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Figure 9.—MILLHOLLAND’s PATENTED CENTRAL-COMBUSTION-CHAMBER BOILER with dead-plate fire grate. 
Note the similarity of this design to the general arrangement, excepting the patented features, of the 
Delaware boiler. 
area, since the firebox in regular wood burners of the 
period was rarely more than 34 inches wide. En- 
couraged by the Warrior's performance, Millholland 
turned his hand to rebuilding more of the Reading’s 
old engines. 
Two years before Millholland joined the Reading, 
several coal-burning, eight-wheel engines had been 
purchased from Ross Winans, who had developed a 
successful coal burner some years earlier. Winans’ 
engines were built to burn soft coal, a fuel far more 
readily combustible than anthracite. These engines 
did not succeed on the Reading, however, although 
Millholland recognized that their builder was correct 
in providing a large grate area. He rebuilt one of the 
machines, the Delaware, in December 1850, and two 
sister engines soon thereafter. 
2 BULLETIN 252: 
(From U.S. National Archives.) 
Some months later the Sczentific American, comment- 
ing on the rebuilt engines, said that they were so 
successful that the Reading planned to rebuild all of 
their power on Millholland’s new plan.'® But the 
statement was premature, for the plan was, in fact, 
very defective. Whatever success was obtained with 
these engines should be credited to the method of 
firing and not to the firebox plan. Millholland had 
instructed the fireman to put only 7 inches of coal on 
the grates in place of the 18 inches previously used. 
(In the end, most locomotive authorities agreed that 
skillful firing was more important to successful coal 
burning than were the many complex boiler and 
16 Scientific American (October 18, 1851), vol. 6, p. 35. 
CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 
