182 Scientific Intelligence—Chemistry. 
expense of this limestone, and only where it existed. It is remarkable 
that the siliceous rock contains various organie forms, which are per- 
fectly preserved; thus there are impressions of Calomopora spongites, 
which are remarkably distinct, and which are surrounded by a mixture 
of epidote, hornblende, quartz, and lamellar limestone; it thus appears 
that the crystallization of the quartz, of these silicates, and of the lime- 
stone, was effected without there being fusion in the mass. Besides 
these animal remains, there are other cavities of indistinet form, which 
are lined with brilliant erystals of acicular hornblende, of epidote, and 
of quartz, and which, from the similarity of their size to the first, may 
be supposed to be also madreporie impressions, but to have had their 
outlines altered more or less by erystallization. It was in one of these 
cavities that I found small crystals of axinite, presenting the planes de- 
nominated 7 and s by Hatiy. The characteristic reactions of this sub- 
stance leave no doubt as to its nature. Before the blowpipe, it swells 
and melts into a blackish enamel, and, with a mixture of fluor-spar and 
bisulphate of potass, it communicates an intense green colour to the 
flame. The same mineral is also found in erystalline masses, and mixed 
with the four other substances indicated above. If tourmaline was not 
very rare in the neighbouring granitic mountain group of the Champ 
. dw Feu, it would be possible that the debris of that mineral had been 
mechanically disseminated in the slates at the time of their deposition, 
and that, by the infiuence of heat, the axinite was produced from ele- 
ments pre-existing in the rock, as frequently takes place with respect to 
epidote, hornblende, or garnet. This, however, is not the case here; 
and it is much more probable that the boracie acid was conveyed into 
the transition beds, in consequence of the eruption of the trap-rock. The 
metalliferous masses of the S.E. of Norway, situated at the very contact 
of the transition formation with hornblendice rock, or with granite, also 
sometimes contain axinite, which was there formed at the same time as 
the metalliferous combinations, probably by a process analogous to that 
to which the axinite of Rothau owes its origin. The same may probably 
also be true regarding the stanniferous slate of Botallack in Cornwall, 
which contains, besides the oxide of tin, shorl, axinite, garnet, and horn- 
plende. The introduction of boracic acid, whichcontributed tothe formation 
of the axinite at Rothau, and in the metalliferous repositories of the en- 
virons in Christiania, has doubtless some analogy with the emanations of 
boracie acid, which, in Tuscany, abound in the vicinity of serpentine, or 
with the boracic acid evolved from the erater of Vulcano in the Lipari 
islands.* 
CHEMISTRY. 
12. Experiments of Brown and Know.—In_ reference to the experi- 
ments of Brown as to the conversion of paracyanogen into silicon, which 
have been refuted on all sides, Knox has performed experiments on the 
simple nature of nitrogen. For this purpose. he employed ammonia- 
* Communicated to the Academy of Sciences, by Mons. A. Daubree ; Comptes 
Rendus, tom. xvili., p. 870, 
"1 
