with  values  divisible  by  5.  Two  different  sets  of equations are used: one  set  for  a  northerly  zone, between latitudes 27.6° and 40.0°N, and the other set from  longitudes  from  65.0°  to  100.0°W.  The  southerly zone  encompasses  the  same  longitudes  as  the  northerly zone, but the latitudes are for 17.5° and 27.5°N. The   method   described   in   the   preceding   two paragraphs was tested by Veigas and Miller on 125 independent  cases,  about  equally  distributed  between the two zones, during the years 1924-27 and 1954-56. The  average  vector  errors  in  24-hour  forecast  position were about 150 nautical miles for the northerly zone and 95  nautical  miles  for  the  southerly  zone. 30-Hour Movement of Certain Atlantic Hurricanes R. J. Shafer has developed an objective method for determining the 30-hour movement of hurricanes by use of sea-level data over the ocean areas and upper air data over  the  land  areas.  Motion  is  described  in  two components: zonzl and meridional. Westerly motion is determined by consideration of the component of the sea-level pressure gradient surrounding the hurricane and  is  opposed  graphically  by  the  mean  temperature field between 850 and 500 hPa. The correlation of these parameters  is  modified  by  extrapolation  and  the geographic locations. Meridional motion is similarly predicted   by   sea-level   and   thickness   parameters modified by extrapolation. The meridional and zonal computations are then combined into the final 30-hour forecast. In a test of dependent and independent data it was found that some 85 percent of the storms predicted in the  31  sample  cases  fell  within  2°  of  the  predicted position. MOVEMENT  OF  TROPICAL  CYCLONES Griffith Wang of the Civil Air Transport Service, Taiwan,  developed  a  method  for  objectively  predicting the movement of typhoons in the western Pacific. The method is titled  A Method in Regression Equations for Forecasting  the  Movement  of  Typhoons.  The  equation utilizes 700-hPa data and is based on the following criteria: . The 700-hPa contour height and its tendency 10° latitude north of the typhoon center. . The 700-hPa contour height and tendency 10° latitude from the typhoon center and 90° to the right of its  path  of  motion. . The 700-hPa contour height and its tendency 10° latitude from the typhoon center and 90° to the left of its path of motion. . The intensity and the orientation of the major axis of  the  subtropical  anticyclone  which  steers  the movement of the typhoon. Percentage  of  frequency  of  direction  of  movement and  speed  tables  are  provided  for  a  rough  first approximation of the movement of the typhoon. This method, as well as all other methods based on a single chart, is dependent upon a good network of reports and a good analysis. A full test of the value of this method has not been made, but in limited dependent and independent data cases tested it appears to have a good verification and provides another useful tool in the integrated  forecast. Full details on the procedure and application of this method can be found in the Bulletin of the American Meteorological  Society,  Vol.  41,  No.  3,  March  1960. Use of the Geostrophic Wind for Steering The expansion of aircraft reconnaissance reports have  made  it  practical  to  carry  out  more  detailed analyses of constant pressure surface over the tropical storm  belt  and  to  make  use  of  a  forecast  based  on geostrophic  components  at  that  level.  This  technique, developed by Riehl, Haggard, and Sanborn, and issued as an NA publication  Objective  Prediction  of  24-Hour Tropical Cyclone Movement  uses this steering concept. The  technique  makes  use  of  500-hPa  height  averages alongside of a rectangular grid approximately centered on the storm. The grid is 15° longitude, centered at the initial longitude of the storm and between 10° and 15° latitude with the southern end fixed at a distance of 5° latitude south of the latitude of the storm center. A more northward extension of the grid is used for storms found  to  be  moving  more  rapidly  northward.  The relatively small size of the grid indicates that tropical cyclone motion for 24 hours is determined to a great extent by circulation features closely bordering the storm, and that the average features outside this area will not greatly affect its movement within the time interval. The 500-mb chart is the basic chart for computations. Comparison  of  Steering  Levels Another method that uses the steering concept is  A Comparison  of  Hurricane  Steering  Levels  by B. I. Miller  and  P.  L.  Moore  of  the  National  Hurricane 11-9