The Bathythermograph
![The Bathythermograph](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/thumbnails/image/Bathythermograph_Great_Lakes.jpg?itok=j8fP1eTs)
Detailed Description
The mechanical bathythermograph was invented as a tool to understand the temperature layers of the ocean. The torpedo-shaped device was attached to a long cord and dropped off the side of a boat. As it sunk towards the sea floor, an internal needle scratched a line on a piece of glass that represented temperature relative to water depth.
Sources/Usage
Public Domain.