PHILOSOPHICAL TRANSACTIONS. 485 



which though not tastable, is yet found and distinguished by other means. 

 6. Waters with sulphur in Hke manner insensible, and to be found by other 

 scrutinies. 7* Acid spirits. 8. Mixed spirits of acid and sulphur. 9. Urinous 

 spirits. 10. Acid urinous spirits. 11. Volatile salts. 12. Black burnt oils. 

 13. Salts fixed, saline or lixiviate. 14 Earth.* 



These are supposed alterations by fire, rather than separations. But for dis- 

 tinguishing, several ways have been thought of, as, the manner of process, as- 

 certaining the degrees of heat by a thermometer, &c. That culinarv heat, and 

 the heat of the stomach may make the same alterations and separations. 



For rectifying these substances, little is used. The particulars of the process 

 are remarked and registered, as the time, degrees of fire, sensible qualities of 

 the parts, &c. And these according to their proportionable quantities and de- 

 grees, and that with great care, exactness, and judgment, collected from dif- 

 ferent ways of examination: taking an account of their weight, gravity, (of 

 which many instances are given). Insensible qualities, found by divers mixtures; 

 as of acids, sulphurs, &c. with turnsole. Volatile spirits, &c. make solution of 

 sublimate white. Sea-salt whitens solution of sacharum saturni. Mixed spirits 

 redden solution of vitriol, &c. 



Next the trying of these extracts in vacuo is propounded to find their air. And 

 several observations of the differences of volatile and fixed salts related. Also 

 ways are shown how to find the degrees of composition of these extracts: 

 particular ways for particular plants. Lastly, the way of analysing juices is 

 mentioned ; and the advantages of this process. 



In the fifth and last chapter is stated the method which the Royal Academy 

 intend to take for completing and publishing the History of Plants. 



Osservationi intomo alle Torpedini fatte da Stephano Lorenzini Fiorentino, In 

 Firenze, 1678. Philos. Collect. N° 1, p. 42. 



In the present treatise, the author gives a description of the torpedo. No- 

 ticing, 1. That this fish is of the flat cartilaginous kind;-}- that there are two 



* Great expectations were once entertained by the French academicians, as to the possibility of 

 ascertaining the virtues of plants by this mode of decomposition ; and an extensive set of experiments 

 was accordingly instituted. But after much time and expence, it was found that this object was not 

 f 'thus attainable. In fact, vegetables which produce the most opposite effects upon the human body, 

 yield, when subjected to destiiictive analysis by fire, similar results. These experiments however 

 were by no means useless in a chemical point of view. 



f It belongs to the Linnaean genus Raja, and much light has within these few years been thrown 

 upon the structure and use of some of its parts, by the late Mr. John Hunter. See Phil. Trans, 

 vol. 63. 



