The fireclay shales have already been described on pages 53 and 116.
Every single joint must be perfectly made with fireclay cement or paste.
To the mouth of each retort is fitted a condenser, also made of fireclay.
Stoves were made of fireclay and mica, which would give both heat and light and would be more efficient than the open fireplaces.
Their ends are connected at the top to two conductors, which pass down inside the tube and end in a fireclay plug at the bottom.
This tube projects from the fireclay casing into the medium to be examined, and can be pushed in or out as required.
There are also numerous collieries, producing coal of superior quality, and iron ore, fireclay and freestone are plentiful.
The oxide is therefore mixed with coal or some other form of carbon and placed in retorts made of fireclay.
For this purpose a mixture of fireclay with finely powdered felspar or Cornish stone is used.
These are the cabins and stores of the bricklayers, and they contain cement, fireclay, and firebricks for the furnaces and forges.