PREFACE. XV 



are made in remote countries, and onr re- 

 sources of various kinds are augmented. 

 The skill of Linnneus b}^ the most simple 

 observation, founded however on scien- 

 tific principles, taught his countrymen to 

 destroy an insect, the Cantharis navalis, 

 which had cost the Swedish government 

 many thousand pounds a year by its ra- 

 vages on the timber of one dockyard only. 

 After its metamorphoses, and the season 

 when the fly laid its eggs, were known, 

 all its ravages were sto])ped bv immersino- 

 the timber in water during that period. 

 The same great observer, by his botanical 

 knowledge, detected the cause of a dread- 

 ful disease among the horned cattle of the 

 north of Lapland, which had previously 

 been thought equally unaccountable and 

 irremediable, and of which ho has given 

 an exquisite account in his Lapland tour, 

 as well as under Ciciita vlrosct, Engl. Bot. 

 t. 479? in his Flora Lapponica. Ona man 



