The De divinatione is the last work Cicero has written and is about the value of divination. The work is set as a dialogue between Cicero and his brother Quintus: Quintus is defending divination but Cicero is rather sceptical, not to say outright denying, though he held the position of augur himself. An augur was supposed to tell the future and the will of the gods by studying the flight of birds. Augurs held an official position and were consulted before taking action, but in due course it was more an honorary position and so Cicero was made an augur. Seeing the fraudulent tricks his fellow augurs made for getting the desired outcome, Cicero was quite dismayed, though he held it for possible that augurs in former times were better.
The work is divided in two parts: in book 1 Quintus is mainly speaking in defence of divination and in book 2 Cicero is refuting it. It contains a wealth of information about religious practises and examples of divination. The following story is told by Quintus and is about Attus Navius, a famous augur under king Tarquinus. According to another story Attus Navius was put to death by Tarquinus because his divinations did not fit into the plans of the king. ..
Cicero, De Divinatione, 31 32
31 Quid? Multis annis post Romulum, Prisco regnante Tarquinio, quis veterum scriptorum non loquitur, quae sit ab Atto Navio per lituum regionum facta discriptio? Qui cum propter paupertatem sues puer pasceret, una ex iis amissa, vovisse dicitur, si recuperasset, uvam se deo daturum, quae maxima esset in vinea; itaque, sue inventa, ad meridiem spectans in vinea media dicitur constitisse, cumque in quattuor partis vineam divisisset trisque partis aves abdixissent, quarta parte, quae erat reliqua, in regiones distributa, mirabili magnitudine uvam, ut scriptum videmus, invenit. Qua re celebrata, cum vicini omnes ad eum de rebus suis referrent, erat in magno nomine et gloria. 32 Ex quo factum est, ut eum ad se rex Priscus arcesseret. Cuius cum temptaret scientiam auguratus, dixit ei cogitare se quiddam; id possetne fieri, consuluit. Ille augurio acto posse respondit. Tarquinius autem dixit se cogitasse cotem novacula posse praecidi; tum Attum iussisse experiri. Ita cotem in comitium allatam inspectante et rege et populo novacula esse discissam. Ex eo evenit ut et Tarquinius augure Atto Navio uteretur et populus de suis rebus ad eum referret.
Quid?: serves to introduce a new exemple `here another one.'
quis veterum scriptorum: As many Roman sources are lost, Cicero’s account in c. 31 is the only one known.
multis annis: ablativus mensurae `many years later’.
Lucius Tarquinius Priscus: 5th king of Rome (ca. 616 - ca. 578 BC.)
discriptio – onis (f.): division
regionum discriptio: a division the heaven (into quarters)
sus, suis (m. and f.): swine, sow (but here f., as una amissa (one having slipped away) shows.)
puer: predicate `as a boy’
pasco pavi pastum: to feed, herd
voveo vovi votum: to vow
recupero: to get again
uva: bunch of grapes
ad meridiem spectans in vinea media dicitur constitisse: he is said to have stood in the middle of the vineyard facing to the South. (This was in order to watch the flight of birds and to conclude from their flight in which part of the vineyard he could find the biggest bunch of grapes.)
abdico abdixi abdictum: to forbid by an unfavourable omen, reject
quarta parte in regiones distributa: he divided the forth part in parts in order to search systematically
mirabili magnitudine: ablative of description
Qua re celebrate: when this became known (mind that celebro does not always mean `to celebrate’.)
ad eum de rebus suis referrent: came to him with their affairs
Ex quo factum est: and from that it happened
arcesso arcessivi arcessitum: to invite
Cuius cum temptaret scientiam auguratus, dixit ei cogitare se quiddam; id possetne fieri, consuluit.: When he tested the knowledge of him about augurship (auguratus –us m.), he said to him that he thought of something; he asked, if it would be possible to happen.
augurium: the observance of omens
cos cotis (f): grindstone
praecido praecidi praecisum: to cut through
experior expertus sum: to try, test
affero attuli allatum: to bring to
utor usus sum (+ abl.): to use
Translation by William Armistead Falconer (1923):
 What ancient chronicler fails to mention the fact that in the reign of Tarquinius Priscus, long after the time of Romulus, a quartering of the heavens was made with this staff by Attus Navius? Because of poverty Attus was a swineherd in his youth. As the story goes, he, having lost one of his hogs, made a vow that if he recovered it he would make an offering to the god [p. 261] of the largest bunch of grapes in his vineyard Accordingly, after he had found the hog, he took his stand, we are told, in the middle of the vineyard, with his face to the south and divided the vineyard into four parts. When the birds had shown three of these parts to be unfavourable, he subdivided the fourth and last part and then found, as we see it recorded, a bunch of grapes of marvellous size.
"This occurrence having been noised abroad, all his neighbours began to consult him about their own affairs and thus greatly enhanced his name and fame.  The consequence was that King Priscus summoned him to his presence. The king, wishing to make trial of his skill as an augur, said to him: 'I am thinking of something; tell me whether it can be done or not.' Attus, having taken the auspices, replied that it could be done. Thereupon Tarquin said that what he had been thinking of was the possibility of cutting a whetstone in two with a razor, and ordered the trial to be made. So the stone was brought into the comitium, and, while the king and his people looked on, it was cut in two with a razor. The result was that Tarquin employed him as his augur, and the people consulted him about their private concerns.