THE VICTORIAN ERA 183 
tific mind was fully awake to the value of completing the 
observational basis of theory; the practical intelligence 
of the country did not fail to grasp the vast possibilities 
of improved navigation. In the “ thirties ” a voyage to 
India, to Australia, where trade was increasing with the 
rising colony of New South Wales, above all to China, 
was a very serious matter and the risk of shipwreck was 
great. Anything which tended to reduce that risk was 
to be welcomed eagerly. Steam navigation was begin- 
ning and the possibility of constructing ships entirely of 
iron promised an unprecedented expansion of ship-build- 
ing. The first iron steamer to attempt a voyage in the 
Irish Sea had been nearly lost on account of her com- 
passes proving useless ; but Mr. G. B. Airy — for so many 
years Astronomer Royal — after devoting much study to 
the question had shown how the disturbing effect of an 
iron ship could be practically neutralised. For a long 
voyage therefore the chief danger of treachery in the 
compasses was reduced to the uncertainty of the magnetic 
conditions of the Earth itself, especially in such places as 
the far south of the Indian Ocean where the declination 
changed rapidly. 
The world is wide and the interests of science are 
many and diverse, so that it is impossible to preserve a 
strict chronological order in describing the steps which 
led to the great era of Antarctic exploration. We are not 
wrong, however, in saying that this revival was a case of 
magnetic attraction, the other causes being combined 
with that in a minor degree. 
At the meeting of the British Association in Dublin 
in 1835 many important magnetic papers were read. 
Robert Were Fox described his newly invented instru- 
ment for measuring the dip, which was capable of being 
