RECENT ADVANCE IN OIL BURNING. 161 
of the maximum, a good spray can be secured all the way down to about 10 per 
cent of the total. 
This method of spraying is the invention of Commander J. O. Fisher, U. S. 
Navy, now fleet engineer of the U. S. Atlantic fleet. He first applied it in an 
attempt to spray oil into the cylinders of an internal-combustion engine, where, 
owing to the intermittent action required, the ordinary mechanical atomizer was 
an entire failure. By introducing the by-pass a continuous flow was secured, 
even when the regular outlet orifice was closed. The application of the principle 
to atomizers for boiler work followed, with the result that a single burner without 
change of tip could be used over a greatly extended capacity range. The Navy 
Department has applied the Fisher burner with great success to small boilers of 
the launch type, where its wide range enables them to operate the boiler with only 
one burner. I have shown the navy design of this burner in Plate 68. The com- 
pany with which I am now connected has developed a modified form of the Fisher 
burner with which some interesting experiments have been carried out with the 
cooperation of the Navy Department. It is believed that the wide range in 
capacity will make the burner especially useful for fluctuating loads or in any 
installation where it is now necessary to change the tips or close off a portion of 
the burners. 
It may be of interest to state that the burners having a maximum hourly output 
of 1,820 pounds which were tested at the Fuel Oil Testing Plant were successfully 
operated at 250 pounds, while smaller tips designed for a maximum of 800 pounds 
were operated at a minimum of 80 pounds per hour. In our design we have dispensed 
with the spindle shown in Plate 68, and we control the capacity entirely by an 
external valve in the by-pass return line, so that by the manipulation of this valve 
any number of burners can be simultaneously increased or decreased in capacity 
over the entire range. Also, the tangential channels and the outlet orifice are 
in a single piece. 
A matter closely allied to the use of oil as fuel, in which there has been no 
advance and, if anything, a retrograde movement, is the measurement of the 
viscosity of oil. Unless I am grossly uninformed, we are no nearer a universal 
standard method of designating viscosity than ever, while, on the contrary, not 
only are new viscometers and new scales being devised, but there is a tendency 
in certain quarters to use Engler “seconds”’ in the same way that Saybolt seconds 
are used, instead of dividing the time of outflow of the oil in the Engler viscometer 
by the time of outflow of an equal amount of water. The latter gives the true 
Engler scale, as we have been taught to regard it, and the use of Engler seconds 
only adds to the confusion. 
It is probable that if the Saybolt viscometer had been obtainable by anybody 
outside the large oil companies ten or twelve years ago when the mechanical 
atomizer began to be used extensively, we should not now be using the 
Engler instrument at all in this country, notwithstanding its extensive use in 
Europe. But some method of determining viscosity became necessary and, as 
usual, the Germans were on the job and supplied us with Engler instruments. 
