VOL. LVII.] PHILOSOPHICAL TRANSACTIONS. 483 



From what has been said, it is evident that the number of true neutral salts* 

 is infinitely greater than what has been supposed, of late, by chemists ; and it is 

 probable that many of the neutral salts, above described, may prove to be excel- 

 lent remedies in the cure of diseases, as well as useful in many manufactories. 



As there is such a variety of vegetable acids, and as each of them produces a 

 distinct neutral salt with each of the 3 alkalies, Dr. M. thinks it would be right 

 to distinguish them from each other by particular names; the salts made with 

 the vegetable alkali may be called vegetable salts, as both the acid and the alkali 

 are vegetable substances; those made with the fossil alkali, neutral salts; and 

 those made with the volatile alkali, ammoniacal salts, as all the neutral salts 

 hitherto made with this alkali have gone by this name. Thus we may call the 3 

 neutral salts made with lemon juice: 1, vegetable salt of lemons; 2, neutral salt 

 of lemons; 3, ammoniacal salt of lemons. 



By means of these neutral salts we may be enabled to discover many of the 

 properties of vegetable acids, and particularly the different degrees of affinity or 

 attraction between them and alkaline salts. Thus, for example, if we dissolve 

 in water some of the neutral salt of currants, and add some lime juice or some 

 vinegar, and then evaporate and crystallize; if we obtain a neutral salt of cur- 

 rants, we conclude that the acid of currants has a greater affinity or attraction 

 to the alkali than the acid of limes or of vinegar; but if we get a neutral salt of 

 limes, or of vinegar, we conclude that these acids have a greater affinity with 

 the alkali than the juice of currants. 



As Dr. M. was sensible that this account of vegetable neutral salts was very in- 

 complete, and that he had done little more than to give a very superficial descrip- 

 tion of their external appearance; and as it would probably require a length of 

 time, and the labours of many, to discover fully their virtues and properties, he 

 recommended it to those who might prosecute this subject, to endeavour to ascer- 

 tain the following facts: 1. What degree of cold or of heat is generated on the 

 mixture of each acid with the diflferent alkaline salts ; and likewise to try the 

 same experiment with each neutral salt at the time of its solution in water. 2. 

 What quantity of pure alkaline salt it takes to saturate any determined quantity 

 of each of the vegetable acids. 3. What figure each neutral salt assumes when 

 it is first crystallized, and likewise after it has been purified, and again dissolved 

 in water and crystallized. 4. What quantity of water it takes to dissolve any 

 determined quantity of sea salt. 5. What effects these salts or their solutions 

 in water have on oils, sulphur, ardent spirits, metals, earths, and other sub- 



* By true neutral salt is meant, a salt made with an acid and one of the 3 alkalies; the word 

 true is added to these salts, to distinguish them from neutral sails, made with earths or metals, and 

 acids. — Orig. 



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