1832.] Progress of Mechanical Science. 427 



" That lie has found no difficulty in travelling over the worst and most hilly 

 roads." 



Mr. James Stone states, " that 36 persons have been carried in one steam car- 

 riage. That the engine drew ft times its own weight, nearly at the rate of from 5 

 to 6 miles per hour, partly up an inclination." 



The several witnesses have estimated the probable saving of expense to the public 

 from the substitution of steam-power for that of horses at from one half to two- 

 thirds. Mr. Farey gives, as his opinion, " that steam coaches will very soon after 

 their first establishment be run for one-third of the cost of the present stage 

 coaches." 



The advantages of steam-power are not confined to the greater velocity gained 

 or to its greater cheapness than horse draught : — 



" There is no danger of being run away with ; and that of being overturned is 

 greatly diminished. It is difficult to control four such horses as can draw a heavy 

 carriage ten miles an hour, in case they are frightened or choose to run away ; and 

 for quick travelling they must be kept in that state of courage, that they are al- 

 ways inclined for running away, particularly down hills, and at sharp turns of the 

 road. In steam, however, there is little corresponding danger, being perfectly con- 

 trollable and capable of exerting its power in reverse in going down hills. Every 

 witness examined has given the fullest evidence of the perfect control which the 

 conductor has over the movement of the carriage. With the slightest exertion they 

 can be stopped or turned, under circumstances where horses would be totally un- 

 manageable." 



The danger of explosion has been greatly reduced by adopting the tube form of 

 boiler, and further benefit is expected from some ingenious modifications of Mr. 

 Trbvjthick. 



The questions of frightening the horses of other carriages, of inconvenience 

 from smoke and steam, are also disposed of by the committee ; but they are of too 

 trivial a nature to need comment, and we know that steam carriages have passed 

 over London bridge in the midst of vehicles of all denominations. 



The mass of evidence taken before the committee is of a most valuable nature, 

 but for this we must refer our readers to the printed report, or to the Mechanic's 

 Magazine for 1831, selecting only a few notes therefrom. 



Mr. Gurney's boilers are of cast-iron tube : he works them up to 100 lbs. on 

 the square inch. On plain ground, one wheel, on hilly or slippery, two wheels are 

 connected with the working crank : the facility of stopping by throwing the 

 steam on the opposite side of the piston is so great, that if going 8 miles an hour, 

 a carriage can be brought up within 6 or 7 yards : it can turn in a circle of 10 

 feet. When moving at a slower rate than 4 miles an hour, the expense of fuel 

 is greater than that of horses. The evaporation of 9 gallons of water per hour is 

 equivalent to one horsepower: Mr. Gurney prefers coke as a fuel, and thinks 

 smoke cannot be consumed without separation of the carbonic acid gas, by passing 

 through lime or other means : considers explosions not always attributable to 

 steam, but frequently to formation of explosive compounds of hydrogen and 

 oxygen, as does Gay Lussac. 



To provide for accidents from the guide falling asleep, he has contrived that the 

 valves of the engine shall only remain in gear while he is awake and at his post. 

 The moment he takes his foot off, the engine stops : the same contrivance 



