Dell;

3 C00+

tt 110

pith ant: les; Cale „0 ar, 'b] many

ne COn*

. 33 X-

morales

1; hei

0,

nto fuot“

', 1

, Ur

and mar

ming tbei ay beloy Wb 100

ADDITIONAL NOTES. 4,81

orafles, hence ſhells ſometimes found on coals and over iron-RKone.

NoTE XVIII--TR0N.

C ALCIFORM oresz; combuſtion of.iron in vital airz ſteel from deprivation of vital air; welding; hardneſs; brittleneſs like Rupert's drops 3 ſpecific levity; hardneſs and brittleneſs compared 3; Keel tempered by its colours; modern produttion of iron, manganeſe, calamy; ſeptar1a of iron-ſtone ejeted from volcanoesz; red-hot cannon- balls.

NoTE XIX.--FLixT.

I. Siliceous rocks from moraſſes; their cements. 2. 8S/- liceous trees 3 coloured by iron or manganeſe; Peak-dia- monds; Briſtol-ftones; flint in form of calcareous ſpar; has been fluid without much heat; obtained from pow- dered quartz and fluor-acid by Bergman and by Achard. 3. Agates and onyxes found in ſand-rocks; of ve getable origin 3; have been in complete fuſion; their concentr

Coloured circles not from ſuperinduction but from con- ef tion 3; experiment of GE 4a ſolution of the blue vitriol; iron and manganeſe repelled in ſpheres as the nodule of flint cooled; circular ſtains of marl in ſalt-mines; ſome flint nodules reſemble Knots of wood or roots.

4. Sand of the ſea 3 its acid from moraſles; its bale from ſhells. 5. Chert or petrofilex Rratified in cooling; their colour and their acid from ſea-animals; labradore-ſtone from mother-pearl. 6. Flints in cbalk-beds; their form, colour, and acid, from the fleſh of ſea-animals; ſome are hollow and lined with cryſtals 3; contain iron; not produced

12ÄARDZD Ei