BRICKWORK. 



107 



in only one course oat of five, the remainder 

 of the wall is unconnected, except by the mor- 

 tar, and thus the principle upon which correct 

 honding is based, that no two mortar-joints 

 should come under one another, is violated. 



The strength of a wall depends, to a great 

 extent, upon the quality of the mortar em- 



ORXAMEXTAL BRICK. 



ployed. To make good mortar, clean, sharp 

 sand is required, and a lime having no in- 

 considerable hydraulic qualities. These are 

 mixed in the proportion of about one of lime 

 to four of sand, with no more water than is 

 necessary to moisten the whole of the parts 



ORNAMENTAL BRICK. 



and allow of the mixture's being thoroughly 

 worked. The custom in many parts of the 

 country is very common of using lime that is 

 but little better than pure chalk. Such lime is 

 not at all suitable, and not a few of the build- 

 ing accidents that have occurred from weak 



ORNAMENTAL BRICK. 



The foundations of a building are obviously 

 important. In localities where stone abounds, 

 they are often constructed in what is known 

 as rough or random rubble, which consi- 

 rough pieces of stone laid, without dressing:, 

 in such a way as to produce the best bond 

 possible under the circumstances. Examples 



EXTERIOR WALL IN RUNNING BOND. 



of this system of the construction of founda- 

 tion are found in nearly all buildings of New 

 York city, formed of the gneiss rock of which 

 Manhattan Island is mainly composed. Brick 

 is a good material for foundations, and, if it is 

 well burned, the moisture has no effect upon it. 

 Where brick is employed for foundations, it is 

 usual to form footings. These consist of widely 



I I 



INTERIOR WALL IN RUNNING BOND. 



spread courses, diminished by offsets equal to 

 half the thickness of a brick till the width of 

 the wall is reached. In good construction, 

 every brick in the footings is laid a header 

 where possible, while all stretchers neces- 

 sitated by the width of the course are placed 

 in the interior of the wall. The brick or stone 

 footings may either be built upon the soil or 



J L 



FOUNDATION OP HOLLOW WALL. 



brickwork may be directly attributed to the upon a bed of concrete, depending upon the 

 bad quality of the mortar by reason of the nature of the soil. Where hard rock or gravel 

 employment of chalk lime. is found on the site of a building, footings may 



