50 BULLETIN OF THE NEW YORK STATE MUSEUM 



to 26 inches in depth and from 3 feet 10 inches to 4 feet 2 

 inches in diameter, with a capacity of 100 to 150 gallons. 

 The metal at the bottom of the kettle is if inches, and at 

 the rim f inch thick. The two lugs are 5 inches long by 

 1^ inches in diameter, situated about 4 to 5 inches below 

 the rim and opposite each other. The arches or flues are 

 formed by a central wall, 3 feet wide at the base and grate, 

 and one foot wide on top, battering an equal amount on 

 both sides and two side walls 18 inches wide at base and 

 grate, battering on the inside to 8 inches on top. These 

 walls are built of ordinary stone and lined on the inside 

 with bricks. That portion of the walls which is especially 

 exposed to an intense heat is lined with fire bricks, which is 

 usually up to the 15th kettle from the front. The distance 

 from the bottom of the kettle to the top of the grate is 3 

 feet 6 inches with a solid fire brick arch in each, extending 

 somewhat beyond the length of the grate. The distance 

 from the bottom of the kettle to the crown of this arch is 

 10 to 12 inches. Beyond the grate the fire brick arches are 

 constructed in sections, the so called " rings " with air 

 spaces between, which increase in size with the advancing 

 distance from the grates. This construction allows the 

 heated gases to pass through these spaces without striking 

 the kettle bottoms directly. While the distance between 

 the bottom of the front kettle and the top of the grate is 3 

 feet 6 inches, these flues decrease in depth as they advance 

 towards the chimney, so that under the last kettle the dis- 

 tance is but 6 or 8 inches. The kettles are hung as close 

 as possible with their rims against each other and the space 

 between the walls and kettles above the lugs is properly 

 covered by masonry, etc. for the purpose of confining all 

 the heat as much as possible within the two arches. The 

 two lugs enable the workman to hang the kettles perfectly 

 free in the arches or flues, leaving an open space of several 

 inches between the walls of the kettles and arches. Thus 

 the heated gases in their passage from the grate to the 



