Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.2- Appendix): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

APPENDIX. 321 tude to the eastward of the flag-staff of Drake's Island ; 10" 2 to the westward of Plymouth old church, and 0' 25"- 1 to the westward of the new church. Tlie longitude, therefore, of the station, by the Ordnance survey, would be 4° 7' 41"-7, but by applying a proportion of the error detected by Dr. Tiarks, in liis chronometrical observa- tions between Greenwich and Falmouth, viz., 4'"09 or 1' 11""3, the corrected longitude of the station will be 4° 8' 43". Our chrono- meters made it 0' 40"' 2 to the eastward of the corrected longitude, and 0' 19"'6 to the westward of the original determination by the Ordnance survey. The Breakwater being the point from whence all my differences are measured, I have considered its longitude west of Green^vich to be as above stated, namely, 4° 8' 43". It now remains to record the results, the details of which are given in another form.* Madeira. — The obsen'ations were made at Mr. Veitch's garden* house, that being the spot used by Dr. Tiarks with ten chrono- meters. The difference between it and the Breakwater is 12" 45' 45" west : the longitude will therefore be 1 6° 54' 28" W. which is 0' 1 7'''4 to the eastward of Dr. Tiarks's determination. Teneriffe (Fort San Pedro) — by eleven chronometers is 0° 40' 6" to the eastward of Madeira, and will therefore be ...16°14'22""W. St. Jago (landing place at Port Praya) — by ten chronometers it was found to be 7° 15' 55" w^est of Teneriffe, and there- fore.,.. 23° 30' 17" Rio DE Janeiro (VUlegagnon Island) — by fourteen chronometers the difference was found between it and Port Praya to be 19° 34' 46" which will make its longitude 43° 05' 03" St. Antonio (Terrafal Bay at the south-west end). — Inconsequence of unfavourable weather we were unable to land at the north-east end, and, therefore, made our observations at Terrafal Bay ; the lon- gitude of which was found by eleven chronometers to be 9° 05' 39" to the westward of Teneriffe which makes it 25° 20' 1 Tkinidada. — On account of the south-east trade being scant, we were, prevented from making this island. Monte Video (Rat Island). — The difference of longitude between this place and Rio de Janeiro was measured, on various occasions, * These details are lodged in the Hydrographical Officct R. F;