SATYANRAYANA RAO, J.

The question is " Whether on the facts and in the circumstances of the case, interest on securities received by the applicants should be treated as earned income, falling under the head 'income from business' (Section 10), or 'income from other sources' (Section 12), and should not be treated as income from 'securities' (Section 8) ?

The assessees during the accounting year ending with 31st December, 1945, had several sources of income, viz., interest on securities, profits of business, didvidends and other interests. The business, however, ended in loss. They claimed earned income relief in respect of the interest on securities on the ground that the securities, the Government Promissory Notes, which they purchased and sold as part of their business formed stock-in-trade and that the profits arising in such purchase and sale including the interest on securities should be treated as business profits. As the other business ended in loss, naturally they could not claim earned income relief in respect of that business. The claim was, therefore, confined to the interest on securities. The definition of " earned income " in section 2(6AA) does not include interest on securities falling under section 8 of the Act, as it does not involve a personal exertion in earning income on the part of the assessee. The attempt, therefore, of the assessees was to bring this activity, viz., purchase and sale of securities, as part of their business under section 10 of the Income-tax Act. They were, howlever, not successful before the revenue authorities who held that the interest on securities is assessable under section 8 and could not be treated as part of the business income

This view of the department has been challenged before us solely on the ground that income treated as interest on securities should also be included in the business income, because it formed part of their business operations. The answer given on behalf of the revenue authorities by Mr. Rama Rao Sahib, learned counsel, was that, as the income which represents interest on securities falls under a head which is specifically provided for by section 8, is not open to the assessees to contend that it should be treated as part of their business income., as it is made separately chargeable under section 8It is necessary in this connection to understand the underlying scheme of the provisions of the Act relating to the charging of income to tax and the mode of computation of income. It is an undoubted fact that income-tax is one single tax on the aggregate total income of an assessee. It is, however, classified under various heads and made chargeable under such heads. Section 3 of the Act is the charging section. Section 4 defines the limits to which the net may be spread by the department. Section 6 classifies the heads, and sections 8 to 12 enumerate the principles on which the computation of the income under various heads should be made. The classification under section 6 under various heads however does not mean that there are as many taxes as there are heads of income. The tax, as stated above, is one tax on the aggregate of the income. If once the income is dealt with under the proper head, it cannot be dealt with again under another head as when once the income is taxed, its source for purposes of taxation becomes exhausted. These principles have been well established both in England and in India. It is not open either to the department or to the assessee to claim that an income which clearly falls under one head should be dealt with under a different head for the purpose of either claiming more tax by the tax gatherers or claiming that the burden should be made light by the taxpayer. The leading case on this subject is that of the House of Lords in Salisbury House Estate Ltd. No doubt, in that case the attempt to tax under a different head the same income was made by the Special Commissioners and not by the assessee but that does not in our opin