‘You, sir, ended with Sebastian Parish. I shall begin with him. If Parish was a murderer how lucky he was! How all occasions did inform against Watchman and favour Parish! It was on the evening after his decision that the brandy was produced, so that was pure luck. He didn’t know Legge would wound Watchman, he only hoped that under the influence of brandy, he might miss his mark. When it so fell out, he had to make up his mind very rapidly and plan a series of delicate and dangerous manoeuvres. And how oddly he behaved! He risked his own immunity by handling the darts, and this, when his whole object was that Legge should seem to be the poisoner. After the accident, instead of putting cyanide in the brandy glass and moving away from it, he stood beside it, in a position that was likely to be remembered. And again, how could he tell that Miss Moore would use that glass? There were seven other glasses about the room. She might have taken a clean glass. Parish made no attempt to force that glass upon her. She chose it. More stupendous luck. Now, with the exception of Miss Moore, this objection applies to the supposition that any of them put cyanide in the brandy-glass. They couldn’t be sure it would be used. Only Miss Moore could be sure of that for she chose it.’

‘You surely don’t—Go on,’ said Colonel Brammington.

‘I entirely agree that, ruling out Legge and assuming that the whole arrangement of the business was an attempt to implicate Legge; Cubitt, Miss Darragh, Will Pomeroy, and Miss Moore, must be counted out, since they have all declared that Legge was unable to meddle with the darts. Our case rests on a different assumption.’

‘Here, wait a bit,’ cried the colonel. ‘No. All right. Go on.’

‘Abel Pomeroy and Parish were the only ones openly to accuse Legge. Abel Pomeroy was particularly vehement in his insistence that Legge deliberately killed Watchman. He came up to London to tell me about it.’

‘Old Pomeroy was my earlier choice.’

‘Yes, sir. To return to the brandy. For the reason I have given you, and for reasons that I hope to make clear, we are certain that cyanide was put on the dart after, and not before, it pierced Watchman’s finger. Otherwise it would have been removed by the trial throw into the cork board or, if there was any trace left, possibly washed off by the blood that flowed freely from Watchman’s finger and with which the dart was greatly stained. The cyanide was found on the point of the dart. Watchman, we think, was poisoned, not by the dart nor by the brandy. How, then?’

‘But, my dear fellow, there was no cyanide in the iodine bottle. They found the bottle. There was no cyanide.’