Sir John Frederick William Herschel (1792-1871) - astronomer, mathematician, chemist - was one of the most important British scientists of the nineteenth century. Son of the famous astronomer William Herschel, he was persuaded by his father to pursue the astronomical investigations William could no longer undertake; John's subsequent career resulted in a knighthood and a lifetime of accolades. This 1849 publication was commissioned by the Admiralty to encourage and assist naval officers to undertake scientific research while abroad. The work provides instructions in making and recording observations in a wide range of disciplines - astronomy; magnetism; hydrography; tides; geography; geology; earthquakes; mineralogy; meteorology; atmospheric waves; zoology; botany; ethnology; medicine; statistics - written by experts in these fields, including Whewell, Darwin, Hooker and Herschel himself. It was hoped that the instructions could also be used by other travellers to advance scientific knowledge, and the work remained in print for over fifty years.