ONE of the country's leading academics will be taking particular care when performing the famous ''capping'' ritual in today's graduation ceremonies.

After being used to cap an estimated 100,000 students at Edinburgh University, staff discovered the tapping of all those braincells had taken its toll on the velvet hat's fabric, causing it to split.

Restoration work on the frayed headgear has now been done to ensure it remains a part of future ceremonies.

The capping ritual is a centuries-old tradition whereby those taking a degree are lightly tapped on the head with the cap by the university's vice-chancellor and principal, Sir Stewart Sutherland.

In the past, some over-enthusiastic dons may have worn out the bonnet's fabric by wildly striking hapless students with the ancient cloth rather than favouring a gentle, more ceremonial tap.

Last year, when the beloved hat was pulled out for another 4000 cappings, the university felt it was looking rather the worse for wear.

Lancashire firm North West Museums offered to patch it up for this summer's graduations.

The restoration, sponsored by tailors Ede & Ravenscroft, uncovered fascinating new evidence on the cap's origins.

Legend has it that the cap was made from the breeches of sixteenth century religious reformer John Knox, though other records trace the fabric to the trousers of the scholar George Buchanan, a contemporary of Knox.

However, a North West Museums conservator last month happened upon inked paper fragments in the inner lining of the cap, bearing the words ''Henry Banks 22 Duke Street Edinr 31 July 1849''.

After studying information provided by the 1851 census, the university discovered that Henry Banks was a successful merchant tailor who employed six men.

If the cap was manufactured in 1849, it would be more difficult to trace its origins to fabric which once belonged to either John Knox or George Buchanan.

For this reason, some staff and students are hoping that the date of ''31 July 1849'' refers to an earlier restoration of the hat, rather than the date of its manufacture.