1893.] NEW YORK ACADEMY OF SCIENCES. 135 



liis contemporaries. In his old age a benevolent person took 

 him to America where he died unhonored and unsung. 



In 1757 Professor Joseph Black, of Scotland, determined the 

 true characteristics of "fixed air," but seems to have made no 

 important addition to the apparatus for studj-ing gases. 



In 1767 Mr. Peter Woulfe published a paper in the Philos. 

 Trans, describing an improved apparatus for condensing vapors 

 without loss and applied it to hydrochloric acid, ammonia, 

 nitric acid, and other substances obtained by distillation. The 

 apparatus still bears his name. 



The prodigious advance made by Dr. Joseph Priestley in the 

 mauijDulation of gases won for him the appellation : " Father 

 of Pneumatic Chemistry." His prime invention was the inser- 

 tion of a shelf into the vessel containing water, and the perfora- 

 tion of this shelf so as to admit of the gases ascending into 

 receivers standing thereupon. This pneumatic trough is not 

 mentioned by Priestley in his first chemical paper, published in 

 1772, entitled " Directions for Impregnating Water with Fixed 

 Air." In this tract the accomj^anying figures illustrate his 

 method of collecting the gases. A bottle for generating the 

 carbonic acid, to the mouth of which is attached a bladder, and 

 this in turn communicates with an inverted jar by a flexible 

 "leather pipe sewn with waxed thread" and having quills 

 thrust in both ends to keep them open. This simple 

 apparatus was the forerunner of the modern soda-water 

 machines. 



In the first edition of Vol. I. of Priestley's " Experiments 

 and Observations on Different Kind of Air," published 

 two years later than the little treatise above noticed, the 

 author modestly says " my apparatus for experiments on air 

 is in fact nothing more than the aj^paratus of Dr. Hales, Dr. 

 Brownrigg, and Mr. Cavendish, diversified and made a little 

 more simple." He then describes the pneumatic trough, both 

 for water and for quicksilver, the method of jDOuring air upward 

 under water, the process of generating gases by heating 

 substances in a gunbarrel, by aid of a burning glass in thin 

 phials filled with quicksilver, and the way to pass an electric 

 spark through gases in a jar over water or over quicksilver. 

 This introductory chapter clearl}- shows the greatest progress 

 in the manipulation of gases, and the way in Avhich Priestley 

 energetically applied his skill by the discovery of nine gases is 

 well known to every student. 



After the disastrous riots in Birmingham, July, 1791, in which 

 Priestley's house and laboratory were wholly destroyed by an 

 angry mob, an inventory was taken of Priestley's laboratory as 



