Nottinghamshire 187 and 90 for 6 (Duckett 37, Harmer 4-32) lead Essex 241 (Browne 67, Fletcher 5-50) by 36 runs

When it came to losing things, the Chelmsford crowd took some beating. Public address announcements periodically crackled across the ground about mislaid wallets, members' cards and even a hearing aid. An announcement about where to collect a lost hearing aid tends to be made more in hope than expectation.

As to who is losing the match, thanks to the bouncy excellence of Simon Harmer it increasingly appears to be Nottinghamshire, although this match has fluctuated so much it would be not be a complete surprise if they were given a reprieve and invited to collect it from the secretary's office by Wednesday evening.

Notts' first innings of 187 had been below par even allowing for searching batting conditions. Essex flirted with disaster at 158 for 8 before taking what appeared to be a priceless 54-run lead. Notts' openers then wiped off the arrears with misleading ease, only to crumble to 90 for 6 by the close. Their lead is only 36.

The architect of that Notts collapse was Harmer, who on another sunny Chelmsford evening revived memories of those heady days in June 2017 when he took 28 wickets in two matches, against Warwickshire and Middlesex, fielders crouched around the bat in expectation, as he lit the fuse on Essex's first title win for 25 years.

Harmer is fun to watch when batsmen are floundering to contain the turning ball. He possesses show as well as substance: white sunnies gleaming, shirt hanging out and bounding hither and thither, and hands outstretched at one point in his jaunty delivery stride as if he is the Pope attending the masses. Essex have felt blessed in the Championship from the moment he arrived.

Notts followed an opening stand of 70 by losing six wickets for 16 runs in 11 overs and Harmer's part in that was a spell of 4 for 3 in 21 balls. From the moment Ben Duckett's ambition to hit him over the top failed with a slice to deep mid-off, he was in his element.

Duckett's fellow opener, Ben Slater, was lbw on the back foot, next ball, to Jamie Porter. Harmer then found big turn to have Joe Clarke caught at first slip off inside edge and thigh; and Steven Mullaney and Samit Patel fell to the classic offspinner's dismissal at short leg. Ryan ten Doeschate's first catch was little more than a sighter; his second, to dismiss Patel first ball, was a cracker as he dived sharply to his left. The nightwatchman, Matt Carter, came out with more than six overs to bat and was leg before to Peter Siddle by the close.

"The wicket was turning so it was nice to be able to throw the ball out wide and know that I was always in the game," Harmer said. "It has been a while since I have played on a Chelmsford wicket like that. It is good to have those feelings and memories.

"I think we always knew it would turn but we didn't think it would turn that much. The turn is quite quick still which is good for me."

Increasingly, this match has developed into a battle of the offspinners. Luke Fletcher, the indefatigable Notts seamer, deserves better than to be overshadowed after returning 5 for 50, the fifth five-wicket haul in his first-class career, but on a pitch that as Harmer indicated has developed over the second day from slightly troublesome seamer to raging turner, it is Carter who must pull off something special in response. First, he needs something to bowl at and much of the onus rests with the overnight pair of Chris Nash and Tom Moores.

Few bowlers approach the crease as sedately as Carter. He walks up to the line with an air of caution, as if not entirely sure that his 6ft 6ins frame can muster a bound without doing permanent damage to himself, but he finds decent loop for such a big man and finished with three first-innings wickets.

Essex threatened more than that 54-run lead. They were sitting pretty at 78 for nought, Alastair Cook and Nick Browne in good order, before they lost their first wicket. Stuart Broad had never played a Championship match at Chelmsford, but he had the satisfaction of wearing down Cook into reaching outside off stump to be caught at slip; Sir Alastair's angry swish of self-admonishment suggested that knighthoods had been rescinded for less.

Tom Westley unveiled a couple of midwicket clips, but was distinctly unfortunate to be adjudged lbw to Broad as he tried to work him through square leg. Fletcher's fortitude began to pay dividends: Dan Lawrence driving at a wide one, Rishi Patel undone by a decent ball that left him and ten Doeschate falling to a leave-alone.

Browne's first half-century for eight Championship matches took him past 5,000 first-class runs, although not quite as quickly as he would have anticipated when some judges, Cook for one, presented him as an England prospect. He had given Essex some solidity, but his mistimed cut at a short ball from Carter left the tail with a rescue job, five wickets lost for 23 in 46 balls.

Harmer and Siddle provided it in an irrepressible ninth-wicket stand of 81 in 23 overs, Carter's threat negated. "We were haemorrhaging wickets when me and Siddle came together and we needed to stop the bleeding," Harmer said. "We played and missed a hundred times but we didn't nick them."

David Hopps writes on county cricket for ESPNcricinfo @davidkhopps