THE COMB-BUILDERS 207 



of a cell on the other side, and then the width of 

 the whole comb be measured, it will be found that 

 the combined depth of the two cells perceptibly 

 exceeds the width of the whole comb. At first 

 glance this seems like a case of the less including 

 the greater, which is a manifest impossibility. 

 But, holding the comb up to the light, a further 

 discovery is made, and the seeming paradox is 

 eliminated. The bottoms of the cells are so thin 

 as to be almost transparent, and it is at once seen 

 that the cells are not built end to end, in line, but 

 that each cell-base on one side of the comb covers 

 part of three cell-bases on the other. If the three 

 diamonds, composing between them the triangular 

 base of a single cell, be perforated with a needle, 

 and the comb turned over, it will be found that 

 the three perforations come each in a separate 

 cell. Thus the saving in the total width of the 

 comb is effected by allowing the pyramidal bases 

 on each side to engage alternately like the teeth 

 of a trap ; instead of meeting point-blank, they 

 overlap each other, and the faces of the pyramids 

 are so contrived that each of them helps to close 

 two cells. 



There is another advantage in this arrangement 

 which will be immediately obvious. The apex 

 and three ribs of each pyramidal cell-base form 

 foundation-lines for the cell-walls on the other side 

 of the comb. This means that not only do all 

 cell- walls abut on an arch, but that every cell-base 



