The Use of Compressed Air in Conjunction with Medicinal Solutions in the Treatment of Nervous and Mental Affections.—­By J. Leonard Corning.—­The enhancement of the effects of remedies by subsequent application of compressed air. 13134

VIII.  Mineralogy.—­A Gem-Bearing Granite Vein in Western
      Connecticut.—­By L.P.  GRATACAP.—­A most interesting
      mineral fissure yielding mica and gems recently opened. 13141

IX.  Natural history.—­Ants.—­By Ruth Ward Kahn.—­An
      interesting presentation of the economy of ants. 13140

X. Naval engineering.—­Armor Plating on Battleships—­France
      and Great Britain.—­A comparison of the protective systems
      of the French and English navies.—­5 illustrations. 13127

      The Redoutable.—­An important member of the French
      Mediterranean fleet described and illustrated.—­1
      illustration. 13127

XI.  Technology.—­New Bleaching Apparatus.—­A newly invented
      apparatus for bleaching pulp.—­2 illustrations. 13133

* * * * *

THE REDOUTABLE.

The central battery and barbette ship Redoutable, illustrated this week, forms part of the French Mediterranean squadron, and although launched as early as 1876 is still one of its most powerful ships.  Below are some of the principal dimensions and particulars of this ironclad: 

Length           318 ft. 2 in. 
Beam              64 "   8 "
Draught           25 "   6 "
Displacement    9200 tons. 
Crew             706 officers and men.

[Illustration:  The French central battery ironclad Redoutable.]

The Redoutable is built partly of iron and partly of steel and is similar in many respects to the ironclads Devastation and Courbet of the same fleet, although rather smaller.  She is completely belted with 14 in. armor, with a 15 in. backing, and has the central battery armored with plates of 91/2 in. in thickness.

The engines are two in number, horizontal, and of the compound two cylinder type, developing a horse power of 6,071, which on the trial trip gave a speed of 14.66 knots per hour.  Five hundred and ten tons of coal are carried in the bunkers, which at a speed of 10 knots should enable the ship to make a voyage of 2,800 knots.  Torpedo defense netting is fitted, and there are three masts with military tops carrying Hotchkiss revolver machine guns.