Electromotive Force to Pressure Src. 



99 



of the current were reduced to a minimum, and the needles 

 usually settled at or near zero in about 5 or 10 minutes 

 after closing the circuit with the tubes in a horizontal position. 

 No perceptible amount of interference was caused by the 

 small difference of temperature, usually equal to about 1°*5 0. 

 of the upper and lower parts of the experiment room. All 

 the experiments were repeated two or three times in order to 

 ensure reliable results. 



The solutions employed were all of them made with dis- 

 tilled water, and were in nearly all cases dilute ; the exact 

 strength used, however, was not a matter of much importance. 

 Those of the halogens usually contained about 3*29 grains of 

 chlorine, 7*41 grains of bromine, or 11*25 grains of iodine in 

 18 ounces of water. Those of the acids contained about 

 55 grains of absolute acid in 40 ounces of water ; and those 

 of neutral salts or of alkalies contained about 300 grains of 

 the substance to that amount of water. The electrodes of 

 cadmium, zinc, aluminium, tin, lead, and copper were formed 

 of thick wire ; and those of nickel, iron, silver, gold, and 

 platinum were thin wires. The following Tables give the 

 particulars and the results. 



Table I. 



Effect of Varying the Electrolyte only. 

 With Electrodes of Zn. 



No. of 

 Expt. 



Substances. 



Grains per oz. 



No. of 

 Tubes. 



Amouut of 

 Deflexion. 



1. 



2. 

 3. 

 4. 

 5. 

 6. 

 7. 

 8. 



CI 



Br 



•164 

 •37 



•18+8-3 



•37+ „ 



•62+ ., 



^sat. soln.+9'4 



6 drops + ,, 



3 grains + „ 



5 

 2 



4 



8° j 







50° f 



28°,, 



12°,, 



J 50°,, 



Very variable. 



20° f 



C1+KC1 



Br+KBr 



I+KI 



C1+KC1 



Br+KBr 



I+KI 





9. 

 10. 

 11. 

 12. 



13. 

 14. 

 15. 

 16. 

 17. 

 18. 

 19. 

 20. 



HC1 



•68 

 •92 



1-6 



1-2 

 •75 

 ? 



2-5 



2-1 



3-7 



10+7-5 



•65+7-5 



5 



M 



3 

 5 



0° 

 11 



11 



20° f 

 0° 



HBr 



H o S0, 



Hb ..: ::: 



hcio 3 



HBr0 3 



HIO3 



Acetic Acid 



Tartaric,, 



Oxalic ,, 



HCIO3 + KOIO3.. 

 HCl + AmCl 



H 2 



