SCIENCE OF COMMON THINGS. 



Essentials for building. Pile. 



Mortising. 



The proper arrangement of the respective parts of 

 the building will insure its usefulness. Its strength 

 will principally depend on the walls being laid on a 

 good and firm foundation, of sufficient thickness at the 

 bottom, and standing perfectly perpendicular. And if 

 all the parts of a building correspond with each other, 

 and are handsome in themselves, then the architect 

 may rely on its beauty. 



S4S What are the essential elementary parts of a "building f 



Those which contribute to its support, indosure, and 

 covering. 



J349 What is a pile? 



A cylinder of wood or metal pointed at one extremity 

 and driven forcibly into the earth, to serve as a support 

 or foundation of some structure. It is generally used 

 in marshy or wet places, where a stable foundation 

 could not otherwise be obtained. 



25O Why are long columns supporting great weights made smaller- at 

 the top than at the bottom f 



Because the lower part of the column must sustain, 

 not only the weight of the superior party but also the 

 weight which presses equally on the ' whole column. 

 Therefore the thickness of the column should gradually 

 decrease from bottom to top. 



251 In the construc- 

 tion of buildings various 

 terms are employed to de- 

 signate the method in 

 which the timbers are 

 fitted into each other: what 

 do we mean by mortising ? 



Mortising is a 

 method of insertion 

 in which the pro- 

 jecting extremity 

 of one timber is 

 received into a perforation in another. (See Jig. 10.) 



S32 Why are steep roofs, or those constructed with considerable incli- 

 nation, best adapted for houses in cold climates ? 



In order that the snow may not be retained upon 



Fig. 10. 



