Huron and summarizes briefly the use of 

 drift bottles by other workers. 



DRIFT-BOTTLE DESIGNS 



History 



Among the first recorded accounts of 

 the use of drift bottles is that of Bernar- 

 din De Saint-Pierre who in 1784 recommended 

 releasing floating bottles from time to time 

 with each bottle carrying a note telling 

 the day, latitude, and longitude of release 

 (Rouch 1954). A French naturalist, Aime', 

 shortly before the middle of the nineteenth 

 century released 50 bottles off the Algerian 

 coast and subsequently obtained returns of 

 3 of them (Schmidt 1913). An interesting 

 early record of drift bottles is that 

 reported by Prince Albert I of Monaco; a 

 bottle released toward the end of the nine- 

 teenth century in the Atlantic Ocean south- 

 west of Ireland was recovered 646 days later 

 on the coast of Tunis in the Mediterranean 

 Sea (Schmidt 1913). 



Evolution of current indicators since 

 these experiments have been along two main 

 lines: indicators of a stationary mechani- 

 cal type that measure the current at a 

 certain point; and passive objects carried 

 along by currents. Since this project 

 utilized the latter type, the following 

 report is limited to passive drift units. 



In 1892, 1893, and 1894 masters of some 

 merchant vessels released nearly 5,000 

 drift bottles at various points throughout 

 the Great Lakes (Harrington 1895). These 

 bottles had no ballast or drags and each 

 contained a reply card. Although the bot- 

 tles floated low in the water, enough Wcis 

 exposed above the surface to cause Harring- 

 ton to remark that the wind may have influ- 

 enced their movements. He reasoned that 

 bias to the results wjis not impxartant since 

 the wind that drifted the bottles would move 

 the surface water in the same direction. 

 He did feel, however, that wind caused the 

 bottles to drift faster than the water but 

 that the effect was slight. 



From the use of plain stoppered bottles, 

 it was but a short step to reduce the wind 

 effect by the inclusion of a ballast to make 

 the bottles float with only a small portion 

 exposed above the surface. Garstang (1898) 

 used ballasted "egg-shaped" soda-water 



bottles on the English Channel. They were 

 9 inches long and the upper half was painted 

 red to make them conspicuous. Ballast con- 

 sisted of lead shot held stationairy in the 

 bottle by paraffin to minimize displacement 

 of the center of gravity. He concluded that 

 movements of ballasted bottles were princi- 

 pally due to the force that local winds 

 exerted upon the surface of the water, sub- 

 ject, in certain areas, to modification by 

 tidal currents. 



Drift bottles used in the Danish Ocea- 

 nographical Expeditions to the Mediterranean 

 Sea in 1908-1910 were ordinary champagne 

 bottles, well corked, with the mouth dipped 

 in pitch (Schmidt 1913). Some bottles were 

 ballasted with sand; others had no ballast. 

 Any difference in travel between bottles 

 with and without ballast was not given in 

 the results of the experiment. Schmidt 

 believed that the wind had considerable 

 direct effect upon the bottles. Platania 

 (1923) in a further report on the Danish 

 Expeditions concluded that drift bottle 

 movements in the western Mediterranean did 

 not reflect true currents, but were influ- 

 enced primarily by the prevailing winds. 



The travel of well-designed surface 

 floaters, when interpreted properly, gives 

 reasonably reliable information on surface 

 currents at a particular time and place. 

 Investigators, however, are frequently 

 interested also in subsurface currents. To 

 obtain information on subsurface currents. 

 Bidder (Carruthers 1927) developed a "bottom 

 trailer" bottle for use in the North Sea. 

 The bottom trailer used by Nelson (1922) 

 was a stoppered glass bottle, the neck of 

 which carried a straight wire tail pointing 

 in the direction of the long axis of the 

 bottle. The bottle was weighted to have a 

 small negative buoyancy in sea water. When 

 released it sank to the bottom. Its descent 

 stopped as the tip of the tail touched the 

 bottom, and it drifted with the current in 

 that position. The weight of the bottom 

 trailer was adjusted so that the bottle 

 weighed 1.7 grams more than the volume of 

 sea water (at 8" C. , specific gravity 

 1.0275) displaced by it. These bottles 

 were expected to become entangled within 

 the nets and trawls of fishermen and the 

 reply cards subsequently to be returned by 

 them. Carruthers (1947) reported that suc- 

 cess in the use of "bottom trailers" had 

 not been great because they "take sanctuary" 

 between the sand ridges. 



