Polytechnic Association Proceedings. 347 



Previous experiments liave clemonstrated that at least one-third of 

 the air required for combustion should be admitted above the fire 

 in the locomotive, and the remaining two-thirds under the grate- 

 bars. Still, the waste resulting from rapid and imperfect combustion 

 required in the locomotive is very large. It is claimed that by- 

 pulverizing coal and admitting it in combination with air above 

 the ordinary coal fire, the rapid generation of heat is successfully 

 accomplished; and what is still more important in the locomotive, 

 that there is an almost entire absence of smoke and particles of 

 unconsumed coal, which in spite of spark-arresters, have been thus 

 far the disagreeable and dangerous resultants of accelerated combus- 

 tion. The trials to which we have referred relate only to bitu- 

 minous coal. It would be interesting to know whether the same 

 advantages can be gained by pulverizing anthracite, which requires 

 a much higher degree of heat for its ignition. 



PROPOSED IMPROVEMENT OF NEW YORK HARBOR. 



The Chairman said, I desire to lay before the Polytechnic my 

 plan for avoiding the dangerous navigation in the East river, at 

 Hell Gate. Instead of expending five million dollars in removing 

 rocks from the bed of that river, the Government may, for a smaller 

 sum of money, construct a ship canal between Flushing bay and 

 Jamaica bay, and the action of the tide will soon deepen the 

 Jamaica inlet, so as to make a passage for ships into the lower bay; 

 or we may close that inlet and deepen the creek that separates 

 Coney Island from the main land, thus allowing vessels of the 

 largest class to pass into Gravesend bay, and thence into New York 

 ba}'. The distance from the east shore of Flushing bay to Castle 

 Garden, or the mouth of the Hudson river, by the new route, 

 would be about double that by way of the East river. Without 

 takmg into account the length of the channel required to be deep- 

 ened, we may estimate the length of the new canal at from five to 

 six miles. Of this, one-half of a mile would be a deep cutting 

 through the dividing ridge of Long Island, which here has an ele- 

 vation of not over one hundred feet above the level of the sea. 

 The earth required to be removed would be worth more than the 

 cost of its removal, for filling in and forming a dock frontage along 

 the new channel, which would bring into immediate use for com- 

 mercial purposes several square miles of land. Probably no rock 

 would be encountered on the whole route, and the work of remov- 



