243 ART OF BUILDING. 



be calculated to sustain more than 50,000 pounds when 9 

 inches in diameter. The piles cannot be placed nearer 

 together than a certain distance, if they are the ground 

 will be so much compressed as to render the driving of 

 them very difficult, if not impossible ; the nearest dis- 

 tance at which they can be placed has been determined 

 by numerous experiments to be 2 feet from centre to 

 centre. 



It is well known that a piece of wood will resist a 

 pressure on its end, acting in the direction of the fibres, 

 in exact proportion to its number of fibres, or its size 

 but its length has some influence upon its resistance. 

 It has been found that as pressure is increased, the 

 length should decrease according to its square ; that is, if 

 a stick of timber or pile be 25 feet long and just support 

 1000 pounds, if the pressure be increased to 2000 pounds 

 the pile must be decreased, not to 12^- feet, but to 5 feet 

 to be just as strong. 



Our conclusions then, from this elementary detail of 

 principles, are as follows ; piles should never be placed 

 nearer together than 2 feet, and should never be calcu- 

 lated to support more than 50,000 pounds. 



The construction of stone arches is the most difficult 

 and useful part of the practical mason's trade. The meth- 

 ods now in use for finding the patterns of the stones for 

 arches of various descriptions, are not only laborious but 

 exceedingly difficult and perplexing. A knowledge of 

 descriptive geometry as applied to finding these patterns, 

 would be an important acquisition to the masons ; by 

 means of this science, what requires the labor of weeks 

 in the old way, may be performed in a few hours. Our 

 limits will nor permit us to explain this highly important 

 science, as it would require the space of two or three tracts. 



Stone Houses. The beauty of a stone building depends 

 mainly upon the kinds and finish of the stone, and where 

 the stones are handsomely. cut and in proper shape, it 

 leaves scarcely anything to be desired. Houses and 

 other buildings are constructed in an economical manner, 

 particularly in the country, of rough stone of any kind, 

 to which great beauty may be given by covering them on 

 the outside with plaster or cement. For this kind of 

 construction the following principles should be adhered 



