This folder contains correspondence and other documents relating to the tasimeter, a heat measuring device invented by Edison. During the summer of 1878 Edison visited Rawlins, Wyoming, along with a group of astronomers, and used his tasimeter to measure the heat of the sun's corona during its eclipse. The correspondents include Edwin M. Fox, a journalist and former telegraph operator who accompanied Edison on the Rawlins expedition; photographer William Curtis Taylor; Joseph Tingley, professor of natural science at Indiana Asbury University (DePauw University); and Charles Augustus Young, professor of astronomy at Princeton University. In addition to the correspondence, there are two pages of instructions for setting up and adjusting the tasimeter, along with a list of what appear to be alternative names for the tasimeter. There is also a page of notes by George Barker, a professor of physics at the University of Pennsylvania who accompanied Edison to Wyoming, regarding the use of the tasimeter during the expedition.

All of the documents have been selected except for duplicates.