SECTIONAL BOILERS.
Probably one of the first sectional boilers brought into practical use is one made of hollow cast iron spheres, each 8 inches in diameter, externally, and 3⁄8 of an inch thick, connected by curved necks 31⁄2 inches in diameter. These spheres are held together by wrought iron bolts and caps, and in one direction are cast in sets of 2 or 4, which are afterwards drawn together so as to give more or less heating surface to the boiler according to the number used.
NOTE.
Owing to their multiplication of parts all sectional, including water tube boilers, should be made with unusual care in their details of construction, setting, fittings and proportions. It is to the attention paid to these “points” that the sectional boilers are now coming into more general favor.