40 Ohscrvathm on the Chans;e of 



Jittle mixed, but afterwards combined, which formed the 

 colour of a fawu'a belly, exceedingly beautiful. These were 

 all the experiments T wns able to iiiake. They are suffi- 

 cient to show the relation between this plant and the car- 

 thamiis : its flowers give in like manner a yellow colour ; 

 and the beautiful red which thev produce becomes purer in 

 proportion as it is sepa'.ated. I wish I could present results 

 more satisfactory ; but, being bufieted by circumstances, I 

 was seldom able to carry mv plans into execution ; and in 

 regard to many other objects I have nothing left but regret : 

 but I easily console myself when I rcfiect, that I shall be 

 txcecdingl)' happy if I can publish what I have left of ten 

 years' observations made in a field almost now. 



Since this memoir was written, having had an opportu- 

 nity of observing the asperula tinctoria, 1 reuiarked that its 

 roots exhibit the same colour as those of the davais. Hav- 

 ing put them into spirit of wine thev gave also a yellow 

 colour, but not so pure as that of the du/iais. I obtained 

 the same thing from the riihia tincturum ; and I have since 

 learned that it had been observed that these plants give two 

 colours, according as they are treated, which still tends to 

 confirm the analosrv I have announced. 



O. 



VIT. Observations on the Change of some of the proximate 

 Principles of Ffgeial'la into Bitumen ; with anali/tical 

 Erperinienis on a peculiar Suhstance wliich is found 

 with the Bovey Coal. By Chaulks Hatch ett, Esq. 

 RR.S.* 



§ I- 

 'ne of the most instructive and important parts of geo- 

 lojrv, is the study of the spontaneous alieralions by which 

 bodies formerlv appertaining: to tlie oruanized kingdoms of 

 nature have, after the loss of the vita! principle, become 

 gradualK' converted into fossil substances. 



In some cases this conversion has been so complete as to 

 destroy all traces of previous organic arrangement j but in 

 (others the original texture and form have been more or 

 Jes'v preserved, although the subslaaces retaining this tex- 

 ture, and exhibiting these forms, arc often decidedly of a 

 mineral nature. Some, however, of these extraneous fossils 

 fas they are called) retain part of their orio;inal substance or 

 principles, whilst others can only be regarded as casts or 

 impressions. 



* From tht TiaHsadions of the Rojal S'jiittj of LonJon fw 1804- 



From 



