76 SCIENCE FROM AN EASY CHAIR 



London before the nineteenth century, just as they are 

 to-day at Gloucester. It would be interesting to know 

 exactly when they ceased to appear in the Thames. A 

 curious fact, however, is that young eels not so small 

 as "elvers," but from three inches in length upwards 

 are taken close above London even to-day. Four years 

 ago I obtained a number of this small size from Teddington. 

 The question arises as to whether these specimens represent 

 just a small number of elvers which have managed to 

 swim through the foul water of London and emerge into 

 the cleaner part of the river above. This is improbable. 

 It is more likely that they have come into the Thames 

 by travelling up other rivers such as the Avon which 

 are connected by cuttings with the Thames tributaries. 

 But it certainly is remarkable that eels of only three 

 inches in length and therefore very young should have 

 managed to get not merely " into " the Thames (to the 

 upper parts of which no doubt many thus travel and 

 remain during growth), but actually " down " the Thames 

 so far in the direction of its tidal water as is Teddington 

 lock. The specimens from Teddington were placed by 

 me in the Natural History Museum. 



