SIR JOHN MURRAY 167 



the present moment about the conditions of the 

 higher atmosphere. Then nearly everything about 

 the surroundings of life in the abysses of the 

 ocean and about the geology of the depths of 

 the sea had to be learnt. Within the last few 

 years man has learnt to dominate the lightest of 

 the three elements which compose the globe, and 

 the Renaissance of science, which is as notable in 

 the reigns of Queen Victoria and her descendants 

 as it was in the time of the Stewarts, is extend- 

 ing its results to the air, which until the de- 

 velopment of petrol engines necessarily remained 

 unconquered. 



In the Stewart times British science led the 

 world, and undoubtedly in the last fifty years 

 British oceanography has done the same. The 

 invention of the self-registering thermometer by 

 Cavendish in the middle of the eighteenth century 

 placed a new and essential instrument in the* 

 hands of those interested in the condition of the 

 depths of the ocean. This thermometer was 

 used in Lord Mulgrave's expedition to the Arctic 

 seas in 1773, and again in James Ross' Antarctic 

 expedition (1839-1843), where the temperature 

 of the water was constantly observed to depths 

 of 2,000 fathoms. On this expedition, and on 



