"The lime trade"
On Llyn, lime
was not always available and some early builders used earth and clay between the
stones. However, with the advent of a busy coastal shipping industry on the
Llyn, Limestone, and culm the fuel needed to convert Limestone into quicklime became
two of the more important imports to the area.
The soil of much
of the Llyn tends to be thin and acidic, not at all conducive to arable farming.
As a result lime was needed for application to the soil to reduce acidity and
thereby increase fertility. Lime was also very much in demand as lime mortar for
building. It was also needed for Lime wash, the original whitewash used to paint
stone cottages white.
The lime industry on Llyn started in the eighteenth century. The following “Porths” had kilns Pistyll, Morfan Nefyn, Porthdinllaen, Porth y Sgaden, Porthgolmon, Porth Oer, Porth Orion, Porth Meudwy, Aberdaron (2), Rhiw (Rhuol), Abersoch and Llanbedrog.
"Porthdinllaen's kiln, behind the cart"
coming of the railways, the only way to get lime to the Llyn was by sea,
limestone was brought in by small trading vessels. Often, it was offloaded into
the water at high tide and then collected from the beach when the tide went out.
To make lime, limestone or calcium carbonate must be heated to 800 - 900 degrees to drive off carbon dioxide and leave calcium oxide or quicklime. This process was achieved in huge masonry kilns with a tapering internal furnace or 'crucible' where alternate layers of limestone and culm were introduced through the opening at the top. It is said that during the day they burned with a transparent blue waving flame while giving off thick acrid yellow smoke. At night they glowed and may have been useful landmarks for travellers both on sea and land.
Some surviving lime kilns from around Llyn.
"Discharging Limestone at Porthsgaden"
from the kilns was sold to farmers who would leave it in small heaps on the
fields to be 'slaked' to take in water and to be converted to calcium
hydroxide before it could be applied to the land. Without slaking, the quick
lime would have killed anything growing. The slaked lime was spread at some four
tons to the acre.
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