---
license: other
license_name: other
license_link: LICENSE
viewer: false
task_categories:
- summarization
- text-generation
language:
- en
tags:
- physics
- electromagnetism
- simulation
- finite-difference
- conductive-media
- signal-processing
- computational-physics
- time-series
- tabular-data
- engineering
- education
- reproducible-research
- physics
- electromagnetism
- finite-difference
- simulation
- conductive-media
- time-series
- computational-physics
- reproducible-research
---

# Telegraphing Without Wires (1884) — Finite-Difference Simulator and Synthetic Dataset Reconstruction

Original manuscript: [Telegraphing Without Wires - An Experiment](https://ieeexplore.ieee.org/document/5570293)

Video: [Reconstructing an 1884 Telegraph Experiment with Modern Simulation](https://www.youtube.com/watch?v=ZmkGXuwWpN0)

**Developed by:** DBbun LLC
**Version:** v1.1
**Data Formats:** CSV · JSON · NPZ · PNG

---

## Who Should Use This Dataset

This dataset is intended for:

- **Students** studying electromagnetism, signal processing, or numerical simulation
- **Engineers** exploring signal transmission in conductive media
- **Data scientists** working with physics-generated structured data
- **Researchers** interested in executable reconstructions of historical experiments
- **Educators** integrating computational laboratories into coursework

It provides a reproducible computational environment for studying signal transmission through conductive media, bridging physical modeling, circuit abstraction, and time-domain system behavior.

---

## Abstract

This dataset provides a computational reconstruction of S. J. M. Bear's 1884 experiment *"Telegraphing Without Wires,"* originally presented before the American Institute of Electrical Engineers. The project transforms a pre-digital manuscript — written decades before computers and numerical modeling — into a fully reproducible finite-difference simulation framework. By solving the variable-conductivity Laplace equation, it enables quantitative analysis of electric potential fields, current density distributions, and receiver behavior in conductive media.

The dataset includes multi-scenario simulations with spatially varying conductivity (uniform media, freshwater–brine interfaces, insulating obstacles, conductive paths, and localized plumes). Receiver behavior is modeled using a Thevenin-equivalent formulation with relay resistance and threshold dynamics. Time-domain simulations capture keying signals, electrode polarization effects, and relay actuation.

Beyond historical reconstruction, this resource serves as an educational and research platform:

- **For students:** a hands-on bridge between electromagnetic theory, partial differential equations, numerical methods, and signal processing.
- **For engineers:** a sandbox for studying signal transmission in conductive environments (e.g., underwater communication, geophysical sensing, bioelectric systems).
- **For data scientists:** structured, multi-modal datasets suitable for statistical modeling, inverse problems, parameter estimation, surrogate modeling, and machine learning experiments on physics-generated data.

All outputs are provided in CSV, JSON, and compressed NumPy formats to support reproducibility and downstream analysis. The included Python source code regenerates all scenarios.

---

## Dataset Structure

Each experiment generates:

| File | Description |
|------|-------------|
| `*_fields.npz` | Spatial field arrays (potential, electric field, current density) |
| `*_timeseries.csv` | Time-domain signal and relay behavior |
| `*_summary.json` | Per-experiment scalar results and circuit parameters |
| `figs/` | Figures directory |

Global outputs:

| File | Description |
|------|-------------|
| `experiment_summary_v1p1.csv` | Aggregated scalar results across all experiments |
| `experiment_summary_v1p1.json` | JSON equivalent of the above |
| `sweep_sigma_v1p1.csv` | Conductivity sweep results |
| `sweep_sigma_v1p1.json` | JSON equivalent of the sweep |
| `manifest_v1p1.json` | File inventory and checksums |
| `run_meta_v1p1.json` | Run metadata (version, timestamp, grid parameters) |

---

## NPZ File Specification (`*_fields.npz`)

### Material Map

| Array | Type | Description |
|-------|------|-------------|
| `sigma` | 2D float | Spatial conductivity map of the tub. Higher values indicate more conductive regions; lower values indicate less conductive or insulating regions. |

---

### Base 1-Volt Sending Condition

| Array | Type | Description |
|-------|------|-------------|
| `V_tub_1V` | 2D float | Potential distribution when 1 volt is applied across the sending electrodes. |
| `Ex_1V` | 2D float | Horizontal component of the electric field under the 1-volt sending condition. |
| `Ey_1V` | 2D float | Vertical component of the electric field under the 1-volt sending condition. |
| `Emag_1V` | 2D float | Magnitude of the electric field at each spatial location. |
| `Jx_1V` | 2D float | Horizontal component of current density. |
| `Jy_1V` | 2D float | Vertical component of current density. |
| `Jmag_1V` | 2D float | Magnitude of current density. |

---

### Delivered Voltage Fields

| Array | Type | Description |
|-------|------|-------------|
| `V_delivered_no_pol` | 2D float | Potential distribution accounting for battery internal resistance and contact resistance, without polarization. |
| `V_delivered_pol` | 2D float | Potential distribution including steady-state electrode polarization effects. |

---

### Receiver-Port Solution

| Array | Type | Description |
|-------|------|-------------|
| `V_port_1V` | 2D float | Potential distribution when 1 volt is applied directly across the receiver electrodes. Used to estimate the receiver's effective resistance. |

---

### Electrode Masks

Binary arrays (0 or 1):

| Array | Description |
|-------|-------------|
| `tx_plus` | Positive sending electrode region |
| `tx_minus` | Negative sending electrode region |
| `rx1` | First receiver electrode |
| `rx2` | Second receiver electrode |

---

## Time-Series CSV Specification (`*_timeseries.csv`)

| Column | Description |
|--------|-------------|
| `t` | Simulation time in seconds |
| `key` | Telegraph key state (1 = pressed, 0 = released) |
| `Vpol` | Electrode polarization voltage |
| `Vtub` | Voltage delivered across the tub |
| `Isource` | Current supplied by the battery |
| `Vth` | Effective voltage at the receiver |
| `Irelay` | Current flowing through the relay |
| `relay_state` | Relay state (1 = closed, 0 = open) |

---

## Per-Experiment Summary JSON Fields (`*_summary.json`)

| Field | Description |
|-------|-------------|
| `name` | Experiment identifier |
| `sigma_map_name` | Conductivity scenario used |
| `battery_voltage` | Battery voltage |
| `battery_internal_resistance_ohm` | Internal battery resistance |
| `electrode_contact_resistance_ohm` | Electrode contact resistance |
| `relay_resistance_ohm` | Relay resistance |
| `relay_pull_in_current` | Current required to activate relay |
| `relay_release_current` | Current below which relay releases |
| `Vth_per_1V` | Receiver voltage scaling factor |
| `Rth_ohm_like` | Effective resistance at receiver port |
| `delivered_tub_voltage_no_pol` | Tub voltage without polarization |
| `delivered_tub_voltage_with_pol` | Tub voltage with polarization |
| `Irelay_no_pol` | Relay current without polarization |
| `Irelay_with_pol` | Relay current with polarization |
| `relay_click_no_pol` | Relay activation without polarization (bool) |
| `relay_click_with_pol` | Relay activation with polarization (bool) |
| `tub_resistance_ohm_like` | Effective tub resistance |
| `source_current_no_pol` | Battery current without polarization |
| `source_current_with_pol` | Battery current with polarization |

---

## Conductivity Sweep Dataset (`sweep_sigma_v1p1.csv`)

| Column | Description |
|--------|-------------|
| `sigma` | Uniform conductivity value |
| `R_tub` | Effective tub resistance |
| `Vth_per_1V` | Receiver scaling factor |
| `Rth` | Effective receiver resistance |
| `Vtub_no_pol` | Delivered voltage without polarization |
| `Irelay_no_pol` | Relay current without polarization |
| `click_no_pol` | Relay activation without polarization (0/1) |
| `Vtub_pol` | Delivered voltage with polarization |
| `Irelay_pol` | Relay current with polarization |
| `click_pol` | Relay activation with polarization (0/1) |

---

## Reproducibility

Run:

```bash
python Bear-1884-Code-v1.1.py
```

Outputs are generated under:

```
output/
output/figs/
```

**Dependencies:**

- `numpy`
- `scipy`
- `matplotlib`

---

## Contribution

Developed by **DBbun LLC**, this project demonstrates how a historical scientific experiment can be transformed into a structured, reproducible computational laboratory suitable for education, engineering analysis, and data-driven research.