If correct plans and descriptions of all the ancient workings had been preserved, these accidents, which happen frequently, might easily be prevented, as an exact knowledge of the localities would enable the owners to leave sufficiently strong barriers in parts where they are now often most inadequate. Such is the importance of accurate mining records that thousands of pounds would be freely given at this moment by many owners for a knowledge of old works of which no plan exists and which no memory can now recall. Fortunately, the legislature has now taken steps to introduce a system of registration such as has already existed long ago in Prussia, Austria, and Belgium, and which, at least, will answer the purpose of obtaining greater security for the future. Sometimes an enormous fall of rain, descending on the neighbouring country, finds its way into the mines through fissures in the ground or by breaking through galleries, and causes irreparable mischief; sometimes even a whole river bursts into the works and ruins them for ever. Thus, in 1856, the South Tamar Consols, in Devonshire, was flooded by the giving way of the bed of the Tamar, under which the workings were carried. Even the Sea has been known to take fatal vengeance for the undermining of her domain. Workington Colliery extended to the distance of 1,500 yards under the Irish Channel, and the workings, being driven considerably to the rise, were brought at length within fifteen fathoms of the bottom of the sea. The pillars of coal which supported the overlying strata were hardly strong enough to support the roof, but the imprudence of a manager eager to produce a larger quantity of coal weakened even this insufficient support by working it partly away. Heavy falls of the roof, accompanied by discharges of salt water, gave repeated warnings of the impending catastrophe, which took place on July 30, 1837. So violent was the irruption that many persons at a distance of hundreds of yards observed the whirlpool commotion of the sea as it rushed into the gulf beneath. Some few workmen near the shaft had time to escape, but thirty-six men and boys and as many horses were destroyed by the waters, which in a few hours entirely filled the excavations, the extension of which had tasked the labour of years.