Discovery
| Parameter | Value |
|---|---|
| Date | May 24, 1844 |
| Sender | Samuel Morse, Supreme Court chamber, Capitol (Washington D.C.) |
| Receiver | Alfred Vail, Mount Clare station (Baltimore, Maryland) |
| Distance | 61 km (38 miles) |
| Message | "What hath God wrought" (Numbers 23:23, Bible) |
| Funding | $30,000 voted by Congress (March 3, 1843) |
| Medium | #16 copper wire (1.3 mm diameter) on wooden poles |
Technical Explanation
1. Line infrastructure — The Washington-Baltimore line followed the route of the Baltimore & Ohio Railroad. Morse initially tried burying the cable in lead pipes (under Ezra Cornell's direction), but the tarred cotton insulation degraded rapidly. The wire was then strung overhead on 7 m chestnut poles, spaced 300 feet (~90 m) apart — a standard that persisted for a century.
2. Power supply and signal — The circuit used Grove batteries (zinc/nitric acid, 1.9 V/cell). Approximately 100 cells in series provided ~190 V to compensate for resistive losses over 61 km. The current in the wire was about 15 mA — enough to actuate the receiving electromagnet.
3. Automatic recording — Vail's receiver used a mechanical stylus driven by a clockwork-fed paper strip. Dots and dashes were physically embossed, creating a permanent and verifiable record of the message.
4. Two-wire circuit — The 1844 line was built with two #16 copper wires forming a complete out-and-back circuit. Earth return (ground return) — a buried copper plate at each end closing the circuit through the soil's conductivity, halving the cost of wire — was only adopted later.
Why It Worked
The choice of distance (61 km) was not arbitrary: it was the maximum practical range without intermediate relays at the available voltage. Morse had empirically calculated that beyond 80 km, resistive attenuation rendered the signal undetectable. The overhead installation, adopted after the failure of the buried cable, proved decisive: air provides far better insulation than damp soil.
The biblical message "What hath God wrought" was chosen by Annie Ellsworth, daughter of the Patent Commissioner. This detail is not trivial: the media coverage of the message gave the telegraph immediate national visibility.
Causal Chain
Morse patent (1837) → Demonstrations to Congress (1838, 1842) → $30,000 funding vote (March 1843) → Buried cable failure → Overhead line Washington-Baltimore (May 1844) → Commercial expansion (1845: first company, Magnetic Telegraph Co.) → National network (1850s, 37,000 km in the USA) → Western Union unifies the network (1856) → Transatlantic cable (1866)
Anecdote
Congress nearly refused to fund the project. The vote on February 23, 1843 passed 89 in favor, 80 against, with 70 abstentions. Some congressmen proposed allocating the $30,000 to mesmerism (therapeutic hypnosis) rather than the telegraph, considering both ventures equally speculative.
Sources
References verified during the August 2026 fact-checking audit: these are the pages
against which this bulletin's claims were checked.