CONTENTS. Xlll 



PAGE 



Explanation of these singular effects Acoustic automaton 

 Droz's bleating sheep Maillardet's singing bird 

 Vaucauson's flute-player His pipe and tabor player 

 Baron Kempelen's talking engine Kratzenstein's speak- 

 ing machine Mr. Willis's researches .... 244 



LETTER IX. 



Singular effects in nature depending on sound Permanent 

 character of speech Influence of great elevations on the 

 character of sounds, and on the powers of speech Power 

 of sound in throwing down buildings Dog killed by 

 sound Sounds greatly changed under particular circum- 

 stances Great audibility of sounds during the night ex- 

 plained Sounds deadened in media of different densities 

 Illustrated in the case of a glass of champagne, and in 

 that of new-fallen snow Eemarkable echoes Eeverbera- 

 tions of thunder Subterranean noises Eemarkable one 

 at the Solfaterra Echo at the Menai Suspension Bridge 

 Temporary deafness produced in diving-bells Inaudibility 

 of particular sounds to particular ears Vocal powers of 

 the statue of Memnon Sounds in granite rocks Musical 

 mountain of El-Nakous ...... 272 



LETTEE X. 



Mechanical inventions of the ancients few in number Ancient 

 and modern feats of strength Feats of Eckeberg particu- 

 larly described General explanation of them Eeal feats 

 of strength performed by Thomas Topham Eemarkable 

 power of lifting heavy persons when the lungs are inflated 

 Belzoui's feat of sustaining pyramids of men Deception 

 of walking along the ceiling in an inverted position 

 Pneumatic apparatus in the foot of the house-fly for 

 enabling it to walk in opposition to gravity Description of 

 the analogous apparatus employed by the gecko lizard for 

 the same purpose Apparatus used by the Echineis remora 

 or sucking fish . . .' . . \ V . 300 



LETTEE XI. 



Mechanical automata of the ancients Moving tripods Auto- 

 mata of Dsedalus Wooden pigeon of Archytus Auto- 

 matic clock of Charlemagne Automata made by Turrianus 



