322 Scientific Intelligence. 



flow through a long tube having three electrodes of gold wire ad- 

 mitted at its ends and center. A battery of two Daniell's cells 

 has one terminal connected with the center electrode, and the 

 other with two of the terminals of a delicate differential astatic 

 galvanometer. The two end electrodes are connected with the 

 other terminals of the galvanometer. The current from the bat- 

 tery divides, and half passes through the tube in each direction. 

 By suitably varying the resistance,"the galvanometer needle will 

 now be at rest. When the water is caused to flow through tlie 

 tube, however, the resistance in one direction will be increased, 

 and that in the other diminished, since, according to Edlund's 

 theory the current is proportional to the amount of ether flowing 

 through a given section per second. Accordingly the needle 

 should deviate, as, in fact, it does. To eliminate the eifects of 

 polarization, the current was inverted without changing the re- 

 sult. That the deviations may be regular, it is essential that the 

 liquid should have a great resistance and the amount of deviation 

 is almost independent of this resistance. Two series of observa- 

 tions were made, one with distilled water, the other with alcohol 

 and water, and gave similar results. A third series with aque- 

 duct water gave the same result. Penally, equal currents were 

 sent in opposite directions through the pipe, when they produced 

 no effect on the needle, but as soon as the lic^uid was set in motion 

 a deviation was always obtained indicating that the resistance 

 was greater in one direction than in the other. These two meth- 

 ods of observation lead to the same result, foreseen by the theory 

 of Edlund, namely, that the galvanic resistance diminishes if the 

 conductor moves in the same direction as the galvanic current 



Mag., 



-Moyal Sicedish Acad., III., 



9. Electric Spark with large Batteries.— Messrs. v\ abrex dk 

 LA Rtte and H, W. 3Iuller presented to the Royal Society at a 

 recent meeting a paper having the following title : On the length 

 of the Spark from a Battery of 600, 1200, ISOO and 2400 rod- 

 chloride of Silver, and some Phenomena attending the discharge 

 of 5640 cells. A year ago some experiments on th 

 of the discharge in vacuo of a battery of 1080 cells were ial-.- 

 This battery has now been augmented to 5640 cells, ai 

 other batteries will soon be added making 9120 cells. I 

 completed 2400 cells and charged them up in a single da; 

 were exactly in the same condition as to electro-motive foi 

 internal resistance, consequentlv they afforded the means < 

 ing the truth of the law of the' length of the spark in a i 

 more efficacious than had hitherto been obtained, the mor 

 cially as by the use of paraffin corks and other precaution-^ ' 

 obtained an excellent insulation. A discharger with a mien 

 screw was constructed by which the length of spark c<> 

 measured to -001 of an inch, or by estimation to one-tenth 

 quantity. In making measurements the terminals were sei 



