488 HABITATIONS OF INSECTS. 



Besides the saving of wax efl'ected by the form of the 

 cells, the bees adopt another economical plan suited to 

 the same end. They compose the bottoms and sides of 

 wax of very great tenuity, not thicker than a sheet of 

 writing-paper. But as walls of this thinness at the 

 entrance would be perpetually injured by the ingress 

 and egress of the workers, they prudently make the 

 margin at the opening of each cell three or four times 

 thicker than the walls. Dr. Barclay has recently dis- 

 covered that though of such excessive tenuity, the sides 

 and bottom of each cell are actually double, or, in other 

 words, that each cell is a distinct, separate, and in 

 some measure an independent structure, agglutinated 

 only to the neighbouring cells, and that when the ag- 

 glutinating substance is destroyed, each cell may be 

 entirely separated from the rest''. 



You must not imagine that all the cells of a hive are 



which compose the cell are equal, i. e. 120"; and he supposes that this 

 equality of inclination facilitates much the construction of the cell, which 

 may be a motive for preferring it, as well as economy. He shows tliat 

 the bees do not economise the wax necessary for a flat bottom in the 

 construction of every cell, near so much as MM. Kcenig and Reaumur 

 thought. 



MacLaurin says, that the difference of a cell with a pyrartiidal from 

 one with a flat bottom, in which is comprised the economy of the hees, is 

 equal to the fourth part of six triangles, which it would be necessary to 

 add to the trapeziums, the faces of the cell, in order to make them right 

 angles. 



M. L'Huillier, professor of Geneva, values the economy of the bees 

 at JL of the whole expense : and he shows that it might have been one- 

 fifth if the bees had no other circumstances to attend to; but he con- 

 cludes, that if it is not very sensible in every cell, it may be considerable 

 in the whole of a comb, on account of the mutual setting of the tw o orv■^ 

 posite orders of cells, lluher, Notivelles Observalions, &c. ii. 31, 

 ' Memoirs of llie Werncrian Society, ii, 259. 



