Description of a chemical barometer in a 19th century apothecary manual. The author of the paper had a special reason to present such a paper because his parents were meteorologists, and he himself is now the director of the Cracow Pharmacy Museum. The description of the barometer has been found in an apothecary manual that in the 19th century belonged to a Polish apothecary family the name of which was Ryl. For about 60 years the manual has been preserved in the Museum's library. In the paper, in addition to information about the Ryl's family and the text of the "recipe", a model of the barometer is presented along with photographs showing changes that occurred in it.