any time that it suited his convenience or seemed good to his caprice; so opening without any risk a new world to his ambition.  It required a knowledge that the causes of military success and political advance lie deeper than statistics can reach—­that they have their roots in the moral nature of man, in the grandeur of his ideas and the energy of his character—­in order to comprehend the fact, that the puny power upon her right flank was the enemy which Persia had most to fear, the foe who would gradually sap her strength, and finally deal her the blow that would lay her prostrate.

CHAPTER II.  CLIMATE AND PRODUCTIONS.

It is evident that an Empire which extended over more than twenty degrees of latitude, touching on the one hand the tropic of Cancer, while it reached upon the other to the parallel of Astrakan, and which at the same time varied in elevation, from 20,000 feet above to 1300 below the sea level, must have comprised within it great differences of climate, and have boasted an immense variety of productions.  No general description can be applicable to such a stretch of territory; and it will therefore be necessary to speak of the various parts of the Empire successively in order to convey to the reader a true idea of the climatic influences to which it was subject, and the animals, vegetables, and minerals which it produced.

Commencing with Persia Proper, the original seat and home of the race with whose history we are specially concerned at present, we may observe that it was regarded by the ancients as possessing three distinct climates—­one along the shore, dry and scorchingly hot; another in the mountain region beyond, temperate and delightful; and a third in the tract further inland, which was thought to be disagreeably cold and wintry.  Moderns, on the contrary, find two climates only in Fars—­one that of the Desbistan or “low country,” extremely hot and dry, with frequent scorching and oppressive winds from the south and the south-east; the other, that of the highlands, which is cold in winter, but in summer pleasant and enjoyable.  In the Deshistan snow never falls, and there is but little rain; heavy dews, however, occur at night, so that the mornings are often fresh and cool; but the middle of the day is almost always hot, and from March to November the temperature at noon ranges from 90 deg. to 100 deg. of Fahrenheit.  Occasionally it reaches 125 deg., and is then fearfully oppressive.  Fierce gusts laden with sand sweep over the plain, causing vegetation to droop or disappear, and the animal world to hide itself.  Man with difficulty retains life at these trying times, feeling a languor and a depression of spirits which are barely supportable.10 All who can do so quit the plains and betake themselves to the upland region till the great heats are past, and the advance of autumn brings at any rate cool nights and mornings.  The climate of the uplands