Mr. Harvey on the Fogs of the Polar Seas. 315 



served the same appearances in very numerous instances, 

 I think I may say in every instance, where a valley bog* has 

 been extensively dug through to its bottom : the nuts, fre- 

 quently in vast numbers, are all whole, without crack or per- 

 foration, and so are the pellicles within the shells, but without 

 remaining vestige of the kernels ! These facts suggest two or 

 three interesting subjects of inquiry ; viz. 



First, Was this country entirely without men or nucivorous 

 animals at the pei'iods when these nuts grew, and fell neglected 

 from the trees or stems? 



Second, Did the peculiar insect which now destroys so many 

 of our hazel nuts by feasting on their kernels, and then eating 

 their way out through the pellicles and shells (as some natu- 

 ralists affirm), not exist here when the nuts of our bogs were 

 growing? or if co-existent with these nut-trees, were its eggs 

 deposited in the flowers or embryo kernels, but perished, owing 

 to the wet state of the vegetables amongst which the ripe nuts 

 became deposited ? And 



Third, Did the nut-trees principally grow on the bogs, or 

 were the nuts conveyed by toi'rents of water into the partial 

 lakes, now often occupied by valley bogs ? 



I write this in great haste, from the office of my son, Mr. 

 Joseph Farey, which I am daily attending, to transact his 

 business relative to patent inventions, &c., during his unfortu- 

 nate illness. I am, sir, your obedient servant, 

 44, Lincolns Inn Fields. JoHN Farey, Sen. 



ON THE FOGS OF THE POLAR SEAS. BY G. HARVEY, ESQ. F.R.S. 



It has been commonly supposed, that the fogs which cover 

 the Arctic Seas during the greater part of the summer months 

 are produced by the moist air depositing its vapour, in conse- 

 quence of being cJiilled by contact "with the sea. But this cause, 

 it is presumed, is not adequate to the formation of mists ; since 

 il has been proved by Dr. Wells f that dew and hoar frost 

 are the only results which arise from air, either perfectly or 

 imperfectly saturated with moisture, coming in contact .with a 

 body colder than itself. To produce mist or fog, as has been 



• The distinction here intended, between valley bogs, partly composed of 

 silt, and mountain bogs of pure peat, occupying high planes of grit-stone 

 chiefly, will be found explained and illustrated by very numerous examples 

 in and near to Derbyshire, in my Report on that county, vol. i. p. 308, and 

 vol. ii. p. 347 : but wherein, as being a mere abstract, and precursor of my 

 then intended mineral history and large map of Derbyshire, I have omitted 

 to mention the hazel nuts, and many other accompaniments of its boggy 

 tracts. 



t Wells on Dew. 



R r 2 satis- 



