330 



APPENDIX. 



to state, that in no one instance did it differ a quarter of a second 

 from theirs ; indeed the figures would bear me out in saying, 

 that it did not differ even a tenth of a second ! These facts are well 

 known to Lieut. Stokes, Lieut. Sulivan, and Mr. Usborne. 



The sextant used throughout the voyage for this purpose, and this 

 alone, was a particularly good one, made expressly for me by Wor- 

 thington and Allan. Its index error never varied, nor was it ever the 

 least out of adjustment. Between morning and afternoon observa- 

 tions it was more than usually guarded, and on no account handled, 

 or exposed to a change of temperature. 



Latitudes were obtained by other sextants, and by circles. I was 

 always anxious to get many results, not only by one observer, or in- 

 strument, but by several observers, and different instruments. It 

 sometimes happened that there were six observers seated on the 

 ground, with as many different instruments and horizons, taking the 

 sun's circum-meridian altitudes, or observing stars at night. Where 

 so many were working against one another, errors were soon de- 

 tected, either in observation or in computing. I have already men- 

 tioned that Dr. Inman's method of calculation was followed ; but it 

 remains to be shown what mode of interpolation was adopted when, 

 as was usually the case, most of the watches were found to be going 

 at rates different from those ascertained at the preceding place of 

 rating. 



With very few exceptions, the method used by Dr. Tiarks* was 

 practised ; and, in the excepted cases, that used by Flinders, Owen, 

 Foster, King, and others, was employed. The following are the 

 principal results upon which all others obtained during the Beagle's 

 last voyage (1831-6) depend. Want of room alone prevents my giv- 

 ing the minutest details upon which they depend ; it would be of 

 little use to give computations without comparisons, or comparisons 

 without rates, or rates without the calculations and observations on 

 which they depend ; or any part of these without the whole, which 

 constitutes a mass of figures filling several thick folio books. All these, 

 however, will be deposited at the Hydrographical Office, so that any 

 one who will take the trouble may, after obtaining the Hydrographer's 

 permission, examine them to the fullest extent. 



Our first station was at the Devonport Baths, exactly in the meri- 



* Chanticleer's Voyage — Appendix, p. 226-8. 



