1. This petition challenges the validity of Act VII of 1956 being an Act passed by Parliament. The petitioner carries on business of dealing in curios, novelty goods, piece goods etc. at Bombay and he is a registered dealer under the Bombay Sales Tax Act 1953. For the period commencing from 1st April 1954 to 31st March 1955 the petitioner elected as and from the 23rd February 1955 to pay tax on his sales instead of tax on his purchases. In the course of assessment for this period he was taxed on his purchases from persons outside the State of Bombay from the 1st April 1954 to the 23rd February 1955 on the sum of Rs. 2,55,534-5-6. The petitioners contention was that these purchases were not liable to tax under the Sales Tax Act as they were made in the course of inter-state trade or commerce.

2. In order to understand the contentions of the parties, it is necessary in the first place to look at the provisions of the Constitution and to consider what are the powers of the State Legislature and of Parliament with regard to imposing tax on sales and purchases. Turning first to the legislative competence of Parliament, we find entry 42 in List I of the Seventh Schedule which de