Neck-bay, in Flushing; and, as lately discovered, in New town. Balls of iron pyrites are frequently found in this clay. By exposure to the air, they are decomposed, and the sulphuric acid unites with the iron and surrounding clay, and forms sulphate of alumine and iron, or alum and copperas. Whenever a piece of wood comes in contact during this process, it becomes blackened, or carbonated, and exhibits a deceptive appearance of coal; specimens of which I have collected on Cow-neck, similar to those from Newtown. Indeed, the same appearances have led some one, years ago, to search for coal on Cow-neck; and on the farm of Joseph Dodge are the remains of two shafts, sunk for the purpose of search, which turned out unsuccessful. Instead of sinking money in the search of coal, if a capital was invested in cleaning and preparing the coloured clay for market as a paint, there is a greater prospect of a favourable result. The red ochre on Mr. Dodge's farm lies on the shore of Cow-neck, above high-water mark, on the west side of Hempsted harbour, and is easily accessible.

XVII. On the Blue Earth of New-Jersey, by Mr. JAMES CUTBUSH.

THIS mineral corresponds exactly with the blue iron

earth of Werner, as described by Professor Jameson in his admirable Treatise on Mineralogy.* The circumstance of its becoming blue on exposure to the air, after it has been taken out of the earth, as well as the other characters given

*External Characters.

In its original repofitory it is faid to be white, but afterwards becomes indigo blue, of different degrees of intensity, which sometimes paffes into smals

blue.

Is ufually friable, fometimes loose, and fometimes cohering.

Occurs maffive, diffeminated, and thinly coating.

Particles are dull and dufty.

Soils flightly.

Feels fine and meagre..

by Jameson, are sufficient proofs of its similarity with the blue iron earth of Werner. When first taken up it presents a yellowish-white appearance, and the change of colour is in proportion to the absorption of. oxygen. Mr. Hemble explains this phenomenon upon a principle truly chemical, viz. That the iron, in its first state, is oxydized to the minimum, or in the state of protoxyde; but, on exposure, it becomes oxydized to the maximum, forming the peroxyde, during which the blue ray, according to some, is reflected; according to others, is absorbed. This fact, however, comes within the province of the optician.

This interesting mineral, I am informed, occurs in several places in New-Jersey. It was first discovered near Allentown, which is not far distant from Trenton, and exists in alluvial soil, sometimes accompanied with what, in Jersey, is called Marl. Whether this is the calcareous marl so generally esteemed in agriculture, I cannot determine; but I am inclined to believe that it is nothing more than indurated clay.

The nodules of the blue earth are generally accompanied with bog iron ore, which serves as a crust, and of course contains the siderite, according to all experiments I am acquainted with, which have been made on bog iron ore.

The blue earth has been used in the arts as a pigment, both with water and oil-colours, and is said to be durable. I am informed that a piece was tried by a coach-painter in Germantown, by grinding it with oil, and he found it work better, and was equal, in point of beauty, to the Prussian

Light paffing into, not particularly heavy.

Chemical Characters.

Before the blow-pipe it immediately lofes its blue colour, and becomes reddish-brown, and lastly melts into a brownish black-coloured flag, which is attracted by the magnet.

It communicates to glass of borax a brown colour, which at length becomes dark-yellow; diffolves rapidly in acids.

VOL. I.

Famefon's Syftem of Mineralogy, vol. ii. p. 341.

M

Blue. Beautiful greens and olives have been formed with it by mixing it with other colours.

With respect to its chemical composition I have only to observe, that from one or two general experiments I could not discover the least quantity of phosphoric acid, though it is generally considered, with us, as a phosphate of iron accompanying alumine and lime.

The experiment I made to discover the phosphoric acid was, (agreeably to the usual method) by digesting a portion in nitric acid, and throwing down the iron and earths from the solution by ammonia, and afterwards, on filtering it, adding to the clear liquor, in different glasses, nitrate of mercury, sulphate of iron, &c. Other gentlemen in Philadelphia have made several experiments without having discovered phosphoric acid.* This fact, respecting the absence of phosphoric acid in the blue iron earth, is also mentioned by Jameson.†

XVIII. Account of the production of the new metals, by the decomposition of Soda and Potash. Communicated by Professor SILLIMAN, in a letter to the Editor.

DEAR SIR,

YALE COLLEGE, AUG. 21, 1810.

As I have not seen any account of the repetition, in this

country, of Professor Davy's experiments on the decomposition of the alkalies, &c. by galvanism, I take the liberty

* Mr. Godon, I understand, however, has examined a piece of this earth, and found it to contain phosphoric acid. I would infer, therefore, according to the experiments I have stated, as well as others I have performed fince, that this earth differs in compofition. I have seen specimens in which the bog iron ore has penetrated the mass.

+ Mineralogy, vol. ii. p. 342.

of mentioning the result of an attempt, which I have recently made, to decompose soda and potash.

My first trials were made with the only apparatus which we then possessed, consisting of one trough of fifty pairs of four-inch plates, and of two others, each of fifty pairs of plates two inches by one and a half. With this apparatus I had no expectations of success; and I was induced to make the attempt principally to satisfy myself that nothing could be effected by an apparatus of this extent. I used the common aqua fortis, diluted with from twenty to thirty parts of water; and, to save repetition, I will now mention that I employed this menstruum in all my experiments, and that, generally, the communication between the poles was established by iron wires, terminated by others of gold. I was agreeably surprised to find, that when this galvanic series was in active operation, there were more than indications of success. Both potash and soda, when placed in the galvanic circuit, exhibited a rapid effervescence, and metallic films appeared on the alkali, between the points of communication: they were transient, however, as there was not power enough to enable the metallic particles to collect into globules; but, occasionally, there were slight explosive combustions, with vivid light, jets of fire, and very caustic alkaline fumes. In a few instances, the alkaline mass which had been subjected to the galvanic action, exhibited a flash when thrown into water.

The success attending these trials, although only partial, was sufficient to induce me to prosecute the subject. The experiments which I have related, were not sufficiently striking to be exhibited before my class: they were performed in the presence of two or three companions. Those which I am next to mention, were executed at a public lecture, as well as previously in private.

I caused an apparatus to be constructed of one hundred and fifty pairs of plates, of copper and zinc, of six inches diameter: they were not soldered together, but were con

nected by straps of sheet-lead, the ends of which were soldered to the plates so as to form a perfect connection. They were then arranged in troughs, divided into compartments by parallel plates of crown glass, (common windowglass) cemented in grooves, precisely as the metallic plates usually are in the common galvanic troughs. The pairs of plates were then arranged in the cells, exactly in the manner of the couronne des tasses of volta, of which this apparatus is, indeed, only a revival in an improved form. In constructing it, I availed myself of the information contained in Mr. Children's paper in Nicholson's Journal, and of hints from other sources. The superiority of this construction is evident: it exposes twice the quantity of surface to the action of the chemical menstruum, and is therefore, weight for weight, much more powerful than the apparatus in common use the insulation of the cells is much more complete it is cleaned with the greatest ease, as the pairs of plates are all moveable; and, for the same reason, it is much more portable: Lastly, the troughs are not liable to injury from the acid following the plate into the cement, and thus causing the cells to communicate with one another.

With this apparatus, even with twenty-nine parts of water to one of acid, I was able to succeed without difficulty, especially when the trough, of fifty pairs of four-inch plates, was added to the series. The decomposition was then rapid and evident, and the phenomena were most striking in the case of soda: alkali was placed upon an insulated platinum-support: when the communication was formed, there was a production of intense light: an abundant effervescence and brilliant metallic globules rose through the fused alkali, many of which burnt spontaneously, or rather exploded, with bright flashes, darting out jets of fire so far that goggles were necessary to save the eyes from injury: the combustion produced, in every instance, white alkaline fumes, so very caustic that the glass which protected the eye, (which, for the sake of more distinct vision, was placed