Dear Peter,
In a valuation of Tavistock Canal machinery and materials dated April 1811, triangles are mentioned several times. The first mention is of 'triangle sheers, blocks & rope, windlasses etc', which clearly refers to the headgear used in sinking a shaft, which of course looks triangular in profile. Later, '21 triangles for flatrods, 155ft by 2/6' are mentioned, in conjunction with 23 pendulums for the rods. It looks very much as if the pendulums were slung from the triangles, pivoting at the top and with the rods suspended at the bottoms. These seem to have supported the rods across an area od undulating ground, while the majority were running on posts and pulleys as was normal on even ground. A further mention refers to 'Movable joints, chains and triangles' in conjunction with another flatrod run which probably crossed the Tavistock Canal at an oblique angle, high enough to clear the canal and towpath.
Hope this helps.
Robert Waterhouse
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Message Received: Feb 26 2007, 07:08 PM
From: "Peter Claughton"
To: [log in to unmask]
Cc:
Subject: Boulton and Watt steam pumping engines
In a letter discussing the disposal of material on a mine at Bere
Ferrers, co. Devon in the UK, including a Boulton and Watt steam
engine, in November 1795, Richard Crawshay gives the following instructions -
"the triangles must not be sold till the engine and pipes are taken
away or removed onto Birch where I learn it should have been fix'd originally."
But what is meant by the term 'triangles'?
Peter
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Dr Peter Claughton,
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