34 How TO Ghow Cut Flowers. 



pacity to carry several houses, it will facilitate the cir 

 lation to have the outlet six inches, and carried b 

 pipe of the same size as a header, from which all 

 four-inch flows may be taken. 



Should it seem advisable to adopt this, as it is tern 

 " the up hill system," it will be necessary to obse 

 four things : 



First. That your boiler is set low enough, so that 

 point from which the water flows out of it shall be 

 least twelve inches lower than where the flow p 

 commences to return to the boiler. 



Second. That at the highest point of the flow th 

 be a vent for the escape of air. This may be provi( 

 for by a regulation stand pipe. A simple way is 

 tap the casting at that point and screw into it a 1 

 inch gas pipe, letting its end be a few inches hig 

 than your expansion tank, or by a simple pet o 

 which can be opened and closed at will. 



Third. That neither th« flow nor return be allo-v 

 to make short dips or depressions from the settling 

 the rests, as by this means the circulation is sometii 

 impeded, but that the pipes be so graded that the ; 

 and fall will be as nearly uniform as possible. 



Fourth. That what is called an "expansion tar 

 be placed at some convenient point near the boi 

 This may vary in size from one-fourth to a full bar 

 according to the amount of pipe it is expected to sei 

 a barrel being as large as will be needed for any o: 



