Dines and the Tilting-Siphon Rain Recorder

Probably all professions have their Heath Robinsons

Probably all professions have their Heath Robinsons. William Heath Robinson, as we recalled yesterday, was an English cartoonist of the 1930s who poked fun at the complexities of modern life. He drew convoluted, yet ingenious, machines, usually dilapidated from perpetual use and kept intact by strings and ill-fitting nuts and bolts, designed to perform some very simple task - like make a cup of tea. Even today, a device which is undependable or patently ill-made, or perhaps unnecessarily complex for its mundane task, is sometimes called "a Heath Robinson affair".

William Henry Dines was the Heath Robinson of meteorology. We have already in this context looked at his "pressure-tube" machine for measuring wind. But the Dines Tilting-Siphon Rain Recorder was an even more engaging example of the genre.

The instrument catered for situations where it was inconvenient for a human observer to be continuously on site to measure the amount of rain. Remote regions required a device which provided a written record of the rainfall on a chart. The Tilting-Siphon Rain Recorder was Dines's answer to this need. The rain-water was collected by a funnel, whose precise diameter was known, and from there it flowed into a container fitted with a float. The float, naturally enough, moved upwards as the water level rose; it, in turn, was connected to a pen which drew a trace on a chart fitted to the slowly-moving curved surface of a revolving clockwork drum. This, for a while, gave a continuous record of the amount of rain that fell.

But what happened when the float-chamber became full? Dines's solution was to balance the whole chamber on a pivot and to hold it in the vertical position with a spring-loaded catch. When the float reached the top of its travel, it tripped a lever to release the catch - which allowed the chamber to overbalance by the weight of water it contained; the water inside began to pour out through a tube, which then continued to function as a siphon until the chamber emptied. Then the float-chamber, now relieved of the water's weight, fell back to its upright position, the catch clicked home, and the operation of recording rain began again.

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There is one striking difference, however, between Heath Robinson's machines and those of William Henry Dines. The former's fantasies were not obliged to work in practice; in fact, much of their humour derived from the fact that they would never work at all. Dines's instruments, on the other hand, were designed for everyday use. They worked - and Tilting-Siphon Rain Recorders are still in operation in many places to this very day