understood in this period. Aftermath The tragedy inspired Hodgson to raise public concern about the hazards of mining. Public interest was fed by a short (16-page) pamphlet written by him and published prior to the second disaster in late 1813. Hodgson wrote for an interested public, not for practical miners, and as such explains mining terms and procedures. His description and analysis of the two explosions was historically significant as one of the first to attempt a scientific analysis of such events. On 1 October 1812 the Sunderland Society was set up consisting of clergymen, doctors, owners and mine managers. One of the doctors was William Reid Clanny (1776-1850) who had already produced a first, impractical, safety lamp. Also present was George Stephenson who at that time was enginewright for the collieries at Killingworth. The society aimed for: greater publicity for accidents and their causes the scientific study of ventilation the development of safety lamps. Stephenson designed a safety lamp, known as the Geordie lamp, with air fed through narrow tubes, down which a flame could not move. It also led Sir Humphry Davy to devise another safety lamp, the Davy lamp, in which the flame was surrounded by iron gauze. The gauze had to have small spaces so that a flame could not pass through, but could admit methane, which then burned harmlessly inside the lamp. The height of the luminous cone above the flame gave a measure of the methane concentration in the atmosphere. 1813 disaster On 24 December 1813 at 01:30 the colliery again exploded, this time with the loss of 9 men and 13 boys along with 12 horses. All the dead were in the headways by William Pit (the upcast pit). Those in the boards away from William Pit were saved. The Newcastle Courant reported the supposition that "the hydrogen took fire at the crane lamp, in the south headways". Thomson also reports this but warns against too early an assumption, mentioning other possibilities such as the failure of a stopping or furnace mismanagement. The southern boards were crossed by several fissures (dykes) from which periodic discharges of gas came through apertures called blowers. The blowers could make "the coals on the floor dance round their orifices, like gravel in a strong spring". The discharges were dealt with by the strong current of air, strong enough to extinguish candles. None of the mine was found