﻿2S0 



Barns and Stronhal — Hydro-electric 



Annealed at 20°. 



(Glass-hard.) 



No. 9. (No. 10. 



exlO z ex 10 z 



= 4 ±13 



±0'009 



Annealed at 360°. 

 (Mercury.) 



No. 5. No. 6. 



exlO 3 ex 10 3 



+ 36±3 +34±3 



+ 0-035 



Annealed at 100°. 

 (Steam.) 

 No. 1. No. 2. 



e x 10 3 ex 10 3 



+ 12 ±4 -2±5 



+ 0-005 



Annealed at 450". 



(Sulphur.) 



No. 7. No. 8. 



exlO 3 ex 10 3 



+ 35±3 +40±3 



+ 0-037 



Annealed at 190°, 



(Aniline.) 



No. 3. No. 4. 



exlO 3 ex 10 z 



+ 19±3 +20±1 



+ 0-020 



Annealed at 1000". 



No. 11. No. 12. 



e x 10 % ex 10 z 



+ 49±4 +54±4 



-rO-052 



The following data are the mean results of four series of five 

 observations per series. Eods scoured before each series. 



Annealed at 20°. 

 No. 9. No. 10. 



exlO 3 ex 10 z 



±5 ±2 



±0-003 



Annealed at 360°. 



No. 5. No. 6. 



exlO 3 ex 10 s 



+ 34±5 +-27 ±1 



+ 0-030 



Annealed at 100°. 



No. 1. No. 2. 



exlO 3 ex 10' 6 



+8±3 +7±1 



+ 0-007 



Annealed at 450 V 



No. 7. No. 8. 



exlO 3 ex 10 z 



+ 35±2 -}-43±2 



+ 0-039 



Annealed at 190 c . 



No. 3. No. 4. 



exlO 3 ex 10 3 



+ 20±3 +24 + 2 



+ 0-022 



Annealed at 1000°. 



No. 11. No. 12. 



exlO 3 ex 10 3 



+ 51 + 2 +65±5 



+ 0-058 



The following data, finally, are the mean results of two series 

 of three observations per series. Eods scoured before each 

 series. 



Annealed at 20°. 

 No. 9. No. 10. 



exlO 3 ex 10 3 



±2 ±4 



±0-003 



Annealed at 360°. 



No. 5. No. 6. 



exlO 3 ex 10 3 



+ 36±2 + 34±1 



+ 0-035 



Annealed at 100". 



No. 1. No. 2. 



exlO 3 ex 10 z 



+6±2 +6±1 



+ 0-006 



Annealed at 450°. 



No. 7. No. 8. 



e x 10 3 e x 10 Z 



+ 37 ±2 +39±2 



+ 0-038 



Annealed at 190°. 



No. 3. No. 4. 



exlO 3 ex 10 z 



+ 16 + 3 +25±1 



+ 0-021 



Annealed at 1000\ 



No. 11. No. 12. 



e x 10 z ex 10 3 



+ 59±6 +65±8 



+ 0-062 



The electromotive forces here encountered are small. It is 

 necessary to take extreme precautions against all sources of 

 error ; otherwise mere discrepancies of polarization will exceed 

 the largest values of electromotive force (e) found. If the parts 

 of the liquid in which the steel wires are immersed differ at all 

 in composition, we may look for a difference of potential at the 

 surface of separation of those parts. The number of such sur- 

 faces in a solution (of solid, liquid or gas) may be indefinite. 

 Hence it appeared desirable to repeat the above experiments 

 with distilled water in place of zinc sulphate ; to exchange the 

 limbs of the U-tube twice for each series of measurements 



