Experimental Researches in Electricity. 471 



one by Jacobi, (Philosophical Magazine, 1838. xiii. 401.) relative to the 

 possible production of a spark on completing the junction of the two metals 

 of a single pair of plates (915.). It is an excellent paper, and though I 

 have not repeated the experiments, the description of them convinces me 

 that I must have been in error. The second is bj' that excellent philosopher, 

 Marianini, (Memoria della Sociela Italiana di Modena, xxi. 205) and is a 

 critical and experimental examination of Series viii. and of the question 

 whether metallic contact is or is not productive of a part of the electricity 

 of the voltaic pile. I see no reason as yet to alter the opinion I have given ; 

 but the paper is so very valuable, comes to the question so directly, and the 

 point itself is of such great importance, that 1 intend at the first opportunity 

 renewing the inquiry, and, if I can, rendering the proofs either on the one 

 side or the other luideniable to all. 



" Other parts of these researches have received the honour of critical at- 

 tention from various philosophers, to all of whom I am obliged, and some 

 of whose corrections I have acknowledged in the foot notes. There are, no 

 doubt, occasions on which I have not felt the force of the remarks, but time 

 and the progress of science will best settle such cases; and, although I 

 cannot honestly say that I ivisli to be found in error, yet I do fervently hope 

 that the progress of science in the hands of its many zealous present culti- 

 vators will be such, as by giving us new and other developments, and laws 

 more and more general in their applications, will even make me think that 

 what is written and illustrated in these experimental researches, belongs to 

 the by-gone parts of science." 



An analytical table of contents succeeds the preface, which, on ac- 

 count of its general utility and as furnishing a clew to the distribu- 

 tion, through the Fourteen Series, of the several objects of specific 

 research, we shall transfer to our pages. 



"Series!. §. 1. Induction of electric currents. §. 2. Evolution of elec- 

 tricity from magnetism. §. 3. New electrical state or condition of matter. 

 §. 4. Explication of Arago's magnetic phenomena. 



"Series II. §. 5. Terrestrial magneto-electric induction. §. 6. Force 

 and direction of magneto-electric induction generally. 



"Series III. §. 7. Identity of electricities from different sources, i. Vol- 

 taic electricity, ii. Ordinary electricity, iii. Magneto-electricity, iv. Ther- 

 mo-electricity, v. Animal electricity. §. 8. Relation by measure of com- 

 mon and voltaic electricity. Note respecting iVmpere's inductive results 

 after. 



"Series IV. §. 9. New law of electric conduction. §. 10. On conducting 

 power generally. 



" Series V. §. 11. Electro-cliemical decomposition. "Ij 1. New condi- 

 tions of electro-chemical decomposition. *l 2. Influence of water in such 

 decomposition. ^. 3. Theory of electro-chemical decomposition. 



" Series VI. §. 12. Power of platina, &c. to induce combination. 



" Series VII. §. 11. Elcctro-cliemical decomposition continued (nomen- 

 clature). IT 4. Some general conditions of electro-chemical decomposition. 

 ^ 5. Volta electrometer. IT 0. Primary and secondary results. ^ 7. De- 

 finite nature and extent of electro-chemical forces. Electro-chemical equi- 

 valents. §. 13. Absolute quantity of electricity in the molecules of matter. 



"Series VIII. §. 14. Electricity of the voltaic pile. U 1. Simple vol- 

 taic circles. 5f 2. Electrolytic intensity. ^ 3. Associated voltaic circles; 

 or batterv. II I. Resistance of an electrolyte to decomposition. ^ 5. (Ge- 

 neral remarks on the active battery. 



" Series IX. §. 15. induction of a current on itself. Inductive action 

 of currents generally. 



