. The Civil engineer and architect's journal, scientific and railway gazette. Architecture; Civil engineering; Science. ming noise and sometimes a loud musical sound is excited by the rapid vibra- tory motion assumed by the fixed magnet during the rapid revolution of the electro-magnet. This musical sound is best observed when the levelling screws of the tripod are placed on a mahogany table in the middle of a large room. For tlie electro-magnet i/^ a simple coil of wire maybe substitued, the rotation of which will be exceedingly rapid, its faces becoming alternately attracted and repelled by
. The Civil engineer and architect's journal, scientific and railway gazette. Architecture; Civil engineering; Science. ming noise and sometimes a loud musical sound is excited by the rapid vibra- tory motion assumed by the fixed magnet during the rapid revolution of the electro-magnet. This musical sound is best observed when the levelling screws of the tripod are placed on a mahogany table in the middle of a large room. For tlie electro-magnet i/^ a simple coil of wire maybe substitued, the rotation of which will be exceedingly rapid, its faces becoming alternately attracted and repelled by Ihe poles of the ; The power of the electro-magnet is a great consideration, and in order to Fig. produce the greatest effect of electro-magnetic induction , thecurrentmust be made to encircle it by passing through a considerable length of insulated copper wire wound round the iron. A great length of wire is, however, found to weaken the effect of the current, and it is considered better that the total length of the wire intended to be used should be cut into several portions, each of which, covered with silk or cotton thread to prevent lateral commu- nication, is to be coiled separately on the wire. Tile ends of all Ihe wires, Mr. Noad directs, must then be collected into two separate parcels and made to communicate with the same voltaic battery, taking, however, precautions that the current shall pass along each wire in Ihe same direction. The accompanying engraving shews a simple arrangement of the electro-magnet, mounted on a wooden stand with a small scale pan attached to Ihe bit or keeper of Ihe magnet. So intense is the magnetic power thus induced on the iron that weights of upwards of half a Ion can be sustained. Mr. Noad's large magnet, weighing one hundred- weight, will sustain, when excited by an energetic compound battery, from 10 to 14 cwt.; but Mr. Richard Robert's magnet, weighing 35 lbs., with an ar- mature 23 lbs. in weight, when exci
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Keywords: ., boo, bookcentury1800, booksubjectarchitecture, booksubjectscience
