unsaturated monomer in the same manner as previously described referring now to fig3 there is shown an embodiment of the invention applied to the float process in which a continuous ribbon of flat glass is manufactured by floating on a bath of a molten metal which is denser than glass in this method of manufacture molten glass coming from a melting furnace not shown in the drawing flows along a feed channel 30 to lip 31 the flow rate of molten glass along the feed channel is regulated by a tweel 32 the vertical position of which is adjusted by a known device not shown the molten glass leaves the lip and falls onto the surface of a bath 33 of a metal denser than glass e g tin the tin bath 33 is enclosed in a completely sealed float tank 34 the molten glass spreads over the surface of the tin bath until it has an equilibrium thickness when it forms a ribbon 35 and subsequently travels over the tin bath at the same rate as it is extracted from float tank 34 float tank 34 contains a protective atmosphere substantially comprising an inert gas usually nitrogen heating elements not shown regulate the heating of float tank 34 in which the molten glass undergoes controlled cooling from approximately 1000 u00b0 c i e the temperature at which it is poured onto the metal bath to approximately 550 u00b0 c the temperature at which the glass leaves the float tank when extracted from the float tank ribbon 35 is lifted from bath 33 and carried by a roller conveyor 36 according to this embodiment of the invention a chamber 37 is disposed in the hot part of float.