41.   Huge cresset torches were placed high on the walls, the tables had been covered with white linen and the only plate used was of the best thick silver.

42.   These represent segments of small circles concentric about the pole of rotation with respect to which the diverging plates are moving.

43.   Heating probably begins at quite shallow depths but because the downgoing plate is cold virtually all of this heat is initially absorbed.

44.   So far we have confined our attention to convergent margins where two plates are in motion towards each other.

45.   Because the plates have already been set up etcetera etcetera.

46.   But the plates like these are not just for the rich.

47.   The plates are of great sentimental value to Keith Whittam, of Devonshire Road, Middlesbrough.

48.   One plate is a limited edition of the RAF College at Cranwell, Lincolnshire.

49.   Yes just all your plate was just and then turnips and potatoes and dishes of that boiling hot set on the table.

50.   There are glass plates somewhere.