156 Intelligence and Miscellaneous Articles. 



The prevailing form consists of the faces 6' placed on the edges 

 of the base of the prism, of the base and of the modification </' 

 parallel to the small diagonal of this base. 



The inclinations of the faces are as follow : — 



6' on the face m of the prism, . . . 147°"30' 



6' on the base of j9 122°-30' 



6' on b"- adjacent 123°-07' 



TO on^> 124°-22' 



The low specific gravity of the small crystals from Dy re fiord, their 

 crjrstalline form, and the analyses which M. Damour has published 

 in the ninth volume of the A/males des Mines, show that they agree 

 perfectly with the species long since separated from harmotome by 

 MM. Gmelin and Nepel, and since by M. Kcihler, under the name 

 of harmotome with a base of lime, or harmotome of Marburg. 



The crystals of this mineral, which are met with in the ancient 

 volcanic rocks of Annerode near Giessen, of Stempel near Marburg, 

 and Habichtswald near Cassel, possess, besides the faces stated to 

 belong to the Iceland variety, a modification also placed on the edges 



of the base of the primary form, and the crystallographical sign is b'^- 

 This modification, which is not known in common harmotome, the 

 primary and prevailing forms of which are almost identical with those 

 of lime harmotome, makes with the base of the prism an angle of 

 138° 54', and with the face 6' an angle of 163° 35'. 



The great external resemblance of the Marburg mineral and the 

 small crystals of Capo di Bove near Rome, and Aci-Reale in Sicily, 

 long since described by M. Levy under the name of philUpsite, in- 

 duced M. Kohler to suppose that these two substances constituted 

 only one species ; but the recent analyses of phillipsite, published 

 by M. Marignac in the 14th volume of the Annales de Chimie et de 

 Physique, demonstrate that this arrangement cannot take place. 



The Iceland and Marburg minerals form therefore a distinct spe- 

 cies, inasmuch as they jjossess a peculiar form and composition; M. 

 Descloizeaux proposes the name of Christianite for this mineral. — 

 Comptes Rendus, Novembre 15, 1847. 



ON THE IDENTITY OF METACETONIC AND BUTYUO-ACETIC 

 ACIDS — PROPIONIC ACID. BY MM. DUMAS, MALAGUTI AND 

 F. LEBLANC. 



M. Gottlieb obtained some years since a new acid by oxidizing 

 sugar by means of potash, which he called metacetonic acid, on the 

 supposition of the possibility which the formulae indicated, and which 

 experiment has confirmed, of obtaining it by subjecting metacetone to 

 the action of oxidizing bodies. M. Redtenbacher has since found 

 that glycerine, under the influence of ferments, also yields metace- 

 tonic acid ; and he has since succeeded in separating considerable 

 quantities of it from the product obtained by oxidizing oleic acid with 

 nitric acid. 



