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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. The concrete 

 layer is divided into two or three parts, and each part is spread 

 over the ground at a different time. After all the parts are 

 joined together, the whole surface is covered with cement mortar. 

 At a glance such a concrete layer seems as satisfactory as the 

 ordinary layers. However, junctions between the sections are 

 not tight enough to prevent the intrusion of the termites, and in 

 many cases it was proved that the concrete layer had been pene- 

 trated by Coptotennes fonnosanus when it was ill-constructed; 

 that is, with the layer divided into several parts. 



Sometimes the architect is required to build the ground floor 

 somewhat higher than the ground level. In such cases the 

 concrete layer should be constructed, and the two layers on dif- 

 ferent levels connected by another vertical layer. This method 

 is not advisable because of the presence of many junctions, which 

 are liable to be passed through by the termite. If it is necessary 

 to raise one part of the floor, it is better to make two concrete 

 layers separately, instead of joining the two. 



First floor. — Dark places with a proper quantity of moisture 

 are most favorable for the habitation of Coptotennes fornw- 

 sanus. It is necessary, therefore, to provide ventilation holes 

 and skylights for inclosed spaces, such as underparts of floors 

 or inner parts of roofs. 



In the case of storehouses or other special buildings the 

 termite-proof concrete layer may be directly used as the first 

 floor, but in ordinary houses the first floor should be raised about 

 3 feet (about 1 meter) above the concrete layer, by means of 

 brick walls and brick supports. Two methods are adopted for 

 constructing the first floor : the external parts of the building are 

 entirely surrounded with brick walls about 3 feet (about 1 meter) 

 high, which are provided with square ventilation holes, 2 by 1.2 

 feet (about 0.6 by 0.4 meter), situated 6 feet, (about 2 meters) 

 apart ; the floor rests upon square brick supporters ; the floor rs 

 placed upon brick arches. Even in wood construction the present 

 method is adopted, all woodwork being placed upon brick sup- 

 ports. 



The advantages of this construction are as follows : None of 

 the woodwork is in contact with the ground; the basement of 

 the building is always kept dry and clean ; the ample light makes 

 inspection easy ; and it is eft'ective in keeping the buiding free 

 from rats and mice, which are the propagators of the plague. 



Second floor; brick building. — The second floor is constructed 

 of reenforced concrete just like the concrete layer on the ground 

 level, making a continuous plane. Its edges are extended to 

 the external part of the walls, instead of being partially inserted 

 into the brick walls. The upper and the lower surfaces of the 

 laver are covered with cement mortar, and all the crevices, even 



