856 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



being three inches diameter, and one and a half inches long, flar- 

 ino- outward to- their junction with the sphere. The efids of those 

 necks are machine-turned, with rebate joints, in such precision as 

 to be interchangeable to an infinite degree, easily put together and 

 as easily dissected. They are usually cast in sets or units of two 

 and four globes each, united in each case in the casting, by necks 

 at rioht angles with the union necks before described. 



In composing a boiler section in the works, a strong platform 

 on wheels is provided, of proper dimensions, upon which vertical 

 rests are secured at proper intervals, to fit and receive the spheres, 

 which are laid into the recesses and fitted together, a two globe 

 unit and a four glol^e unit in line, transverse with the section form- 

 ing a width of six spheres. The next line is varied by placing a 

 two globe unit parallel with one of four in the former case, the 

 third line being a duplicate of the first, and so on until the num- 

 ber — usually twelve series — is completed, but terminating at the 

 bottom end of the slab with a four globe unit only, and this placed 

 at one side. See Figs. 1, 2, 3, 4. 



The outer spheres of the units have but three necks, being closed 

 at their extreme ends. Round iron rods are now passed through 

 the globes by the open necks. At the lower end a strong cast iron 

 cap or hood, fitting the neck of the sphere, is secured to the rod; 

 a cap of diflerent shape is fitted to the opposite end of the rod, on 

 which there is a screw thread, taking a strong nut, •s\'hich, being 

 properly tightened, binds the Avhole together. 



The platform or truck is then moved to the hydraulic pump, 

 and the section tested to a pressure of 300 pounds per inch, after 

 which it is packed away with the finished work, for sale, either by 

 itself, a six-horse power boiler, or united Avith others precisely 

 like it, to form its proportionate part of 600 or other horse power. 



Usually the sections are placed vertically on their longest edge, 

 with the front end elevated to about 45°, and if two or more sec- 

 tions are added, they are fixed parallel with the first, with an inter- 

 vening space of about one inch between the globes. The sections 

 are often made up in diflferent shapes to that described, and set 

 perpendicularly, with equal advantage. 



Each pair of sections are connected at top and bottom through 

 their open necks, ])y curved union pipes, having in the middle a 

 short flanched branch pipe extending outwards from the sections. 

 To the lower branch pipe a transverse feed water pipe is con- 

 nected, extending across the boiler, and at the top a similar trans- 



