CONTENTS V 



VI. Optical phenomena — Continued. 



Refraction phenomena — Continued. P^^ec 



Towering 82 



Sinking 82 



Stooping 82 



Refraction by water drops 82 



Rainbow 82 



Refraction by ice crystals 83 



Parhelia of 22° 84 



Halo of 22° 84 



Arcs of Lowitz 85 



Parhelia of 46° 85 



Halo of 46° and 90° 85 



Cir cumzen ithal and cir cumhorizontal arcs 85 



Tangent ares 86 



Unusual halos 86 



Diffraction phenomena 87 



Coronas 87 



Iridescent clouds 87 



Mirage 87 



Aurora polaris 88 



Color 88 



Height 88 



Cause 88 



VII. Preparation of weather maps on shipboard 89 



Code used 89 



Radio broadcasts 89 



Preparation of weather maps 90 



The isobars 92 



Use of the weather map 96 



VIII. Glossary 1 96 



A. Technical terms 96 



B. Colloquial terms 108 



IX. A selected list of works on meteorology 110 



Elementary and popular meteorology 110 



Practical meteorology and weather forecasting 110 



Advanced meteorology HO 



Climatology HI 



Climatography 111 



Climate of the United States HI 



Storms 111 



Clouds 111 



Atmospheric electricity 112 



Instruments, instructions, tables, etc 112 



X. Tables: 



Correction of mercurial barometer for temperature 112 



Reduction of barometric reading to sea level 113 



Reduction of mercurial barometer to standard gravity 114 



Equivalent temperatures (Centigrade and Fahrenheit) 114 



Equivalent lengths (millimeters and inches) 114 



Conversion of millimeters to millibars 115 



For obtaining the relative humidity of the air (sling psychrom- 



eter) 115 



Table for obtaining the true direction and force of the wind from 



the deck of a moving vessel 116 



Time of observation 118 



Distance of visibility of objects at sea 119 



Chart of local time corresponding to Greenwich mean noon 120 



