entire length.
The concept was tested at Lawrence Berkeley Laboratory, and General Electric became interested. In 1978 GE purchased a one-year license from Spellman in order to conduct further tests but determined that the necessary glasswork would make the lamp too expensive for commercial production. GE donated one of their test lamps to the Smithsonian in 1998—the only known surviving example of this experimental design.
Lamp characteristics: No base. Two stranded lead-wires extend about 2" from either end, and each end has one lead wire encased in a glass insulating tube. Two coiled tungsten electrodes are mounted in a hollow cylindrical envelope. The exhaust tip is near one set of leads, and the envelope has an internal phosphor coating. A coil of bare copper wire held together with black string is inserted into the center of the envelope. A current passing thru this coil spreads the arc between electrodes so that more of the phosphor is activated.