Aquastatic

Heat is provided by a low-pressure burner with electric automatic igniter, and an aquastatic control shuts off the unit when material has reached the desired temperature.

The cushion comprises an outer cushion of flame-retardant foam, with a slip cover and, fitting in the hollowed out centre, another cushion of aquastatic gel covered with a strong reinforced slightly textured material.

[…] nor did such treatment disturb the precise aquastatic mechanism previously observed in this species.

When dampproofing concrete and masonry walls below grade, a check should always be made that no aquastatic pressure can develop in the future, as these dampproof coatings are not waterproof.