162 RECENT ADVANCE IN OIL BURNING. 
Various methods of interconversion of the two scales have been suggested, but the 
problem is not as easy as it looks, as the conversion factor is not constant through- 
out the viscosity range and it also varies with the character of oil. These dif- 
ferences are perhaps more academic than of real importance, as approximation 
to the viscosity results will usually serve. 
Roughly speaking, the Engler degrees are 1/36 of the Saybolt seconds, 2. e., 
S=36E, or H= = where S=Saybolt seconds and E = Engler degrees (not seconds). 
I am fortunate in being able to present a chart (Plates 69 and 70) prepared by 
Mr. R. C. Brierly, chemist at the Fuel Oil Testing Plant, showing the relation of the 
two scales by actual test of samples of the same oil at the same temperature in the 
two types of viscometer. The solid line in the chart represents the ratio E= ae 
which is sometimes used for approximate determinations. The dotted line con- 
necting the various points determined by test favors the ratio of 36 to I. 
Mr. Brierly states :— 
“T am sending you enclosed the graphical representation of the theoretical 
Engler-Saybolt ratio and points plotted from our determinations. It is unfor- 
tunate that these ratio tests were not run at one or two certain temperatures, as 
temperature variation is undoubtedly a most important factor. However, I have 
noted oil temperature beside each plotted point. 
“As a matter of interest I ran a sample of “Binderine’—paper pulp refuse—on 
both machines for comparison. I have shown it on the curve. Two of the most 
important references for the 1:37 ratio are the U. S. Navy Oil Fuel Specifications 
of 1917 and H. G. Nevitt in Chemical and Metal Engineering for June 23, 1920, 
page II7I.” 
