510 



pitate from the apple-juice, by acetate of lead, was reduced to 

 a mere trifle; new water having been, in all cases, added to 

 compensate the loss by evaporation. As it is my intention to 

 resume the subject hereafter, it is not necessary, in this place, 

 to assign a reason for the several decompositions of the preci- 

 pitate with sulphuric acid, and its recomposition with acetate 

 of lead : it is enough to say that, without these processes, the 

 mass cannot be converted into crystals. 



" Thus the whole of the original precipitate was dissolved 

 in water ; almost the whole of it crystallized, but a small por- 

 tion remained in solution. The mother-waters were therefore 

 evaporated down to one-sixth, and set by to cool : a dark- 

 coloured precipitate, mixed with irregular crystals, was depo- 

 sited, which, by other processes, was made to furnish crystals 

 like the former. Further evaporation and similar treatment 

 afforded a little more crystallized matter. In short, the whole 

 of the original precipitate from apple-juice and acetate of lead 

 was converted into crystals, except a very small portion which 

 appeared to be neutral vegetable matter, mixed with earthy 

 salts from the water evaporated. 



" The crystals were sorbate of lead; mere inspection by 

 an eye familiarized to their striking appearance was sufficient 

 to determine their nature. But, to put the matter beyond 

 doubt, I decomposed the whole crop first by means of an insuf- 

 ficient quantity of sulphuric acid, and lastly by an excess of 

 sulphuretted hydrogen. The acid thus insulated proved by its 

 habitudes with lime, potash, soda, and magnesia, to be sorbic 

 acid ; and in this manner the whole of the acid which exists in 

 apples was demonstrated to be the same as that which imparts 

 acidity to the berries of the Sorbus aucuparia, a position which 

 had been only previously assumed. 



" To conclude: the objects of the foregoing statements 

 have been, 1st, to establish my claim to the discovery of sorbic 

 acid ; 2nd, to show that Scheele's so-named malic acid, which 

 has been confounded with the sorbic, was not an acid sui ge- 



