378 INFLUENCES OF CULTIVATION 



myriads of birds hover around and dash against the stout 

 glass of the lantern with such vehemence that the sea around 

 becomes covered with thousands of dead bodies. 



" Hosts of glittering objects " wrote Dr Eagle Clarke, of migration at the 

 Eddystone Lighthouse, " birds resplendent as it were in burnished gold, 

 were fluttering in, or crossing at all angles, the brilliant revolving beams of 

 light. Those which winged their way up the beams towards the lantern were 

 innumerable, and resembled streaks of approaching light. These either 

 struck the glass, or, recovering themselves, passed out of the ray ere the 

 fatal focal point was reached. Those which simply crossed the rays were 

 illuminated for a moment only, and became mere spectres on passing into 

 the gloom beyond. Some of those which struck fell like stones from their 

 violent contact with the glass ; while others glanced off more or less 

 injured or stunned to perish miserably in the surf below." 



Even refinements of invention may make their influ- 

 ence felt. The Field records that since the lighthouse at 

 the Skaw was fitted with a revolving in place of a fixed 

 light, the number of birds attracted to their destruction has 

 increased enormously. On the night of 1 1 October 1907 no 

 fewer than 1000 birds of different kinds were killed by flying 

 against the lighthouse windows. And again, the alteration 

 of the light of the Galloper Lightship from white to red, 

 stayed the destruction, for whereas, Dr Eagle Clarke informs 

 me, the keepers when relieved from duty formerly took 

 ashore clothes-baskets full of Larks, now no migrants 

 approach the light a simple consequence of the reduced 

 actinic power of red rays. 



Insects, as well as birds, are attracted in large numbers 

 by the beams of lighthouses, witness the records of Mr 

 William Evans, who obtained from a dozen Scottish light- 

 houses in one or two years, 7500 individuals (excluding 

 2000 Gnats) representatives of 241 species of Moths, Butter- 

 flies, Caddis- flies and Lacewings, Beetles and Two-winged 

 Flies or Diptera, while as many as 400 Moths representing 

 30 species have been taken on a July night at the Isle of 

 May lighthouse. It is also on record that the Diamond- 

 backed Moth, a highly undesirable alien, has clustered in 

 such numbers round a lantern, that the keeper spent the 

 whole night sweeping them off, so that his light might, be 

 visible at sea. 



Probably a greater number of dusk-flying insects are 

 yearly destroyed by the artificial lights of towns and houses. 



