 | National cyclopaedia - 1879
...those trees abound ; but that made in the north <rf Europe is considered the best. A conical cavity U made in the ground (generally in the side of a bank...and billets of the same, being neatly trussed in a stack of the same conical shape, are let into this cavity. The whole is then covered with turf, which... | |
 | Robert Bentley, Henry Trimen - 1880
...tar is principally extracted, are always most productive in such places. A conical cavity is first made in the ground (generally in the side of a bank...together with logs and billets of the same, being toeatly trussed in a stack of the same conical shape, are let into this cavity. To prevent the volatile... | |
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... a stack of the same conical shape, are let into this cavity. The whole is then covered with turf, to prevent the volatile parts from being dissipated, which, by means of a heavy wooden mallet, and a wooden stamper worked separately by two men, is... 
