Messrs. Clegg and Samuda afterwards, in 1840, patented their plan of an atmospheric railway; and they publicly tested its working on an unfinished portion of the West London Railway. The results of the experiment were so satisfactory, that the directors of the Dublin and Kingstown line adopted it between Kingstown and Dalkey. The London and Croydon Company also adopted the atmospheric principle; and their line was opened in 1845. The ordinary mode of applying the power was to lay between the line of rails a pipe, in which a large piston was inserted, and attached by a shaft to the framework of a carriage. The propelling power was the ordinary pressure of the atmosphere acting against the piston in the tube on one side, a vacuum being created in the tube on the other side of the piston by the working of a stationary engine. Great was the popularity of the atmospheric system; and still George Stephenson said “It won’t do: it’s but a gimcrack.” Engineers of distinction said he was prejudiced, and that he looked upon the locomotive as a pet child of his own. “Wait a little,” he replied, “and you will see that I am right.” It was generally supposed that the locomotive system was about to be snuffed out. “Not so fast,” said Stephenson. “Let us wait to see if it will pay.” He never believed it would. It was ingenious, clever, scientific, and all that; but railways were commercial enterprises, not toys; and if the atmospheric railway could not work to a profit, it would not do. Considered in this light, he even went so far as to call it “a great humbug.” “Nothing will beat the locomotive,” said he, “for efficiency in all weathers, for economy in drawing loads of average weight, and for power and speed as occasion may require.” The atmospheric system was fairly and fully tried, and it was found wanting. It was admitted to be an exceedingly elegant mode of applying power; its devices were very skilful, and its mechanism was most ingenious. But it was costly, irregular in action, and, in particular kinds of weather, not to be depended upon. At best, it was but a modification of the stationary-engine system, and experience proved it to be so expensive that it was shortly after entirely abandoned in favour of locomotive power. {288} One of the remarkable results of the system of railway locomotion which George Stephenson had by his persevering labours mainly contributed to establish, was the outbreak of the railway mania towards the close of his professional career. The success of the first main lines of railway naturally led to their extension into many new districts; but a strongly speculative tendency soon began to display itself, which contained in it the elements of great danger.