New York City (The Battery) Tide Tables for 1942-Continued Source: U. S. Coast and Geodetic Survey; Eastern Standard Time. Meridian 75° W. Time meridian 75° W. Heavy-faced type indicates p. m. tides. Oh is midnight, 12h is noon. Heights are reckoned from the datum of soundings on charts of the locality which is mean low water. Time of Tides at Points on the Atlantic Coast Source: United States Coast and Geodetic Survey. To be added to or subtracted from Time of Tides tables at New York City, as shown on pages 178, 179. League Island, Pa. 1 05 Marblehead, Mass. Poughkeepsie, N. Y... add 4 35 Baltimore, Md. add 11 00 Nahant, Mass Providence, R. I. .sub. 0 55 Bar Harbor, Me.. Nantucket, Mass.. Newark, N. J. Block Is. Hbr., R. I..sub. 1 00 Boston, Mass.. New Bedford, Mass..sub. 0 55 Rockland, Me. add 2 20 3 25 Rockport, Mass. 2 50 Salem, Mass. 1 05 Sandy Hook, N. J....sub. 0 35 .add 0 20 add 0 55 Eastport, Me. Old Pt. Comfort, Va.. add 150 0 25 2.00 add 2 40 Plymouth, Mass. ..add Point Lookout, Md. AVERAGE RISE AND 2 45 add 5.00 FALL OF TIDE Southport, N. C. .sub. 0 30 2 55 12 25 0 20 3 25 2 15 At New Orleans, the periodic rise and fall of the tide varies with the stage of the Mississippi River, being about one foot at low river stage and zero at high river stage. Weather Bureau Signals Source: Weather Bureau, United States Department of Agriculture Small Craft Warning-A red pennant indicates that moderately strong winds that will interfere with the safe operation of small craft are expected. No night display of small craft warnings is made. Northeast Storm Warning-A red pennant above a square red flag with black centre displayed by day, or two red lanterns, one above the other, displayed by night, indicates the approach of a storm of marked violence with winds beginning from the northeast. diy, or a white lantern below a red lantern displayed by night, indicates the approach of a storm of marked violence with winds beginning from the southwest. Southeast Storm Warning-A red pennant below a square red flag with black centre displayed by day, or one red lantern displayed by night, indicates the approach of a storm of marked violence with winds beginning from the southeast. Southwest Storm Warning-A white pennant below a square red flag with black centre displayed by Barometer High and steady Northwest Storm Warning-A white pennant above a square red flag with black centre displayed by day, or a white lantern above a red lantern displayed by night, indicates the approach of a storm of marked violence with winds beginning from the northwest. Hurricane, or Whole Gale Warning-Two square flags, red with black centres, one above the other, displayed by day, or two red lanterns, with a white lantern between, displayed by night, indicate the approach of a tropical hurricane, or of one of the extremely severe and dangerous storms which occasionally occur. High and falling slowly E to NE Low and falling slowly E to NE SE to NE SE to NE Going to W Fair and little temperature change for one or two days. Increasing wind with rain in 12 to 24 hours Increasing wind with rain in 12 hours. Summer-light winds, fair. Winter-rain in 24 hours. Winter-rain or snow and increasing winds. Rain will continue one or two days. Rain and high wind; clearing and cooler in 36 hours. Severe storm soon, clearing and cooler in 24 hours. Clearing and colder. To reduce Fahrenheit to Centigrade subtract 32 to Fahrenheit multiply by 9/5 and add 32 degrees; degrees and multiply by 5/9; to reduce Centigrade to reduce Reaumur to Centigrade multiply by 5/4. The Atmosphere Source: United States Weather Bureau, Washington The atmosphere is composed of a mixture of gases and surrounds or envelops the whole earth. It is sometimes likened to a great sea of gases, at the bottom of which we live. The principal constituents are oxygen and nitrogen. in about the proportion of 21 per cent of the former and 78 per cent of the latter by volume, the remaining 1 per cent being made up of five other gases. Water vapor, which is really water in a gaseous form, is always present in the lower atmosphere, but in a variable quantity. It occupies space independently of the other gases, and may comprise up to 3 per cent of the total weight of a given volume of air. The tendency for these gases to escape into space is overcome by the earth's attraction, and they rest upon its surface with about the same weight as a layer of water 34 feet in depth. In other words they press downward, and obeying the law of gases they also press in every other direction at sea level with a force of nearly 15 pounds per square inch of surface. We can not see the gases. and since they permeate all our tissues we do not feel their pressure except when they are in motion as wind. It used to be supposed that the atmosphere had no weight, and hence the saying "light as air." Since the density of air at sea level is only about one eight-hundredth part that of water. It follows that the atmosphere would be eight hundred times 34 feet, or about 5 miles in depth if it were of the same density at all altitudes, which it is not. Gases are easily compressed, and therefore the layers near sea level have the greatest density because they are compressed by the weight of all that lies above. With increase of distance above sea level this weight is decreased steadily by the amount of air that is left below. and thus the pressure and density gradually diminish to nothingness. So much of the atmosphere is compressed into the lower layers that one-half of it lies below an elevation of 311⁄2 miles. although traces of some of its gases have been revealed at an altitude of nearly 200 miles. Only one sixty-fourth of the atmosphere lies above an altitude of 21 miles, so we may realize that this gaseous envelope is relatively very thin as compared with the diameter of the earth. The air holds in suspension many substances. such as bacteria and dust particles. We may sometimes think that it would be a great advantage to have all such foreign matter eliminated, but if so it is because we do not realize the results. Only a small portion of the bacteria are of the disease-breeding types, while many of the remainder are of real benefit to mankind. Bacteria are the chief factors in manufacturing all of the products of fermentation, and also they are the active agents that disintegrate the organic matters in the soil and prepare them for plant food. Some of the dust particles in the air are very important as they form nuclei on which water vapor condenses when air is cooled sufficiently, and without which there could be no clouds or rain. The Poles of the Earth with any great degree of accuracy. Source: Dep't of Research in Terrestrial Magnetism, Carnegie Institution of Washington The geographic (rotation) poles, or points where the Earth's axis of rotation cuts the surface, are not absolutely fixed in the body of the Earth. The pole of rotation describes an irregular curve about its mean position. Two periods have been detected in this motion: (1) an annual period due to seasonal changes in barometric pressure, load of ice and snow on the surface and to other phenomena of seasonal character; (2) a period of about fourteen months due to the shape and constitution of the Earth. In addition there are small but as yet unpredictable irregularities. The whole motion is so small that the actual pole at any time remains within a circle of thirty or forty feet in radius centered at the mean position of the pole. The pole of rotation for the time being is of course the pole having a latitude of 90° and an indeterminate longitude. The north magnetic pole of the Earth is that region where the magnetic force is vertically downward and the south magnetic pole that region where the magnetic force is vertically upward. A compass placed at the magnetic poles experiences no directive force. There are slow changes with time in the distribution of the Earth's magnetic field. These changes were at one time attributed in part to a periodic movement of the magnetic poles around the geographic poles, but later evidence refutes this theory and points, rather, to a slow migration of "disturbance" foci over the Earth. There appears to be a small irregular migration of the magnetic poles, but there are not sufficient observations available as yet to define the motion The center of the area designated as the north magnetic pole is in about latitude 70.5 N and longitude 96 W. The position of the south magnetic pole has been tentatively accepted as in latitude 72.4 S and longitude 154 E. The direction of the horizontal component of the magnetic field at any point is known as magnetic north at that point, and the angle by which it deviates east or west of true north is known as the magnetic declination, or in the mariner's terminology the variation of the compass. A compass without error points in the direction of magnetic north. (In general this is not the direction of the magnetic north pole). If one follows the direction indicated by the north end of the compass, he will travel along a rather irregular curve which eventually reaches the north magnetic pole (though not usually by a greatcircle route). However, the action of the compass should not be thought of as due to any influence of the distant pole, but simply as an indication of the distribution of the Earth's magnetism at the place of observation. There is always some part of the Earth where the variation of the compass is zero, that is, the northward compass-direction coincides with the true northward direction. About 1800. the line of no variation crossed the United States, passing between Washington and Baltimore. It now crosses the United States from Michigan to Florida. In Europe the line of no variation passed through London in 1655, through Paris in 1670, and now passes near Bucharest. The Aurora Source: Dep't of Research in Terrestrial Magnetism, Carnegie Institution of Washington The Aurora Borealis and Aurora Australis are displays of light in the high levels of the Earth's atmosphere which at times become very bright and colorful. They are most frequently seen in two broad belts which lie approximately along the boundaries of the polar regions. two hundred miles above the Earth's surface. Analysis of the light of aurorae has shown that it is produced by electrical discharges in oxygen and nitrogen. The Aurora Borealis or northern lights show greatest intensity and frequency along a path which crosses North America from Alaska in a southeasterly direction to Hudson Bay and Labrador. This line of maximum intensity crosses Northern Norway and skirts the Arctic coast of Siberia. The Australis or southern-light zone is situated over the Antarctic continent and the little-known Antarctic seas. Intense and widely spread auroral displays are associated with high sunspot-activity and worldwide magnetic-electric storms. At such times auroral displays are seen as far south as the West Indies in the Northern Hemisphere, and as far north as Australia and New Zealand in the Southern Hemisphere. The region in which auroral displays occur has been found to be approximately between fifty and The various shapes and directions usually assumed by the aurorae and their positions with respect to the Earth's magnetic field show that this magnetic field and its variations are controlling factors in the formation of displays. The association of aurorae with solar and terrestrial magnetic-electric phenomena indicates that the sun is the source of energy that produces the aurorae. The electrical condition of the upper atmosphere is largely determined by the incident ultra-violet light and streams of charged corpuscles from the sun and by high-speed charged corpuscles from outer space, known as cosmic rays. The exact mechanism by which one or more of these forms of energy produce the aurorae is not known. New researches under way upon auroral and geomagnetic data, also using radio waves to analyze the different regions of the Earth's upper atmosphere, will facilitate an understanding of this mechanism. The minus (-) sign indicates temperature below | Gabriel mountains of California, 1.03 inches of zero. Fahrenheit thermometer registration. rain-equivalent to 116 tons of water per acre-fell On April 5, 1926, at Opid's Camp, in the San in one minute. Monthly Mean Temperature and Precipitation Source: United States Weather Bureau UNITED STATES CITIES (TEMP., FAHRENHEIT; PRECIPITATION, IN INCHES Philadelphia.. St. Paul. Salt Lake City. Seattle. 54 4.3 57 4.2 63 4.7 69 5.2 75 4.6 81 5.9 82 6.4 82 5.8 79 383.6 49 3.2 613.2 693.3 744.2 73 4.3 67 50 2.0 60 3.3 68 4.9 783.6 813.2 793.4 74 2.8 63 2.7 52 4.2 44 4.5 5.0 69 8.4 72 2.0 68 1.7 2.1 32 1.3 20 1.0 3.6 59 3.0 52 5.0 3.3 62 3.1 56 4.8 3.5 44 3.0 35 3.6 2.9 49 1.9 39 1.5 2.8 46 5.0 71 3.4 56 3.0 62 3.1 58 2.7 36 3.4 674.1 72 3.6 670.8 760.5 74 0.8 64 1.4 41 812.5 84 2.2 84 2.4 79 3.0 70 2.2 60 1.9 54 1.6 57 0.8 580.2 580. 59 0.0 61 0.4 60 1.1 56 2.4 51 4.0 56 1.3 651.1 69 2.4 67 2.3 61 1.4 50 1.2 39 0.7 31 0.7 541.9 591.3 630.6 630.7 58 1.8 51 2.8 46 5.0 42 5.6 18 0.7 21 0.8 482.7 604.0 70 4.0743.5 723.1 63 3.0 51 1.8 35 1.0 23 0.9 32 7.8 34 6.8 37 5.9 41 5.6 47 4 1 52 3.3 554.3 567.1 52 10.3 42 12.6 39 10.0 35 9.0 28 2.2 31 1.8 40 1.2 48 1.1 56 1.4 631.3 690.7 68 0.6 59 0.9 48 1.2 38 2.1 30 2.2 333.6 35 3.3 433.8 533.3 643.7 724.1 774.7 754.0 68 3.2 57 2.8 45 2.4 37 3.3 THE MEANING OF "1 INCH OF RAIN" An acre of ground contains 43,560 square feet. | Consequently, a rainfall of 1 inch over 1 acre of ground would mean a total of 6,272,640 cubic inches of water. This is equivalent to 3,630 cubic feet. As a cubic foot of pure water weighs about 62.4 pounds, the exact amount varying with the density. It follows that the weight of a uniform coating of 1 inch of rain over 1 acre of surface would be 226,512 pounds, or 1134 short tons. The weight of 1 U. S. gallon of pure water is 8.345 pounds. Consequently a rainfall of 1 inch over 1 acre of ground would mean 27,143 gallons of water. This is equivalent to 603 barrels of 45 gallons each. A rainfall of 1 inch on a roof of 3,000 square feet would mean 432,000 cubic inches, or 250 cubic feet, available for the cistern. This is equal to 1,870 U. S. gallon, or 41.5 barrels of 45 gallons each. Ten inches of snow equals in water content, on the average, about one inch of rain. 69 3.0 61 3.1 49 2.2 32 1.3 19 1.1 1.0 52 1.4 32 1.4 Days' Lengths at N. Y. City-Sunrise to Sunset The above table is one of averages and is approximately correct for an average year. There are slight variations from year to year, in extreme cases as much as 2 or 3 minutes a day. Table does not show length of day in seconds. Daily Normal High and Low Temperature at New York City Jan. Feb. Mar. Source: United States Weather Bureau Apr. May June July Aug. Sept. Oct. Nov. Dec. 12. O 10.40 9.33 9.14 14.31 13.19 11.57 14.29 13.17 11.54 14.27 13.15 14.25 13.12 38 26 37 24 41 26 51 66 70 Means 37 24 38 24 45 30 57 42 68 53 77 60 82 66|80| 66 74 60 64 49 51 37 41 29 Extremes of Precipitation and Snowfall at New York (Inches) |