280 
PLINY's ISTATURAL HISTORY. 
[Book XXVIII. 
were at war at the time. The prayer used upon the occasion 
of this ceremonial, and which is usually pronounced first by 
the Master of the College of the Quindecimviri,^^ if read by a 
person, must assuredly force him to admit the potency of 
formulae ; when it is recollected that it has been proved to 
be effectual by the experience of eight hundred and thirty 
years. 
At the present day, too, it is a general belief, that our Yestal 
virgins have the power, by uttering a certain prayer, to arrest 
the flight of runaway slaves, and to rivet them to the spot, 
provided they have not gone beyond the precincts of the 
City. If then these opinions be once received as truth, and if it 
be admitted that the gods do listen to certain prayers, or are 
influenced by set forms of words, we are bound to conclude 
in the affirmative upon the whole question. Our ancestors, 
no doubt, always entertained such a belief, and have even 
assured us, a thing by far the most difficult of all, that it is 
possible by such means to bring down lightning from heaven, 
as already^"'' mentioned on a more appropriate occasion. 
CHAP. 4. THAT PEODIGIES AND POETENTS MAY BE CONFIRMEI), OE 
MADE OE IfO EFFECT. 
L. Piso informs us, in the first Book of his Annals, that King 
TuUus Hostilius,^^ while attempting, in accordance with the 
books of Numa, to summon Jupiter from heaven by means of a 
sacrifice similar to that employed by him, was struck by 
lightning in consequence of his omission to follow certain 
forms with due exactness. Many other authors, too, have 
attested, that by the power of words a change has been 
effected in destinies and portents of the greatest importance. 
"While they were digging on the Tarpeian Hill for the founda- 
tions of a temple, a human head was found ; upon which de- 
puties were sent to Olenus Calenus, the most celebrated 
diviner of Etruria. He, foreseeing the glory and success which 
The immolation of the Gauls is supposed to have happened in the beginning 
of the reign of Vespasian. 
26 Originally the " Decemviri Sacris Faciundis," whose number was in- 
creased by Sylla to fifteen. They had the management of the Games of 
Apollo, and the Secular Games. 
27 In B. ii. c. 54. 
25 It has been suggested that Tullus Hostilius was acquainted with some 
of the secrets of electricity, and that he met his death while trying ex- 
periments with a lightning conductor. See B. ii. c. 54, 
