Gridiron valve. 
Griffith’s screw. 
Grinding corn, power necessary for. 
Grinding of cylinders. 
Gudgeons, strength proper for. 
Guides of locomotives. 
Guides of direct acting screw engine. 
Gun metal, strength of. 
Gyration, centre of.

Harvey and West’s pump valves. 
Hawthorn, expansion valve by. 
Heat, latent, definition of. 
Heat, specific, definition of. 
Heat, Regnault’s experiments on. 
Heat, loss of, by blowing off marine boilers. 
Heating surface of boilers. 
Heating surface per square foot of fire bars in locomotives,
  a cubic foot of water evaporates by five square feet of heating surface. 
Heating of bearings, causes of,
  bearings should always be slack at the sides, else the pressure is
    infinite. 
High pressure engine, definition of. 
High pressure engines, power of. 
High speed engines,
  arrangements proper for high speeds. 
Hoadley’s portable engine. 
Hodgson’s screw. 
Hoe & Co.’s steam engine. 
Holding down bolts of marine engines,
  or bolts for securing engines to hull. 
Holms’s screw propeller. 
Horses power, definition of,
  nominal horse power;
  actual power ascertained by the indictator;
  Admiralty rule for. 
Hot water or feed pump, description of. 
Hot well, description of.

Increasing pitch of screw. 
Incrustation in boilers. See also Salt. 
India rubber valves for air pump. 
Indicator, description of the,
  by McNaught, structure and mode of using;
  Gooch’s continuous indicator. 
Injection cock. 
Injection cocks of marine engines at ship’s sides. 
Injection orifice, proper area of. 
Injector, Giffard’s. 
Injection valve. 
Inside cylinder locomotives. 
Iron, strength of,
  limits of elasticity of;
  proper strain to be put upon iron in engines and machines;
  aggravation of strain by being intermittent;
  increase of strain due to deflection;
  strength of pillars and tubes,
    combination of malleable and cast iron. 
Iron, cast, strength of,
  cast iron beams;
  may be strong to resist strains, but not strong to resist shocks;
  should be combined with wrought iron to obtain maximum strength. 
Iron, if to be case hardened, should be homogeneous.

Jacket of cylinder, advantages of. 
Joints, rust, how to make.

Kingston’s valves.

Lamb’s scale preventer. 
Lantern brass in stuffing boxes. 
Lap and lead of the valve, meaning of. 
Large vessels have least proportionate resistance. 
Latent heat, definition of. 
Latta’s steam fire engine. 
Lavagrian, expansion valve by. 
Lead and lap of the valve, meaning of. 
Lead of the valve, benefits of. 
Lever,
  futility of plans for deriving power from a lever. 
Lifting apparatus for screw propeller. 
Limits of elasticity. 
Links, main description of.