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Vintage Speedy Moisture Tester Type D1
This large Speedy soil moisture tester D1 model is made by Thomas Ashworth & Co. in Burnley England. Originally it would have come in a sturdy wooden box signed Cheney England. The contents of the box would have included its original soil basket and balance, scoop, cleaning brush, a bottle of calcium carbide (500gm), a set of 4 crushing steel balls, a clean cloth, the tester itself (a sealable metal flask with a pressure gauge attached to the base (calibrated from 0 to 50% which when converted is equivalent to a dry moisture content of up to 20%) and a spare washer for it.
Unfortunately due to its age we are only left with the key parts - the original soil basket and balance, tester (with gauge) and 2 of the 4 crushing steel balls.
We are advised that these items were also used by cereals grain companies to monitor the water content of their grains in their godown (warehouse). Dating from the 1970s and before, the balance being replaced by an electronic scale in later versions.
An interesting piece of equipment from the pre-digital age and worthy of conservation.
Using a speedy moisture meter, the moisture content of soil, sand and other fine grained material can be obtained quickly with reasonable accuracy. The test technique is based on the fact that water will react with calcium carbide to form acetylene gas and the quantity of gas formed is directly proportional to the water present, leaving a surplus of the chemical used in the test. The quantity of acetylene gas produced is indicated on a built-in pressure gauge which is calibrated in percentage of moisture on wet weight basis. A conversion formula gives the corresponding moisture content based on dry weight.