Part 15

6. When the snow is blown about after the storm and before measurements have been made.

A bucket and a spring balance are used. The bucket is filled with snow, but not packed down too hard, and weighed. The reading of the index hand on the spring balance gives the density of the snow. The depth of the snow in the vicinity of the spot from which the bucket was filled is obtained and this figure is multiplied by the density, thus giving the water equivalent of the snow collected. For instance, if the reading of the balance was .16, and the depth of the snow was 7 inches, multiply .16 by 7, and the result, 1.12, is the water equivalent of the snow.

THERMOMETER SCALES

The first thermometer scale to give satisfaction was devised in 1714 by Fahrenheit. He determined the fixed points on the thermometer in a very novel manner. Having been born at Dantzig, he took for the zero point on his scale the lowest temperature observed by him at Dantzig, which he found was that produced by mixing equal quantities of snow and sal-ammoniac. The space between this point and that to which the mercury rose at the temperature of boiling water he divided into 212 parts. He determined, with his thermometer, that the atmospheric pressure governed the boiling point of water. Today the Fahrenheit thermometer is used extensively, and has for its freezing point 32° and for its boiling point 212°.

Another scale that has not become too well known, because of the fact that it did not meet with public favor, was devised by a Frenchman, named Reaumur, in 1730, and bears his name. He determined the freezing point of the scale at 0° and the boiling point of water at 80°.

Another Frenchman, named Anders Celsius, devised a scale with the boiling point of water at 0° and the freezing point at 100°. In 1743 a Frenchman, named Christin, living at Lyons, France, reversed the points, and today the scale is known as the Centigrade scale, and, together with the Fahrenheit scale, is used almost exclusively wherever thermometers are required.

HOW TO CHANGE ONE SCALE INTO ANOTHER

Centigrade degrees into Fahrenheit: multiply by 9, divide the product by 5 and add 32.

Fahrenheit degrees into Centigrade: subtract 32, multiply by 5, and divide by 9.

Reaumur degrees into Fahrenheit: multiply by 9, divide by 4, and add 32.

Fahrenheit degrees into Reaumur: subtract 32, multiply by 4, and divide by 9.

Reaumur degrees into Centigrade: multiply by 5 and divide by 4.

Centigrade degrees into Reaumur: multiply by 4 and divide by 5.

WEATHER BUREAU STATIONS OF THE UNITED STATES AND WEATHER BUREAU MAPS

The following is a list of the Weather Bureau Stations of the United States, and from any of these offices, preferably the one nearest you, you will be able to obtain the weather reports and weather map (see Fig. 52), indicating many things of interest, and from which you will be able to make a careful study of the weather.

ABILENE, TEX. ALBANY, N. Y. ALPENA, MICH. AMARILLO, TEX. ANNISTON, ALA. ASHEVILLE, N. C. ATLANTA, GA. ATLANTIC CITY, N. J. AUGUSTA, GA. BAKER, ORE. BALTIMORE, MD. BENTONVILLE, ARK. BINGHAMTON, N. Y. BIRMINGHAM, ALA. BISMARCK, N. D. BLOCK ISLAND, R. I. BOISE, IDA. BOSTON, MASS. BROKEN ARROW, OKLA. BUFFALO, N. Y. BURLINGTON, VT. CAIRO, ILL. CANTON, N. Y. CAPE HENRY, VA. CAPE MAY, N. J. CHARLES CITY, IA. CHARLESTON, S. C. CHARLOTTE, N. C. CHATTANOOGA, TENN. CHEYENNE, WYO. CHICAGO, ILL. CINCINNATI, OHIO CLALLAM BAY, WASH. CLEVELAND, OHIO COLUMBIA, MO. COLUMBIA, S. C. COLUMBUS, OHIO CONCORD, N. H. CONCORDIA, KANS. CORPUS CHRISTI, TEX. DALLAS, TEX. DAVENPORT, IA. DAYTON, OHIO DEL RIO, TEX. DENVER, COLO. DES MOINES, IA. DETROIT, MICH. DEVILS LAKE, NO. DAK. DODGE CITY, KANS. DREXEL, NEB. DUBUQUE, IA. DULUTH, MINN. EASTPORT, ME. ELKINS, W. VA. ELLENDALE, NO. DAK. EL PASO, TEX. ERIE, PA. ESCANABA, MICH. EUREKA, CAL. EVANSVILLE, IND. FORT SMITH, ARK. FORT WAYNE, IND. FORT WORTH, TEX. FRESNO, CAL. GALVESTON, TEX. GRAND HAVEN, MICH. GRAND JUNCTION, COLO. GRAND RAPIDS, MICH. GREEN BAY, WIS. GREENVILLE, S. C. GROESBECK, TEX. HANNIBAL, MO. HARRISBURG, PA. HARTFORD, CONN. HATTERAS, N. C. HAVRE, MONT. HELENA, MONT. HONOLULU, HAWAII HOUGHTON, MICH. HOUSTON, TEX. HURON, SO. DAK. INDEPENDENCE, CAL. INDIANAPOLIS, IND. IOLA, KANS. ITHACA, N. Y. JACKSONVILLE, FLA. JUNEAU, ALASKA KALISPELL, MONT. KANSAS CITY, MO. KEOKUK, IOWA KEY WEST, FLA. KILAUEA, HAWAII KNOXVILLE, TENN. LA CROSSE, WIS. LANDER, WYO. LANSING, MICH. LEESBURG, GA. LEWISTON, IDAHO LEXINGTON, KY. LINCOLN, NEB. LITTLE ROCK, ARK. LOS ANGELES, CAL. LOUISVILLE, KY. LUDINGTON, MICH. LYNCHBURG, VA. MACON, GA. MADISON, WIS. MANTEO, N. C. MARQUETTE, MICH. MEMPHIS, TENN. MERIDIAN, MISS. MIAMI, FLA. MILWAUKEE, WIS. MINNEAPOLIS, MINN. MOBILE, ALA. MODENA, UTAH MONTGOMERY, ALA. MOUNT TAMALPAIS, CAL. NANTUCKET, MASS. NASHVILLE, TENN. NEAH BAY, WASH. NEW HAVEN, CONN. NEW ORLEANS, LA. NEW YORK, N. Y. NORFOLK, VA. NORTHFIELD, VT. NORTH HEAD, WASH. NORTH PLATTE, NEB. OKLAHOMA, OKLA. OMAHA, NEB. OSWEGO, N. Y. PALESTINE, TEX. PARKERSBURG, W. VA. PENSACOLA, FLA. PEORIA, ILL. PHILADELPHIA, PA. PHOENIX, ARIZ. PIERRE, SO. DAK. PITTSBURGH, PA. POCATELLO, IDAHO POINT REYES LIGHT, CAL. PORT ANGELES, WASH. PORT ARTHUR, TEX. PORT HURON, MICH. PORTLAND, ME. PORTLAND, ORE. PROVIDENCE, R. I. PUEBLO, COLO. RALEIGH, N. C. RAPID CITY, SO. DAK. READING, PA. RED BLUFF, CAL. RENO, NEV. RICHMOND, VA. ROCHESTER, N. Y. ROSEBURG, ORE. ROSWELL, NEW MEX. ROYAL CENTER, IND. SACRAMENTO, CAL. SAGINAW, MICH. ST. JOSEPH, MO. ST. LOUIS, MO. ST. PAUL, MINN. SALT LAKE CITY, UTAH SAN ANTONIO, TEX. SAN DIEGO, CAL. SAND KEY, FLA. SANDUSKY, OHIO SANDY HOOK, N. J. SAN FRANCISCO, CAL. SAN JOSE, CAL. SAN JUAN, PORTO RICO SAN LUIS OBISPO, CAL. SANTA FE, NEW MEX. SAULT SAINTE MARIE, MICH. SAVANNAH, GA. SCRANTON, PA. SEATTLE, WASH. SEKIOU, WASH. SHERIDAN, WYO. SHREVEPORT, LA. SIOUX CITY, IOWA SPOKANE, WASH. SPRINGFIELD, ILL. SPRINGFIELD, MO. SYRACUSE, N. Y. TACOMA, WASH. TAMPA, FLA. TATOOSH ISLAND, WASH. TAYLOR, TEX. TERRE HAUTE, IND. THOMASVILLE, GA. TOLEDO, OHIO TONOPAH, NEV. TOPEKA, KANS. TRENTON, N. J. TWIN, WASH. VALENTINE, NEB. VICKSBURG, MISS. WAGON WHEEL GAP, COLO. WALLA WALLA, WASH. WICHITA, KANS. WILLISTON, NO. DAK. WILMINGTON, N. C. WINNEMUCCA, NEV. WYTHEVILLE, VA. YANKTON, SO. DAK. YELLOWSTONE PARK, WYO. YUMA, ARIZ.

You will notice that on this map different lines are drawn: First, the Isobar lines—these are solid lines drawn through places which have the same barometric pressure. Second, the Isotherm lines—these are dotted lines drawn through places having the same temperature.

The Weather Bureau Maps are gotten out on the same day all over the country, and the preparation of them is quite interesting.

At 7:40 A. M. simultaneous readings are taken at all weather bureau stations of the country. On the coast, where the time is three hours different than at New York, the readings are taken at 4:40, so that the hour corresponds at all places. At 8:00 A. M. the various stations telephone their findings to the Western Union Office located in their city and immediately the messages are transmitted by Western Union to a central district office, or circuit center as it is called. For New England, the circuit center is Boston. All messages are received at this office, and from here transmitted to the next office, which is New York, and from New York to the next center, until the news is transmitted to the coast. The wires are open from 8:00 until 9:30 A. M. The western offices follow the same procedure until the weather indications are received by all stations. Immediately the preparation of the map is begun and they are mailed to interested parties by the Weather Bureau Stations of the United States.

Figs. 52, 53 and 54 show three maps, typifying storms traveling from the west to the east, and by studying them on successive days you can at once grasp the importance of studying the weather from these maps.

Fig. 53 shows a storm of low pressure and how this area of low pressure is progressing and moving from the west to the east. Particular notice should be taken of how fast the storm travels, that is, the distance it goes each day, and the direction it is going and the results.

Fig. 52 ]

Fig. 53 ]

Fig. 54 ]

The arrows denote the direction of the wind, and you will notice they point to the region of low barometric pressure. In the regions of high barometric pressure the winds are in the opposite direction. This readily explains to you why it is that you can expect changes in weather conditions when the wind changes.

From the markings and printed matter on each map, information is secured regarding observations of the barometer, thermometer, wind velocity, direction of the wind, kind of clouds, and their movements, and the amount of precipitation (rain or snow), in different localities.

HOW THE STATE OF THE WEATHER IS INDICATED

Clear, partly cloudy, cloudy, rain or snow indications are symbolized. The shaded area designates places or areas where precipitation has occurred during the preceding twelve hours.