Constants of Igneous Rock. 

 Table II. (continued). 



303 



Cruc. 



No. 



T. 



e. 



Mean 9. 

 M. 



m. 



1171° 

 1192 g. 



32-20 g. 



Time. 



0. 



Correc- 

 tion 

 0. 



Correc- 

 tion 

 h. 



h. 





I. 



°c. 



10 



°c. 



1177 

 1170 

 1166 



Minutes. 







14 



°C. 



19-88 

 27-37 



°C. 



i-io 



g.-cal. 

 16 : 7 



g.-cal. 

 301-6 



Immersion 

 Solid. 



M M 1 hi 



r 1 



11 

 11 



1106 

 1094 



1088 



1096° 

 1195 g.- 

 32-21 g. 





 14 



16-28 

 23-24 



"■68 



i'o : 5 



268-2 



Immersion 

 Solid. 



1262 

 1244 

 1238 



1248° 

 1191 g. 

 25-49 g. 







14 



1972 

 26-55 



"•89 



211 



338-8 



Immersion 

 Liquid. 



11 



1237 

 1216 

 1202 



1218° 

 1188g. 

 29-43 g. 





 14 



1367 

 2160 



"•69 



iff 



330-3 



Immersion 

 Liquid. 



ii. 



11 



1224 

 1216 

 1205 



1215° 

 1185 g. 

 25-57 g. 





 14 



19-73 

 26-27 



"•95 



204 



326-6 



Immersion 

 Liquid. 



For brevity the later observations were averaged per 

 3 minutes, and under h the mean value for the last 11 minutes 

 is usually given. 



In Series I. the increase of temperature from top to bottom of 

 the crucible is as large as 60° at 1200°, usually much smaller, 

 however, and falling off pretty regularly to 6° at 829°. In 

 Series II. the corresponding mean difference is about 25° at 

 1300°, 14° at 1000°, 10° at 800°. The errors thus involved 

 cannot be greater than 2 per cent, in the extreme case ; but 

 since the distribution of temperature is measured, it is probably 

 negligible except at very high temperatures. I am inclined 

 to infer that the greater constancy of the solid distribution 

 as compared with the liquid is due to greater thermal con- 

 ductivity in the former case (solid), convection being neces- 

 sarily absent in both. 



Considering the observational work as a whole, the data 

 are satisfactory, seeing that an error of 0*1° C. in the calori- 

 metric temperatures, initial or final, must distort the results 

 at least 1 per cent. But the real source of error is probably 

 accidental, and is encountered when the hotbodv falls through 

 the surface of the cold water. 



Inferences. 



11. Digest and Charts. — In Tables III. and IV. I have 

 summarized the chief results on a scale of temperature. The 



