NARRATIVE OF THE CRUISE. 



27 



of the sea, and the latitude of the place of observation, 

 researches, the heights being given in Paris lines. 



At page 434 is a rough statement of the results of his 



The Expedition might contribute to the examination of this law, not only by giving especial attention to 

 the barometer observations at about the critical latitudes 0°, 30°, 65°, 70°, but also by comparing any barometers 

 with which long series of observations have been made at any port they may touch at, with the ship's standard 

 barometer. 



It appears probable from Schouw's paper, that certain meridians are meridians of high pressure and others 

 of low pressure. 



For comparison of barometer and measures of heights, it appears that the aneroid barometer constructed by 

 Goldschmid of Zurich would be very useful. 



It is very desirable that the state of the barometer and thermometer should be read at least every 

 two hours. 



II. Chemical Observations. 



1. Samples of sea water should be collected for chemical analysis at the surface and at various depths 

 and in various conditions. Each sample should be placed in a Winchester quart glass-stoppered bottle, 

 the stopper being tied down with tape and sealed in such a manner that the contents cannot be 

 tampered with. 



2. Portions of the same samples should bo, immediately after their collection, boiled in vacuo, the gases 

 collected, their volume determined as accurately as may be, and a portion, not less than one cubic inch, 

 hermetically sealed in a glass tube, to be sent home at any time for complete analysis. 



3. Frequent samples of sea water taken at the surface, and others taken beneath as opportunity offers! 

 should have determinations of chlorine made upon them at once, or as soon as convenient. 



This operation could easily be carried on in any but very heavy weather. On the other hand, it is not 

 thought that any trustworthy analyses of gases could be made on board ship, unless in harbour or in the calmest 

 weather. 



4. Such samples of the sea bottom as are brought up should be carefully dried and preserved for examina- 

 tion and analysis. 



5. The gas contained in the swimming-bladders of fishes caught near the surface and at different depths 

 should be preserved for analysis. In each case the species, sex, and size, and especially the depth at which the 

 fish was caught, should be stated. 



III. Botanical Observations. 



The duties of a botanist in travelling are twofold, and in the case of the voyage of circumnavigation 

 about to be undertaken by H.M.S. Challenger they are of equal importance. 



Of these, the one refers to forming complete collections of the plants of all interesting localities, and 

 especially of the individual islands of oceanic groups. 



