1915] Michael, ct al.:Hiidro<jrapliic Records of Scripps I nsiUution 13 



readiness for a second series. The Richter self-recristerina: deep-sea 

 thermometers (see p. 15) have been exclusively used in connection 

 with these water bottles. 



(g) A comhination apparatut^. — Durinfr July, 1912. a method was 

 devised whereby two Ekman bottles and an Ekman current-meter 

 (Ekman. 1905b) were suspended below the Kofoid net, as indicated in 

 the accompanying figure. Upon the opening of the net a messenger. 1. 

 is freed, causing the reversal of one of the bottles which, in reversing. 

 frees a second messenger, 2. thereby starting the current-meter. [Jpon 

 closure of the net another messenger, .5, is released, which caiLses the 

 reversal of the second water bottle, which in turn frees a fourth mes- 

 senger. 4. thereby stopping the current-meter. With this combination 

 it was possible to obtain two water .samples, one at the beginning and 

 one at the end of each net haul. In addition the current-meter regis- 

 ters the distance of the haul or, more properly, the number of meters 

 of water through which the net passes during the interval of its haul. 

 While this method is somewhat awkward, the value of the collections 

 was increased many times, and the results proved very satisfactory. 



(7i) Other apparatus. — Under this heading a variety of trawling 

 and dredging apparatus might be described. However, since 1908, 

 .such apparatus has been too seldom used to justify taking the space 

 here to describe it, while prior to that year the particular kind of 

 trawl or dredge used was seldom recorded. Suffice it to say that, in 

 addition to the apparatus above described, the "Agassiz" is well 

 equipped with various trawls and dredges, ranging in size from the 

 four-foot Tanner trawl to a fiftv-foot Otter trawl. 



3. COLLECTION OP WATER SAMPLES AND MEASUREMENT OP 

 TEMPERATURE 



(a) Surface samples. — It has been our custom since 1908 to collect 

 surface water samples at intervals varying from ten to twenty miuvites 

 when the "Agassiz" is under way. The average speed of the boat 

 being seven and one-half knots per hour, samples are thus obtained 

 at intervals varying from one to three knots, in addition to those 

 usually taken in connection with surface-net hauls. A canvas bucket 

 having a capacity of about two gallons is used to dip up the water, 

 after which a thermometer (manufactured by L. Steger, Kiel) reading 

 directly to two-tenths of a degree C is immediately immersed. Two 



