I 



ON THE EARTHQUAKE AND VOLCANIC PHENOMENA OF JAPAN. 313 



avoided. Private buildings should be of wood. In all cases the limitino- 

 spans of roofs were specified, and the roofs must be light. Lieut.t 

 Colonel Cortes, who wrote at some length on structures in earthquake 

 countries, shows that buildings must be light as well as strong, and this 

 may be obtained by building their parts together much in the same 

 manner that the timbers of a ship are bound together. Foundations and 

 walls should be continuous. Timber work and masonry should not come 

 in contact, otherwise they may be mutually destructive. 



After criticising the system of building in Manila, and showing how 

 it may be improved, especially with regard to balconies and roofs, Colonel 

 Cortes proposes as a foundation a timber platform almost in the surface 

 of the ground, from which rises a building with iron or timber framing 

 footed on a dado of masonry, surmounted by a light roof. The waU 

 framing may be filled with brick or plaster. Colonel Cortes' descriptions 

 are accompanied by an elaborate series of illustrations. 



The Californian .system of construction, for which a patent has been 

 granted, appears to be very similar to that proposed by Mr. Lescasse, 

 the essential feature in which is to tie a masonry construction together at 

 each story by a set of iron or steel rods, which run from end to end, and 

 from back to front in the interior of the walls of a building. There are 

 also rods running vertically. 



Prom South America but little information has been obtained. In 

 Columbia the smaller houses have been built of thick adobe bricks, while 

 the Spanish have used stone. 



In Equador (Quito) occasionally a special earthquake-proof room is 

 built, the walls of which are a wooden framework filled in with adobe. 

 Many houses which have adobe walls three feet thick have only one 

 story, and there are few houses with more than one upper story. 



In Venezuela, also, the houses are low. In Mexico and Bolivia the 

 houses are solidly built ; while in Lima certain buildings are constructed 

 lightly so that they may yield. 



From Guatemala (San Salvador) I received from Messrs. Clark & Co., 

 contractors, the drawing of a house supposed to be earthquake-proof. It is 

 of timber well framed together, and very similar to the bungalows in Japan. 



These latter descriptions are particularly meagre, and for a full 

 description of the system to which they allude it is necessary to refer to 

 vol. xiv. of the ' Trans. Seis. Soc' of Japan, 



16. Conclusions. 



If we wish to mitigate the effects of earthquakes, one general conclu- 

 sion that may be drawn from what has been written is, that it is 

 essential to select a site where we know from expei-ience and from 

 experiment that the ground suffers but slight motion. This will generally 

 be the hard ground, which is usually the high ground. Soft ground, 

 slopes, and scarps should be avoided. 



Having obtained our site, we can follow one of two general systems 

 of construction— either to give so much rigidity to a structure that it may 

 be hkened to a steel box, or to erect a building which is light, but which 

 has so much fle3;ibinty that it may be compared to a wicker basket— in 

 either of these structures we ought to have lightness, especially in their 

 upper parts. 



Amongst the former class of buildings, which, from the materials of 



