428 JAMES WATT. 



phenomena, and exhibits changes of properties which 

 imply the notion of composition. The numerous obser- 

 vations at Hales ; the successive discoveries of carbonic 

 acid by Black, of hydrogen by Cavendish ; of nitrous 

 acid, of oxygen, of muriatic acid, of sulphurous acid, and 

 of ammonia by Priestley, definitively banished the old 

 idea of there being a unique and elementary air ; that 

 being among the almost constantly false conceptions haz- 

 arded by people, who have the audacity to think them- 

 selves called upon, not to discover, but to guess the course 

 of nature. 



Amidst so many remarkable incidents, water had still 

 preserved its character as an element. The year 177G * 

 was at last signalized by one of those observations that 

 were to lead to the upsetting of this general belief. It 

 must be acknowledged that we must also assign the same 

 year for the singular efforts made by the chemists, not to 

 surrender to the natural results of their experiments. 

 The observation of which I wish to speak belongs to 

 JMacquer. 



That judicious chemist having placed a white porcelain 

 saucer over the flame of hydrogen gas which was burning 

 tranquilly out of the mouth of a bottle, remarked that 

 this flame was not accompanied by any smoke properly 

 so called ; that it deposited no soot ; that the part of the 

 saucer which was licked by the flame was, on the contrary, 

 evidently covered by small drops of a fluid resembling 

 water, and which, after verification, was found to be pure 

 water. This was certainly a singular result. Observe 

 carefully, it was in the midst of the flame, on that part of 



* It was in this year, 1776, according to Priestley, tliat Volta fired 

 iifiaiTimable air by tlie electric spark: the experiment of Macquer 

 appears to have been made two years afterwards. — Translator. 



