656 



GLASS 



close together when annealing : an operation which takes from eight to fourteen days 

 at most. There is thus less risk of anything dropping from the roof of tho furnace. 



1094 



~\ 



1095 



The inside of the square of tho furnace is built either of Stourbridgo fire-clay an- 

 nealed, or of fire-stone, to the thickness of sixteen inches. The outside is built of 

 common brick, about nine inches in thickness, 



The furnace is thrown over an ash-pit, or cave as it is called, which admits the 

 atmospheric air, and promotes the combustion in the furnace. This cave is built of 

 stone until it comes beneath the grate room, when it is formed of fire-brick. Tho 

 abutments are useful for binding and keeping the furnace together, and are built of 

 masonry. The furnaces are stoutly clasped with iron all round, to keep them tight. 

 In four-pot furnaces this is unnecessary, provided there be four good abutments. 



Fig. 1096 is an elevation of the flashing furnace. The outside is built of common 

 brick, the inside of fire-brick, and the mouth or nose of Stourbridge fire-clay. 



1096 



1097 



Fig. 1097 is the annealing kiln. It is built of common brick, except round tho grato- 

 room, where fire-brick is used. 



Few tools are needed for blowing and flashing crown-glass. Tho requisite ball of 

 plastic glass is gathered, in successive layers as for bottles, on tho end of an 



