viii PREFACE 



Magazine of the Royal Scottish Geographical Society. 

 These maps consist of two series. In the first series 

 (Volumes III. and IV.), the contours of depth in the lakes 

 are shown in shades of blue, and the contours of the height 

 of the surrounding land are shown in brown shades of 

 colour; in the second series (Volumes V. and VI.), the 

 contours of depth are shown in shades of blue, the brown 

 shades on the land being omitted. 



In addition to the bathymetrical maps, there are also 

 a few maps showing the surface geology, the rainfall, and 

 other physical features of some of the districts. 



These maps have all been prepared and printed by 

 Dr J. G. Bartholomew, and we desire to express our in- 

 debtedness to him for the care with which these have 

 been produced, and for his assistance and advice in many 

 directions. We are also indebted to Messrs G. Cornwall & 

 Sons, Aberdeen, for their assistance and advice with regard 

 to the binding of the maps, and to Messrs Neill & Co., Edin- 

 burgh, for their advice in connection with the letterpress. 



We feel confident that the whole investigation has 

 resulted in very substantial contributions to knowledge. 

 Some of the observations those regarding the temperature 

 seiche, and the variation of the viscosity of the water with 

 temperature, for example throw much light on obscure 

 oceanographical problems. Most of the observations 

 could, with advantage, have been carried further, by means 

 of improved instruments and methods suggested during 

 the progress of the work, but it was found necessary to 

 terminate the survey, at least in the meantime, and to 

 review what had been accomplished. We are conscious 

 of many shortcomings. 



In conclusion, we tender our best thanks to all who 

 have assisted us in carrying these investigations to a 

 successful conclusion. 



JOHN MURRAY. 

 LAURENCE PULLAR. 



CHALLENGER OFFICE, EDINBURGH, 

 February 1910. 



