rds the end
of Nero's reign, when purely technical subjects alone could be treated
without danger to an author. Cf. _N.H._ praef. 28, 'libellos quos de
grammatica edidi.'

6. _A fine Aufidii Bassi_, in thirty-one Books. At what point Bassus'
history ended and Pliny's began is not known: but the latter certainly
dealt with the closing years of Nero's reign (_N.H._ ii. 199, 'anno
Neronis principis supremo, sicut in rebus eius exposuimus'), as well
as with the times of Vespasian and Titus (_N.H._ praef. 20, 'Vos
omnes, patrem te fratremque diximus opere iusto, temporum nostrorum
historiam orsi a fine Aufidii Bassi'). The work was completed in A.D.
77, but not published till after the author's death. His nephew says
he wrote with scrupulous care: _Ep._ v. 8, 5, 'historias et quidem
religiosissime scripsit.' The book was used by Tacitus (_Ann._ xiii.
20; xv. 53; _Hist._ iii. 28).

7. _Naturae Historiae_, in thirty-seven Books, is Pliny's only extant
work. As he speaks of Titus as 'sexies consul,' the date of its
presentation to him was A.D. 77. Book i. consists of a dedicatory
epistle to Titus and a table of contents. The body of the work is
arranged as follows: Book ii., the universe and the elements;
iii.-vi., geography of Europe, Asia, and Africa; vii., anthropology
and human physiology; viii.-xi., zoology; xii.-xix., botany;
xx.-xxvii., the use of vegetable substances in medicine;
xxviii.-xxxii., the use of animal substances in medicine;
xxxiii.-xxxvii., mineralogy applied to medicine and the fine arts.

This work, which was meant not for continuous perusal, but for
consultation as a book of reference, contained twenty thousand facts;
and its preparation involved the reading of about two thousand volumes
by one hundred authors (see _N.H._ praef. 17). The extracts he had
made from these sources Pliny bequeathed to his nephew in one hundred
and sixty volumes. He makes a point of acknowledging his obligations
to other writers (praef. 21, 'in his voluminibus auctorum nomina
praetexui, est enim benignum ... et plenum ingenui pudoris fateri per
quos profeceris'); cf. the lists of authorities, Roman and foreign,
prefixed to the work. Such devotion to natural science was unusual in
men of Pliny's class, and not generally appreciated; cf. xxii. 15,
'Plerisque ultro etiam irrisui sumus ista commentantes atque frivoli
operis arguimur.' As a scientific writer Pliny fails because he is not
an original investigator, and because he