556 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



On placing the tube now in the bath of pure water, the steam 

 filled just one inch, and on heating this steam to 216* and to 228°, 

 its volume was not doubled and trebled, as in Mr. Frost's exper- 

 iments, but was simply expanded in accordance with the well- 

 known law of the expansion of gases, by which their volume at 

 32« is doubled by the addition of 480° of heat. 



From these experiments, Mr. Rowell comes to the conclusion 

 that Mr. Frost had too much water in his tube, and that the great 

 increase of volume which took place in his steam resulted from the 

 evaporation of this water. 



Mr. Godwin. — I was well acquainted with Mr. Frost, and 

 examined his experiments with a great deal of interest. I ask 

 permission to read, from the Scieiitijic American^ an extract from 

 the London Engineer, taken from the annual report of Mr. Flet- 

 cher, Chief Engineer of the Manchester Association for the Pre- 

 vention of Steam Boiler Explosions. He directs the attention of 

 those who use condensing engines to the fact that these motors 

 generally do not execute work in proportion to the quantity of 

 steam delivered from the boilers. The 4oss, as measured fre- 

 quently, is about thirty-three per cent. This is due to the alter- 

 nating connection of the cylinder at each stroke of the engine, 

 with the boiler at a high tefnperature, and the condenser at a 

 low one — about lOO*' Fah. In such engines there is an alternate 

 action of condensation and re-evaporation in the internal sur- 

 faces of the cylinder, and it is thus a considerable per centage 

 of steam passes from the boiler to the condenser, through the 

 engine, without doing useful work. This action is so silent and 

 subtle that it has escaped detection for many years. Such a loss 

 is of much consequence in steamships, which have to carry their 

 c^n fuel. It amounts to about three hundred tons of coal in one 

 of the larger class of steamers in a voyage across the Atlantic 

 ocean. " The remedy for this loss " is to adopt the steam 

 jacket for the cylinder, or superheat the steam. There is 

 nothing new, or untried, or dangerous, in either of these. 

 Some have held up superheated steam as a bugbear, and 

 have asserted that it destroyed the interior surface of the cyl- 

 inders, cut the faces of the valves, corroded the metal, and 

 prevented proper lubrication. Actual experience has proved 

 these objections to be visionary. Mr. Fletcher says, on this 

 head, " I find that where superheated steam has been fully 

 tested no difficulty is experienced in its use, and no alteration 



