On Tuesday (16 Sept.) the lord mayor gave a full account of all that had taken place to the Court of Aldermen, and informed that body that he had caused advertisements to be published offering a reward of £100 for the apprehension and conviction of the person or persons who had written or caused to be stuck up the inflammatory placards on the Monument.[624] At the suggestion of the Duke of Portland the amount of the reward was afterwards raised to £500.[625] The Court of Aldermen passed a vote of thanks to the mayor for what he had done. They also placed on record their opinion that, but for business in the Corn Market being hindered by the mob, the price of wheat and flour would have experienced a greater fall than it actually had done on the 15th, and further, that as nothing would more tend to the reduction of the existing high price of the principal articles of food than the affording protection to dealers bringing corn and other commodities to the market, the Court was resolved at once and by force (if necessary) to put down any attempt to impede the regular business of the markets of the metropolis.[626] [Sidenote: Letter of the Duke of Portland to the mayor, 16 Sept., 1800.] Whilst the mayor was presiding over the Court of Aldermen a letter was placed in his hands from the Duke of Portland, informing him that the duke had instructed Colonel Herries, commanding the London and Westminster light horse volunteers, to lose no time in placing his services at the lord mayor's disposal. The duke at the same time seemed to suggest that the lord mayor had been somewhat remiss in apprehending the ringleaders in yesterday's disturbances.[627] The mayor sent a reply that evening. He thanked the duke for his offer of assistance; but he had no occasion for it, as the city was perfectly quiet. As to his grace's suggestion that the arrest of some of the ringleaders might have been useful, the mayor begged to inform him that four of them had been arrested, and had been committed for trial. If his grace thought that their prosecution by the crown would be more efficacious than by the city, he would forward the minutes of evidence that had been taken. The letter concluded by an assurance that at the time of writing (5 p.m.) the mayor had not the smallest intimation of any disorder in any part of the city.[628] [Sidenote: Precautions taken by the lord mayor.]