114 COKRESPONDENCE WITH HIS FAMILY. 



be in a very uneasy situation during the business of incubation; 

 yet the way will be to examine whether some birds that do sit 

 for certain are not formed in a similar manner, because then 

 the notion of incapacity in the cuckow from formation falls to 

 the ground. Now this enquiry I intend to make with a fern- 

 owl, and as soon as opportunity offers. 



G.W. 



LETTEE XIII. 



TO SAMUEL BARKER. 



Selborne, Nov. 15, 1775. 

 DEAR SAM, 



AFTER some consideration I am in no manner of doubt but 

 that murmur electricum is an error of the press ; and that it 

 should be murmur elasticum. For what in the world has 

 electricity to do with hop-poles ? Why, if it had, should the 

 wind call it forth ? Now as to an elastic murmur, or a deep 

 humming sound, occasioned by the vibration of the naked 

 poles when agitated by the wind, I have heard it twenty 

 times in the months of March and April ; and moreover, when 

 I came to question my servant Thomas, he readily recollected 

 to have heard such a rushing in hop-gardens in the spring 

 months, and added, pertinently enough, that such a murmur 

 might be observed every spring in gardens among kidney- 

 bean-sticks, as I perfectly well remember. Therefore read 

 (meo periculo) elasticum, instead of electricum. The only thing 

 that sticks with me is that since this murmur may be so easily 

 and naturally accounted for by elastic vibration, why Linnaeus 

 should express any wonder, or be in the least pother about so 

 plain a matter, since it seems to me that it is as obvious why 

 a pole should hum when put in brisk motion, as why the 

 strings of an JEolian harp should, when brushed over by the 

 wind, produce those delicate chimings and unisons- that is, by 

 vibration.- It is most probable, therefore, that there are no 

 hop-gardens in Sweden, and that Linnaeus never was witness 



