( 1 ) THE present rule was issued on 11-7-1977 at the instance of the writ petitioner, Seth Chemical Works Private Ltd. praying, inter alia, to strike down the assessment orders levying duty on ultramarine blue form 1962-63 till 1976-77 for the sum of Rs. 26,84,539/- and subsequent amounts and further praying to restrain the respondents from assessing any duty on ultramarine blue produced by the petitioner in its factory and for refund of the excise duty so illegally realised.

( 2 ) IT is stated that the petitioner has been carrying on manufacturing operation of the product of ultramarine blue and marketing the same through its customers and/or stockists or dealers. According to the petitioner the trade in ultramarine blue has various brand names and are used in the market as Robin ultramarine blue, Crown blue, Atlantic blue and Robin super. It is placed on record that the end product of ultramarine blue is a compound of sodium, aluminium, silicon, sulphur and oxygen and is ordinarily and predominantly used as an agent for temporarily brightening the whiteness of things particularly textiles. In the common parlance in the industry and trade it is known as Dh