David Napier by David Napier and David Bell: Note 19
19. STEAM CARRIAGE
David Napier's steam carriage ran, it is understood, between Kilmun and Lock Eck in 1827 and 1828 its continued use being found impracticable owing to the difficulties referred to in the Memoir. A Kilmun gentleman who saw the carriage at work has stated that "the roads were of no account at that time, and the motor was not a success." Nothing is known as to its design, but presumably the main difficulty was in the weight of boiler and water, the great obstacle to success both before and after Napier's time. A safe and manageable road carriage had long been desired, and attempts to produce such a vehicle had been made by Cugnot in 1770; Murdoch and Watt, 1784; Symington, 1786; Fourness and Ashworth, 1788; Trevithick, 1800; Henry Bell, and others. The boiler proposed by Watt was to be "made of wooden staves joined together and fastened with iron hoops like a cask; the furnace to be of iron, and placed in the inside of the boiler, so as to be surrounded on every side with water." He, however, never built a steam carriage, and his opinion as to the strict limitation of steam pressure is well known. It is said that Trevithick's was the first road carriage to carry passengers; but Napier's was, it is believed, the first to ply regularly for hire. A patent for improvements in steam carriages was taken in 1831 by David, James and William Napier (relatives of David), but they had no greater success than the earlier inventors. The Memoir states that Napier had "again resumed the subject," but no record has been found of further experiments. "Legislation, prejudice, and the advent of the railway combined latterly to discredit the steam road-carriage, and it was finally driven off the field by the further legislation of 1861 and 1878."
The splendid success of the modern motor-car and motor-boat has, of course, been largely due to their independence of the cumbrous boiler and apparatus which the early engineers had to deal with; and Napier's anticipation that "the work done by horses, and a good deal of what is done by steamboats," would be performed by road vehicles, is now being realised, but by petrol instead of steam. There is a certain interest in the fact that the Napiers whose auto-cars have been so very successful are descendants of the David Napier who was joint-author of the 1831 patent.