290 Mr. N. Eumorfopoulos on the Determination 



As an example of the curve of temperatures obtained, see 

 fig. 3. At the abscissa marked min. cold water was turned 

 on, and at 15 min. steam. The points marked are experi- 

 mental points. There are no points marked at and 15 min. 

 as I had to be in another part of the room at those instants. 

 It will be noticed that the cold water or the steam (as the case 

 may be) has done nearly all it can do, before the other is 

 turned on, especially in the case of A. This can also be seen 

 from the numbers given below. 



The following are the details for each rod: — 



Bod I. (J- inch).— Diam. = '3377 cm. Density = 8*49. 

 Specific electrical resistance = 7*24 x 10~ 6 ohms. 

 7 cms. between junctions. Time-period 10 min. 

 Determination of temperature every half-minute. 





Set I * 





Set II. 



Set III. 



(Mean of 3 cycles.) 



(Mean of 3 cycles.) 



(Mean of 4 cycles.) 



Excess Temperature 



Excess Temperature 



Excess Temperature 





in degrees 





in degrees. 



in degrees. 



Time in 



A. 



B. 



A. 



B. 



A. 



B. 



mins. 

 

 1 















22-25 



913 



22-27 



9-26 



19-82 



867 



1 



1591 



8-88 



15-95 



8-98 



1405 



8-35 



n 



10-95 



7-81 



11-01 



7-88 



979 



724 



2 



7-90 



6-58 



7-87 



6-50 



672 



600 



n 



5-67 



5-29 



5-68 



5-29 



4-83 



4-71 



3 



4-35 



4-35 



4-27 



4-29 



342 



3-79 



H 



3-32 



352 



3-30 



349 



261 



306 



4 



2-64 



2-98 



255 



2-88 



1-97 



2-52 



4* 



5 



5* 



205 



2-36* 



202 



2-31 



1-56 



2-01 



1-80 



1-78 



143 



1-60 



1-10 



1-48 



6 



911 



1-65 



8-63 



1-56 



7-46 



1-42 



H 



15-47 



2-58 



14-95 



2-52 



1397 



2-36 



7 



19-16 



4-06 



18-95 



397 



1759 



3-81 



7* 



2091 



5-42 



20-77 



5 40 



1942 



5-10 



8 



22-21 



6-53 



22-31 



658 



20-75 



6-16 



8* 



. 23-08 



741 



23-31 



7-42 



21-65 



6-99 



9 



23-69 



7-95 



2396 



8-16 



22-49 



7-65 



9* 



24-14 



8-47 



24-34 



8-62 



22-53 



8-05 



Mean 

 Temp. 



J27° 



19£° 



j 



27° 19£° 



27i° 21° 



Mean 

 Temp. A 



} 1 



4° 



14° 



16° 



The results, in C.G.S. units, calculated from these numbers 



are 



* At the end of this set the joint B was found displaced through about 

 2 mm. away from A. This introduces a possible error of about 2| p. c. in 

 the distance, or 5 p. c. in the conductivity, while leaving the emissivity 

 practically unaffected. 



