(1)A person shall not be convicted of an offence against section two of this Act, and an order for forfeiture shall not be made under the foregoing section, if it is proved that publication of the article in question is justified as being for the public good on the ground that it is in the interests of science, literature, art or learning, or of other objects of general concern.
(2)It is hereby declared that the opinion of experts as to the literary, artistic, scientific or other merits of an article may be admitted in any proceedings under this Act either to establish or to negative the said ground.