(iii.) _Prefixes._--Notice especially the force of prepositions and inseparable particles in composition, e.g.:-- +re-+ in +re-iectis+, +re-vellerent+, +restitutum+. +in-+ in +impetus+, +insilirent+. +ex-+ in +exceperunt+, +expeditior+. (iv.) _Simple Phonetic Changes in Composition_, e.g.:-- +a+ to +i+ in +insilirent+, +cominus+ (+con + manus+). (v.) _Groups of Related Words._ Thus +acies+ √+ac+ = _sharp_, is related to +ăc-er+, sharp; +ăc-ervus+, a heap; +ăc-utus+, sharp, &c. +expeditior+ √+ped+ = _tread, go_, is related to +pes+, a foot; +impedio+ = entangle; +impedimentum+ = hindrance, etc. II. _Historical and other Allusions._-- (i.) Read a summary of Caesar’s campaign against Ariovistus. (ii.) _Terms relating to War._--Thus notice:-- +pilum+, the distinctively _Roman_ infantry weapon, and see a good illustration. _phalanx_; cf. the Roman +testudo+. +tertiam aciem+--_i.e._ the line of reserves, kept for just such emergencies. Read, if necessary, some short account of the +triplex acies+, the usual Roman order of battle. III. _Some Authorities._-- (i.) _Caesar_, Allen and Greenough, published by Ginn & Co. (an admirable edition). (ii.) Froude’s _Caesar_, p. 50. (iii.) Mommsen’s _History of Rome_, vol. iv. p. 295. (iv.) Napoleon’s _Caesar_, vol. ii. cap. 4, and vol. ii. p. 405. DEMONSTRATION I. CAESAR, _B. G._ i. 52: ‘_Reiectis pilis ... restitutum est._’ SENTENCE Kind of Sentence CONNECTIVE SUBJECT _Simple_ _Enlarged_ PREDICATE _Simple_ _Enlarged_ OBJECT _Simple_ _Enlarged_ A. Id cum animadvertisset Publius Crassus adulescens, qui equitatui praeerat, quod expeditior rat quam hi ui inter aciem versabantur, tertiam aciem laborantibus nostris subsidio misit. PRINCIPAL (complex) +CRASSUS+ 1. Publius 2. adulescens 3. qui ... praeerat +MISIT+ 1. Id cum ... adulescens (= _when_) 2. quod ... versabantur (= _why_) 3. laborantibus ... subsidio (= _how_) +ACIEM+ tertiam A1. Id cum animadvertisset Publius Crassus adulescens Subordinate _adverbial_ to +MISIT+ in +A+ cum Crassus Publius animadvertisset -- id -- A2. qui equitatui praeerat Subordinate _adjectival_ to +CRASSUS+ in +A+ qui qui (= Crassus) -- praeerat equitatui -- -- A3. quod expeditior erat quam hi qui inter aciem versabantur Subordinate _adverbial_ to +MISIT+ in +A+ quod (Crassus) -- erat expeditior quam ... hi versabantur -- -- DEMONSTRATION II. _The Music of Arion._