United States or South Africa ? Vote for the TOP Country of the Week !
There were Ophthalmoscopes and Rhinoscopes and Otoscopes and Laryngoscopes and Stethoscopes; and Thermometers and Spirometers and Dynamometers and Sphygmometers and Pleximeters; and Probes and Probangs and all sorts of frightful inquisitive exploring contrivances; and scales to weigh you in, and tests and balances and pumps and electro-magnets and magneto-electric machines; in short, apparatus for doing everything but turn you inside out.
For a moment I thought this a new discovery; but on looking over the literature of the subject, it appeared that Faraday had observed, multiplied, and explained the same effect during his researches on diamagnetism. His explanation was based upon his own great discovery of magneto-electric currents. The effect is a most singular one.
As soon as the magneto-electric machine attained a size in the hands of experimenters that took it out of the field of scientific toys it began to be what we now know as a dynamo. A paragraph in the encyclopedia referred to says, in speaking of Ladd, of London, "These developments of electric action are not obtained without corresponding expenditure of force.
One pole of the magneto-electric machine is connected by means of a rod or wire to the machine frame upon which it is to be used, and the other pole to the electromagnet in the ordinary way of conductivity of current, which means stretching the wire from one to the other.
As is well known, it is electric currents and not sound-waves that are transmitted over a telephone circuit. The magneto-electric telephone in its simplest form consists of a pair of instruments called respectively the transmitter and the receiver. We talk into the transmitter and listen at the receiver.
The discovery in question is certainly fraught with very great consequences to the mechanical world; but in itself it is no discovery of importance, and naturally follows from Faraday's far greater and more original discovery of magneto-electric generation. In 1874, Dr. Siemens published a treatise on the laying and testing of submarine cables.
One of the best known of the modern machines is Edison's, represented in the picture at the head of this article. In it the field magnet answering to the horseshoe magnet of the magneto-electric machine is plainly distinguishable to the unskilled observer. It is not even solid, but is made of several pieces bolted together.
In the "magneto-electric" machine the FIELD MAGNETS are simply steel bars permanently magnetised, but in the ordinary dynamo the field magnets are electro-magnets excited to a high pitch by means of the current generated in the moving conductor or armature. In the "series-wound" machine the whole of the current generated in the armature also goes through the coils of the field magnets.
These considerations relative to the direction and intensity of the magnetic field are of the highest importance for the physical theory of magneto-electric machines. The following is another method of fixing phantoms, as employed by Prof. Bailie, of the Industrial School of Physics and Chemistry of the City of Paris.
And here arises a difference and a change of name. All generating machines to this date had been called "Magneto-electric" because they used permanent steel magnets with which to generate a current by the whirling of the bobbin which we now call an armature. The time came, led to by the improvement of Wilde, in which those steel permanent magnets were no longer used.
Word Of The Day