Of Pedro Vazquez, who succeeded Barrionuevo as governor of Castilla del Oro, little is known; but of Doctor Robles, the successor of Vazquez, under whose administration the government was continued till 1546, it is alleged, and probably with truth, that he wrought more harm to his fellow-man in a twelvemonth than the malign genius of a Pedrarias even could accomplish in a decade. In his greed for wealth he was rivalled only by the all-grasping Pedro de Los Rios, and in the astute cunning with which he cloaked his evil deeds he was without peer even in a community where the prevailing code of morals taught neither fear of God nor regard for man. Appointed oidor of the audiencia of Panamá, in 1538, he held office for several years, and the abolition of that tribunal was probably due in a measure to his malefeasance. There are no explicit details as to the precise charges which were brought against Robles, but we learn that in every instance he contrived to baffle the scrutiny of his judges. The licentiate Vaca de Castro was first ordered to bring the offender to justice, but called in vain on his fellow-oidores of the audiencia of Panamá to aid him in so doing. On the establishment of the audiencia of the Confines, the trial was yet unfinished, and as the aggrieved parties still clamored that it be brought to a conclusion, Ramirez, one of the oidores, and the first alcalde mayor of Panamá, was ordered to take his residencia. Robles appears to have escaped punishment, for he soon afterward figures as senior oidor of the audiencia of Lima. He returned before long to Panamá, and we learn that on the capture of that city in 1550, by Hernando and Pedro de Contreras, some of Gasca's treasure was captured at the house of Robles, who thenceforth disappears from the page of history.[XV‑1] * * * * * [Sidenote: ISTHMUS HIGHWAY.] When Pedro de los Rios set out for Nicaragua he left orders with Captain Hernando de la Serna and the pilot Corzo to make a survey of the Rio de los Lagartos, now known as the river Chagre, for the purpose of facilitating communication between the two seas. They were directed also to examine the river Panamá, flowing in the opposite direction, and to explore the country between the highest navigable points on the two streams. This was done with a view of discovering the best route for a grand thoroughfare across the Isthmus, over which the tide of commerce might flow between Spain and the Spice Islands; and although this object was never realized, the discovery which reduced land carriage to a distance of nine leagues proved most useful in the subsequent intercourse of Spain and Peru.