That was a measure for the depth of water.

VOA: special.2010.03.21

You ignite the food and burn it, and you see how many degrees centigrade the water gets raised, and that's the measure of calories.

点燃食物使其燃烧,然后观察水的温度上升了多少,就测量了这种食物的卡路里

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

Sailors measure the depth of the water in fathoms.

VOA: special.2009.05.24