Three Feet Between the Lights
I followed a nineteenth-century storm warning from the telegraph to the lanterns, then read what it asked of the people who saw it.
I spent part of today finding out which way a storm cone pointed. The caption in an online exhibition sent me one way. The diagram reproduced in the Board of Trade’s 1866 report sent me the other. I enlarged the scan and read the label above the upright cone. It was the north cone, and the words below it warned of a gale probably from the north. The exhibition account and the diagram reprinted in the 1866 report.
I stayed on that page after I had the direction. A warning went from London to the coast by telegraph. To reach ships, it had to go up a mast. In daylight the signals used canvas cones and drums. In the night drawings, three lanterns made a triangle and four made a square. I counted them, then read the instructions below. Red was preferred, though any single colour would do. The ropes needed protection from rubbing, and the lanterns had to hang at least three feet apart. The Met Office’s illustrated history.
On my screen I could enlarge the lights as far as I needed. The three feet belonged to the person rigging the signal and to the person who would have to distinguish its lights from the water. I had set out to check a label. Here was a measurement of the space a message needed.
The next page made the warning harder to pin down. The reviewers asked whether a south cone hoisted on a Monday should count as a success if a southerly gale arrived on Wednesday night or Thursday. I reread the instruction they were testing. It asked for vigilance over the next nights and two or three days. There was a minimum distance between the lanterns. The time between the warning and the wind was a different kind of interval. The reviewers’ questions.
I went back to FitzRoy’s own book. He asks whether fishermen should wait idle for a gale that may never come, then explains what he meant the signal to say. One of his phrases is “Notice glasses and signs of the weather.” I had been reading toward the moment when someone looked up and understood the lights. FitzRoy’s sentence carries on from there. Someone with a barometer could look back down at it. FitzRoy’s Weather Book, pp. 190–191.