. Calcutta Journal of Natural History. Electricity and Galvanism. 255 nishes us with large quantities of electricity of tolerably high tension, and possesses advantages for medical purposes which no other mode of exciting electricity affords. To illustrate the mode of exciting electricity by induction in the simplest manner, I will connect this piece of copper wire wound into a circular coil with the terminal screws of a N. S. The magnetic needle of the galvanometer, D. E. The circular wire coil connected with the wires of the galvanometer. A. B. The wooden cylinder covered with
. Calcutta Journal of Natural History. Electricity and Galvanism. 255 nishes us with large quantities of electricity of tolerably high tension, and possesses advantages for medical purposes which no other mode of exciting electricity affords. To illustrate the mode of exciting electricity by induction in the simplest manner, I will connect this piece of copper wire wound into a circular coil with the terminal screws of a N. S. The magnetic needle of the galvanometer, D. E. The circular wire coil connected with the wires of the galvanometer. A. B. The wooden cylinder covered with wire, the ends of which, Z. C. are connected with the terminal plate of a battery. I have here a wooden cylinder, round which is wound a piece of in- sulated wire, so as to form thirty or forty convolutions, and will place this in the centre of the coil connected with the galvanometer. The needle of the instrument is now at rest; but observe what occurs the instant I connect the ends of the wire coiled on the wooden cylinder with the zinc and copper plates of a single galvanic battery. In an instant the needle darts off, as if acted upon by some tangential force; and, after several violent oscillations through a considerable arc, it slowly attains a state of rest, several degrees out of the magnetic meridian. Now, as the wire on the cylinder had no connection what- ever with that of the coil, it is obvious that the battery merely acted as an exciting agent in disturbing the normal electric equilibrium of the wire, causing the electricity to circulate in the form of current. This current, you will observe, is of momentary duration, and is excited only at the instant that the battery current first traverses the con- ducting wire. But now, the needle being perfectly quiet, I will sudden- ly break contact with the battery, and once more the needle rushes out of the meridian line, and traverses a considerable arc, but in a direc- tion opposed to that in which it travelled when conn
Size: 2650px × 943px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bhlconsortium, boo, bookcollectionbiodiversity, bookleafnumber271
