BOOK XVII. iii. 30-32
also the vines have begun to be nipped, which did not occur before; while on the other hand the city of Aenos, since the river Maritza was brought near to it, has experienced an increase of warmtha and the district round Philippi altered its climate when its land under cultivation was drained. On the other hand on land belonging to Syracuse a farmer who was a newcomer to the district by removing the stones from the soil caused his crops to be ruined by mud, until he carried the stones back again. In Syria they use a light ploughshare that cuts a narrow furrow, because the subsoil is rock which causes the seeds to be scorched in summer.
Soil and climate.Again, immoderate heat and cold have a similar effect in certain places. Thrace owes its fertility in "* corn to cold, Africa and Egypt to heat. There is one place in the island of Chalcia belonging to Rhodes which is so fertile that they reap barley sown at its proper time and after carrying it at once sow the field again and reap a second crop of barley with the other harvest. In the district of Venafrum a gravel soil is found to be most suitable for olives, but in Baetica a very rich soil. The vines of Pucinumb are scorched on rock, whereas those of Caecubum grow in the damp ground of the Pontine Marshes. So much variety and diversity obtains in the evidence of experience and in soil. Vopiscus Caesar when appearing in a case before the Censors spoke of the plains of Rosia as 'the paps of Italy', where stakes left lying on the ground the day before were hidden with grass; but these plains are only valued for pasture. Nevertheless Nature did not wish that we should be uninstructed, and has caused errors to be fully admitted even where she had not given clear23
