506 



SCIENCES AND SOCIAL AKTS. 



[PART IV. 



Ceylon, the minute subdivision of whose lands under 

 their system of irrigation necessitated frequent calcula- 

 tions for the definition of limits and the division of the 

 crops. 1 



Lightning Conductors. In connection with physical 

 science, a curious passage occurs in the Mahawanso which 

 gives rise to a conjecture that early in the third century 

 after Christ, the Singhalese had some dim idea of the 

 electrical nature of lightning, and a belief, however erro- 

 neous, of the possibility of protecting their buildings by 

 means of conductors. 



The notices contained in THEOPHEASTUS and PLINY 

 show that the Greeks and the Eomans were aware of the 

 quality of attraction exhibited by amber and tourmaline. 2 

 The Etruscans, according to the early annalists of 

 Eome, possessed the power of invoking and compelling 

 thunder storms. 3 Numa Pompihus would appear to 

 have anticipated Franklin by drawing lightning from 

 the clouds ; and Tullus Hostilius, his successor, was killed 

 by an explosion, whilst unskilfully attempting the same 

 experiment. 4 



CTESIAS, a contemporary of Xenophon, spent much 

 of his life 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 5 ; 



1 The " Suriya 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. MOTJNT- 

 SXTJART ELPHINSTONE'S India, b. iii. 

 ch. i. p. 129. 



2 _The electrical substances "lyn- 

 curium " and " theamedes " have each 

 been conjectured to be the "tourma- 

 line" which is found in Ceylon. 



3 " Vel cogi fulmina vel impetrari." 

 PLINY, Nat. Hist. lib. ii. ch. Iii. 



4 Ibid. There is an interesting 



paper on the subject of the knowledge 

 of electricity possessed by the an- 

 cients, by Dr. FALCONER in the 

 Memoirs of the Manchester Philo- 

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

 p. 279. 



5 PHOTITTS, who has preserved the 

 fragment (ibl. Ixxii.), after quoting 

 the story of CXESIAS as to the iron in 

 question being found in a mysterious 

 Indian lake, adds, regarding the 

 SWOrd, " (fiijffl St irtfjl O.VTOV art Trriyvv- 

 pivng iv ry yrj t'tfyovG Kai ^aXd^r/f Kid 

 TrpriffTijpwv iffriv cnroTpoiraioQ. Kl 

 IStlv avTOV ravra (jirirrl Paai\ew< dig 

 Troir'iffavTOC." See BAEITR' 



Reliquia; "&c., p. 248,271. 



