74 



On the Production of Steam from heated Iron. 



3d series. 2f oz. generated in 518" 

 10 intervals, 6.5" each 65 



whole time of the series 583 



4th ser. If oz. generated in 727.5" 

 12 intervals, 6.8" each 82.5 



'^'- whole time of the series 810 



5th ser. If oz. generated in 536" 

 13 intervals, 12.9" each 169 



whole time of the series 705 



6th ser. If oz. generated in 534.5" 

 13 intervals, 10.8" each 140.5 



whole time of the series 675 



7th ser. If oz. generated in 567" 

 14 intervals, 10" each 140 



whole time of the series 707 



Sth series. 2-i-oz. generated in 695" 

 16 intervals, 6" each 96 



Avhole time of the series 791 



9th ser. 2| oz. generated in 724" 

 16 intervals, 11" each 176 



whole time of the series 900 



10th ser. 2| oz. generated in 598.5" 

 17 intervals, 16" each 271.5 



whole time of the series 870 



11th ser. IyV oz. generated in 613" 

 24 intervals, 7" each 168 



Avhole time of the series 781 



12th ser. l|f oz. gener'd in 780.5" 

 28 intervals, 8.2" each 230.5 



whole time of the series 1011 



As the water covered generally but a small part of the surface of 

 the basin even at the commencement of the experiment, the heat in 

 the latter terms of each series, must have been furnished to the water 

 more slowly than in the preceding terms, both on account of the 

 diminution of difference between the metal and the liquid, and on 

 account of the necessity of depending on the conducting power of 

 the metal, to bring the heat from the exterior to the center of the 

 basin. Hence we might expect to find the terms obeying some law 

 of geometrical progression. If we examine the last seven or eight 

 experiments in each series, we shall clearly perceive such a progres- 

 sion. Omitting the last of each column, as presenting anomalies 

 obviously derived from the final disappearance of vaporization, and 

 the substitution of mere evaporation, we may divide the last number 

 but one, by that which precedes it ; this latter, by the next preceding, 

 and so on, until we obtain five quotients. These quotients will con- 

 stitute the ratios of the series, at the particular points where the ex- 

 periments took place. The mean results for each series may then 

 be obtained in the usual mode. But it will soon be perceived that if 

 we extend the divisions beyond five or six, the ratio will be essentially 

 varied in its character, and the series, in some instances, becomes 



