Today he was talking about clocks. While I knew about the anachronistic striking clock in Julius Caesar, I hadn't taken in (though it should have been obvious) that in Richard II, too, when Richard compares himself to a clock, he is using much later model than any available in the fourteenth century:
For now hath time made me his numbering clock:
My thoughts are minutes; and with sighs they jar
Their watches on unto mine eyes, the outward watch,
Whereto my finger, like a dial's point,
Is pointing still, in cleansing them from tears.
The minute hand was a very recent invention in Shakespeare's day, so that this passage is a bit like a modern playwright having George III compare himself to an iPad. (MacGregor wasn't vulgar enough to use this analogy.)
MacGregor doesn't mention it, but hearing his programme also made me realise (with a cry of "Duh!") that at school I'd misread a line in Henry IV Part 1. When Falstaff claims to have fought Hotspur "a long hour by Shrewsbury clock" I'd fondly imagined that the battle must have taken place within sight of the clock-tower, so used am I to thinking of the telling of time as a visual act. But to Falstaff, as to most Elizabethans, it was an aural experience: Falstaff's referring to the sound of the bell, not the sight of the dial.
This got me thinking about the phrase "tell the time". It's a two-way phrase: the clock tells (i.e. communicates) the time to us, and we can tell (i.e. perceive) the time by looking at the clock. But in both directions time is also being told in another sense, that of counting. The clock tells the hours as the beadsman tells his rosary, one chime at a time; and we tell them the same way, by counting off the chimes (at midnight or otherwise). So there's a little fossil of the aural primacy of time-telling, hidden away in a phrase that has been assimilated to other senses of "tell".
Tolling, on the other hand, has a different root entirely, and seems to be related to the action of pulling on a rope to make the bell ring.