WIND RECORDS 121 



Steered in a direction normal to the coast ; but she was allowed to drift off this course 

 according to the strength of wind and current in a direction parallel to the coast. The 

 differences between the observed and the dead reckoning positions of the stations are 

 consequently a measure of this drift : and the track chart is therefore a graphic repre- 

 sentation of the combined effects of wind, tide and current upon the ship's course. By 

 this method their combined force is more easily assessed than it would have been had 

 an attempt been made to place the stations on a straight line. 



At each station, where depth allowed, observations were made at the following depths : 

 surface, 10, 20, 30, 40, 50, 60, 80, 100, 150, 200, 300, 400, 600, 800, 1000, 1500, 2000, 

 2500 and so on at 500 m. intervals to the bottom. When running outward from the 

 shore into deep water, soundings were made at alternate stations: on this series of 

 stations hydrological observations were made all the way to the bottom ; on the alter- 

 native series, the hydrological observations were made no deeper than the depth of the 

 preceding sounding. 



The work included determinations of temperature, salinity, phosphate and oxygen, 

 and nets of different mesh were fished vertically from 100 to o m. and obliquely from 

 250 to 100 m. and 100 to m. to sample the plant and animal constituents of the 

 plankton. A complete schedule of these observations will be published in due course 

 as a Station List in the present series. When the ship was under steam from one station 

 to another a routine of four-hourly observations of surface temperature and salinity was 

 performed ; but additional surface temperatures were taken as occasion demanded, and 

 here the want of a continuous thermograph was acutely felt. Phosphate was estimated 

 by Deniges' coeruleomolybdic method as modified by Atkins (1923). 



The equipment used on this survey was essentially similar to that described by Kemp 

 and Hardy (1929). Water samples from depths not exceeding 400 m. were collected 

 with the Nansen-Pettersson insulating water bottle, while at greater depths the Ekman 

 reversing water bottle was used. 



Throughout this report, figures referring to the same locality are printed as far as 

 possible on comparable pages. As far as possible they have also been reduced to a 

 common scale. Thus track charts are not only comparable with one another, but their 

 scale has been adjusted to fit the scale in miles of the various sections of temperature, 

 salinity and phosphate, and of the curves illustrated in Figs. 29 and 30. Exceptions are 

 furnished by Figs. 2, 3, 28, 35, 42 and 51. 



WIND 



Records of wind, based on personal estimates of its direction and force, were kept 

 every four hours by the officers of the watch ; and in addition we have had access to 

 daily weather bulletins issued by the Chilean Meteorological Office. The data may 

 conveniently be considered under three heads : observations on board ship at a distance 

 of more than 50 miles from land ; observations within 50 miles of land ; and those of 

 Chilean coastal stations. The former two are plotted in Fig. 4 separately as residuals 



