342 Philippine Journal of Science m» 



termite, since the foundation timbers are laid in contact with the 

 ground. 



From the point of view of economy, it is impossible to elim- 

 inate such nonresistant timbers from Japanese buildings. 

 Therefore, a discovery of a new method of building construction, 

 by which the attack of the termite can be absolutely prevented, 

 becomes an important problem. 



As a result of bitter experience during the last twenty years, 

 the method of constructing buildings and the treatment of 

 nonresistant timbers have been greatly improved. As it is 

 practically proved that the termite-proof building construction 

 that has been recently adopted by the Government of Formosa 

 is somewhat satisfactory, I, having been chiefly concerned with 

 the investigation, wish to explain the method in detail. 



Disinfection of the ground. — Not only is Coptotermes formo- 

 sanus widely distributed throughout Formosa, but it occupies 

 the whole ground densely; so that, as a first step in erecting 

 a building, it is absolutely necessary, to destroy the pest, to keep 

 the site free from the source of the damage. For this purpose, 

 heavy oil of petroleum, creosote oil, or Termitol (a mixture of 

 heavy oil of petroleum and cresol) is sprinkled over the whole 

 surface of the site, using 1 gallon (about 4 liters) of the fluid 

 to 6 square feet (about 0.6 square meter) of area. 



These fluids are nonvolatile at ordinary temperature and in- 

 soluble in water. They are effective for a long time, as they 

 remain in the ground unchanged. 



Footings. — To keep a wooden building free from termites, 

 care should be taken not to use timbers in contact with the 

 ground. To do this, it is necessary to use bricks and concrete 

 in footings, even in the case of a wooden building. 



The termite-proof concrete layer. — In order to prevent the 

 entering of the termite, it is necessary to disconnect the upper 

 parts of buildings from the soil. After the footings have been 

 completed, a layer of cement concrete about 6 inches (about 15 

 centimeters) thick is spread over the whole area of the site at 

 ground level, the edges being extended about 3 feet (about 1 

 meter) beyond the external walls of the building. Along the 

 edges small drains are made, surrounding the whole concrete 

 layer. Then the entire surface of the layer is covered with a 

 thin stratum of cement mortar to fill up all the pores and cracks 

 (Plate IX, fig. 1). 



To reach the building, termites must either penetrate the 

 concrete layer or cross the drains from the outside. It is proved, 



