Jyotirmoyee Nag, J.
1. This rule is directed against an order dated 14th January, 1971, passed by the Assistant Commissioner of Commercial Taxes, Calcutta 'C' Circle, in Revision Case No. RVN-8-70-71 and also against an order dated 31st July, 1972, passed by the Additional Commissioner of Commercial Taxes, West Bengal, in Revision Case No. 433 (Misc.) of 1970-71. It is the case of the petitioner that he is carrying on a business as proprietor under the name and style of M/s. Sreemany Optician at 96B, Shyama Prosad Mukerji Road, Calcutta-26. Since March, 1957, the petitioner has been carrying on the business of purchase and sale of optical frames and glasses and items incidental thereto. The petitioner claims that he is not a manufacturer or importer of goods sold by him and the petitioner maintains primary books of account of his business. The petitioner states that in the course of his business, a customer comes to him with a prescription from a doctor, selects a particular frame, settles the price thereof and the frame is then appropriated to the contract of sale within the meaning of explanation 2(a) to Section 2(g) of the Bengal Finance (Sales Tax) Act, 1941. The petitioner then fixes the glasses, according to prescription, to the frame which has already become the chattel of the customer. There are thus two distinct sales-one of frame and the other of the glasses-and it is the case of the petitioner that he does not charge anything for fitting. It is alleged that the Commercial Tax Officer, Alipore, who examined the petitioner's books of account, records and documents under Section 14(1) of the Act, completely misunderstood the nature of the transaction and the legal implication thereof and by an order dated 7th April, 1970, held that the petitioner manufactures spectacles from parts of spectacles purchased by him and sells such spectacles to customers. According to the said officer, the petitioner is a manufacturing dealer whose liability under the Act would arise upon the taxable quantum of Rs. 10,000 within a year or part thereof. The Commercial Tax Officer estimated that the gross turnover of the petitioner as a manufacturing dealer exceeded that taxable quantum on 31st October, 1966 and, accordingly, the petitioner was liable under Section 4(2) of the said Act to pay taxes from 1st January, 1967. Being aggrieved by this order, the petitioner moved a petition for revision under Section 20(3) of the said Act to the Assistant Commissioner of Commercial Taxes who, by his order dated 14th January, 1971, rejected the petitioner's contention that there were really two distinct resales one in respect of the frames and the other, in point of time, of the glasses. The Assistant Commissioner held by the said order that there was only one contract for sale of manufactured spectacles as has been held by the learned Commercial Tax Officer and estimated that the petitioner's turnover really exceeded the taxable turnover of Rs. 10,000 on 30th April, 1965, with liability to pay tax commencing from 30th June, 1965. The petitioner moved the Commissioner of Commercial Taxes, West Bengal, against the said order passed by the Assistant Commissioner. The learned Additional Commissioner of Commercial Taxes by his order dated 31st July, 1972, modified the order of the learned Assistant Commissioner but maintained the order of the Commercial Tax Officer. The Additional Commissioner rejected the contention of the petitioner that he is not a manufacturer of spectacles and that his liability arises not on the taxable turnover of Rs. 10,000 but on Rs. 50,000.
2. The learned Advocate appearing for the petitioner submits that Section 4 of the Act provides that every dealer whose gross turnover during the year immediately preceding the commencement of this Act exceeded the taxable quantum shall be liable to pay tax under this Act on all sales effected after the date so notified. It is necessary under the provisions of Section 4 of the said Act that there should be an assessment first of the gross turnover of the petitioner before a notice can be issued to him under the said section to make him liable to pay tax as has been done in the present case. In Sub-section (5) of Section 4 of the Act, 'taxable quantum' has been defined, which means (a) in relation to any dealer who imports for sale any goods into West Bengal or manufactures or produces any goods for sale, 10,000 rupees ; or...(c) in relation to any other dealer, 50,000 rupees-It is the contention of the petitioner that he is not a manufacturer, nor is he a producer. Therefore, unless there is a finding that his gross turnover is over Rs. 50,000, he is not liable for being taxed according to the said Act.
3. In the present case, under Section 11(2) of the said Act, it is necessary that if upon information which has come into his possession, the Commissioner is satisfied that any dealer who has been liable to pay tax under this Act, in respect of any period, but has failed to get himself registered or to obtain a special certificate, as the case may be, the Commissioner shall proceed in such manner as may be prescribed to assess to the best of his judgment, the amount of tax due from the dealer in respect of such period and all subsequent periods and in making such assessment shall give the dealer a reasonable opportunity of being heard. Therefore, such a decision of the Commercial Tax Officer determining the liability of a dealer is incidental and ancillary to the exercise of his power under Section 11(2). Exercise of such power under Section 11(2) necessarily involves determination of the period of liability. Liability to pay for a certain period or from certain date under Section 4(2) of the said Act is to be determined in a proceeding under Section 11(2) of the said Act. The impugned order determining the liability of the petitioner to pay tax independently of any proceeding under Section 11(2) of the said Act is, according to the submission of the learned Advocate for the petitioner, without jurisdiction. In this connection, the petitioner's learned Advocate has referred me to a decision of this court in Sudhir Ch. Mukherjee v. Additional Commissioner, Commercial Taxes  37 S.T.C. 554, where it has been held that it is well-settled that statutory powers are to be exercised in the mode prescribed by the statute and not in any other manner. If the statute directs that certain acts shall be done in a specified manner, or by certain person, their performance in any other manner than that specified or by any other person than one named, is impliedly prohibited. Accordingly, it is submitted by Mr. Chakravarti that the impugned order is without jurisdiction being in violation of Section 11(2) of the said Act.
4. Next it has been contended by Mr. Chakravarti that the petitioner is not a manufacturer and he relies upon the decision cited above. It has been held in that case that 'manufacture' implies a change but every change is not manufacture and yet every change of an article is the result of treatment, labour and manipulation. But something more is necessary and there must be transformation ; a new and different article must emerge having a distinctive name, character or use. As for instance, when oil is produced out of oil-seeds, the process certainly transforms the raw material into a different article for use and as such it is manufacture. Following that decision and applying the same test to the facts of the present case, it cannot, by any stretch of imagination, be held that the petitioner is a manufacturer of spectacles by assembling of frames of the spectacles and thereafter upon prescriptions fitting glasses to individual frames and then selling them to the customers. Assembly of parts of the frames does not create something new and hence it cannot be termed to be a manufacture to come within the meaning of Section 4(5) of the said Act.
5. I accordingly hold that the petitioner is not a manufacturer of spectacles as found by the learned Assistant Commissioner of Commercial Taxes. Accordingly, he is not liable to be taxed for a gross turnover of Rs. 10,000 or above, but he will come within the provision of Section 4(5)(c), i. e., if his gross turnover is above Rs. 50,000 he will be liable to be taxed. Apart from this, relying upon the decision cited above, I hold that the learned Assistant Commissioner erred in not completing assessment under Section 11(2) before fixing the liability of the petitioner to pay tax under Section 4(2) of the said Act.
6. Accordingly, I set aside the impugned order of the Additional Commissioner of Commercial Taxes, West Bengal, dated 31st July, 1972, affirming the order passed by the learned Commercial Tax Officer dated 7th April, 1970, with some modification, i. e., making him liable under Section 4(2) of the Act with effect from 1st January, 1967. The rule is thus made absolute. There will be no order as to costs.