380 



Waters that 

 contain no 

 essential oil 

 spoil. 



The author's 

 theory. 



Green matter in 

 distilled water. 



OX' KEEPING DISTILLED WATERS, .-. 



and its smell resembled that of sulphuretted hidrogen gas. 

 Being left a few weeks exposed to the open air, the fetid 

 S^ell vanished, and was replaced by tha,t of roses*. So^ie 

 i:osewater, the putrefaction of which was very evident, re. 

 covered its smell by the addition of a little lime and iron. 



It appears certain therefore, that the oils in distilled 

 waters change their nature. 



Waters, that have been distilled with too strong a heat, 

 contain lest oil; which would seem to prove, that a part of 

 it has undergone some sort of alteration. 



But there are waters, that contain no essential. oil, as 

 those of elder-flowers, borage, nettles, &c. These wcj.ter5 

 probably carry up in distillation volatile odorant principles, 

 which approach the nature of essential oils, and are de- 

 composed still more easily. 



But how are these principles converted into mucilage? 

 As the flocculent matter forms more commonly in well 

 stopped bottles, than when exposed to the air, this c^ues- 

 tion may be easily answered. It is well known, that es- 

 sential oils exposed to the air are converted into resins. 

 This cannot be employed to explain the phenomenon. We 

 roust suppose then, that the oil, in passing to the state 

 of mucilage, loses a part of its hidrogen; or that the oil 

 becomes mucilage by nniting with one of the constituent 

 principles of water, which however appears less probable. 

 Perhaps it may be supposed, that the nitrogen of the air 

 combines with the oil, or with the volatile odorant prin- 

 ciples, to form mucilage. 



An analysis of the flocculent matter would tend to elu- 

 cidate this point. However the remark made by Priestley 

 and Sennebicr would still remain to be explained. They 

 both observed a green ijiatter in distilled water exposed to thcs 



Freezing ad- 

 vantageous to 

 distilled waters. 



* Mr. Nachet, professor at the School of Pharmacy, long ago 

 remarked, that distilled waters, which had been frozen, acquired 

 a more powerful smell, and kept longer. He observed this to be 

 particularly the case with balm, mint, and orange-flower water. 

 Fogel. 



The experiment of Bauhoff, given in the text, tends to confirm 

 the opinion, that the change is not owing to a decomposition of the 

 essential oil, C. 



ra;^S, 



1 



