[ 378 ] 

 LXVIII. Proceedings of Learned Societies. 



ROYAL SOCIETY. 



Muy 3. — \ PAPER was read, entitled, " An Account of certain 

 -t^ 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. — The reading of Mr. Fox's Paper was resumed and con- 

 cluded. 



May 17. — The reading of a Paper, entitled, "On Harriot's As- 

 tronomical Observations contained in his unpublished Manuscripts 

 belonging to the Earl of Egremont," by Stephen Peter Rigaud, Esq. 

 M.A. F.R.S. Savilian Professor of Astronomy in the University of 

 Oxford, — was commenced. 



May 24. — The reading of Professor Rigaud's Paper was resumed 

 and concluded. 



In the Memoirs of the Royal and Imperial Academy of Brussels, 

 for the year 1788, the Baron de Zach published a paper on the pla- 

 net Uranus, in a note to which he states that, in the summer of 1/84, 

 he found in the library of Lord Egremont at Petworth, some old ma- 

 nuscripts of the celebrated Thomas Harriot, which he alleges afforded 

 proofs that he had observed the solar spots, and the satellites of Ju- 

 piter before Gclileo, In the Berlin Ephemeris for 1788, Baron 



