70 



Mr. E. H. Griffiths on the Influence of 



Table III. 



Showing the Corrections necesssary for the Reduction of 

 Experiment 26. July 28. 



Observed time over range (t) ... 



Change in external temp, (therm. A) 

 during the experiment 



Change in range consequent on 

 change in therm. A (1 mm. A = 

 4'05 mm. of bridge-wire) 



Eef. 



Range en Range on Range on 



bridge-wire bridge-wire, bridge-wire. , - 

 55-5-62-5 cm. 1 62-5-69*0craJ 690-760cm. JN0 ' 



d9 



Uncorrected rise per 1 sec, i. e. - 1 



F ' dt 



Mean value of I cm. of the bridge- 

 wire over this range in terms of 

 mean bridge-wire cm 



Correction of ^to mean bridge- I 



dB, 



( wire cm. J 



» „ for temp, of Clark I 



cells. J 



», „ for temp, of 1 



bridge-wire. J 

 », ,, for stirring to 1 



rate 5*00. J 



d9 i n. 



~rr alter corrections 



at 



Mean point of range (bridge- wire). . 



252*5 sees. 

 + •05 mm. 



+ •020 cm. 

 •027802 



100245 



+ •000068 

 + •000010 

 + •000037 

 + •000012 



•027929 

 5900 



2371 sees. 

 + *015min. 



+ •006 cm. 



•027440 



•99281 



261*6 sees. 

 -•010 mm. 



-•004 cm. 



•026743 



•99494 



-•000197 

 + •000010 



+ -000037 

 + •000011 



•027301 

 65-75 



B. 



•026664 

 7250 



C. 



Since the points thus found should lie on a straight line, the best result is 

 arrived at by treating the results so as to obtain 2 points only. If we mean 

 A and B, and again B and C ; we attach undue value to B. The true mean 

 is obtained by 2A+B , B+2C 



— o— and -31 



We thus get :— 6 6 



Bridge-wire readings 61*25 cm. 



Mean value of 



d\ 

 dt 



We can thus obtain (either arithmetically or 

 -3- at B.W. readings 60-00 cm. 



70-25 cm. 



•027720 -026877 



by plotting) the values of 



70 00 cm. 



which are -027837 -026900 



Now the value of R x near the ''null point" (about 62 5 b.w.) was 

 found to be 8*46093 true ohms. To this add "00720 for the rise in resistance 

 due to a potential-difference of 4 Clark cells (Table II.) ; hence R =8-4681 

 hence correction to R= 8-5000 is - -000104 



HenCe It at BM ' ™ din & 60 "°0 cm. 7000 cm. 



when R is 8*5000, = -027733 -026796 



dt 4 2 



•001733 



•001675 



-•000135 IT. 



+•000009 V. 



+ •000036 IV. 



+ •000011 III. 



VI. 



