The Naturales Quaestiones ( Natural Questions ) is a work of natural philosophy that was written by Seneca starting in 62 AD after his retirement to private life . This work is addressed to Lucilius and is composed of 7 books that treat astronomic , geographical , and meteorological problems. In particular: Book I METEORS, HALO, RAINBOW, MOCK SUN - Book II THE NATURE OF AIR. THUNDER AND LIGHTNING - Book III THE DIFFERENT FORMS OF WATER - Book IV SNOW, HAIL, AND RAIN, THE NILE - Book V WINDS AND ATMOSPHERIC MOVEMENT IN GENERAL - Book VI EARTHQUAKES - Book VII COMETS The hypothesis that are made by the philosopher are curious and they show us the difficulties of the ancients in understanding and analyzing natural phenomena. The purpose of this work is non-scientific but is to reassure man by freeing him from ignorance of natural phenomena so that he may understand the wonderful rationality of the universe .