HABITATIONS OF INSECTS. 



433 



manner, and, winding round the whole building to the top, 

 intersect each other at different heights, opening either imme- 

 diately into the dome in various places, and into the lower 

 half of the building, or communicating with every part of it 

 by other smaller circular or oval galleries of different dia- 

 meters. The necessity for the vast size of the main under- 

 ground galleries evidently arises from the circumstance of 

 theu^ being the great thoroughfares for the inhabitants, by 

 which they fetch their clay, wood, water, or provision ; and 

 their spiral and gradual ascent is requisite for the easy access 

 of the Termites, which cannot but with great difficulty ascend 

 a perpendicular. To avoid this inconvenience, in the interior 

 vertical parts of the building, a flat pathway, half an inch 

 wide, is often made to wind gradually, like a road cut out 

 of the side of a mountain, by which they travel with great 

 facility up ascents otherwise impracticable. The same in- 

 genious propensity to shorten their labour seems to have given 

 birth to a contrivance still more extraordinary. This is a kind 

 of bridge of one vast arch, sprung from the floor of the area 

 to the upper apartments at the side of the building, which 

 answers the purpose of a flight of stairs, and must shorten 

 the distance exceedingly in transporting eggs from the royal 

 chambers to the upper nurseries, which in some hills would 

 be four or five feet in the straightest line, and much more if 

 carried through all the winding passages which lead through 

 the inner chambers and apartments. Mr. Smeathman mea- 

 sured one of these bridges, which was half an inch broad, a 

 quarter of an inch thick, and ten inches long, making the side 

 of an elliptic arch of proportionable size, so that it is wonder- 

 ful it did not fall over or break by its own weight before they 

 got it joined to the side of the column above. It was strength- 

 ened by a small arch at the bottom, and had a hollow or 

 groove all the length of the upper surface, either made pur- 

 posely for the greater safety of the passengers, or else worn 

 by frequent treading. It is not the least surprising circum- 

 stance attending this bridge, the Gothic arches before spoken 

 of, and in general all the arches of the various galleries and 

 apartments, that, as Mr. Smeathman savf every reason for be- 



YOL. I. F F 



