6o4 THE POPULAR SCIENCE MONTHLY. 



applying earth more or less mixed with chopped hay against the 

 walls which are to support the edifice. At the summit of the con- 

 struction a hole is left for entry and exit. During the whole of 

 its sojourn in our country the swallow uses this dwelling, and 

 even returns to it for many years in succession, as long as its work 

 will support the attacks of time. The faithful return of these 

 birds to their old nest has been many times proved by attaching 

 ribbons to their claws ; they have always returned with the dis- 

 tinctive mark. 



Masons Working in Association. Ants have already fur- 

 nished us with numerous proofs of their intelligence and their 

 prodigious industry. So remote from man from the anatomical 

 point of view, they are of all animals those whose psychic facul- 

 ties bring them nearest to him. Sociable like him, they have un- 

 dergone an evolution parallel to his which has placed them at the 

 head of insects in the same way as he has become superior to all 

 other mammals. The brain in ants, as in man, has undergone a 

 disproportionate development. Like man, they possess a lan- 

 guage which enables them to combine their efforts, and there is 

 no human industry in which these insects have not arrived at a 

 high degree of perfection. If in certain parts of the earth human 

 societies are superior to those of ants, in many others the civili- 

 zation of ants is notably superior. No village of Kaffirs can be- 

 compared to a palace of the Termites. The classifications separate- 

 these insects (sometimes called " white ants ") from the ants, since 

 the latter are Hymenoptera, while the former are ranked among 

 the Neuroptera, but their constructions are almost alike, and may 

 be described together. These small animals, relatively to their 

 size, build on a colossal scale compared to man ; even our most 

 exceptional monuments can not be placed beside their ordinary 

 buildings. (Fig. 8.) The domes of triturated and plastered clay 

 which cover their nests may rise to a height of five metres ; that 

 is to say, to dimensions equal to one thousand times the length of 

 the worker. The Eiffel Tower, the most elevated monument of 

 which human industry can boast, is only one hundred and eighty- 

 seven times the average height of the worker. It is three hun- 

 dred metres high, but to equal the Termites' audacity it would 

 have to attain a height of sixteen hundred metres. 



The lofty nest, or Termitarium, constitutes a hillock in the 

 form of a cupola. The interior arrangement is very complicated, 

 and at the same time very well adapted to the life of the inhabit- 

 ants. There are four stories in all, covered by the general ex- 

 terior walls. The walls of the dome are very thick ; at the base 

 they measure from sixty to eighty centimetres. The clay, in dry- 

 ing, attains the hardness of brick, and the whole is very coherent. 

 The sentinels of herds of wild cattle choose these tumuli as ob- 



