Rubuta ci gaba don wannan sakin layi - Koyo game da quinine a London, Castro Sarmento ya kirkiro wani magani da aka sani da Água de Inglaterra, wanda ya zama sananne a Fotigal inda zazzabin cizon sauro ya yadu a kudancin kasar. A shekara ta 1731 ya tsara wani shiri na lambun tsirrai a Coimbra. Castro Sarmento ya yi rubutu tare da masana da yawa, a tsakanin wasu tare da Farfesa João Mendes Sachetti Barbosa na Lisbon, wanda ya ba shi rahoton girgizar ƙasa mai ban tsoro
wanda ya hallaka babban birnin kasar Portugal a 1755, da kuma Jesuit B. Soares, wanda ya sanar da shi abubuwan da ya gani a cikin mulkin mallaka na Portugal na Brazil. Ya kasance mai goyon bayan Newtonianism kuma ya yi ƙoƙari ya haɗa shi da ilimin tauhidi na Yahudawa. Ya wallafa "Theorica verdadeira das marés, conforme à philosophia do incomparable cavalhero Isaac Newton" (Treatise on the true theory of tides, according to the philosophy of the incomparable gentleman Isaac Newton), littafi na farko a cikin Fotigal don ba da shawara ga ra'ayoyin Newton (London, 1737).