In this paper we present several measures taken in Lisbon to prevent contagion by the plague, from the ships that arrived at its port. Some of the legislation that was enacted from the 15th century onwards will be analysed, especially to control, from the health point of view, the arriving travellers and to ensure the isolation of those who were a potential threat. Special attention will be paid to two regiments written at the end of the Sixties, regulating, in a detailed way, how to carry out such control.

In the first aerial crossing of the South Atlantic, by Gago Coutinho and Sacadura Cabral in 1922, several methods of astronomical maritime navigation were used with adaptions to aerial navigation. In order to apply these methods, the navigator needed to know the approximate altitude of the aircraft so that its position could be determined. The instrument available at that time, the altimeter, did not give reliable values for altitude. Therefore, Coutinho had to devise a method that enabled the navigator to determine the altitude quickly and efficiently. The method Coutinho devised is based on a mathematical and geometrical procedure. In this paper, we study in detail Coutinho's method to determine altitude, with diagrams to aid understanding of the deductions and calculations. We also present a real example of how this method would be used during the flight.

Ao longo da história da humanidade podem identificar-se diversos elementos que se mantiveram constantes durante milénios. Um deles é certamente a necessidade permanente que os povos sentem de levar a cabo ações de expansão e conquista territorial. Foi assim com os grandes impérios da Antiguidade clássica, como o foi depois com os povos bárbaros que invadiram o último desses grandes impérios, o romano. No século xv iniciou-se um processo de expansão diferente dos anteriores pelo facto de se basear essencialmente na realização de longas viagens oceânicas. Diversos povos europeus, nomeadamente franceses, ingleses e holandeses, participaram neste processo de expansão, mas a dianteira foi assumida pelos reinos ibéricos e, entre estes, destacou-se Portugal.