This abundance of streams in India the Greeks explained by the fact that the lands which surrounded the country--Ariana, as the Greeks call eastern Iran, Bactria, and the land of the Scythians--were higher than India, so that the waters from them flowed down, and were collected there.[35] The water was also the cause of the great fertility of India, which the Greeks unite in extolling. The rivers not only brought down, as Nearchus observes, soft and good earth into the land from the hills,[36] but they traversed it in such a manner that, from the universal irrigation, it was turned into a fruit garden.[37] Onesicritus tells us that India is better irrigated by its rivers than Egypt by its canals. The Nile flows straight on through a long and narrow land, and so is continually passing into a different climate and different air, while the Indian rivers flow through much larger and broader plains, and continue long in the same region. Hence they are more nourishing than the Nile, and the fish are larger than the fish in the Nile;[38] they also refresh the land better by their moist exhalations.[39] Besides, there were the inundations caused by the rivers; and the land was also watered by the heavy rains, which fell constantly each year at a fixed period with the regular winds, so that the rivers rose fully 20 cubits above their beds,--a statement quite accurate,--and in many places the plains were changed into marshes,[40] in consequence of which the Indus had sometimes taken a new channel through them.[41] Since, then, the warmth of the sun was the same in India as in Arabia and Ethiopia,--for India lay far to the south, and in the most southern parts of the land the constellation of the Bear was seen no longer, and the shadows fell in the other direction, i.e. to the south,--[42]while in India there was more water and a moister atmosphere than in those other countries, the creatures of the water, air, and land were much larger and stronger in India than anywhere else.[43] Further, as the water in the river and that which fell from heaven was tempered by the sun's heat, the growth of the roots and plants was extraordinarily vigorous. The strength of the tiger, which, according to Megasthenes, is twice the size of the lion, the docility of the elephant, the splendour of the birds, were the admiration of the Greeks. With horror they saw the whale for the first time in the Indian waters. Nearchus caused his ship to be rowed forward at double speed to contend with this peaceful monster of the deep.