MECHANICS AND USEFUL ARTS. 37 



struction of this engine, by which the pressure or tractive power of 

 the driving-wheels may be increased or reduced, as the grades or other 

 circumstances may require ; in other words, the weight of the machine 

 may be distributed so as to fall equally upon all the wheels. The ad- 

 hesive power of the drivers may thus be graduated from 6,000 to 

 25,000 pounds. Where the maximum of traction is required, as in 

 starting a heavy train, or in ascending a steep grade, the whole power 

 of the machine may be made available ; while on a level or descend- 

 ing grade, the pressure or weight of the engine may be reduced or 

 distributed over all the truck or supporting wheels. It is obvious that 

 if the traction can be thus varied and adapted to circumstances, a 

 great saving may be effected in the wear and tear of the rails. Wheth- 

 er any difficulty will arise from concentrating the pressure upon a sin- 

 gle point, as must necessarily be the case when it is mainly applied to 

 the two driving wheels, experience must determine. We understand 

 that the idea is new with Mr. Winans, and that he has patented the 

 improvement, as well in Europe as in this country. 



The qualities of the engine were tried with a single car only, to 

 Worcester and back. It is calculated for great speed, IP it no attempt 

 was made to test its capabilities in this respect, although for a short 

 distance a speed of 60 miles an hour \vas attained. As far as can be 

 judged from a short experience, the machine has realized all that was 

 desired from it. The use of anthracite coal in locomotives, if it can 

 be successfully effected, will be a great improvement, in respect to 

 convenience as well as economy. It is calculated that in this engine 

 one ton of coal will be equivalent to two cords of vrood. Boston 

 Traveller. 



STEAM-CARRIAGES ON COMMON ROADS. 



We find in a late number of the London Railroad Gazette, a com- 

 munication on the subject of the use of steam as a propelling power 

 on common roads. The writer says that it is agreed that steam-car- 

 riages on common roads are perfectly practicable and safe, and he cites 

 several Parliamentary reports which prove them to be so. The only 

 difficulty has been the liability of the carriages to get out of order, and 

 the great cost of repairing them. A Scotch gentleman, after 30 years' 

 study, and the expenditure of a large sum of money, has, it is said, 

 succeeded in perfecting a steam-carriage, which will remove every 

 difficulty hitherto met with. The improvements claimed are in " con- 

 densing the steam and using distilled water," " in working the steam 

 expansively to its utmost power," ' : in preventing all loss of heat from 

 radiation," "in suspending the carriages and machinery on springs," 

 " in applying elastic wheels to prevent shocks," " in the mode of 

 working the engines at their maximum speed," " in preventing the 

 slipping of the driving-band and lateral friction from the journal of 

 the wheels," " in using common coal as fuel and consuming the 

 smoke," "and in reducing the expense of working by dispensing with 

 water-stations alono- the road.' : No doubt is entertained of the entire 



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success of this new steam-carriage, and long and seemingly conclusive 



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