KEY AND INDEX 



Storm Center. An area of low barometric pressure an area 

 where the air has become lighter than the air of surrounding 

 regions. See "The New Science of Meteorology," Vol. Ill, 

 p. 202. 



Submarine Cable. The name given to submerged telegraph 

 wires which are insulated and made waterproof. The first suc- 

 cessful telegraphic cable seems to have been laid across the 

 Hugli River, India, in 1838. See "The Submarine Cable," Vol. 

 VIII, p. 30. 



Submarine Signaling. A recent innovation in the field of nav- 

 igation, by which the position of ships and other objects may 

 be determined approximately by the use of a telephone receiver 

 and the ringing of a submerged bell. See "Submarine Signaling," 

 Vol. VII, p. 83. 



Submarine Vessels. Vessels which run beneath the surface of 

 the water, now very generally referred to as "submersibles." 

 See "Submarine Vessels," Vol. VII, p. 93. 



Suction. The phenomenon produced in any enclosed space in 

 which the air is partially or completely exhausted. The word, 

 as commonly applied, has no proper application, as the apparent 

 "suction" from within is really a manifestation of the air-pressure 

 from without. See "Suction and Pressure," Vol. VI, p. 64. 



Sulphuric Ether. A light, inflammable fluid obtained from 

 alcohol, which, when mixed with air and inhaled, produces in- 

 sensibility. See "Painless Surgery," Vol. IV, p. 208. 



Sun-spots. Changes on the surface of the sun, which were 

 first recognized as such by Galileo, and enabled him to demon- 

 strate that the sun itself revolves on its axis. For the dis- 

 coveries of Galileo, see Vol. II, p. 77. 



Telautograph. An instrument for the instantaneous transmis- 

 sion of a facsimile copy of writing or pen drawing. The ap- 

 paratus was invented by Elisha Gray, who also named it. 



Telegraph. At the present time the name is applied to the 

 instrument for sending messages by means of electric signals. 

 For the description of the development of modern telegraph 

 systems, see "The Development of the Telegraph," Vol. VIII, 



P- 3- 



Telephone. For the story of the development of the tele- 

 phone, and telephone systems, see "The Development of the 

 Telephone," Vol. VIII, p. 66. 



Telescope. An optical instrument by the use of which dis- 



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