gears into a large spur wheel fixed on the shaft which carries the clip
drum. In the arrangement of hauling gear above described the ratio of
the gear is 1:8.44, in the case of tugs Nos. I. to IV.; while in tugs
Nos. V. to VIII. the proportion has been made 1:11.82. In tugs I. to IV.
the diameter of the clip drum is 2.743 meters (9 feet), while in the
remaining tugs it is 3.056 meters (10 feet).

From some interesting data which have been placed at our disposal by Mr.
Thomas Schwarz, the manager of the Central Actien-Gesellschaft fur
Tauerei und Schleppschifffahrt, we learn that in the tugs Nos. I. to IV.
the hauling machine develops on an average 150 indicated horse, while in
the tugs No. V. to VIII. the power developed averages 180 indicated
horse power. The tugs forming the first named group haul on an average
2,200 tons of cargo, contained in four wooden barges, at a speed of 4½
kilometers (2.8 miles) per hour, against a stream running at the rate of
6½ kilometers (4.05 miles) per hour, while the tugs Nos. V. to VIII.
will take a load of 2,600 tons of cargo in the same number of wooden
barges at the same speed and against the same current. In iron barges,
about one and a half times the quantity of useful load can be drawn by a
slightly less expenditure of power.

The average consumption of coal per hour is, for tugs Nos. I. to IV., 5
cwt, and for tugs Nos. V. to VIII., 6 cwt.; and of this fuel a small
fraction (about one-sixth) is consumed by the occasional working of the
screw propellers at sharp bends. The fuel consumption of the wire rope
tugs contrasts most favorably with that of the paddle and screw tugs
employed on the Rhine, the best paddle tugs (with compound engines,
patent wheels, etc.) burning three and a half times as much; the older
paddle tugs (with low pressure non-compound engines), four and a half
times as much; and the latest screw tugs, two and a half times as much