HYDROGRAPHY, METEOROLOGY, NAVIGATION, AND ASTRONOMY GROUPS.

H1 Hydrography, oceanography, and allied topics.

H2 Navigation and navigational aids.

H3 Obstructions to navigation.

H4 Meteorology.

H5 Astronomy and astronomical reports.

H6 Physics.

H7 Time.

H1 HYDROGRAPHY, OCEANOGRAPHY, AND ALLIED TOPICS.

(For Grand Divisions, Water, see QH; for Geographic Divisions, Water, see QX)

H1-1 Anchorages and Harbors (includes reports of dredging).

Anchorages, forbidden.
Berthing facilities. (See L24).

H1-2 Channels (includes reports of dredging).

H1-3 Charts and Hydrographic publications.

Request for.

H1-4 Distances.

H1-5 Earthquakes (seismic disturbances).

H1-6 Fish banks, nets, stakes, etc.

H1-7 Islands (new ones, existence, nonexistence, change of form, location on charts, etc.).

H1-8 Magnetism and magnetic disturbances.

H1-9 Ocean currents, Gulf, Japanese, Equatorial, etc.

Bottle papers.

H1-10 Reefs, rocks, shoals, and banks.

H1-11 Rips and tide rips.

H1-12 Rivers and canals.

HI-13 Routes, ocean.

H1-14 Sea level, tides.

H1-15 Sea water.

Constituents and specific gravity.
Discolored.
Great waves.
Oil spots.
Oil used to calm sea.
Temperature.
Tidal waves.
Waterspouts.

H1-16 Sound, sound waves, and echoes.

Aberrations and silent areas.
Means of detecting.

H1-17 Soundings, deep-sea, etc.

H1-18 Surveys.

Aircraft surveys.
Hydrographic.
Reconnaissance,
Topographic.

H1-19 Trial courses, location of (obsolete, see NE.)

H1-20 Volcanoes

H1-21 Chart portfolios.

H1-22 Pollution of navigable waters.

H1-23 Air routes.

H1-24 Whales, seals, etc., observation of.

H1-25 Geographic positions.

Charted positions.
Latitude and longitude established.
Observation spots.
Records and methods of establishing.

H1-26 Geographic names, decisions of Geographic Boards. (For geographic locations, see also QG.)

H2 NAVIGATION AND NAVIGATIONAL AIDS.

H2-1 Anchorage.

Anchors for mooring.

H2-2 Beacons and ranges (other than radio and aerial).

H2-3 Buoys and dolphins, channel, mooring, range, and rack.

H2-4 Buoys, surveying.

H2-5 Fixing position (including computations and formulae),

H2-6 Hydraulics (as applied to action of passing vessels).

H2-7 Leader systems.

H2-8 Lighthouses and light vessels (location and character).

H2-9 Range-finder signals and stations.

H2-10 Rescue work.

H2-11 Seamanship.

H2-12 Structures, trees, earth formations (aids).

H2-13 Submarine signaling stations.

H2-14 Target and torpedo ranges.

H2-15 Zone system (obsolete, see H7-Time).

H2-16 Fog-signal stations.

Beacons.

H2-17 International ice patrol.

H2-18 Time balls and shapes.

H2-19 Life-saving stations (location and character).

H2-20 Radio beacons, ships and aircraft.

H2-21 Magnetic survey ranges.

Correspondence on erection and repair of structures, see N20.
For work on light vessels, see QS9.

H3 OBSTRUCTIONS TO NAVIGATION.

H3-1 Buoys adrift.

H3-2 Derelicts (vessels adrift out of control).

H3-3 Logs, timbers, trees, small boats, rafts, broken parts of vessels, etc.

H3-4 Fog and smoke.

H3-5 Ice, icebergs, and ice formations.

H3-6 Mines, surface or subsurface, explosive or nonexplosive. (See also S76 Mines.)

H3-7 Sea and gulfweed.

H3-8 Wrecks (vessels fast to bottom or stranded).

H3-9 Clearance of structures over navigable waters.

H3-10 Obstructions to air navigation (high buildings, towers, chimneys, flagpoles, high-tension wires, etc.).

H4 METEOROLOGY AND AEROLOGY.

H4-1 Aurora borealis and aurora australis.

H4-2 Lightning striking ship or affecting the compass (St. Elmo's light).

H4-3 Meteorites, meteoroids, meteors, and bolides.

H4-4 Meteorological and aerological instruments and equipment (aerographs, anemometers, anemographs, barometers, theodolites, pilot balloons, etc.).

Experimental and development projects.
Instructions for installation, operation, maintenance, etc.
Specifications, descriptions, prices, estimates.

H4-5 Requests or requisitions for serological instruments equipment, and supplies.

Invoices.
Requisitions.
Shipment notices.
Surveys.

H4-6 Observatories and stations; meteorological storm-warning towers and signals.

H4-7 Weather service (includes communications and instructions concerning.)

Forecasts and advices.
Observations and reports.

H4-8 Aerological forms (including instructions therefor).

H4-9 Weather phenomena.

Blizzards.
Floods,
Fog and fog dispersal.
Gales.
Hurricanes.
Ice formations.
Monsoons.
Static electricity.
Typhoons.

H4-10 Weather averages and statistics; climatology. (Filed by localities or regions.)

H4-11 Aerological policy, plans, and programs.

Annual report data.
News.
Progress.
Quarterly survey data.

H5 ASTRONOMY AND ASTRONOMICAL REPORTS.

H6 PHYSICS.

H7 TIME.

Central.
Daylight saving.
Eastern.
Greenwich.
Mountain.
Pacific.
Standard.
Times adopted in other countries and zone systems. (For time signals see A6-2.)
Washington Naval Observatory.