188 Dr Balfour's Descriptionof Bare Plants. 



the density of the substance is very nearly the same as that 

 of the diamond. By means of long calcination at a bright- 

 red heat in a covered crucible, the specimens were not altered ; 

 they retained their aspect, hardness, and weight ; they do 

 not, therefore, contain any substance volatilizable by calcina- 

 tion out of contact of the air. This result, certainly, does not 

 prove the igneous origin of these diamonds, but renders im- 

 probable the idea expressed by M. Liebig, that diamonds 

 are derived from the transformation of organic vegetable 

 matter. 



The three specimens were successively burned in pure 

 oxygen gas in the appai-atus employed by M. Dumas for the 

 combustion of the diamond. The oxygen obtained from chlo- 

 rate of potash was contained in a gasometer ; it was dried and 

 purified before it reached the combustion tube, by passing 

 through two tubes containing sulphuric acid and pumice, and 

 one tube with potash ; employing this method with the pre- 

 cautions indicated by M. Dumas, 100 of the first specimen 

 gave, carbon 96-84, ash 2-03 ; loss 1-13 : second specimen 

 gave, carbon 99-73, ? -a 024 ; loss 003 : third specimen gave, 

 carbon 9987. ash <^;^7 ; loss 0-36. 



In the combustion of the first specimen, only one bulb-tube 

 with potash was employed, so that a portion of the carbonic 

 acid produced by the combustion was lost ; but in the other 

 two experiments, in which two bulb-tubes, containing pot- 

 ash, were used, the second increased in weight some centi- 

 grammes. 



The last two analyses prove perfectly that the specimens 

 are composed entirely of carbon and ash. The ash was yel- 

 lowish ; and in the first specimen it had retained the form of 

 the diamond. When examined by the microscope, the ash 

 appeared to be composed of ferruginous alumina and small 

 transparent crystals, the form of which could not be ascer- 

 tained. — {L'Inslitut, Mars 2, 1849 : Fhilosophical Magazine, 

 vol. xxxiv., 3d series, No. 230, May 1849, p. 397.) 



Notice of some Plants which have flowered recently in the Poyal 

 Botanic Garden. By J. H. BALFOUR, M.D., Professor of 

 Botany in the University of Edinburgh. (With a Plate of 

 the Quassia amara) Communicated by the Author. 



Quassia amara, Linn. Spec. Plant, ed. Willd., torn, ii., 

 p. 567. Linn. fil. Suppl, p. 235. Lamarck Illust., t. 434. 

 Decandolle, Annales du Museum, xvii. 323; Prodromus I. 

 733. Ad. Jussieu, Memoires du Museum, xii., tab. 27, 

 No. 43, Hayne, Darstellung und Beschreibung der in 

 der Arzneikunde gebraUchlichen Gewachse, ix. 14 (tab.). 



