VIII.  Naval engineering—­The New Spanish Armored Cruiser Reina
      Regente.—­Illustration and full description of this recent
      addition to the Spanish navy.—­1 illustration. 9895

      The Spanish Torpedo Boat Azor—­Illustration and note of speed,
      etc., of this new vessel—­1 illustration. 9895

IX.  Ophthalmology—­The Bull Optometer—­An apparatus for testing
      the eyesight.—­The invention of Dr George J. Bull.—­3
      illustrations. 9908

X. Sanitation and Hygiene—­The Sanitation of Towns—­By J. Gordon,
      C.E.—­A presidential address before the Leicester meeting of
      the Society of Municipal and Sanitary Engineers and Surveyors
      of England. 9909

XI.  Technology—­A New Monster Revolving Black Ash Furnace and the
      Work Done with It—­By Watson Smith—­The great furnace of the
      Widnes Alkali Company described, with results and features of
      its working—­4 illustrations. 9900

      Apparatus Used for Making Alcohol for Hospital Use during the
      Civil War between the States—­By Charles K. Gallagher—­A curiosity
      of war times described and illustrated.—­1 illustration. 9900

      Confederate Apparatus for Manufacturing Saltpeter for Ammunition
      —­By Charles K. Gallagher—­Primitive process for extracting
      saltpeter from earth and other material—­1 illustration. 9900

      Electrolysis and Refining of Sugar—­A method of bleaching sugar
      said to be due to ozone produced by electric currents acting on
      the solution—­1 illustration. 9903

Improvements in the Manufacture of Portland Cement—­By Frederick Ransome, A.I.C.E.—­An important paper recently read before the British Association, giving the last and most advanced methods of manufacture. 9901

      Roburite, the New Explosive—­Practical tests of this substance,
      with special application to coal mining. 9897

      The Mechanical Reeling of Silk.—­An advanced method of treating
      silk cocoons, designed to dispense with the old hand winding of
      the raw silk.—­3 illustrations. 9898

* * * * *

THE SPANISH TORPEDO BOAT AZOR.

[Illustration:  The Spanish torpedo boat Azor.]

The Azor was built by Yarrow & Co., London, is of the larger class, having a displacement of 120 tons, and is one of the fastest boats afloat.  Her speed is 241/2 miles per hour.  She has two tubes for launching torpedoes and three rapid firing Nordenfelt guns.  She lately arrived in Santander, Spain, after the very rapid passage of forty hours from England.