He taught students to think for themselves and not trust anybody. The Saturday botanical excursions during summer were more popular than his lectures. Linnaeus and students explored the flora and fauna in the vicinity of Uppsala. Additionally, he let some of the best students live with him at his house. Among Linnaeus' notable students, the most promising and committed ones made botanical expeditions to various places in the world, often with the help of their professor. These seventeen adventurers were referred to as Linnaeus' apostles. The amount of this help varied; sometimes he used his influence as Rector to grant his apostles a place on an expedition or a scholarship. Most apostles were given instructions of what to find during their journeys. The apostles collected, organised and classified new plants, animals and minerals according to Linnaeus' classification system. Most gave their collections to Linnaeus when their journey finished. Christopher Tärnström (1703–46) was the first apostle. Linnaeus permitted Tärnström to conduct a botanical expedition in China. In early 1746, Tärnström received free passage on the Swedish East India Company ship "Calmar" to China. He took a list, written by Linnaeus, of things to collect which included plants, animals and insects. However, "Calmar" stopped sailing beyond Côn Sơn Island (off the modern-day Vietnamese coast) because it had been forced to find a winter berth. On 4 December 1746, Tärnström died of a tropical fever without a botanical or zoological specimen having been sent to Sweden. His widow blamed Linnaeus for making her children fatherless. Following the death of Tärnström, Linnaeus allowed only unmarried men to become his apostles. Pehr Kalm (1715–79) was born in Sweden to Finnish parents and became a student of Linnaeus in December 1740. He proposed to Linnaeus that he travel to North America on a botanical expedition. Linnaeus concurred and in November 1747 Kalm began his journey to North America sponsored by the universities in Uppsala and Åbo. After a long stay in England, on the way he reached Philadelphia in autumn 1748. Once there, he stayed in North America for two and a half years, visiting the states of Pennsylvania, New Jersey, New York and southern Canada. He then returned to Sweden. Kalm is one of the few apostles who actually lived up to Linnaeus' hopes; bringing with him a large collection of pressed plants and seeds.