ial. The prescription of the design
is given in the following table:</p>

<table>
  <tr> <th>Radius</th> <th>Thickness</th> <th>Material</th> <th>Index</th> <th>V-no</th> <th>sa</th> </tr>
  <tr><td>40.940</td> <td>8.740</td> <td>SSK4</td> <td>1.618 </td><td>55.1</td> <td>18.5</td> </tr>
  <tr> <td>inf.</td><td>11.050</td> <td>air</td> <td>-</td> <td>-</td> <td>18.5</td> </tr>
  <tr> <td>-55.650</td> <td>2.780</td> <td>SF2</td><td>1.648</td> <td>33.8</td> <td>14.9</td> </tr>
  <tr><td>39.750</td> <td>1.000<