XV. 4 



Oshima: Formosan Termites 



343 



Fig. 2. Detail of termite-proof construction ; a continuous layer of ce- 

 ment at ground level. 



however, that cement concrete is quite safe against the attack 

 of the termite, while lime concrete is not. Not only is the 

 first method of attack almost impossible, but the second as well, 

 for the drains are so constructed that they catch rain water from 

 the eaves and thus prevent the intrusion of the pest. In the 

 dry season the termite very often crosses the drains; but its 

 covered tunnels can be found at once and it is readily driven 

 out, because the outer parts of the concrete layer extend beyond 

 the external wall and are used as sidewalks. 



The aim of constructing a continuous layer of concrete above 

 the ground level is to prevent absolutely the entering of the 

 termite by means of an impermeable barrier. Great care should 

 be taken, therefore, to keep the whole layer perfectly compact, 

 and to avoid the occurrence of cracks and pores. To do so, 

 the entire layer must be spread at the same time, in a continuous, 

 even plane. 



One of the practical difficulties of constructing a continuous 

 concrete layer is that it stops construction of all other parts 

 of the building until the concrete is entirely set. To get rid 

 of this difficulty, the methods shown in figs. 3 and 4 are very 

 often adopted. The concrete layer is divided into two or three 



Fig. 3. Detail of termite-proof construction ; a layer of cement 

 at ground level laid in two parts. 



