506 



SCIENCES AND SOCIAL AETS. 



[Part IV. 



Ceylon, tlie minute subdivision of whose lands under 

 tlieir system of irrigation necessitated frequent calcula- 

 tions for the definition of Hniits and the division of the 

 crops. ^ 



Lightning Conductors. — In connection with physical 

 science, a curious passage occurs m the Mahawanso wliich 

 gives rise to a conjecture that early in the third century 

 after Christ, the Singhalese had some dim idea of the 

 electrical nature of hghtning, and a behef, however erro- 

 neous, of the possibility of protecting their buildings by 

 means of conductors. 



The notices contained m Tiieophrastus and Pliny 

 show that the Greeks and the Eomans were aware of the 

 quahty of attraction exhibited by amber and tom^mahne.^ 

 The Etruscans, according to the early annahsts of 

 Eome, possessed the power of invoking and compelhng 

 thunder storms.^ Numa Pompilius would appear to 

 have anticipated Frankhn by drawing lightning from 

 the clouds ; and TuUus Hostihus, his successor, was kiUed 

 by an explosion, whilst attempting unskilfully the same 

 experiment.* 



Ctesias, a contemporary of Xenophon, spent much 

 of his hfe in Persia, and says that he twice saw the 

 king demonstrate the efficacy of an iron sword planted 

 in the ground in dispersing clouds, hail, and lightning ^ ; 



^ The " Suriija Sidhanta,'^ gene- 

 rally assigned to the fifth or sixth 

 century, contains a system of Hindu 

 trigonometry, which not only goes 

 beyond anything known to the 

 Greeks, but involves theorems that 

 were not discovered in Europe till 

 the sixteenth century. — MouNT- 

 STUART Elphinstone's India, b. iii. 

 ch. i. p. 129. 



2 The electrical substances " lyn- 

 curium " and " theamedes " have each 

 been conjectm-ed to be the " tourma- 

 line" which is found in Ceylon. 



3 " Vel cogi fidmina vel impetrari." 

 — Pliny, Nat. Hid. lib. ii. ch. Iii. 



* Ibid. There is an interesting 



paper on the subject of the knowledge 

 of electricity possessed by the an- 

 cients, by "^Dr. Falconer in the 

 Ilemoirs of the 31anchester Philo- 

 sophical Societij, A.D. 1788, vol. iii. 

 p. 279. 



^ Photitjs, who has preserved the 

 fi-agment (Bibl. Ixxii.), after quoting 

 the story of Ctesias as to the iron in 

 question being foimd in a mysterious 

 Indian lake, adds, regarding the 

 sword, " (jirjai St irtpi avrov on Trrjyvv- 

 fjLEVog tv Ty yri VEcpovi; Kal x(^^<^Z>IC f«i 

 ■Kpu(TTijp(»v tariv airoTpuTzaioQ. K«i 

 iStlv avTov Tavra (fiiiffi (ia<Ji\i(i}Q Sig 

 7roi»;(T«vroc." See Baehr's CtesicB 

 Eeliqui(s,'&c.,^. 248,271. 



