Ramaswami it must inevitably happen from time to time that legislation, though purporting to deal with a subject in one list, touches also on a subject in another list, and the different provisions of the enactment may be so closely intertwined that blind adherence to a strictly verbal interpretation would result in a large number of statutes being declared invalid becuase the Legistature enacting them may appear to have legislated in a forbidden sphere. Hence the rule which has been evolved by the Judicial Comittee whereby the impugned statute is examined to ascertain its pith and substance or its true nature and character for the purpose of determining whether it is legislation with respect to matters in this list or in that. It is thus clear from the aforesaid decisions that merely becuase a tax on land or building is imposed with reference to its income or yield, it does not cease to be a tax on land or building. The income or yield of the land/building is taken merely as a measure pf tje tax; it does not alter the nature or character of the levy. It still remains a tax on land or building. There is not set pattern of levy of tax on lands and buildings indeed there can be no such standardisation. No one can say that a tax under a particular entry must be levied only in a particular manner, which may have been adopted hitherto. The legislature is free to adopt such method of levy as it chooses and so long as the character of levy remains the same within the four corners of the particular entry no objection can be taken to the method adopted. In the cases before us, the cess is no doubt calculated on the basis of the yield for every kilogram of tea leaves produced in a tea estate, a particular cess is levied. But that is well accepted mode of levy of tax on land. The tax is upon the land upon the tea estate which is classified as a separate category as a separate unit for the purpose of levy and assessment of the said cess quantified on the basis of the quantum of produce of the tea estate. It cannot be characterised as a tax on production for that reason. As pointed out in Moopil Nair a tax on land is assessed on the actual or potential productivity of the land sought to be taxed.