368 Mr. J. T. Buchanan [May 29, 



with steamers knows bow expensive in coal is the operation of 

 keeping station. 



The material collected at each station had to be examined, pre- 

 served and stored, before the ship arrived at the next one. The 

 stations were generally about 200 miles apart, so that in the passage 

 from one port to another a station was made about every second day. 

 This was easily accomplished under sail and it added enormously to 

 the comfort and the interest of the voyage. All the advantages of 

 having a wooden sailing ship were not fully realised at the time. 

 It was not until I had taken part in one or two expeditions in well 

 found iron or steel ships in tropical waters that I found out the 

 discomfort which we escaped by being on board of an " old wooden 

 ship." The temperature of the air in the ship was, of course, never 

 lower than that of the air outside ; but, on the other hand it was never 

 higher. Nothing astonished me more than the perfect uniformity of 

 temperature of the air of the main deck of the ship in the tropics. 

 I was able to make experiments on the effects of pressure on the deep 

 sea thermometers in a hydraulic apparatus on the main deck, which 

 I could not have made anywhere else. The temperature of the air did 

 not vary by one-tenth of a degree (C.) during the whole of the day. 



Iron or steel ships, even the magnificent yacht of the Prince of 

 Monaco, get heated through by the sun in the course of the day, and 

 at first they do not cool as much during the night. They are like 

 a black bulb thermometer, they do not lose as much heat as they 

 gain until their temperature has risen a good many degrees above the 

 mean temperature of the air, and that can be pretty high. The 

 voyage of the Challenger lasted three years and five months. Of 

 this time three years were spent between the parallels of 40° S. and 

 40° N., and the greater part of that time, between the tropics. I 

 have no hesitation in saying that the work could not have been 

 carried on continuously in these tropical seas for such a length of 

 time in any other kind of ship. The principal points of advantage 

 were, the thick wooden walls, which completely prevented over heating 

 and over cooling, the splendid ventilation which was provided by the 

 twenty gun ports on the main deck, and the practice of making the 

 passage under sail. 



A word with regard to the equipment. Throughout the voyage 

 hemp sounding line and hemp dredging rope were used, and much 

 of the success of the expedition is due to this fact. There was 

 really no temptation to use anything else, because wire sounding 

 had not passed the experimental stage, and all that was known for 

 certain was that the same wire could not be expected to be used in 

 many soundings without breaking. As our sounding line was on 

 every occasion to carry a load of valuable instruments, this risk 

 could not be run. Captain Narcs knew that he could do all that was 

 wanted with sounding line, and he was brilliantly justified by the 

 result. There was no question of using wire rope for dredging. It 



