INSTRUCTIONS. 281 



15. In the possible event of the ships being detained during a winter 

 in the high latitudes, the expedition has been supplied with a portable 

 observatory, and with instruments similar to those which are employed 

 in the fixed magnetical and meteorological observatories instituted by 

 Her Majesty's Government in several of the British colonies. 



16. It is our desire that, in case of such detention, observations 

 should be made with these instruments, according to the system adopted 

 in the aforesaid observatories ; and detailed directions will be supplied 

 for this purpose, which, with the instruction received at Woolwich, will 

 be found, as we confidently anticipate, to aiford full and sufficient guid- 

 ance for such observations, which will derive from their locality peculiar 

 interest and a high theoretical value. 



17. We have also directed instruments to be specially provided for 

 observations on atmospherical refraction at very low altitudes, in case 

 of the Expedition being detained during a winter in the high latitudes. 

 On this subject also particular directions will be supplied, and you will 

 add any "other meteorological observations that may occur to you of 

 general utility; you will also take occasions to try the depth of the 

 sea and nature of the bottom, the rise, direction, and strength of the 

 tides, and the set and velocity of currents. 



18. And you are to understand that although the effecting a passage 

 from the Atlantic to the Pacific is the main object of this expedition, 

 yet that the ascertaining the true geographical position of the different 

 points of land near which you may pass, so far as can be effected with- 

 out detention of the ships in their progress westward, as well as such 

 other observations as you may have opportunities of making in natural 

 history, geography, etc., in parts of the globe either wholly unknown 

 or little visited, must prove most valuable and interesting to the science 

 of our countiy ; and we therefore desire you to give your unremitting 

 attention, and to call that of all the officers under your command, to 

 these points, as being objects of high interest and importance. 



19. For the purpose, not only of ascertaining the set of the currents 

 in the Arctic Seas, but also of affording more frequent chances of hear- 

 ing of your progress, we desire that you do frecpiently, after you have 

 passed the latitude of 65 N., and once every day when you shall be in 

 an ascertained current, throw overboard a bottle or copper cylinder 

 closely sealed, and containing a paper stating the date and position at 

 which it is launched ; and you will give similar orders to the commander 

 of the 'Terror,' to be executed in case of separation ; and for this purpose 

 we have caused each ship to be supplied with papers, on which is 



