| 释义 |
Secchi diskn.（名词）- A disk, divided into black and white quarters, used to gauge water clarity by measuring the depth at which it is no longer visible from the surface.透明度盘：分为黑白两色四等份的圆盘状物，借着测量从水表不可见的深度来测定水的清澈度
- After Pietro Angelo Secchi (1818-1878), Italian astronomer hired to test such a disk After Pietro Angelo Secchi (1818-1878), Italian astronomer hired to test such a disk
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