Steam:
Its Generation and Use

In No. 16 the headers were made in the form Nos. 18 and 19 were designed for fire protec- expanded in place, and to the drum by tubes bent so as to come normal to the shell. The joints between the headers introduced an ele- ment of weakness, and connections to the drum were insufficient to give the adequate circulation. ability to raise steam quickly and hold the pres- sure ; economy of fuel and dryness of steam being of secondary consideration. They both served their special purpose admirably, but were not found to be either economical or desirable were tried, alternately shifted right and left, to give a staggered position to the tubes. These These experiments, as they may be called, although many boilers were built of some of the headers were connected to each other and to the styles illustrated, clearly demonstrated that the drum by expanded nipples. This proved to best construction and efficiency be too rigid in construction, and -g, required adherence to the following 32