ON HEATING VINERIES 19 



with two sets of roof ventilators, these being hung from 

 the ridge, on either side, at intervals of four or five 

 bays, the ventilators on one side being fixed angle-wise 

 to those on the other side, water-tight hinges being used 

 for the purpose. 



ON HEATING VINERIES 



To begin at the beginning, where any extent of four 

 inch pipes say, from five hundred feet upwards is to 

 be heated, the horizontal tubular boiler is to be recom- 

 mended, sizes being supplied to meet special require- 

 ments in the matter of heating, as under : 



No. i. Nine pipes on top, three pipes at side, four feet six inches 



long ; heating power in four-inch pipes, 750 feet. 

 No. i. Nine pipes on top, three pipes at side, six feet six inches 



long ; heating power in four-inch pipes, 1250 feet. 

 No. i. Nine pipes on top, three pipes at side, nine feet six inches 



long; heating power in four-inch pipes, 1750 feet. 

 No. 2. Eleven pipes on top, three pipes at side, four feet six inches 



long; heating power in four-inch pipes, 1250 feet. 

 No. 2. Eleven pipes on top, three pipes at side, six feet six inches 



long ; heating power in four-inch pipes, 1750 feet. 

 No. 2. Eleven pipes on top, three pipes at side, nine feet six inches 



long ; heating power in four-inch pipes, 2250 feet. 

 No. ^b pattern. Eleven pipes on top, three pipes at side, nine feet 



six inches long ; heating power in four- inch pipes, 4000 feet. 



The tubes in the No. 2b pattern boiler, at sides and 

 over fire, are four inches inside in diameter, while 

 those in the other six boilers mentioned are three 

 inches inside in diameter. It is important in setting 

 boilers in position on a bed of brickwork or concrete, 

 that a proper rise from front of furnace to back should 

 be allowed, in order to secure a good free circulation 

 of hot water from the boiler to the flow pipes, in which 

 also a rise of from half an inch to three-quarters of an 

 inch should be allowed in each nine feet length of 

 pipe. Thus a rise of two and a half inches should 



