The Telephone: An Account of the Phenomena of Electricity, Magnetism, and Sound, as Involved in Its Action. With Directions for Making a Speaking TelephoneLee & Shepard, 1877 - 128 páginas |
Outras edições - Ver tudo
The Telephone: An Account of the Phenomena of Electricity, Magnetism, and ... Amos Emerson Dolbear Visualização integral - 1877 |
The Telephone: An Account of the Phenomena of Electricity, Magnetism, and ... Amos Emerson Dolbear Visualização integral - 1905 |
The Telephone: An Account of the Phenomena of Electricity, Magnetism, and ... Amos Emerson Dolbear Visualização integral - 1878 |
Palavras e frases frequentes
acid armature battery bobbins body brane circuit coil of wire condensation connected copper Cremona current of electricity Daniell Cell difference effect elec electric current electrified electro-magnet experiments feet fluid fork form of motion front galvanometer Grove cells hear heard heat helix Helmholtz Hence high sounds hole hundred inches in diameter inches long induced induction coil inductive action invented kind length Leyden jar light mechanical membrane metals molecular molecules move musical instruments musical sound nail needle nitric acid number of cells number of vibrations octave opposite direction ordinary organ-pipe overtones passing permanent magnet piece of iron pitch plate platinum polarity pole produce Prof prongs rarefaction re-enforce receiving instrument red end reeds reproduced respond secondary coil soft iron sound-waves speaking-telephone spectrum string struck supposed surface sympathetic vibrations telegraph telephone thermo-pile tion tone tricity tube tuning-fork velocity vibrations per second violin wave wave-length zinc
Passagens conhecidas
Página 3 - The Telephone. An Account of the Phenomena of Electricity, Magnetism, and Sound, as Involved in its Action ; with Directions for Making a Speaking Telephone. By Prof. AE DOLBEAR, Author of "The Art of Projecting, &c.
Página 74 - ... mechanical disturbances, harmless in their origin, assume a troublesome and perhaps a dangerous character, when they enter bodies all too ready to move at the required rate, and sometimes beyond the sphere of their stability. When the bridge at Colebrooke Dale (the first iron bridge in the world) was building, a fiddler came along and said to the workmen that he could fiddle their bridge down. The builders thought this boast a fiddle-de-dee, and invited the itinerant musician to fiddle away to...
Página 99 - If the rod be of considerable size, say a foot or more in length, and half an inch or more in diameter, and the current be strong enough to make a powerful magnet of it, whenever the current from the battery is broken, the bar may be heard to give out a single click. This will happen as often as the current is broken. This is occasioned by a molecular movement which results in a change of length of the bar. When it is made a magnet, it elongates about 35^55 of its length ; and, when it loses its...
Página 60 - I strike my pencil upon the table, I hear a snap that appears to the ear to be simultaneous with the stroke : if, however, I see a man upon a somewhat distant hill strike a tree with an axe, the sound does not reach me until some appreciable time has passed ; and it is noted, that, the farther away the place where a so-called sound originates, the longer time does it take to reach any listener. Hence sound has in air a certain velocity which has been very accurately measured, and found to be 1,093...
Página 115 - This, the greatest by far of all the marvels of the electric telegraph, is due to a young countryman of our own, Mr. Graham Bell, of Edinburgh and Montreal and Boston, now becoming a naturalized citizen of the United States.
Página 12 - In particular, it received the distinguished honour of being crowned by the Institute of France, although that country and England were then engaged in fierce hostility. Buonaparte had proposed a prize of sixty thousand francs " to the person who by his experiments and discoveries should advance the knowledge of electricity and galvanism, as much as Franklin and Volta did...
Página 127 - ... years to be invented. The reason is probably this : Men of science, as a rule, do not feel called upon to apply the principles which they may discover. They are content to be discovering^ not inventing. Now, the schools of the country ought to make the youth quite familiar with the general principles of physical science, that the inventive ones — and there are many such — may apply them intelligently. Mechanism is all that stands between us and aerial navigation • all that is necessary...
Página 21 - ... acid. Now, it happens under such circumstances as the above, that the liberated hydrogen adheres very strongly to the platinum, as there is nothing for it to unite with chemically ; and therefore the plate will very soon be visibly covered with bubbles, which may be scraped off with a feather or a swab, but only to have the same thing repeated. This coating of bubbles will prevent the acid from touching the plate, and so practically diminishes the surface of it ; but the quantity of electricity...
Página 12 - THE impulse which the discovery of galvanism, in 1791, and of the voltaic pile, in 1800, had given to the study of electricity as a mechanical science, had nearly died away in 1820. It was in that year that M. Oersted, of Copenhagen, announced that the conducting wire of a voltaic circuit acts upon a magnetic needle...
Página 62 - ... same time. Let us try to picture to ourselves the physical condition of the air in front of one of these prongs. As the latter strikes outward, the air in front of it will be driven outward, condensed, and, on account of the elasticity of the air, the condensation will at once start to travel outward in every direction, a wave of denser air; but directly the prong recedes, beating the air back in the contrary direction, it will, of course, rarefy the air in front of the prong. But the disturbance...