No.III.Account of an experiment made at Calais, on the transmission of Galvanism through an arm of the sea. ByJ.Aldini.Theexperiments made at the Lake of Geneva by Mr. de Luc and his brother, and those made in England on the banks of the Thames, by which it has been proved that common electricity is susceptible of transmission through a considerable space of water, induced me to try some analogous experiments in regard to Galvanism by endeavouring to make it traverse a certain extent of sea.Some philosophers, to whom I communicated this project, seemed to entertain doubts on the subject, as they conceived that a considerable extent of sea water might perhaps destroy or impede the action of the Galvanic fluid. My late passage at Calais afforded me an opportunity of removing all these doubts by an experiment which was attended with complete success.M. Sept-Fontaines, distinguished by his philosophical knowledge, was desirous of assisting me in my proposed researches; M. Cheely, chemist of the military hospital, prepared the necessary instruments; and M. Debaudre, the port engineer, conducted the arrangement of the Galvanic arcs.On the 27th of February, the sky being serene, and the sea calm, every thing seemed to be favourable for the experiment. A gentle south-west wind prevailed at the time; the temperature of the water of the sea was 47·4°of Fahrenheit, that of the atmosphere 49·4°, and the barometer stood at 30·37 inches.Fort Rouge and the West Mole afforded me two fixed points proper for my purpose. A Galvanic pile consisting of eighty plates of silver and zinc was constructed on the West Mole on an insulated stool, and the animals destined to be exposed to the Galvanic action were placed at Fort Rouge. The Galvanic chain was composed of the arm of the sea which separates Fort Rouge from the Western Mole, and of three wires disposed in the following manner.The first wire proceeded from the base of the pile, and, being supported by an insulator, fell vertically into the sea to the depth of about three fathoms.The second wire, insulated in the same manner, proceeded from the summit of the pile, and was conveyed in a horizontaldirection at the height of from six to nine feet above the surface of the sea, as far as the platform of Fort Rouge.A third wire, also insulated, and placed at one corner of the platform, descended perpendicularly into the sea in the same manner as the first.When this arrangement was made, if a person on the platform touched the extremities of the second and third wires, and thus completed the Galvanic circle, he always experienced a shock; and when animals recently killed were substituted in the room of the person, they were thrown into strong convulsions. We therefore concluded that the portion of sea water between the pile and the animal subjected to its action formed a part of the Galvanic circle: such was the consequence we thought ourselves authorised to deduce from this experiment. The breadth of the water was about 200 feet.I must freely confess, that in repeating these experiments, we found, that to receive the shock, it was not absolutely necessary that the person should hold in his hands the two conductors, and that it was sufficient to touch the wire alone which proceeded from the summit of the pile. This apparent anomaly deranged at first the result of my researches; and we suspected that the shocks before received had been transmitted without the intervention of the water of the sea. It was therefore necessary that this doubt should be cleared up by new observations.I tried separately, on the platform, the action of the two conducting wires, and found that by touching the wire which fell into the sea no shock was produced. I then took in my hand the other wire, which proceeded from the summit of the pile; and having thus brought its action into equilibrium, I experienced a shock: which shows that the Galvanic fluid took its course from the bottom of the pile traversing the sea. M. Sept-Fontaines proposed that we should lower to the level of the sea the wire which proceeded from the summit of the pile, and which was extended to Fort Rouge. The action of the Galvanism was then checked, but was immediately restored by placing the conductor in its former position. Thus, notwithstanding the large extent of water by which the metallic conductors were separated; and notwithstanding the agitation produced by the sea, the Galvanism found no obstacle to its propagation, and pursued its usual direction.Hence it may be readily perceived, that though the experiments here described are analogous to those formerly made with the Leyden flask on lakes and rivers, they are new of their kind, and may contribute to establish the similarity between the properties of common electricity and of Galvanism. I will even venture to assert, that these experiments, if pursued and varied, may lead to some interesting discoveries in natural philosophy.After making these observations at Fort Rouge, I repairedin company with M. Sept-Fontaines to the West Mole, to try the power of the pile unconnected with the sea. Having formed an arc, we found that the action of the pile, in this case, was stronger; which induced us to conclude, that the Galvanic power in traversing the sea had been in some measure weakened. There is reason to suppose, that by transmitting the Galvanic influence gradually to greater distances through the sea, the point of the minimum of its action, that is, a distance at which it will no longer be sensible, may be discovered. This distance remains to be determined, and also the difference between the propagation of common electricity in fresh water, and that of Galvanism in salt water.I observed that the sea shore, still moist after the water retires in consequence of the reflux, is endowed with the power of conveying Galvanism to very great distances. I made several experiments on this subject with M. Bastide, physician of Calais, who acknowledged that he had received very strong shocks, the effects of which were sensible the day following.THE END.Wilks and Taylor,Printers, Chancery-lane.
Account of an experiment made at Calais, on the transmission of Galvanism through an arm of the sea. ByJ.Aldini.
Theexperiments made at the Lake of Geneva by Mr. de Luc and his brother, and those made in England on the banks of the Thames, by which it has been proved that common electricity is susceptible of transmission through a considerable space of water, induced me to try some analogous experiments in regard to Galvanism by endeavouring to make it traverse a certain extent of sea.
Some philosophers, to whom I communicated this project, seemed to entertain doubts on the subject, as they conceived that a considerable extent of sea water might perhaps destroy or impede the action of the Galvanic fluid. My late passage at Calais afforded me an opportunity of removing all these doubts by an experiment which was attended with complete success.
M. Sept-Fontaines, distinguished by his philosophical knowledge, was desirous of assisting me in my proposed researches; M. Cheely, chemist of the military hospital, prepared the necessary instruments; and M. Debaudre, the port engineer, conducted the arrangement of the Galvanic arcs.
On the 27th of February, the sky being serene, and the sea calm, every thing seemed to be favourable for the experiment. A gentle south-west wind prevailed at the time; the temperature of the water of the sea was 47·4°of Fahrenheit, that of the atmosphere 49·4°, and the barometer stood at 30·37 inches.
Fort Rouge and the West Mole afforded me two fixed points proper for my purpose. A Galvanic pile consisting of eighty plates of silver and zinc was constructed on the West Mole on an insulated stool, and the animals destined to be exposed to the Galvanic action were placed at Fort Rouge. The Galvanic chain was composed of the arm of the sea which separates Fort Rouge from the Western Mole, and of three wires disposed in the following manner.
The first wire proceeded from the base of the pile, and, being supported by an insulator, fell vertically into the sea to the depth of about three fathoms.
The second wire, insulated in the same manner, proceeded from the summit of the pile, and was conveyed in a horizontaldirection at the height of from six to nine feet above the surface of the sea, as far as the platform of Fort Rouge.
A third wire, also insulated, and placed at one corner of the platform, descended perpendicularly into the sea in the same manner as the first.
When this arrangement was made, if a person on the platform touched the extremities of the second and third wires, and thus completed the Galvanic circle, he always experienced a shock; and when animals recently killed were substituted in the room of the person, they were thrown into strong convulsions. We therefore concluded that the portion of sea water between the pile and the animal subjected to its action formed a part of the Galvanic circle: such was the consequence we thought ourselves authorised to deduce from this experiment. The breadth of the water was about 200 feet.
I must freely confess, that in repeating these experiments, we found, that to receive the shock, it was not absolutely necessary that the person should hold in his hands the two conductors, and that it was sufficient to touch the wire alone which proceeded from the summit of the pile. This apparent anomaly deranged at first the result of my researches; and we suspected that the shocks before received had been transmitted without the intervention of the water of the sea. It was therefore necessary that this doubt should be cleared up by new observations.
I tried separately, on the platform, the action of the two conducting wires, and found that by touching the wire which fell into the sea no shock was produced. I then took in my hand the other wire, which proceeded from the summit of the pile; and having thus brought its action into equilibrium, I experienced a shock: which shows that the Galvanic fluid took its course from the bottom of the pile traversing the sea. M. Sept-Fontaines proposed that we should lower to the level of the sea the wire which proceeded from the summit of the pile, and which was extended to Fort Rouge. The action of the Galvanism was then checked, but was immediately restored by placing the conductor in its former position. Thus, notwithstanding the large extent of water by which the metallic conductors were separated; and notwithstanding the agitation produced by the sea, the Galvanism found no obstacle to its propagation, and pursued its usual direction.
Hence it may be readily perceived, that though the experiments here described are analogous to those formerly made with the Leyden flask on lakes and rivers, they are new of their kind, and may contribute to establish the similarity between the properties of common electricity and of Galvanism. I will even venture to assert, that these experiments, if pursued and varied, may lead to some interesting discoveries in natural philosophy.
After making these observations at Fort Rouge, I repairedin company with M. Sept-Fontaines to the West Mole, to try the power of the pile unconnected with the sea. Having formed an arc, we found that the action of the pile, in this case, was stronger; which induced us to conclude, that the Galvanic power in traversing the sea had been in some measure weakened. There is reason to suppose, that by transmitting the Galvanic influence gradually to greater distances through the sea, the point of the minimum of its action, that is, a distance at which it will no longer be sensible, may be discovered. This distance remains to be determined, and also the difference between the propagation of common electricity in fresh water, and that of Galvanism in salt water.
I observed that the sea shore, still moist after the water retires in consequence of the reflux, is endowed with the power of conveying Galvanism to very great distances. I made several experiments on this subject with M. Bastide, physician of Calais, who acknowledged that he had received very strong shocks, the effects of which were sensible the day following.
THE END.
Wilks and Taylor,Printers, Chancery-lane.