<s xml:space="preserve">
The calculation in the upper left corner shows the number of seconds, thirds, fourths, and fifths in a minute of a degree.
The number of fifths (12960000) is then doubled to give the number of half-fifths (25920000).
</s>
<lb/>
<s xml:space="preserve">
In the upper right corner, Harriot calculates that if 1 minute is represented by 1 mile,
a half-fifth of a degree would be represented by
<math>
<mstyle>
<mfrac>
<mrow>
<mn>1</mn>
</mrow>
<mrow>
<mn>4</mn>
<mn>3</mn>
<mn>2</mn>
</mrow>
</mfrac>
</mstyle>
</math>
of an inch, a distance that, as he observes, would be invisible. </s>
