THE FRENCH IRONCLAD WAR SHIP COLBERT.

The central battery ironclad Colbert is one of the ten ships of the French navy that constitute the group ranking next in importance to the squadron of great turret ships, of which the Formidable is the largest.  The group consists of six types, as follows: 

  1.  The Ocean type; 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.

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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.

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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.