30 THE VOYAGE OF H.M.S. CHALLENGEE. 



University, Edinbuegh, January 2, 1877. 



The special object of the Challenger Exploring Expedition was to investigate the jphysical and biological 

 conditions of the great ocean basins ; and with this object in view, during an absence from England of three 

 years and a half, and at intervals as nearly uniform as cu'oumstances would permit, throughout a course of 

 68,890 miles, 362 observing stations were established. 



The following list of these stations has been compiled for the use of those naturalists who have consented 

 to assist in the working out of the scientific results of the expedition, with a view to their being published 

 in an oflScial account of the voyage. Interesting observations were made on land as opportunity occurred 

 during the short periods of the Challenger's stay in port, and during her short visits to remote islands ; but 

 these observations were necessarily desultory and incomplete, and it has been decided to omit their considera- 

 tion from the present work, and to publish such as may appear of sufficient value in the transactions of learned 

 Societies. The official report wUl thus consist strictly of an account of the additions which have been made 

 to the knowledge of the physical and biological conditions of the ocean by the expedition. 



At each station the following observations were made, so far as circumstances would permit. The 

 position of the' station having been ascertained — 



1. The exact depth was determined. 



2. A sample of the bottom, averaging from 1 oz. to 1 lb. in weight, was recovered by means of the 



sounding instrument, which was provided with a tube and disengaging weights. 



3. A sample of the bottom water was procured for physical and chemical examination. 



4. The bottom temperature was determined by a registering thermometer. 



5. At most stations a fair sample of the bottom fauna was procured by means of the dredge or trawl. 



6. At most stations the fauna of the surface and of intermediate depths was examined by the use of the 



tow-net variously adjusted. 



7. At most stations a series of temperature observations were made at different depths from the surface 



to the bottom. 



8. At many stations samples of sea-water were obtained from different depths. 



9. In aU cases atmospheric and other meteorological conditions were carefully observed and noted. 



10. The direction and rate of the surface current was determined. 



11. At a few stations an attempt was made to ascertain the direction and rate of movement of water at 



diiferent depths. 



The numerical results of observations yielding such are now available in the logs, in the various reports 

 to the Admiralty, and in the note-books and official journals of the Naval and Civilian Scientific Officers attached 

 to the expedition. 



The samples of the bottom procured by the sounding instrument were carefully preserved in tubes or in 

 stoppered bottles, either dry or wet, with the addition of alcohol 



The samples of bottom and intermediate waters were determined as to their specific weight ; in some 

 samples the amount of carbonic acid, and in others the amount of chlorine, was determined ; in others the 

 contained gases were boUed out and sealed in tubes for future examination ; and a large number of sampiles 

 were reserved in stoppered bottles for analysis. 



The mud and minerals and inorganic concretions brought up by the dredge or trawl were preserved in 

 large quantity in boxes or jars for exammation and analysis. 



The collection of invertebrate animals is of great extent ; and from most of the species being undesoribed, 

 and from the great peculiarity of the distribution of the fauna of the deep sea, it wUl perhaps yield the most 

 generally interesting results. 



The invertebrate animals from the deep-sea stations were, with few exceptions, placed in jars of rectified 



