 In 1898 and again in 1899 Norman Heathcote visited the islands and wrote a book about his experiences . During the 19th century , steamers had begun to visit Hirta , enabling the islanders to earn money from the sale of tweeds and birds ' eggs but at the expense of their self @-@ esteem as the tourists regarded them as curiosities . It is also clear that the St Kildans were not so naïve as they sometimes appeared . " For example , when they boarded a yacht they would pretend they thought all the polished brass was gold , and that the owner must be enormously wealthy " . The boats brought other previously unknown diseases , especially tetanus infantum , which resulted in infant mortality rates as high as 80 percent during the late 19th century . The cnatan na gall or boat @-@ cough , an illness that struck after the arrival of a ship off Hirta , became a regular feature of life . 
