AMERICAN INSTITUTE. 571 



locomotion, while on land and sea safety is rather enhanced than 

 diminished. 



If the cloud engine be based on correct principles, and will 

 accomplish its prophesied saving of 50 per cent, then that modi- 

 fication of the steam engine may be applied with equal success in 

 the present case, and again the already trifling expense may be 

 diminished by half. And lastly, assuming that air in any statu 

 will fill the globules of steam and double its force, and that a 

 certain heat expands all volumes alike, the application of 500° 

 to a condenser charged with 50 atmospheres, will double their 

 volume, and necessitate half the supply of air and half the 

 power to di'ive the pump. 



If the use of this high steam be found impracticable, " stame" 

 may be economically generated by a part of the same apparatus; 

 and " stame" has been found to save 50 per cent, the objection 

 lying wholly in the method of production. These speculations, 

 unliiie those which rest wholly on mathematical deductions and 

 uncertain theories, are already partially demonstrated and reali- 

 zed. The existence of practical objections in the early career of 

 steam, did not insure their continuance and supremacy, nor will 

 it now. 



Before such success can be completely achieved, however, the 

 expense of generating steam- is yet susceptible of essential modifi- 

 cations. Past changes suggest the principles of future improve- 

 ment, and contribute to its realization. In land locomotion, in- 

 creased fire surface, both in fire-box and flues, more perfect com- 

 bustion by chambers, hollow stay-bolts, and better proportioned 

 smoke arches and draft promoting parts, the variable exhaust, 

 and the saving of exhaust heat, and the heat evolved in coking 

 and charring, are among the most important changes yet attempt- 

 ed. The downward draft, greater direct contact of iron and fire, 

 grates for heating water and better holding and disposing fuel, 

 and increased protection against radiation and condensation, are 

 highly suggestive of improvement. 



That locomotive which preserves the complement of steam with 

 the damper almost closed, is thrice economical. It directly saves 

 wood, it produces that most excellent fuel, charcoal, and it pro- 

 motes free exhaust, by allowing large nozzles. When unconsum- 

 ed gaseous and solid fuel is saved, and when waste heat is allowed 

 to raise both feed water and air, to approximately the maximum 

 temperature, railway economy will be very considerably en- 

 hanced. 



