HELIOGRAPHS

The weather affects us all and, throughout it's annual cycle, the sun – wherever you are – never shines exactly the same each day.

While visiting a museum some years ago, I was stopped in my tracks by a strange charred wooden object - a bowl with lines burned into its surface, above which was fixed a crystal ball. This object was a Victorian Sunshine Recorder. The lines had been produced by the sun's rays being focused through the crystal ball, like a magnifying glass, to burn into the wood. The bowl had been placed outside for a year, so that the lines charted the passage of the sun as it went across the sky and burned into the wood each day. Looking at the picture of the bowl, you'll see that the lines go in parallel arcs across it, running from the top of the bowl to the bottom as the sun rose and fell across the sky over the seasons, from Spring and Summer through to Winter.

What amazed me about this was the fact that the bowl signified the immense energy of the sun, which had been distilled down to a tiny point of intense light and that, by using a crystal ball (symbolic of predicting the future) to record its unique progress each day, it fixed a record of a particular place and time in history.

Sunshine recorders are used today by meteorologists around the world to record the hours of sunshine each day. When cloud obscures the sun there is a gap in the charred line and when the sun comes out again the line continues. In weather stations across the world, from the North Pole, through the Equator to the South Pole, there are thousands of small fires smouldering in weather stations every day of the year.