Louis Thénard had explained to Thilorier that his "snow" was actually solidified carbon dioxide.

Dry ice is solidified carbon dioxide that is so cold (minus 109.3 degrees Fahrenheit) that touching it without gloves can cause severe frostbite.

At the Oct. 12, 1835 meeting of the French Academy of Sciences, a letter from Adrien Thilorier was read in which he stated that he had solidified carbon dioxide:

The confusion was compounded when Paul Thénard wrote a biography of his father, Louis Thénard, the chemist who explained to Thilorier in 1835 that his "snow" was actually solidified carbon dioxide.

What is particularly interesting about Thilorier's discovery of dry ice is that he did not realize that he had solidified carbon dioxide until a group of scientists from the French Academy of Sciences explained to him what he had accomplished: