NATURAL PHILOSOPHY. 169 



silk dress, does the same. It is startled by the plashing of a rain- 

 drop. I speak to the flame, repeating a few lines of poetry; the 

 flame jumps at intervals, apparentl}' picking certain sounds from 

 my utterance to which it can respond, while it is tnaffected by 

 others. In our experiments downstairs, we have called this 

 the vowel flame, because the different vowel sounds affect it dif- 

 ferently. I utter the words boot, boat, and beat, in succession. 

 To the first there is no response ; to the second, the flame starts; 

 but by the third it is thrown into violent commotion. The sound 

 'Ah ! ' is still more powerful, the vowel sounds characterized by the 

 sharpest overtones being the most powerful excitants of the flame. 

 If the most distant person in the room were to favor me with a 

 * hiss,' the flame would be instantly shivered into tumult. This 



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hissing sound contains the precise elements that most forcibly af- 

 fect the flame. The gas issues from its burner with a hiss, and an 

 external sound of this character added to that of a gas-jet already 

 on the point of roaring, is equivalent to an augmentation of pres- 

 sure on the issuing stream of gas." 



SUMMARY OF NEW FACTS IN NATURAL PHILOSOPHY. 



Electricity of Combustion. Prof. Faraday has demonstrated that 

 the electricity evolved during the combustion of a few grains of 

 charcoal or a common candle, would, if arranged in a continuous 

 circuit, exceed that of the most powerful batteries. The theory 

 is that the heat generated by combustion is owing to the union of 

 the two electricities. If a key to this source of power could be 

 discovered, a new career, almost, would be opened to science and 

 mechanics. 



The Convertibility of Electricity and Heat. This has been ap- 

 plied by General Morin so as to produce a self-registering elec- 

 trical thermometer. A thermo-electric battery developing 

 electricity by the application of heat is arranged with one ex- 

 tremity of the pile in a medium of uniform and low temperature 

 (ice), and the other in the medium the temperature of which is to 

 be measured. A needle is magnetized by the thermo-electric 

 current produced by this temperature, and its consequent deflec- 

 tion from a certain natural position is registered by punctures 

 made by it in a dial of paper which is caused by clock-work to 

 complete a revolution in 24 hours, and also to rise to meet the 

 puncturing point at equal intervals, hours, half-hours, etc., as 

 may be desired. The punctures made at the several hours will 

 indicate, by their variation from a circle, the changes of tempera- 

 ture throughout the day. 



Telegraphic Mdeoromcters . Prof. Wheatstone has devised a new 

 class of instruments for taking observations in stations which for 

 any cause are not accessible for very long periods. The tele- 

 graphic thermometer, a type of this class, consists essentially of 

 two parts : the first is the" magnetic-motor, constructed on a plan 

 similar to that used by the inventor in his alphabetical magnetic 

 telegraph, and is so arranged that by turning a handle the lever 

 at the other extremity of the line will describe by regular steps a 



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