ype; three vessels; the Marengo, Ocean, and Suffren.
2. The Friedland type, of which no others are built.
3. The Richelieu type, of which no others are built.
4. The Colbert type, of which there are two; the Colbert and the
Trident.
5. The Redoubtable type, of which no others are built.
6. The Devastation type, of which no others are built.

[Illustration: THE FRENCH IRONCLAD WAR SHIP COLBERT.]

The Colbert was launched at Brest in 1875, and her sister ship, the
Trident, in 1876. Both are of iron and wood, and the following are the
principal dimensions of the Colbert, which apply very closely to the
Trident: She is 321 ft. 6 in. long, 59 ft. 6 in. beam, and 29 ft. 6
in. draught aft. Her displacement is 8,457 tons, her indicated horse
power is 4,652, and her speed 14.4 knots. She has coal carrying
capacity for 700 tons, and her crew numbers 706. The thickness of her
armor belt is 8.66 in., that protecting the central battery is 6.29
in. thick, which is also the thickness of the transverse armored
bulkheads, while the deck is 0.43 in. in thickness. The armament of
the Colbert consists of eight 10.63 in. guns, two 9.45 in., six 5.51
in., two quick firing guns, and fourteen revolving and machine
guns.--_Engineering._

* * * * *

A compound locomotive, built by the Rhode Island Locomotive Works, has
been tried on the Union Elevated Railroad, Brooklyn, N.Y. The engine
can be run either single or compound. The economy in fuel was 37.7 per
cent, and in water 23.8 per cent, over a simple engine which was
tested at the same time. The smoothness of running and the stillness
and comparative absence of cinders was fully demonstrated.

* * * * *

STEAM ENGINE VALVES.

[Footnote: Lecture delivered at Wells Memorial Institute, Boston, in
the Lowell Free Course for Engineers. From report in the _Boston
Journal of Commerce_.]

By THOMAS HAWLEY.

RIDING CUT-OFF VALVES--PECULIARITIES AND MERITS OF THE DIFFERENT
STYLES.

In considering the slide valve in its simple form with or without lap,
we find there are certain limitations to its use as a valve that would
give the best results. The limitation of most importance is that its
construction will not allow of the proper cut off to obtain all the
benefits of expansion without hindering the perfect action of the
valve in other particulars. At this economical cut off the opening of
the steam port