composed by acids appears also to be completely analogous with the decomposition of alcohol, in the formation of those compounds to which the name of ether has been already appropriated.

Pyroacetic spirit is strikingly distinguished from the pyroxylic in many of its most important characters. Its specific gravity is inferior, being only 0-786. Its taste and smell are also different; and it burns with an intense white flame, very different from the blue flame of pyroxylic spirit. It is also completely soluble in oil of turpentine.

Sulphuric acid neither blackens it, nor renders it turbid, but communicates to it a fine orange-yellow colour; and the mixture continues transparent, even after the application of heat.

When distilled along with muriatic acid, a volatile fluid passes over having the odour of that acid; but this is completely removed by re-distilling it off potash,

A current of chlorine, sent through the pyroacetic, spirit, communicates to it a slightly-yellowish shade, but without presenting the subsequent phenomenon of a sudden discoloration. The resulting fluid has a suffocating odour, somewhat similar to that of the chloro-pyroxylic ether, but stronger. After a few instants, it separates into two distinct fluids; the one, thick, heavy, oily, and transparent; the other, lighter, and slightly opalescent. The latter burns with a light flame, of a bluish colour, and leaves an abundant acid residue. It dissolves in water, and imparts to it a hot taste, followed by a sensation of sweetness; but it does yield a trace of the horse-radish flavour, which characterises the ether formed by chlorine and the pyroxylic spirit.

The oily fluid, after a few days, acquires a slight yellowish colour, and burns with a thick flame of a deep-green colour, emitting suffocating fumes, which contain abundance of muriatic acid. It is soluble in alcohol, but insoluble in water. When poured into the latter, it subsides to the bottom in separate drops.

Both of these spirits were analyzed, by volatilizing a known weight of them through red-hot oxide of copper. The pyroxylic spirit, decomposed in this way, was found to consist of

Or very nearly, of 6 atoms of carbon, 4 of oxygen, and 7 of

hydrogen.

The pyroacetic spirit was found to consist of

Or very nearly, of 4 atoms of carbon, 2 of oxygen, and 3 of hydrogen. (Bibliotheque Universelle, Oct. 1823.)

3. Argillaceous Iron Ore.

The analysis of this ore, given in the last number of the Annals, was incorrectly stated. The reader will perceive that the quantities of lime and carbonaceous matter, having been obtained from 200 grains of the ore, should have been divided by 2; and a small quantity of alumina separated from the precipitated oxide of iron being added, the composition will be nearly as follows, and as it will be found stated in Phillips's Mineralogy, p. 237, viz.

Protoxide of iron, with a trace of man

This limestone, which is highly esteemed for the goodness of the lime which it yields, I have found to consist of

MINERALOGY.

5. Composition of Tourmaline.

86.17

7.10

3.40

1.67

1.00

0.66

100.00 R. P.

M. Gmelin, who has devoted a good deal of attention to the analysis of this mineral, deduces the following conclusions from his researches. All the tourmalines hitherto examined by him contain from two to six per cent. of boracic acid, which appears to be quite an essential ingredient. All of them contain also

two alkaline bases, which are a mixture in some cases of potash and soda, in others of potash and lithia. Magnesia also exists in most specimens, but does not appear to be so essential an ingredient as the preceding. Oxide of iron is sometimes present in a very large proportion; sometimes it is altogether wanting.

The rubellite, from Rozena, in Mahren, consists, according to his analysis, of

The substance

This mineral does not contain a trace of soda. which Klaproth and Bucholz mistook for that alkali was in fact a mixture of boracic acid, potash, and lithia.

The schorl from Eibenstock, in Saxony, which was more recently analyzed by Klaproth, consists, according to Gmelin, of

The tourmalines examined by him were six in number, and were all from different localities.-(Schweigger's Journal, vol. xxxviii. p. 514.)

6. Petalite.

Dr. Bigsby has discovered Petalite on the north shore of lake Ontario, on the beach in front of York, the capital of Upper Canada. It is a rolled mass weighing about a ton. The mineral has been examined by Dr. Troost; it occurs in crystaline masses, of a greyish white colour, with a tinge of green, and resembles some varieties of Tremolite, for which indeed it was first taken. (See Jour. Acad. Nat. Sciences, No. 8, vol. 3.) 7. New Localities of American Minerals. By John W. Webster, MD. MGS. Lond.

Zircon and Green Felspar of Beverly (Mass). In a former

number of this Journal, page 390, we have noticed the discovery of green felspar at Beverly in this state. The specimens first found were met with in a stone wall; it was ascer→ tained that the materials for the construction of the wall were taken from the common, or parade ground of Beverly, many years ago. Application was made to the proper authorities for permission to open the ground and make a thorough examination. The result of this undertaking has been highly satisfactory. The green felspar has been found in narrow veins traversing sienite, accompanied with crystals of zircon, and some other substances, the nature of which has not as yet been satisfactorily determined.

The crystals of zircon have an amber-brown colour, a resinous and oily lustre, with a fracture somewhat conchoidal and foliated. The cleavages, in some of the crystals, are tolerably distinct and indicate the octohedral primitive form. A few perfect octohedral crystals have been found.

The largest crystal in my possession, weighs 30 grains ths, and its specific gravity is 406; it is a four-sided prism terminated by a four-sided pyramid; the terminal planes being set upon the lateral edges of the prism.

With the reflective goniometer I find the angle of inclination 130° 12'. The angles scratch rock crystal.

The hornblend and felspar which accompany these interesting substances, very much resemble those of the zircon sienite cf Von Buch, with a specimen of which in my collection I have carefully compared it. The structure of this rock, and its geological connexions, are highly interesting. The following is Von Buch's description of the Norway zircon sienite. It is strongly distinguished from every porphyry by the magnificent, coarse granular, and sometimes large granular felspar, partly of a pearl-grey, and partly of a red colour, which always strongly characterises the blocks by its high degree of lustre. It is equally distinct from granite, sienite, or other similar granular stones, by the preponderance of the felspar. All the other ingredients seem to be sunk in this as a basis, and they often appear only occasionally; but hornblend is never wanting, and this hornblend is generally pretty characteristic and distinct; long black crystals, which possess a double foliated fracture by way of discrimination from mica-folia of mica also make their appearance but very rarely; and quartz shows itself in small grains, so as not to be altogether missed. It appears, in general, accidentally in the composition, and we search through whole hills without finding it again. Wherever the grains of the felspar meet, there remains almost always a small angular cavity into which crystals project. Among these, are the crystals of zircon, which give name to the rock. Epidote is associated with them in fine needles.

In the rock at Beverly, there is a great tendency of the component parts to assume regular crystalline forms, and a few perfect crystals of green felspar have been obtained.

Phosphate of Lime.-I have lately found a few pretty distinct crystals of phosphate of lime near the village of Stow, in this state. The crystals are disseminated in rolled masses of a coarse grained granite. They are portions of hexædral prisms, of a greenish-white colour. The fracture in the direction parallel to the base of the prism is distinctly foliated, and the powder phosphoresces on burning coals.

The same granite contains well defined crystals of beryl, and here and there a small crystal of tourmaline.

Andalusite.-This mineral I found in a rolled mass of white quartz, in small imperfect four-sided prisms, near Lancaster. The colour is a reddish-brown.

Spodumen. A notice of this mineral has lately been published in the Journal of the Academy of Nat. Sci. of Philadelphia. I have visited the locality at Sterling, and find it very abundant. The principal rock in which it occurs is a compound of quartz, mica, and spodumen, weighing probably about thirty tons. may be called spodumen rock.

It

Cleavelandite occurs in small quantity at Sterling.-(Boston Journ. of Philos. and the Arts, No. 6, May, 1824.)

MISCELLANEOUS.

8. On the Cause of the Rotatory Motion of Camphor in Water. (To the Editor of the Annals of Philosophy.)

SIR,

If your Cambridge correspondent E. A. (see Annals of last month) will look at page 51 of the first volume of Nicholson's Journal, 8vo. series, he will find that he is mistaken in supposing that no cause has been hitherto assigned for the rotatory motion of a particle of camphor when placed on the surface of water. Several eminent men, as he will there see, have turned their attention to this curious subject, amongst whom are Benedict Prevost, Venturi, and Caradori; and the results of their experiments will, I dare say, both interest and amuse your friend E. A. The paper alluded to is an abstract of M. B. Provost's inquiries on the subject, by M. Biot, who considers that we may infer from them, as an established fact, that "camphor is moved upon the surface of water by the effect of the emission of the particles which compose it; an emission that becomes perceptible to our senses by the smell which it produces, and by the repulsions which it exercises against small bodies floating upon the surface of water. As the effect resulting from these different impulses does not pass through the centre of gravity of the piece of camphor, this centre has a progressive motion, and the body revolves round it," &c. E. A. conceives the rotatory