[69] The arguments used by Mr. Stephenson with the directors in favor of the locomotive engine were afterward collected and published in 1830 by Robert Stephenson and Joseph Locke, as "compiled from the Reports of Mr. George Stephenson." The pamphlet was entitled "Observations on the Comparative Merits of Locomotive and Fixed Engines." Robert Stephenson, speaking of the authorship many years after, said, "I believe I furnished the facts and the arguments, and Locke put them into shape. Locke was a very flowery writer, whereas my style was rather bald and unattractive; so he was the editor of the pamphlet, which excited a good deal of attention among engineers at the time." [70] The conditions were these: 1. The engine must effectually consume its own smoke. 2. The engine, if of six tons' weight, must be able to draw after it, day by day, twenty tons' weight (including the tender and water-tank) at ten miles an hour, with a pressure of steam on the boiler not exceeding fifty pounds to the square inch. 3. The boiler must have two safety valves, neither of which must be fastened down, and one of them be completely out of the control of the engine-man. 4. The engine and boiler must be supported on springs, and rest on six wheels, the height of the whole not exceeding fifteen feet to the top of the chimney. 5. The engine, with water, must not weigh more than six tons; but an engine of less weight would be preferred on its drawing a proportionate load behind it; if of only four and a half tons, then it might be put on only four wheels. The company to be at liberty to test the boiler, etc., by a pressure of one hundred and fifty pounds to the square inch. 6. A mercurial gauge must be affixed to the machine, showing the steam pressure above forty-five pounds per square inch. 7. The engine must be delivered, complete and ready for trial, at the Liverpool end of the railway, not later than the 1st of October, 1829. 8. The price of the engine must not exceed £550. Many persons of influence declared the conditions published by the directors of the railway chimerical in the extreme. One gentleman of some eminence in Liverpool, Mr. P. Ewart, who afterward filled the office of Government Inspector of Post-office Steam Packets, declared that only a parcel of charlatans would ever have issued such a set of conditions; that it had been _proved_ to be impossible to make a locomotive engine go at ten miles an hour; but if it ever was done, he would undertake to eat a stewed engine-wheel for his breakfast!