“Find that it is not competent to open up the decree of declarator of the expiry of the legal of the lands of Woodside, in the year 1758, in so far as it concerns the interest of Dr Mackinlay, the last purchaser; but find it competent to open up the said decreet ad hunc effectum , to make the heirs of James Shearer liable to account to the appellant for the price at which the lands in question were sold to James