MORSE AND SHUDDEMAGEN. — AN A.LUMINIUM ANODE. 393 



It is evident from this summary that alternating current methods of 

 measurement will give much simpler and in some respects more useful 

 results than the ballistic method. If a definite wave-form and a 

 definite frequency are available, we have at once disposed of charging 

 time, insulation time, discharge time, and the constants of the circuit. 

 Making these factors constant is a very great simplification, and the 

 other factors can be approached much more easily than by any ballistic 

 method. But the factors mentioned are of scientific interest, and ac- 

 curate study of their variations leads to analytical results which could 

 hardly be obtained by the aid of alternating current measurements. 



Jefferson Physical Laboratory, 

 Harvard University. 



December 23, 1908. 



Literature. 



1. Askenasy. 



Ztsch. f. Elektrochem., 4, 70 (1897). — Discussion at Bunsen So- 

 ciety meeting. 



2. Bartorelli. 



N. Cimento, (5), 1, 112 (1901). — General study of aluminium 

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3. Bartorelli. 



Phys. Ztsch., 2, 469 (1901). — Aluminium kathode especially. 



4. Beetz. 



Pogg. Ann., 127, 45. — Polarization in general. 



5. Beetz. 



Pogg. Ann., 156, 464. — Polarization at aluminium plate. 



6. Beetz. 



Wied. Ann., 2, 94. — Analyses of electrode, etc. 



7. Berti. 



L'Elettricita, 11, 101 (1902). 



8. Blondin. 



L'Eclair, Electr., 18, 117 (1901). —Report on Pollak's rectifier. 



9. Bottome. 



Electr. Engineer., Mar. 11, 1891. — Suggests application as 

 rectifier. 



10. Buff. 



Lieb. Ann., 102, 269 (1857). — Polarization at aluminium anode. 



11. Burgess and Hambuechem. 



Trans. Am. Electrochem. Soc, 1, 147. — Ohmic resistance theory. 



