PROCEEDINGS 



OF 



THE ROYAL SOCIETY. 



1831-1832. No. 10. 



May 3, 1832. (Continued.) 

 JOHN BOSTOCK, M.D., Vice President, in the Chair. 



A Paper was read, entitled, "An Account of certain new Facts and 

 Observations on the Production of Steam," by Jacob Perkins, Esq. 

 Communicated by Ralph Watson, Esq. F.R.S. 



Having observed that water on the surface of melted iron was very 

 slowly affected by the heat, although it exploded violently when the 

 same fused metal was dropped into it, the author made a series of 

 experiments on the time required for the evaporation of the same 

 quantity of water successively poured into a massive iron cup, at first 

 raised to a white heat, and then gradually cooled by the addition and 

 evaporation of the water. The first measures of water were longer 

 in being evaporated than those subsequently added, in consequence 

 of the reduction in the temperature of the iron, until this tempera- 

 ture reached what the author calls the evaporating point, when the 

 water was suddenly thrown off in a dense cloud of steam. Below 

 this temperature, the time required for the complete evaporation of 

 the same measure of water became longer in proportion as the iron 

 was cooler, until it fell below the boiling point. The author accounts 

 for these results from the circumstance that when the metal is at the 

 higher temperatures, the water placed on its surface is removed from 

 contact with it by a stratum of interposed steam. From these and 

 other experiments, he is led to infer the necessity of keeping water 

 in close and constant contact with the heated metal in which it is 

 contained, in order to obtain from it, in the shortest time, the greatest 

 quantity of steam. 



The reading of a Paper, entitled, " On certain Irregularities in the 

 Magnetic Needle, produced by partial warmth, and the relations 

 which appear to subsist between terrestrial Magnetism and the geo- 

 logical Structure and thermo-electrical Currents of the Earth," by 

 Robert Were Fox, Esq. — communicated by Davies Gilbert, Esq. 

 V.P.R.S. — was commenced. 



May 10, 1832. 



JOHN WILLIAM LUBBOCK, Esq. M.A., V.P. and Treasurer, 

 in the Chair. 



The reading of Mr. Fox's P.iper was resumed and concluded. 



