Sun Compass : 無料・フリー素材/写真
Sun Compass / eschipul
| ライセンス | クリエイティブ・コモンズ 表示-継承 2.1 |
|---|---|
| 説明 | Terrible photo. Amazing example of innovation. This is a "sun compass" which was invented out of necessity. The wall plate reads:William Burt and the Solar CompassBurt's solar compass enabled him to complete his survey of Upper Peninsula lands accurately and on time despite the presence of large deposits of iron ore.The sensitivity of the magnetic compass to iron in the ground led William Austin Burt to devise the solar compass, which he patented in 1936. It soon became the preferred instrument for use in areas where the standard magnetic surveyor's compass was unreliable. |
| 撮影日 | 2007-06-30 18:39:11 |
| 撮影者 | eschipul , Houston, TX, US |
| タグ | |
| 撮影地 | |
| 露出 | 0.025 sec (1/40) |
| 開放F値 | f/4.0 |
| 焦点距離 | 24 mm |