Wherever the ships sent by Darius may have gone it is quite clear that they did not sail _up_ the Indus, or there would have been no objective for an expedition which was organised to determine where the Indus met the sea by the process of sailing down that river. Moreover, the voyage up the Indus would have been tedious and slow, and could only have been undertaken in the cold weather with the assistance of native pilots acquainted with the ever-shifting bed of the river, which, so far as its liability to change of channel is concerned, must have been much the same in the days of Darius as it is at present. The possibility, therefore, is that Scylax made his way to the Upper Indus overland, for we are told that the expedition _started_ from the city of Carpatyra in the Pactyan country. This in itself is exceedingly instructive, indicating that the Pactyans, or Pathans, or Pukhtu speaking peoples have occupied the districts of the Upper Indus for four-and-twenty centuries at least; and coincident with them we learn that the Aprytæ or Afridi shared the honour of being resident landowners. Nor need we suppose that the beginning of this history was the beginning of their existence. The Afridi may have rejoiced in his native hills ten or twenty centuries before he was written about by Herodotus. We need not stay to identify the site of Carpatyra. The Upper Indus valley is full of ancient sites. A century and a half later Taxilla was the recognized capital of the Upper Punjab, and Carpatyra meanwhile may have disappeared. Anyhow we hear of Carpatyra no more, nor has the ingenuity of modern research thrown any certain light on its position. It is, however, probably near Attok that we must look for it. Scylax made his way down the Indus in native craft that from long before his day to the present have retained their primitive form, a form which was not unlike that of the coast crawling "ships" of Darius. He proved the existence of an open water-way from the Upper Punjab to the Persian Gulf, and incidentally his expedition shows us that the chief lines of communication through the width of the Persian Empire were well known, and that the road from Susa to the Upper Indus was open. The outlying satrapies of the Persian Empire could never have been added one by one to that mighty power without definite knowledge of the way to reach them. It was not merely a spasmodic expedition, such as that of Scylax, which pointed the way to the conquests of the Far East; it was the gathered information of years of experience, and it was on the basis of this experience (unwritten and unrecorded so far as we know) that Alexander founded his plans of campaign.