14 Mr. E. H. Griffiths. The Value of [Feb. 16, 



Table XVII * 



Range Em. 



Range C 

 Thermometer steady. 



Range C. 

 Thermometer rising. 



_ 



87 5 — 127 5 



i)7o 



"973 



127 5 — 177 5 



1 '233 



1 "235 



177-5— 217-5 



-989 



-987 



217 *5 — 257 '5 



'993 



-995 



257 -5—297 '5 



1-016 



1-016 



297-5—347-5 



1-278 



1-278 



347-5—397-5 



1-281 



1-282 



397 5—447-5 



1 -306 



1-307 



447-5—507-5 



1-601 



1-598 



507-5— 537*5 



0-809 



0-811 



We have now indicated bow the various quantities in equation (2) 

 were determined, with the exception of J and M' ; we can therefore 

 deduce from equation (2) the time (T) of rising 1° C. at any point 

 of our range when R = liv and E is the potential difference of one 

 Clark cell. 



We thus get 



If w be the weight of water, and w x the water equivalent of the 

 calorimeter at the standard temperature, and if / and g be the tem- 

 perature coefficients of their specific heats, then 



* [_Note, February 18, 1893. — On February 14, ult., I received a mercury 

 thermometer (by M. Tonnelot) which had been under observation by Dr. G-uillaume 

 for the previous two months. I have made a direct comparison of this thermometer 

 with Em, at three points, observing all the precautions enjoined by Dr. Gruillaume, 

 and the results are as follows : — 



Beading Ej», 

 thermometer 

 steady. 



6y by Paris 

 hydrogen 

 thermometer. 



&i as given by 

 our platinum 

 thermometer. 



Range, 

 Paris standard. 



Range from 

 Table XVII, 

 supra. 



87-5 



13 -975 



13-990 



} 6 -483 



6-484 



347-5 



20 -458 



20 -474 



} 4-183 



507-5 



24 -641 



24-662 



4-188 



Thus, although we differ by 0-015° C. in actual elevation at 14° C, our agreement as 

 to the value of the above ranges is close. Want of time has prevented a complete 

 comparison, and the observations have been somewhat hurried. They serve, however, 

 to indicate that ou^ thermometric errors are small. — E. H. Gr.] 



