華爾騰湖測量圖

When I had mapped the pond by the scale of ten rods to an inch, and put down the soundings, more than a hundred in all, I observed this remarkable coincidence. Having noticed that the number indicating the greatest depth was apparently in the centre of the map, I laid a rule on the map lengthwise, and then breadthwise, and found, to my surprise, that the line of greatest length intersected the line of greatest breadth exactly at the point of greatest depth, notwithstanding that the middle is so nearly level, the outline of the pond far from regular, and the extreme length and breadth were got by measuring into the coves; and I said to myself, Who knows but this hint would conduct to the deepest part of the ocean as well as of a pond or puddle? Is not this the rule also for the height of mountains, regarded as the opposite of valleys? We know that a hill is not highest at its narrowest part.

梭羅在池畔生活的第一年冬季，即1946年初，便對華爾騰池進行測量。他的測量技術是自學的，但1946年所繪製的測量結果卻真實呈現了華爾騰池的形狀：（圖中箭頭所指是北方）

圖右下角的 D點現在叫作梭羅灣（Thoreau's Cove），他的池畔小屋則位在D點右下標示著 House 的位置。

底下是google map 的地圖：

檢視較大的地圖

梭羅所繪地圖翻轉180度後如下：