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!
[71] Some correspondence took place between Boulton and Watt on the subject, when the latter was scheming the application of the steam-engine to locomotive purposes. In a letter to Boulton, dated the 27th of August, 1784, Watt said, "Perhaps some means may be hit upon to make the boiler cylindrical with a number of tubes passing through, like the organ-pipe condenser, whereby it might be thinner and lighter; but," he added, "I fear this would be too subject to accidents."
[72] The inventor of this engine was a Swede, who afterward proceeded to the United States, and there achieved considerable distinction as an engineer. His caloric engine has so far proved a failure, but his iron cupola vessel, the "Monitor," must be admitted to have been a remarkable success in its way.
[73] Mr. Wood's speech at Newcastle, 26th of October, 1858.