Exhibition ..., Volumes 12-13

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After 215 pp of the 12th exibition, we find the 13th exhibition 1878.

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Page 170 - Mr. Bell perceived that he must produce a variation of strength of current in the telegraph wire as nearly as may be in exact proportion to the velocity of a particle of air moved by the sound ; and he invented a method of doing so — a piece of iron attached to a membrane, and thus moved to and fro in the neighbourhood of an electro-magnet, which has proved perfectly successful.
Page 23 - ... one of the most important as well as one of the most legitimate sources of his power.
Page 106 - One piston acts to give steam to the other, after which it finishes its own stroke and waits for its valve to be acted upon before it can renew its motion. This pause allows all the water valves to seat quietly, and removes everything like harshness of motion.
Page 170 - In addition to his electro-phonetic multiple telegraph, Mr. Graham Bell exhibits apparatus by which he has achieved a result of transcendent scientific interest, — the transmission of spoken words by electric currents through a telegraph wire. To obtain this result, or even to make a first step towards it,— the transmission of different qualities of sound, such as the vowel sounds, — Mr. Bell perceived that he must produce a variation of strength of current in the telegraph wire as nearly as...
Page xx - ... commendation. Let me follow the silent monition, sustained, perhaps, by the impatience of the audience, and hasten to the last topic of my address. The object of our present exhibition is not mere show, however innocent and gratifying. It is to make the community better acquainted with the state of the arts, by a public display of their products ; to excite a generous emulation, by their comparison : and thus to lead on our ingenious artificers, improvers, and inventors, to higher degrees of...
Page 29 - The change of seasons is caused by the annual revolution of the earth around the sun with its axis inclined to the plane of its orbit at an angle of 23J degrees in 28 minutes.
Page x - Proprietors, that this arrangement affords an invaluable opportunity for displaying the advantages and capabilities of their various machines, in competition with others, under one view ; so that there can be no question as to their relative merits.
Page 106 - As one or the other of the steam-valves must always be open, there can be no dead point. The pump is therefore always ready to start when steam is admitted, and is managed by the simple opening and shutting of the throttle-valve.
Page 168 - The ltght moves towards the opposite end from which it starts, then changes and goes back, always moving towards the place where the carbons are nearest together. If from any cause the light goes out the circuit is broken, and the electric magnet ceases to act. Instantly the upper magnet falls, the circuit is closed, it relights, and separates the carbon again.
Page 145 - The particular points for which the committee claim the superiority of the Gatling gun over the Montigny are as follows : 1st. Greater destructive effect, owing to the rapidity with which it can be fired. 2d. Greater command of range ; the Montigny system being necessarily restricted to small calibres, whereas the Gatling is equally adapted to large as to small calibres. 3d. The Gatling gun, so far as the experience of the committee goes, is capable of being worked by fewer men than the Montigny....

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