(1)For a period of three years after the commencement of this Act paragraph (b) of section seven of this Act shall apply, where the process for the concentration of sulphuric acid is that known as the over-heat pan process, as if in that paragraph two grains of sulphuric anhydride were substituted for one grain and a half of sulphuric anhydride.
(2)For the purposes of this section " the over-heat pan process " means the process in which the concentration of sulphuric acid is effected by the passage of the heated gases resulting from the combustion of fuel over the surface of the acid.