806 Transactions of the American Institute. 



Mr. J. K. Fislier — If the steam is at 370 degrees, the water itself 

 would contain heat enough to evaporate about one-seventh of the 

 water, when the pressure is removed. But will not some of the 

 water be blown off with the steam in the shape of foam, and how 

 much % 



Mr. John B. Root — I have seen it done a number of times, and I 

 have never seen over twenty-five per cent of the water blown off under 

 the best circumstances. 



;:!, Dr. P. H. Yan der Weyde — At 350 degrees you have 13S degrees 

 surplus of heat in the water. Dividing by 966 shows that exactly 

 one-seventh is evaporated. 



Steam Boiler Explosions. 



Dr. Van der Weyde — I wish to report a curious attempt at a boiler 

 explosion that took place at Williamsburgh, yesterday, at the new gas- 

 house. The workmen were alarmed by a shock in one of the upright 

 tubular boilers, and they at once stopped work and drew the fire. It 

 was a very high boiler, with interior vertical tubes, surmounted by a 

 dome. The water stood around the tubes and the fire passed through 

 them. They found, on examination, that several of the tubes had 

 sunk down, making a depression both at the top and the bottom ; 

 but there was no leak. Now, what was the cause of that ? I ascribed 

 it to scale, which had formed at the bottom and allowed the iron to 

 become very hot and soft, and, probably, the weight of the water 

 forced it down, drawing down the crown sheet with it. 



Mr. J. B. Root — If there was scale deposited upon the bottom of 

 that boiler, allowing the lower part of the bottom plate to be heated 

 fifty to 100 degrees hotter than the upper side, that difference of 

 temperature would cause it to bulge down. 



Ellis's Bi-sulphide of Cakbon Engine. 

 Dr. Yan der "Weyde — Mr. Ellis, of Boston, has lately constructed 

 a bi-sulphide of carbon engine, using the waste steam from the engine 

 to heat the bi-sulphide of carbon, and work another piston attached 

 to the same engine. There have been two objections made to this, 

 which I wish to answer. One objection is that we might just as 

 well have two steam cylinders, making a compound engine, the 

 steam from a high pressure engine working a low pressure engine. 

 The other objection is, that if we are to use the bi-sulphide of 

 carbon, we do not need the steam, and I will reply to this objec- 

 tion first. Volatile substances require very little heat to convert 



