The nineteenth company was formed on the 1st of April and appropriated for the duties of the survey.[32] On the 1st of September, another company, numbered the 20th, was organized, which increased the establishment from 1,800 to 2,000 of all ranks. The detachment of one sergeant, one corporal and twelve privates, formed by royal warrant in July, 1839, for service in South Australia, merged into the establishment in December, by an order dated 15th of that month, and thus reduced the corps from 2,000 to 1,985 of all ranks. This measure was effected to simplify details and to make the detachment form part of a company, without removing it from the province. Its expense still continued to be borne by the colonial government. The company at Portsmouth, ninety-eight strong, under Captain Robertson, R.E., was sent by rapid conveyances to Dublin, and arrived there on the 2nd of April, to assist in quelling the rebellion in Ireland. Late in July, Lieutenant Akers, R.E., with one sergeant and fifteen rank and file, accompanied the troops under the command of Major-General Macdonald to Thurles, and encamped about a mile from the town, and returned to Dublin in September, without any necessity for their services arising. The meditated revolt was crushed, and Smith O’Brien with some other demagogues, convicted of traitorous designs, were expatriated. The company on being withdrawn from Ireland, removed to Woolwich, where it arrived on the 19th of February, 1849. A rising of the Chartists being anticipated, measures were taken to thwart their designs. Troops were collected with rapidity from all quarters and appointed to various posts in London, to act if occasion required. Late in the evening of Saturday the 8th of April, a company of 100 strong with sergeant-major Bradford, under the command of Captain Tylee, R.E., was detached from Woolwich to the Tower of London. Each man took with him forty rounds of ammunition. The company slept in the Tower that night, but early next morning, two sergeants and thirty-two rank and file, under Lieutenant Sedley, R.E., were sent to the Ordnance Office, Pall Mall, to oppose any attempt at possession by the Chartists. Another party with sergeant-major Bradford under Lieutenant Wilkinson, R.E., was removed to the Bank of England. On the roof of this edifice were built platforms; and at certain places, massive timbers with loop-holes were run up as positions for defence. Several thousand sand-bags filled the upper tier of windows facing the Royal Exchange, and others as high as a man were piled upon the parapet of the roof, with apertures between them for musketry. Over the entrance of the building, a strong wooden machicouli, resting upon ponderous beams, projected into the street, which held a party of the corps ready to open a volley on the rabble, had an attempt been made to force an entrance. In the yard leading to the workshops, &c., the sappers also erected an enormous barricade of casks, handcarts, &c.