RULES AND REGULATIONS FOR FREEBOARD. 149 
in the paper to the high capacity run, which I think stands as the world record for high 
boiler capacity, and high burner capacity with good economy. ‘The oil burned per square 
foot of heating surface was 1.5 pounds. The combustion was excellent, as shown by 
the fact that more than 76 per cent efficiency was obtained, while the output of the 
boiler, figured in pounds of water evaporated per square foot of heating surface from 
and at 212 degrees, was nearly 23 pounds. 
As many of you know, the ordinary land horse-power value calls for an evaporation 
of 3.5, and that shows what can be done with a large unit with mechanical atomizers, 
using oil. In that test there were eleven burners each of which burned more than 
1,000 pounds of oil per hour, but last summer the Babcock & Wilcox Company brought 
out a larger type of the same design of burner in which they were able to obtain a burner 
capacity of 1,500 pounds of oil per burner per hour, with six of the burners in operation 
in one boiler. 
The next step in development was indicated in a test of the burner which I will 
describe later, a wide-range mechanical atomizer that was installed under the Normand 
boiler at the Fuel Oil Testing Plant. In this test more than 1,800 pounds was burned 
per burner per hour with good efficiency. This performance was followed in September 
by the tests I referred to with a larger size of the same type of Babcock & Wilcox burner. 
More than a ton of oil per hour per burner was burned, the maximum figure being at 
the rate of 2,287 pounds for half an hour’s run. 
While the evaporation figures show a little less efficiency for these large units at the 
same capacity than a larger number of smaller units, it must be realized that the advance 
is recent, and all these tests are really in an experimental stage. We have seen repeatedly, 
and we shall see again, a small number of large units beat out the larger number of small 
units. 
Plate 63 shows a chert where the highest curve was obtained with eleven burners 
and the second from the bottom with sixteen units of smaller size. In the test of the 
Normand boiler, three burners were used against about eleven in the previous test. So 
that while I say that the tests shown here do not actually give the same efficiency as a 
larger number of small units, the day will come when the efficiency will be maintained 
with the smaller number of very large units. I feel that that is the trend of development. 
As an example of what the large unit means, note that the battle cruisers, which 
are now being laid down to develop 180,000 horsepower, were only a few months ago to 
have fifteen burners per boiler. On the basis of the 1,800-pound test, it would only 
require seven burners per boiler, and when it is considered how this simplifies the pip- 
ing and saves the necessity for the care of all of these small units, one will appreciate 
what this increase in the capacity of the burner means when dealing with large powers. 
While fifteen burners were assigned to the boiler, I think it is questionable whether 
they could have been put on the front. I doubt if there would be room enough to do 
that, but there is ample room for the seven burners. 
I have referred, at the end of the paper, to a question On has always interested 
me, and in which I regret to say there has been no advancement, and that is the mea- 
surement of viscosity. 
As you all know, there are a half dozen viscometers and scales, and I have recently 
seen a reference to a new complication, namely, ‘“‘Engler seconds.’’ JI am fortunate 
in being able to present data showing some relation between the Saybolt seconds and 
the Engler degrees, which is probably accurate enough for practical purposes. 
