(1.) THIS tax revision case raises the question whether high density polyethylene (HDPE) woven fabrics are "artificial silk fabrics" within the contemplation of item 4 of the Third Schedule to the Tamil Nadu General Sales Tax Act, 1959. Item 4 of the Third Schedule to the Sales Tax Act reads as under : "Cotton fabrics, woollen fabrics and rayon or artificial silk fabrics, as defined in items 19, 21 and 22 respectively of the First Schedule to the Central Excises and Salt Act, 1944 (Central Act 1 of 1944)." * The scope of the exemption provision in the Sales Tax Act is clear. That which is exempt from sales tax is rayon or artificial silk fabrics. What rayon fabric is or artificial silk fabric is must be determined by turning to their definition in the First Schedule to the Central Excises and Salt Act. But when we turn to the Central Excises and Salt Act, we almost draw a blank. Here is how the relevant articles are defined in item 22 of the First Schedule to that Act :