THE STEAM TURBINE—PARSONS. eed 
plane surfaces parallel to the axis; and their purpose is to assist the 
flow and to stop the rotation of the air after being acted on by the 
moving blades. Each row of moving and fixed blades adds a little 
to the pressure, and compresses the air gradually along the annular 
space between the drum and the ease. Balance pistons or dummies 
are provided for balancing the end thrust of the air, as in the steam 
turbine. The speed of rotation is 3,600 revolutions per minute and 
the tip velocity of the air blades about 400 feet per second. 
Norr.—Since this lecture was given, many of the predictions con- 
tained therein have been realized. The two new large express 
Cunarders, the Lusitania and the Mauretania, have given eminently 
satisfactory results. The steam consumption of the main turbines 
has been ascertained to be 12% pounds per shaft ‘horsepower at full 
power. 
In view of the satisfactory results obtained in the earlier war ves- 
sels fitted with turbine machinery for the British Navy, the Ad- 
miralty decided to adopt the Parsons turbine exclusively for new 
construction, from the largest battle ship and cruiser down to and 
including torpedo boats. 
The progress of the Parsons turbine in other countries has also 
been very noteworthy. In the United States the results attained 
recently on the trials of the scout Chester, equipped with Parsons 
turbines, when compared with a sister vessel, the Birmingham, fitted 
with reciprocating engines, have shown in favor of the turbines at 
all speeds. At full speed, on a six hours’ trial, the Chester obtained 
a speed of 26.5 knots per hour, as against 24.3 in the Birmingham. 
In addition to the above, there are in the United States six mercan- 
tile vessels now on service (passenger and freight), and five torpedo- 
boat destroyers are also at present under construction, representing a 
total horsepower of 110,000 built and under construction. 
In Japan there are two large liners now nearing completion, one 
of which has already completed her official trials, having exceeded 
the contract speed of 19} knots by 1 knot. Two small passenger 
vessels are now on service in Japan. A dispatch boat is also being 
fitted out for the Japanese Government, and two new passenger ves- 
sels and one large liner are at present under construction, representing 
a total horsepower of 90,000. 
In France six large battle ships and three destroyers are under 
construction of 150,000 horsepower; in Germany excellent results 
were obtained recently with torpedo-boat destroyer G. 137, and at the 
present time a large and powerful cruiser, as well as a small cruiser 
and several torpedo-boat destroyers, are under construction, of about 
110,000 horsepower; in Italy a cruiser; in Austria a cruiser; and in 
