first time was given a comprehensive picture of 

 the sort it could understand. Dozens of people 

 now could see what more had to be done and in 

 this sense the CHALLENGER'S report became a text 

 book. It is an interesting fact that one of the 

 lessons taught (perhaps just a tiny bit too 

 emphatically) was that patience and skill to- 

 gether with simple, conservative equipment will 

 lead to satisfying success in deep sea measure- 

 ments. The CHALLENGER spent three years at sea, 

 went around the world, made many measurements and 

 many collections, some to as deep as 3>000 

 fathoms. After the first year's shakedown she 

 could proudly report having lost "not a fathom 

 of cable or a single instrument." 



This is a remarkable record--who has equalled 

 it? No wonder a tradition grew out of these 

 teachings and no wonder the image of the instru- 

 ments she used became frozen in the minds of most 

 later expedition planners - This image is not 

 much blurred even now some 90 years later. Nansen 

 bottles and reversing thermometers are today a 

 prime consideration in the planning of any major 

 expedition. It so happens that this is exactly 

 the neat package that grew out of the success of 

 this great survey. 



CHALLENGER Equipment 



It would be almost, but not quite, accurate 

 to say that the familiar Nansen bottle assembly 

 with its thermometric temperature and pressure 

 registers were completly developed aboard the 

 CHALLENGER. Actually, Nansen was only 11 years 

 old at this time. However, the water bottle used 

 on the CHALLENGER was very like the later Nansen 

 modification with a major difference that the 

 CHALLENGER most commonly used thermometers that 

 registered without being upset. Therefore, they 

 were not attached to water bottles; in fact, 

 neither did the bottles themselves have to be 

 upset. No messengers were used to actuate the 

 valves and registering mechanisms; triggering was 

 carried out by vanes or propellers that rotated 

 only during haul-in. Nevertheless, as many as 

 eight registering thermometers and water bottles 

 were "bent" onto the sounding cable and the whole 

 procedure at sea, as well as the general charac- 

 ter of the results, was very close to that of a 

 hydrographic cast on a present day vessel. 



It is of no real significance, but of some 

 curiosity to us now, that the preferred cable 

 was made of 1-inch (circumference) Italian hemp, 



carefully spliced, that was paid out and hauled 

 in from a reel turned by two hand cranks. Both 

 the messenger and steel cable had come into com- 

 mon practice before the "Narrative" was published 

 in 1885, however. A bottom-coring tool, not 

 unlike those used now, was attached at the bottom 

 of the cast but the heavy iron weights were dropped 

 automatically after a core was taken. Three 

 thousand fathoms of cable required 2 1/2 hours to 

 run out free. 



Reversing Thermometer 



The CHALLENGER went out with some thirty self- 

 registering thermometers of the minimum-and- 

 maximum reading type. This type had been used on 

 land and on sea for more than two decades. During 

 the cruise, the London instrument firm of Negretti 

 and Zambra patented a workable form of their novel 

 thermometer that was constructed so as to register 

 when it was turned upside down. Several were 

 sent out to the expedition for trial. The now- 

 seasoned staff recognized the inherent merits of 

 the new construction but, of course, readily 

 recognized the failings of these prototypes in 

 small but important detail and diligently reported 

 them. Non-reproducibility in the breaking point 

 of the mercury was even then the first complaint. 

 Inadequacy of the scale construction was also 

 noted. These complaints are still common--now 

 directed toward features vastly improved. 



Although the CHALLENGER had to rely mostly upon 

 other types of thermometers, the reversing type 

 was being rapidly improved by Negretti and Zambra 

 back in London. A protected* model having a 

 cylindrical external shell quite like that of 

 the modern instrument was available before the 

 "Narrative" was published in 1885 but it had not 

 yet acquired an auxiliary thermometer. This 

 appeared some fifteen years later and was the 

 last significant change in outward appearance of 

 the classical oceanographic thermometer. 



Piezometer 



The CHALLENGER'S staff was well aware of the 

 effect of the ocean's pressure squeeze on tempera- 

 ture reading; in fact, they overestimated it. 

 Even earlier minimum registering thermometers 

 designed for deep- sea work were shielded from 

 hydrostatic effects by a glass envelope of some 

 kind but this usually surrounded only the main 

 bulb. Since the general effect of pressure was 



*The earliest reference that I can find to the protected instrument is in a statement from the 

 N & Z Company (page 6 of reference k) : 



"In l857> we specially devised and constructed for Admiral Fitzroy the double bulb 

 Deep Sea Thermometer for taking sea temperatures at great depths. This is the 

 only type employed at the present day for great depths ..." 



Fitzroy had just become Rear Admiral at this period and was ashore writing reviews of his long and 

 broad experiences as geographer, meteorologist and hydrographer . His curiosity reached even to 

 behavior patterns in primitive races . 



