114 WILD SPAIN. 



The composition of the human mind is undoubtedly 

 speculative : and to those of deep thought, as distinguished 

 from others the bent of whose energies tends rather towards 

 action, the temptation to theorize — to venture on the 

 dangerous regions of inference and deduction — appears 

 irresistible. The contemplative thinker formulates theories 

 the apparent beauty of which fascinate his imagination. 

 Collateral evidence which seems to substantiate, is, in 

 general, not difficult to find — that of a negative or preju- 

 dicial characteris not sought. Then with a mind uncon- 

 sciously biassed in favour of a preconceived idea, it may 

 happen that probabilities are mistaken for facts, evidence 

 for proof : and thus a new hypothesis is duly launched, 

 based on ten, fifty, or a hundred adduced circumstances, the 

 whole of which may be merely coincidences, and exceptions 

 to the rule if applied to the millions of unadduced cases, 

 and perhaps, even in relation to the particular examples 

 cited, of no direct bearing in the sense in which it is sought 

 to apply them. 



As an example of the class of theories alluded to, we 

 have read that the colours of the sea-gull tribe are dark 

 above and light below in order, on the one hand, that they 

 may escape the searching scrutiny of the eagle soaring 

 above, and, on the other, avoid alarming their finny prey 

 beneath. If there was anything in this idea, it would, at 

 least, be a hard case for those sea-birds not so coloured, 

 and it should be added that of the birds which are so 

 coloured several species take three or four years to attain 

 adult dress. How do they survive those earlier years? 

 But a very slight acquaintance with the subjects in life 

 shows that there is actually nothing in it. Lying in one's 

 gunning-punt, the whitest-breasted gulls, as viewed from 

 below against the lightest of cloud backgrounds, are seen 

 as clearly as if the bird's colour was actually black. Every 

 detail of form and movement is clearly distinguishable — 

 the clean-cut wings and tail, legs pressed close up under 

 the latter, the pointed head turning from side to side as it 

 searches the waters. Its colour makes no difference, and 

 is no factor at all. Then from high above, from the heights 



