There are two rows of books in a library facing each other and each row has five books. Each row has one book each on Physics, Chemistry, Economics, History and Mathematics. All the books are identical in dimension and at equal distances from their neighbours. The rows are called Row 1 and Row 2.
The following facts are known.
(i) The Economics book in Row 2 is at a corner.
(ii) In both the rows, the Economics book in next to the Chemistry book. Further, in both rows, the Chemistry book is next to the Physics book.
(iii) The Physics book is the only book in either row to face its counterpart. (A counterpart is a book on the same subject.)
(iv) The History book is as farther as possible from its counterpart. Only one pair of books on the same subject is as far as the two History books are.
Which subjects are at the centre in row 1 and 2, in that order?