Experimental Inquiries respecting Heat and V^apor. 813 



^ f. g^i, ( Rapidity increased by deficiency of tempera- 



"' ( ture to maintain the repulsion uninterrupted. 



- .rr^^ li'on kept some time on the fire without liquid 

 G 150 < 1 r .1 • • ^ 



( betore this experiment. 



7 143 



8 134 



9 123 



10 120 — Very faintly luminous in the dark, 



11 115 ' 



13 113 



14 100 ^Redness gradually increased. 



15 95 



16 82 

 The surface of the basin about tlie spirits exhibited when the room 



%vas darkened, a very distinct luminousness, like a faint lambent 

 flame, owing, probably, to the vapor being heated nearly to redness 

 at the moment of production. A similar appearance had been ob- 

 served in the vapor of water, produced from metal at a white heat. 

 Having now removed the basin from the fire, the experiments 

 were continued, and the time was observed to increase from eighty 

 two seconds to one hundred and five, and then to one hundred and 

 thirty five, after which it began to diminish, as the establishment of 

 cohesion between the liquid and the metal became more decided, thus 

 Exp. 17 - - 105'' Exp. 20 - - 17'' 



18 - - - 135 21 - - 10 



19 - - 90 



The above series of experiments is in accordance with several of 

 those made upon water, where the initial temperature of the iron was 

 very great and the mass sufficient to supply heat of a high tension, 

 to the evaporating surface, for a considerable length of time after 

 being removed from the fire. This was the case in the^rs^, second, 

 Jtfth and eighth series in the second course on the rate of decrease.* 

 In those cases, the times exhibited either a succession of numbers 

 nearly equal, or an actual increase during the first five or six experi- 

 ments of each series. This is particularly remarkable in the eighth 

 series, of which a projection has been given. The order of magni- 

 tudes, for the first six experiments, beginning viith the highest, was 

 followed in that projection, merely for the purpose of exhibidng the 



* See page 76 of this volume. 



Vol. XXL— No. 2. 40 



