Towards the end of the last century one Professor Göttling, who taught chemistry in the schools of Jena, conceived the idea of preparing a portable chest of chemistry, or complete, collection of Chemical Tests. Chemical knowledge being in those days somewhat limited, we are not surprised to find that the contents of the chest could be stowed within a space nine inches square by twelve deep.

This cosmopolitan collection was intended for the use of chemists, physicians, mineralogists, scientific artists, manufacturers, farmers, and the cultivators of natural philosophy. The tests were prepared by a Mr. Hunneman, a friend of the author, and pupil of Klaproth and Hermbstaedt of Berlin; and were put up in thirty five glass bottles and some small wooden boxes.

When I read my first paper on “Recent Mineral-growth at ordinary temperatures” under (what we, perhaps, rather carelessly call) “ordinary conditions,” I was met with the reasonable remark that, time enough had not elapsed for me to be certain of my facts.

Since then, I have had more than three years of affectionate watching in my “Gold-garden” (as Mr. Ruskin pleasantly calls it); and I am glad to say that the interim has been productive of some new and striking spontaneous changes; which, for convenience of expression, I continue to term “mineral-growth.”

I have before me a number of mineralogical facts of much interest, and I propose to notice first, some recent alterations in 47 of the specimens described in the paper referred to; and then to add a few short notes of similar changes in 35 specimens, not therein alluded to.

In my former paper (Min. Mag., vol. IV, page 1) the different modes of occurrence of oxide of tin in Cornwall were briefly described, and the characters both macroscopic and microscopic of the ordinary tin-stones and tin-capels were illustrated in considerable detail. I have now to describe the peculiar varieties of “wood-tin” or Cornish tin-ore, which are certainly characteristic of many of the Cornish deposits, although their occurrence is not limited to Cornwall as was at one time supposed.

The chemical composition of Cornish wood-tin differs very little from that of ordinary Cassiterite, as was shown long ago by Klaproth.

I give this name to a substance which may be regarded as of the nature of a hydrated magnesian felspar.

It was found by Mr. Dudgeon and myself in granular limestone, about one third of a mile above and north-east of the hamlet of Balvraid; this hamlet is situated six miles up the Glen Beg of Glen Elg, Inverness-shire.

Only a single large mass containing the mineral was found. In this mass it was associated with blue necronite (orthoclase of limestones), Biotite, and a hydrated labradorite.

Its colour is purplish brown of a pale cast; its structure is crystalline granular, it may be called saccharoid; its hardness is 6; its specific gravity from 2·905 to 2·908