66 Observations Conducted on Sailing-Ships 



important results as to the character of certain fauna at certain depths, 

 and the life-history of certain species, it is rendered much more 

 valuable by the use at the same time of the water-bottle, whereby 

 samples of water can be taken from the same depth and the salinity 

 be subsequently determined, and by the simultaneous use of the 

 thermometer attached to the tow-net. The temperature of the water 

 at successive depths in the open ocean (e.g., the Atlantic) exhibits 

 such a fairly regular graduated scale, that the temperature taken by a 

 thermometer attached to a tow-net at the time of opening and closing- 

 is a pretty accurate guide to the actual depth at which the net has 

 really been. It has been our habit to attach to the tow-net when 

 lowered two thermometers — generally a Negretti and Zambra revers- 

 ing thermometer and a maximum or minimum thermometer. 



Sometimes it is desirable to collect samples of sea-water from 

 various depths for analysis of the contained gases. Such examinations 

 are of great scientific interest taken in conjunction with the salinity 

 observations, and were of especial interest in our 1904 cruise in 

 elucidating the extent of water of Mediterranean origin then occup}'- 

 ing patches in the Bay of Biscay. 



For the method of preservation of these samples very little extra 

 apparatus is requisite. When the water-bottle is raised on board, 

 a sample of its contents is introduced into a glass bulb, which has been 

 partially exhausted, so as to obtain a partial vacuum ; the long, thin 

 capillary neck being introduced into the nozzle of the water-bottle is 

 then fractured by a special pair of ' scissors.' The sea-water fills the 

 bulb, which, with its long neck, is then removed, and sealed by bending 

 the end in the flame of a spirit-lamp. Put away in special boxes made 

 so that the bulb and its two prolonged necks can lie in slots specially 

 made to receive them, the flasks may safely be packed and carried on 

 board, awaiting transmission to the laboratory for analysis. 



As to the apparatus required in trawling in a sailing-vessel, 

 experience must be the best teacher. This experience may be more 

 quickly and profitably obtained by having on board, in charge of this 

 apparatus, a professional trawler. The adventures of a trawl in inex- 



