60 PROCEEDINGS OF THE AMERICAN ACADEMY 



alcoholic solution is a fact sufficiently important to merit close atten- 

 tion. Unfortunately, the small sample of wine given me was com- 

 pletely exhausted in the severe confirmatory tests by which the results 

 above mentioned were controlled, and I have had no opportunity to 

 determine the precise manner in which the lead was held in solution in 

 that particular case. Several conjectures as to the cause of the # phe- 

 nomenon will be discussed below. 



That lead compounds should still be employed in the treatment of 

 wine will surprise no one familiar with the tenacity with which tradi- 

 tions are held by successive generations of operatives in many of the 

 chemical arts. According to Taylor,* " litharge was formerly much 

 used to remove the acidity of sour wine and convey a sweet taste. 

 Acetate of lead, or some other vegetable salt of the metal, is in these 

 cases formed ; and the use of such wine may be productive of alarm- 

 ing symptoms. Many years since a fatal epidemic colic prevailed in 

 Paris owing to this cause ; . . . . the adulteration was discovered by 

 Fourcroy, and was immediately suppressed." 



Beckmann in his History of Inventions f dwells at some length on 

 the antiquity and enduring character of the practice of neutralizing 

 the acid which spoils wine by means of litharge. According to this 

 author, the practice was forbidden by legal enactment in France as 

 early as 1696, but a hundred years later " the art of improving wine 

 by litharge was taught in England as a method perfectly free from 

 danger." t 



The sulphuric acid in the sample of wine examined by me was prob- 

 ably added, with the view of removing the dissolved lead resulting 

 from the previous use of litharge. It is not unlikely that the addition 

 of the free acid was preceded by that of a solution of sulphate of 

 ammonium. 



In seeking for an explanation of the fact that a certain proportion 

 of lead may remain dissolved in wine, even in presence of free sul- 

 phuric acid, the following hypotheses suggest themselves : — 



1st. It seemed not impossible, in case a mixture of weak alcohol, 

 dilute sulphuric acid, and sulphate of lead was left to itself for a long 



* On Poisons, p. 502 of the London edition. 

 t Chapter on Adulteration of Wine. 



J William Graham's Art of Making Wines from Fruit, Flowers, and Herbs. 

 London, sixth edition. 



