The movement of the gases through all this complicated set of apparatus is produced by a Root's blower placed at the end of it all.
The blower then heats the end of the cylinder again and rapidly spins the pipe about its axis; the centrifugal effect is sufficient to spread the soft glass at the end to a radius equal to that of the rest of the cylinder.
The blower therefore stops the process when he has blown a predetermined quantity of air through, counting from the drop of the flame; but as a check on his forecast he usually tests the blown metal before recarburizing it.
The hot water from B, freed from tar, is pumped into a third tower C, through which cold air is forced by means of a Root's blower by the pipe w.
Dean managed to whistle down a young boy who agreed to use his snow blower on Dean's unfinished sidewalk, for an amount Dean considered ridiculous, but he knew he needed to get up to snuff on Shipton's fall before he was totally on the defensive.
The blower repeatedly heats the lower part of the mass of glass and keeps it distended by blowing while he swings it over a deep trench which is provided next to his working platform.
The blower places the glass in the mould, closes the mould by pressing a lever with his foot, and either blows down the blowing iron or attaches it to a tube connected with a supply of compressed air.
Over to the blower proper.
The delay which this test causes is so unwelcome that in all other countries the blower continues the blow until decarburization is nearly complete, because of the very great accuracy with which he can then read the indications of the flame, an accuracy which leaves little to be desired.
The lower end of the cylinder is opened, in the case of small and thin cylinders, by the blower holding his thumb over the mouthpiece of the pipe and simultaneously warming the end of the cylinder in the furnace, the expansion of the imprisoned air and the softening of the glass causing the end of the cylinder to burst open.