Applicability of the Electric Light to Lighthouses. 325 



Golden-winged "Woodpecker (Picus auratus, Linn.). 



Hairy Woodpecker (Picus villosus, Linn.). Surely Montagu 

 was mistaken in supposing that this species was common in the 

 North of England. 



Great Black Woodpecker (Picus martins, Linn.). The nest 

 of this bird, containing four eggs, was found by my friend 

 Mr. Wise in the New Forest, Hants. 



Three-toed Woodpecker (Picus tridactylus, Linn.). This 

 and the preceding species are not uncommon in certain districts 

 of the European continent. 



Middle Spotted Woodpecker (Picus medius, Linn.). This 

 is now proved beyond doubt to be the young of the Great 

 Spotted Woodpecker (Picus major, Linn.). 



DESCRIPTION OF THE PLATE. 



Fig. 1. Green Woodpecker (Picus viridis) ; Fig. 2. Great 

 Spotted Woodpecker (Picus major) ; Figs. 3 and 4. Male and 

 female of the Lesser Spotted Woodpecker (Picus minor). 



ON THE APPLICABILITY OF THE ELECTRIC LIGHT 

 TO LIGHTHOUSES. 



BY PROFESSOR M'GAULEY. 



Nothing can be more important to any maritime country, but 

 especially to one having so extended a commerce as ours, than 

 the subject of lighthouses. Their importance is evident from 

 the fact that the sudden and unexpected extinction of one of the 

 lights on our coasts might cause the loss of many lives, and the 

 destruction of many hundreds of thousands of pounds of pro- 

 perty ; and accordingly we consider it good policy to spend 

 very large sums annually in the construction and maintenance 

 of lighthouses. 



Vv r arning the mariner of the dangers which he incurs 

 on his approach to land is not a mere modern practice. 

 Beacon fires are of high antiquity; they are alluded to by 

 Homer and several ancient writers. The celebrated Pharos of 

 Alexandria was erected about three hundred years before 

 Christ ; but whether its light was that of a fire, or was pro- 

 duced by some more elaborate contrivance, cannot now be 

 ascertained. It is said to have been visible at the distance of 

 forty miles, but this is more than improbable. The famous 

 Colossus of Rhodes, one of the wonders of ancient times, an 

 immense statue of bronze, was erected about the same period ; 

 but, after a very few years, it was thrown down by an earth- 



