On Vegetalle IFax, &c, 493' 



man, he informed me, that he could hitroduce this extended 

 scale of 39 Notes on a Grand Piano Forte ; using movable 

 bridges, tor producing the sharpening ot one or of two 

 commas, of an improved construction, (hat for such small 

 alterations, would be free of the evils formerly produced by 

 Mr. Clagget's movable bridges, for changing sharps to 

 flats, &c. ; but he has no inclination to embark in such a 

 speculation, unless some Nobleman or Gentleman would 

 order such, an Instrument . Mr. Liston informs me, that 

 this was one of the first applications of his principles, that 

 occurred to him ; but that on application to Mr. Stoddard^ 

 he dissuaded him from thinking of applying them, on any 

 Instrument but the Organ. 



LXII. On Vegetable IVax, &c. By R. Mac-Culloch, 

 M.D. i'VooLu.'ich. Communicated by the Author. 



XT is now well known that wax is a vegetable product, as 

 well as the result of an animal process in bees and other 

 insects, and the wax of various plants has been successively 

 examined by different chemists. Some slight differences 

 have been observed in the several varielie^ but they are not 

 sufficient to lead us to consider them aT'aifferent species ; 

 rather, like the generality of the resins, to be varieties of 

 one common substance. To those already described there 

 is still to be added one, which as far as I know has not yet 

 been noticed. This is a substance held in solution in the 

 essential oil of the rose (the attar of roses) and in that of 

 lavender. I have not searched among the other oils, but it 

 will probably be found in some of them. All the varieties 

 of these two oils do not however contain it; it is frequently 

 absent in the oil of lavender, although but rarely in that of 

 the rose. 



I am not acquainted vvi«h the circumstances under which 

 this variation occurs. When these oils are cooled below a 

 certain point,- a portion of this matter is deposited in the 

 form of minute crystals, giving them an appearance some- 

 what similar to that which the fixed oils assume on freezing. 

 On the addition also of alcohol it is separated in the form 

 of minute brilliant scales, and by this method I obtained 

 the portion which I examined. It is equally separated by 

 water, which, if enough be used, dissolves the whole of the 

 oil, and leaves it in a pure state. It is thus that it is col- 

 lected in the pipes of the stills in which rose-water is made, 

 as it is volatilized in combmation with the oil, and precipi- 

 tated 



