SEA-FISHERIES LABORATORY. 221 



mediate times, except in December, when pressure of 

 other work prevented us from making the cruise. The 

 same stations, with one or two exceptions, were visited on 

 all these occasions ; and not only were the usual observa- 

 tions made, but surface temperatures were also taken at 

 positions nearly intermediate to those of the regular 

 stations. These latter data are not tabulated, but they 

 are plotted in the series of sketch charts showing the 

 surface isotherms. As a general rule, Richter thermo- 

 meters were used to take surface temperatures, but a 

 " Kiel " thermometer was employed at stations other than 

 the " hydrographic " ones. The error of this instrument 

 (about 0°'15 C.) was frequently determined , and its 

 readings are corrected. Deep temperatures were some- 

 times taken by means of a Bichter Reversing thermo- 

 meter of the latest pattern, used on the Nansen-Pettersson 

 water-bottle frame. The readings of the latter instru- 

 ment always agreed with those of the Nansen deep-sea 

 thermometer used in the water-bottle, and in the end the 

 latter only was used; and this procedure seems to be 

 preferable as there must always be some degree of 

 uncertainty attached to the readings of a reversing 

 thermometer, no matter how perfectly made, when used 

 alone. The water-bottle was necessarily worked from the 

 windward side of the ship, the latter being brought into 

 position. Surface water samples for the determination of 

 temperatures were always taken from the leeward side : 

 this was the practice, though I do not suppose there 

 would have been a perceptible difference in temperature 

 on the two sides of the vessel. 



In addition to data obtained in this way, I have also 

 considered observations made on board the " James 

 Fletcher " in the course of her ordinary patrol work. The 

 surface temperature is taken hourly when the vessel is at 



