120 HONEY. 



portant ingredient in those fine ales which are brew- 

 ed in Scotland ; and certainly it must add not a little 

 to the nutritive qualities of that wholesome beverage. 

 It will not, perhaps, be considered out of place to 

 take notice here of the Honey-dew. When the close 

 of summer happens to be hot and sultry, and the air 

 calm, the bees find a large supply of food on the 

 leaves of certain plants and trees. This is the honey- 

 dew. It is believed, generally, to be an exudation 

 of the surplus sap of trees, by means of the pores of 

 the upper surface of the leaves ; and is most fre- 

 quently found in the oak, the elm, the plane, the 

 lime, and the beech, and also in many fruit-trees and 

 ever-green plants. The idea has been entertained 

 of its falling from the atmosphere ; and perhaps the 

 supposition is, in a certain sense, not altogether with- 

 out foundation, nor inconsistent with the notion of its 

 being originally a vegetable exudation. Certain it is 

 that, in very sultry evenings, we have observed not 

 only the leaves of trees shining with the liquid, but 

 the dry stones also and gravel completely bespotted 

 with it, as if it had fallen in a gentle shower or dew. 

 White of Selbourne regarded it as the effluvia of 

 flowers, evaporated and drawn up into the atmos- 

 phere by the heat of the weather, and falling down 

 again in the night with the dews that entangle them. 

 Curtis* is of opinion that it is neither an exudation 

 of the sap of trees, nor falls from the atmosphere, 

 but that the true and only source of this saccharine 

 matter is to be found in the insect Aphis, or vine- 

 * Linnaean Transactions, vol. vi. page 75. 



