Of these methods one of the chief is the plan of tubbing, or lining the excavation with an impermeable casing of wood or iron, generally the latter, built up in segments forming rings, which are piled upon each other throughout the whole depth of the water-bearing strata.
And 5 in., the lengths of tube forming the casing being screwed together.
The side of the casing which is next to the seller is pierced centrally by two slots, one a vertical slot through which the weight is read on the drum, and the other a horizontal slot, half of it on each side of the vertical slot, through which the money values of the goods, corresponding to the different rates per lb, are read.
Built in brick, it was found necessary to give a more monumental appearance to the walls by a casing of stucco, which remains in fair preservation to the present day.
Puddling furnaces are usually entirely cased with iron plates, and blast furnaces with hoops round each course of the stack, or in those of thinner constructions the firebrick work is entirely enclosed in a wrought iron casing or jacket.
L is the producer-shaft, with an iron casing B and peep holes B 1 to B4, passing through the brick lining M.
The weight of the goods is recorded by means of an index pointer fixed to the casing on one side of the vertical slot, and the money values are opposite the figures defining the rates per lb, which are marked on the edge of the casing below the hori zontal slot.
The decoration of the interior consists of the casing of the walls with marble with enriched borders, and (about 20 ft.
In some soils foundations may be obtained by the device of building a masonry casing like that of a well and excavating the soil inside; the casing gradually sinks and the masonry is continued at the surface.
After cooling, the casing is lifted out of the drum by a crane, assisted by compressed air, and is then conveyed by a travelling crane to a vertical centrifugal, inside of which it is made fast.