(4)Where a person having contracted for the purchase of any property but not having obtained a conveyance thereof, contracts to sell the whole, or any part thereof, to any other person or person and the property is in consequence conveyed by the original seller to different person in parts, the conveyance of each part sold to a sub-purchaser shall be chargeable with ad valorem duty in respect only of the market value of the property purchased by such sub-purchaser and the conveyance of the residue (if any) of such property to the original purchaser shall be chargeable with ad valorem duty in respect only of the market value of such residue:Provided that the duty on such last mentioned conveyance shall in no case be less than one hundred rupees.
