482 PHILOSOPHICAL TRANSACTIONS. [aNNO 1767. 



of sides, others appeared somewhat triangular, and others of different figures ; 

 and in some parts the crystallization appeared like a piece of rock-work. He 

 dissolved some of this salt in water, and crystallized it a 2d time, but the crystals 

 were in general smaller than in the first operation ; this salt is extremely dif- 

 ferent in its taste from that of sea-salt, and certainly likewise in its virtues and 

 properties.* 



2. To ascertain more fully that the sal succini is an acid sui generis, Dr. M. 

 saturated some of it with the volatile ammoniac salt, crystallized it, and obtained 

 a neutral ammoniacal salt very different from that of the common sal ammo, 

 niacum; it was composed of a number of small long narrow flattish crystals, 

 whose sides were made up of 4 flat surfaces, and laid in an irregular order, some 

 lying across others, and some standing on one end.-|- 



The sal succini generates a great degree of cold in the time of its saturation 

 with the volatile alkali; for it sunk the quicksilver in the thermometer from 32 

 to 40: in this it agrees with the common sal ammoniacum. 



The conclusion. — From the experiments above related, it is evident that phy- 

 sicians have hitherto been in a great mistake, in believing that all vegetable acids 

 were nearly of the same nature; for from them it should seem that almost each 

 of the acids, called vegetable, has something peculiar to itself, and on future 

 trials may be found to have different virtues and properties.^ 



The different appearance of the neutral salts above-mentioned, from that of 

 those produced by the union of the fossil alkali with any of the mineral acids, 

 seems to make it doubtful whether the vegetable acids derive their origin from 

 the mineral, or whether they are not new substances, generated either in the 

 vessels of plants by means of the vegetative process, or by fermentation, or by 

 the force of fire. If they owe their origin to the mineral acids, they are cer- 

 tainly so much changed in their virtues, and properties, by the combination of 

 new particles, and by the processes they have undergone, that they may be con- 

 sidered as distinct bodies in many respects. 



* The salt thus formed by combining the acid of amber with the fossil alkali is termed in the new 

 nomenclature, succinate of soda. 



+ Dr. Stockar de Neuforn says, that this ammoniacal salt does not precipitate silver from aqua- 

 fortis, nor change aquafortis into aqua regia ; and when put in a silver spoon, and set over the fire, 

 it melts and flies off in form of a vapour. — Orig. In the new nomenclature the salt thus formed 

 by combining the acid of amber with the volatile alkali, is termed succinate of ammonia. 



X However, it ought to be remarked, that when any of the concentrated saturated liquors stood 

 for 10 or 12 days, before they crystallized, for the most part some crystals of a flat, square, or of 

 a narrow oblong parallelogram figure, were found adhering to the sides of the cup or basin in which 

 the liquor stood; but whether this was owing to the alkaline basis of these salts, or to the acids 

 approaching to each other in their nature, is what can only be determined by future experiments. 

 —Orig. 



