The same applies to heavy industries, such as in the gas industry, where vertical retorts, and so on, are utilised.
They used the old horizontal retorts, for instance; now, of course, the vertical method is employed in all up-to-date gas undertakings.
Powdered activated carbon is produced along with the granular in crushing the lumps or pieces of carbon from the retorts where it is made.
I retorted that professional writers tend to he frequent, if rather laborious, speakers, and that no one ever said that they spoke particularly well.
In general there was another difficulty, that the retorts, which were made of cheap metal, were found to distort and require frequent replacement.
Oil is extracted from the shale in retorts, and, therefore, all the fire-producing qualities of that material are removed.
Carbonisation in a further 72 retorts will follow in a short time.
In the case of shale oil there are pits which are worked entirely for the production of coal to heat the retorts.
