192 



Rolborn and Day — Gas Thermometer at 



time curve remained in general the same except perhaps that 

 the limits of the slow rise or fall of the temperature were 

 moved closer together, and if the stirring was energetic, could 

 be lowered some degrees. 



Table XVII contains a number of results partly with stir- 

 ring and partly without. G indicates the weight of the melted 

 metal in grams, t x and £ 2 the upper and lower limits of the slow 

 change of temperature about the melting point, and t their 

 arithmetical mean. The letters F and M distinguish freezing 

 and melting points. The strength of the oven current i may 

 serve to give an idea of the comparative expenditure of energy 

 in the different determinations though only a rough one, as the 

 resistance of the coil on different days was not always the 

 The mean value of t for the observations where the 



same. 



metal was stirred is 954*9° and differs only lj3° from the result 



Table XVII. 

 Melting- Point of Silver in Air. 



1899. 



G 

 (gr.) 



i 

 (Amp.) 





k 



U 



t 



Novem'r. 



MV 



Degrees. 



MV 



Degrees. 



Without 



















stirring. 

 16 



350 



6-0 



F 



8940 



954-4° 



8983 



9582° 



956 3° 







8-3 



M 



8960 



956-1 



9016 



961-0 



958-6 







o-o 



F 



8973 



957*3 



9000 



959-6 



958-5 







8-0 



M 



8970 



957-0 



9014 



9609 



959-0 







6=5 



F 



8926 



953-2 



9006 



960-2 



956-7 







9-0 



M 



S970 



957-0 



9014 



9609 



959-0 



17 



500 



5-0 



F 



8968 



956-8 



9001 



9597 



958-3 







8-0 



M 



8963 



956-4 



9018 



961-2 



958-8 







5-5 



F 



8942 



954-6 



8995 



959-2 



956-9 







8-0 



M 



8950 



955-3 



9011 



960-6 



958-0 



"With 



















stirring. 



















18 



500 



5-0 



F 



8931 



953-6 



8947 



955-0 



954 3 



20 



380 



6-0 



F 



8950 



955.3 



8967 



956-7 



956-0 







10-7 



M 



8931 



953 6 



9004 



960-0 



956-8 







8-0 



F 



8890 



950-0 



8943 



954-6 



952-3 



obtained by the wire method. We assume therefore 955° as 

 the mean melting point of silver in air, but at the same time 

 we wish to emphasize the fact that the point is not well defined 

 and, especially with the wire method, may suffer considerable 

 variations with the nature of the surrounding atmosphere. 



The "spitting" was also frequently observed through the 

 mica covers. It took place between 933° and 940°, in the 

 mean at about 936°, and was much more violent when the melted 

 metal had been previously stirred. 



