THE 



VOYAGE OF H.M.S. CHALLENGER. 



PHYSICS AND CHEMISTRY 



REPORT on Atmospheric Circulation based on the Observations made 

 on board H.M.S. Challenger during the years 1873-1876, and other 

 Meteorological Observations. By Alexander Buchan, M.A., LL.D., 

 Secretary of the Scottish Meteorological Society. 



In the Narrative of the Cruise of the Challenger, vol. ii. pp. 300 to 304, the conditions 

 are detailed under which the meteorological observations were made during the voyage, 

 and the observations themselves are printed in externa, pp. 305 to 744. 



The instruments employed, which had been previously verified, were furnished by the 

 Meteorological Department of the Board of Trade. The observations were uniformly made 

 at two-hourly intervals, except when the Challenger was in Sub-Antarctic waters, from 

 December 21st, 1873, to March 17th, 1874, the observations being then made every hour. 



Tem peratu re. — Th e 

 dry and wet bulb ther- 

 mometers were, in the 

 early part of the voyage, 

 suspended in the small 

 screen provided by the 

 Meteorological Depart- 

 ment, which was fastened 

 to the after upright of 

 the steering wheel, under 

 the pilotage bridge ; but 

 as this screen was too 

 small to contain a maxi- 

 mum and minimum ther- 

 mometer in addition to 

 the dry and wet bulbs, 

 a larger one was con- 



(PHYS. CHEM. CHALL. EXI\ — 



Fig. 1. — Showing position of Thermometers. 



A, dry bulb thermometer ; B, wet bulb thermometer ; c, maximum thermometer ; D, 

 minimum thermometer ; E, pilotage bridge ; F, bollard for boat's fall ; G, signal locker ; 

 H, platform and ladders leading to bridge; K, skylight over naturalists' workroom; L, 

 towing bollard. 



1 



TART V. 



-1889.) 



