1008 TliAXSACTTOXS OF THE AMERICAN INSTITUTE. 



sectional shape the better. Tliere are some ideas in it wliieh are of 

 some value and should be looked into. 



Mr. C. E. Emery remarked that a boiler somewhat like this has 

 been working for some time in Center street in tliis city, 



Mr, J, K. Fisher said he was told by locomotive engineers, that 

 steam of 120 pounds pressure is injurious, as it cuts the valve seats, 

 and cylinder bore. He wished to get at the fact. Does any one know 

 of the cutting of valve seats by high pressure steam ? He also 

 wished to know if smoke was not drawn into the cylinder when there 

 was a strong vacuum produced. The smoke and not the high pres- 

 sure may be the cause of the cutting. It has been said that locomo- 

 tives going down a grade with the steam shut off, the cylinders 

 would " howl " as it is termed ; but when the steam is on this noise 

 was not heard. 



Mr. James Montgomery stated that he had known as high a pres- 

 sure as 400 pounds to the sijuare inch being used on the Mississippi 

 steamers. There were other steamers on which the pressure in the 

 boiler could not be known, as there were pigs of lead hung on the 

 safety valve lever. He had been on boats that had steam of 500 

 pounds in the boiler and with a forty-eight inch cylinder. Fairbairn 

 found that the cylinder part of a locomotive boiler will stand a pres- 

 sure of 800 pounds of cold pressure ; and a certain form of the 

 upright boiler some 1,400 pounds. The question of high aiul low 

 pressure is one of much importance, especially at this time. A cer- 

 tain quantity of coal will do as much M^ork as a far greater amount, 

 if the pressure is sufficiently high. In the English boilers the steam 

 pressure is about an atmosphere and a half. Steam at TOO pounds, 

 pressure would be red hot. Tlie boilers of ocean steamers should 

 always be placed on deck, like those on the Mississippi steamers, so 

 that in case of springing a leak the fires in the boilers would not be 

 put out fii'st. 



Mr. Amory said the captain of the ill-fated steamer San Francisco 

 told him that the ship was lost on account of the large quantit}' of 

 coal she carried above the water-line, which made her unsteady, 



Mr, J. B. Eoot remarked that he had never seen any gain in using 

 steam over 120 pounds. When we get to 150 pounds there is con- 

 siderable difficulty in keeping the machinery in order, and this over- 

 comes any extra pressure which is obtained. He saw no way to 

 obtain the mifaculous results claimed for high pressure. Over 120 

 pounds there is no gain. Steam can be worked at 300 pounds pres- 



