Meanwhile war had again broken out between the master builders and their operatives, caused partly by a renewed agitation for the Nine Hours Day, and partly by the employers’ desire to substitute payment by the hour for the previous custom of payment by the day.[381] For the historian of the general movement the dispute is chiefly important as furnishing the occasion of the first intervention of the talented group of young barristers and literary men who, from this time forth, became the trusted legal experts and political advisers of the leaders of the Trade Union Movement. The workmen had totally failed to make clear their objection to the Hour System, or even to obtain a hearing of their case. Their position was, for the first time, intelligibly explained in two brilliant letters addressed to the newspapers by eight Positivists and Christian Socialists, which did much to bring about the tacit compromise in which the struggle ended.[382] Of more immediate interest to us is the action taken by the newly formed London Trades Council. Among the building operations suspended by the dispute was the construction, by a large contractor, of the new Chelsea barracks. The War Department saw no harm in permitting him to engage the sappers of the Royal Engineers to take the place of the men on strike. A similar course had been taken by the Government in strikes of 1825 and 1834. But the Trade Unions were now too powerful to allow of any such interference in their battles. A delegate meeting of the London trades, comprising representatives of fifty industries and fifty thousand operatives, sent a deputation to the War Office. Sir George Cornwall Lewis returned at first an equivocal answer, but the new Trades Council proved the efficacy of Parliamentary agitation by getting questions put to the Minister in the House of Commons, and stirring up enough feeling to compel him to withdraw the troops.