10 Resinous Substance found at Highgate. [July, 



Nitric acid acts upon it slowly when assisted by heat, and 

 partly dissolves it, and partly converts it into a red coloured 

 substance. The acid itself becomes red, and when diluted with 

 water lets the resin again fall in white flocks. These flocks when 

 dry are in the state of a light yellow coloured powder, having a 

 bitter taste. 1 could not dissolve it in water; but it dissolved in 

 alcohol, at least as easily as the unaltered resin. 



Sulphuric acid readily chars this resinous body when assisted 

 by heat. 



V. When reduced to the state of a fine powder alcohol readily 

 dissolves a small portion of it, and lets it fall again when mixed 

 with water; but alcohol is a bad solvent of this resinous body. 

 The same observations apply to ether. 



VI. I cannot find that either potash or subcarbonate of potash 

 dissolve this resin, though boiled with it for some time in the 

 state of powder. This is the property which distinguishes High- 

 gate resin from every other with which I am acquainted. Even 

 amber is partially acted upon by alkaline leys, and tinges them 

 yellow very speedily. 



VII. Nor do I find that acetic acid dissolves any perceptible 

 portion of this resin after a week's digestion in it, when in the 

 state of a fine powder. I even triturated them together for a 

 considerable time in a mortar, and then boiled them in a glass 

 tube, but no solution was effected. Here, again, another cha- 

 racter which Mr. Hatchett has assigned to the resinous bodies 

 fails when applied to the Highgate resin. 



VIII. I have not tried the action of oils upon Highgate resin ; 

 but from the properties above described I conceive there is reason 

 to presume that, like copal, it will not dissolve in any of them. 



IX. It burns all away before the blow-pipe upon a piece of 

 metal without leaving any perceptible ash behind it, when we 

 make choice of pieces quite free from any earthy matter attached 

 to them. 



Such are the properties of this substance, as far as I have 

 examined them. They are sufficient, I think, to distinguish it 

 from all the vegetable substances hitherto observed. It approaches 

 nearest to copal and amber; but is distinguished from the first by 

 its solution in alcohol, and its non-solution in potash ley ; from 

 the second, by its readily melting when heated, and by its melting 

 without any perceptible change of its properties. Thus the che- 

 mical properties of this singular substance throw no light upon 

 the source from which it was derived ; and cannot, therefore, 

 facilitate our inquiries into the revolutions which the southern 

 part of this kingdom has undergone, and the various animal and 

 vegetable remains so thickly scattered in its bowels. 



