[3] Douglass prospered in Boston, and put his money into property, both in the city and in remote parts of the Massachusetts Bay colony.
[7][8][9] He knew five languages, accumulated a collection of 1,100 American plants, observed the weather, and studied magnetic deviation and astronomy.
He claimed that his fellow physicians were a major cause of death for their patients, and that they too often relied on a single treatment, such as bloodletting or emetics, for all conditions.
[22][23] By the next year, however, Douglass admitted that the inoculations were safer and more effective than he had believed they would be in 1721, and he eventually performed them himself, although he remained on bad terms with Mather.
[2][5] His Summary of ... the British Settlements in North America attracted favorable notice from Adam Smith, who cited the work in The Wealth of Nations, and called Douglass "honest and downright.
"[2][30] Douglass also wrote about wampum, the Bank of Amsterdam, the ideas of John Law, the South Sea Bubble, taxation, and "political arithmetic.
Douglass held that the expedition had been poorly planned and inadequately manned for an attack on the powerful fortress at Louisbourg, and had succeeded only by a string of lucky turns of events.
Bullock, however, notes that historians largely agree with Douglass's assessment of the inadequacy of the preparations for the expedition against Louisbourg, and the role played by luck in it.
[34][35] In 1747 Royal Navy Captain Charles Knowles, who had served as governor of Louisbourg after its capture, sought to impress American seaman from Boston to bring the ships in his squadron up to strength.
"[31] Trent and Wells described the Summary of ... the British Settlements in North America as "interesting" and "valuable, in spite of its prejudices and inaccuracies.