388 ANNUAL REGISTER, 1800. 



a very small surface only is affect- 

 ed. 



Thirdly. That the most green 

 and sour wine that could be met 

 with in the neighbourhood of Paris, 

 dissolved only an insensible quan- 

 tity of lead, after having remained 

 from eight to ten days in vessels 

 made of pewter which contained 18 

 per cetit of lead. 



Fourthly. That nearly the same 

 effect toot place when vinegar was 

 used instead of wine ; and that no 

 sensible appearances were produced 

 byre-agents, except when the pew- 

 ter of the vessel in which the vine- 

 gar had stood contained more than 

 18 per cent of lead. In proportion 

 as the vlnesjar becomes saturated 

 with pewter, a small quantity of 

 tartrite of lead is deposited ; but 

 the quantity of this deposit is ex- 

 tremely small, even when the ves- 

 sels in which the vinejrar stanfis are 

 of great diameter, and have a large 

 internal surface. 



Fifthly. When red wine remains 

 in pewter vessels, it loses its colour. 

 This effect arises from the colour- 

 ing matter being precipitated, after 

 being combined with oxide of tin. 

 The precipitate does not appear to 

 contain any lead ; yet the taste of 

 the bad wine^ made use of in this 

 experiment, became more sweet. 

 There is, however, reason to thiiik, 

 that this effect arose rather from the 

 precipitation of the colouring mat- 

 ter, and the saturation of a part of 

 the acid of the wine, than from any 

 lead contained therein. 



From the above experiments, the 

 commissioners concluded, that ves- 

 sels made of a mixture of tin and 

 lead might be used for wine, and for 

 vinegar, provided the proportion of 

 the latter metal was not more than 

 from 15 to 18 per cent and that no 



injury to health need be apprehend- 

 ed, from the use of vessels made 

 within the above-mentioned pro- 

 portions. 



The object of the second part of 

 this inquiry was to find some 

 means by which the proportion of 

 lead in pewter might easily bedeter- 

 mined. The hydrostatic balance is 

 well known to offer the surest me- 

 thod of doing it ; yet this method 

 has not been made use of in any 

 country. Instead ofit, various con- 

 jectural methods were adopted, such 

 as, the appearance of the metal, 

 the flexibility of it, or other cir- 

 cumstances equally uncertain. A 

 chymical analysis is capable of as- 

 certaining the matter with preci- 

 sion : but such an analysis would be 

 tedious and troublesome ; besides 

 which, it would be necessary to 

 take away a part of the vessels 

 themselves, for the purpose of ana- 

 lysis. An examination of the spe- 

 cific gravity has none of these in- 

 conveniences ; but, in order to 

 make it the basis of legal determi- 

 nation, it was necessary to ascer- 

 tain, by experiment, in what man- 

 ner tin and lead, when united in 

 various proportions, were affected 

 in this respect. It had been sus- 

 pected, that mixtures of these two 

 metals did not possess exactly that 

 specific gravity which they would 

 appear to do by calculating upon 

 that which each of them possess 

 separately. But, was their specific 

 gravity augmented or diminished .'' 

 did the two metals penetrate each 

 other when mixed, or was there, 

 on the contrary, a greater vacuum 

 between their particles than existed 

 in them when separate ? These were 

 questions which experiments only 

 could determine : for, the opinions 

 of the philosophers who have writ- 



