Page:Report from the Select Committee on Steam Carriages.pdf/191



Mr. Joseph Gibbs. 19 August, 1831. goods, fuel and water, and draw the rest in a separate Carriage or Carriages after them. This will show the great difficulty of levying a toll upon the weight of Steam Carriages; as for instance, 600lbs, of water and 100 lbs, of coke are requisite per hour on an even road, with a Steam Carriage as now constructed; but upon a road, abounding with hills, 1,000lbs, of water and 160 lbs, of coke will be required. Now if the weight is taken when the water and fuel are one-half diminished, say on the average 400lbs, of water and 65lbs, of coke, and the toll is levied upon the weight of the Steam Carriage, the Carriages (being drawn) paying as ordinary Carriages, the weight of water and coke can be transmitted to those Carriages which paying, not by weight but by the number of wheels, will of course receive an augmentation of from five to six hundred pounds additional weight. Likewise the danger from explosion will be increased if tolls are collected upon the weight of Steam Carriages, inasmuch as by loading the safety valve to double the pressure, a Carriage can be made to draw double the weight with only an alteration in the fire place, and an increase of water, air, and fuel; a diminution of weight will likewise take place to a considerable amount in the boilers and engines, although it is more essential an increase of strength should take place rather than any diminution. I can state a case in point; I have a Steam Carriage now constructed, from which I could abstract 900lbs, of iron without making it too weak to travel even on rough roads, but I should not be induced to do so except as a matter of economy in case the tolls are levied upon the weight and at too high a rate. The Steam Carriage as used upon common roads, being an invention of recent date, sufficient has not been done with them for practical men to decide what arrangements of machinery are best for their construction. It may be found hereafter that it is proper to place the Engine in one Carriage and the boiler on another, and blowing apparatus in another, all carrying other weights, so that three distinct Carriages (although they each carry only a part of a Steam Engine with them), yet if so arranged