501 



with some powerful voltaic batteries, for the purpose of determining 

 the possibility of obtaining a spark before the completion of the cir- 

 cuit. This anticipated effect was not, however, produced. A short 

 time after, Mr. Cross stated that he had succeeded in procuring a 

 spark from a battery of 1626 cells of copper and zinc, acted upon by 

 river water. The author, pursuing his researches, constructed a bat- 

 tery consisting of 3520 pairs of copper and zinc cylinders, each pair 

 being placed in a separate glass vessel, well covered with a coating 

 of lac varnish, and insulated by being placed on slips of glass covered 

 on both sides with a thick coating of lac. The cells were placed on 

 44i separate oaken boards, also covered with lac varnish, each board 

 carrying 80 cells, and sliding into a wooden frame, where they are 

 further insulated by resting on pieces of thick plate-glass, similarly 

 varnished. 



In describing the effects which this apparatus has produced, the 

 author endeavours to draw a distinction between the static and the 

 dynamic effects of the developed electricity, and treats of each se- 

 parately. The conclusions to which he is led from the series of ex- 

 periments narrated in this paper, are the following : — 



1. The elements constituting the voltaic battery assume polar ten- 

 sion before the circuit is completed, even in a single cell ; this polar 

 state being shown to exist by the action exerted on the electroscope 

 being different at each polar extremity of the battery, 



2. The tension, so produced, when exalted by a succession of series, 

 is such, that a succession of sparks passes between the polar extre- 

 mities of the battery before their actual contact. 



3. The static effects precede, and are independent of the com- 

 pletion of the voltaic circuit, as well as of any perceptible develop- 

 ment of chemical or dynamic action. 



4. When the current is established, either by actual contact of the 

 extremities, or merely by their approximation, so as to admit of a 

 succession of sparks, its dynamic effects on the galvanometer are the 

 same in both cases ; each spark producing a constant deflection of 

 the needle. It is hence inferred that the current, even when the 

 circuit is closed, may be regarded as a series of discharges of elec- 

 tricity of tension, succeeding each other with infinite rapidity. 



5. In a battery, of which the chemical elements have but a feeble 

 mutual affinity, as is the case with the water battery, the tension rises 

 very slowly. 



6. In order to produce static effects in the voltaic battery, it is an 

 indispensable requisite that the elements be such as are capable of 

 combining by their chemical affinities : and the higher those affini- 

 ties are exalted, the smaller is the number of parts composing the 

 series requisite to exhibit the effects of tension. The static effects 

 elicited from a voltaic series, afford, therefore, direct evidence of the 

 first step towards chemical combination, or dynamic action. 



The author observes, in conclusion, that the chemical effects, when 

 obtained in most of the experiments he has described in this paper, 

 are very feeble ; but are precisely the same in character as those ex- 

 hibited by the more powerful voltaic combinations ; and he thinks 



