which this substance has when slowly oxydizing in the air, while to those, unacquainted with the odor of oxydizing phosphorus, the universally known odor of burning sulphur has been cited as an exemplification. Hence, the often repeated allegation of a sulphurous smell being consequent to the passage of lightning. A similar property was likewise observed in oxygen, which had been extricated from water by electrolysis. I observed a like odor about twenty-five years ago, when a large tube, used in the inflammation of explosive mixtures of hydrogen and atmospheric air, was burst by the process; as well as upon other occasions, when similar burstings ensued.

Schönbein, who has attained much celebrity as the inventor of gun cotton, was the first to associate phenomena of the kind alluded to, under one view; and to show that the air which had acquired the odoriferous property in question, however obtained, had certain chemical properties in common. These properties were analogous to those displayed by chlorine, bromine, iodine, fluorine, and cyanogen, which constitute the halogen class of Berzelius; and hence the distinguished investigator conceived that they might be due to some body of that class, which had escaped detection.

To this supposed body he gave the name of "Ozone," from Greek words which signify the production of odor.

As cyanogen is known to consist of two atoms of carbon and one of cyanogen, it would not, a priori, be unreasonable that another body should be formed deserving to be ranked in the same class.

Latterly, Schönbein has advanced the idea that ozonification may be owing to a combination consisting of peroxyd of hydrogen and bioxyd nitrogen, or in other words, of oxygenated water and nitric oxyd. But this inference seems to have been invalidated by an experiment made by de la Rive and Marignac. These distinguished chemists ozonized oxygen by passing electric sparks through the gas, while exclusively occupying a tube in which it had been evolved from chlorate of potassa previously fused, and consequently devoid of moisture.

Hence Berzelius, and other distinguished chemists, deemed it reasonable to ascribe the phenomena to a peculiar state of oxygen.

It had long been known that certain elements were capable of very different states; as for instance, carbon in the forms of tinder, charcoal, anthracite, plumbago, and the diamond.

According to Prof. Draper, chlorine after exposure to the solar rays, becomes more capable of combining with hydrogen under a feeble illumination.

This diversity is displayed in many instances by bodies in what has been called their nascent state, which is assumed just as they escape from combination. Under these circumstances, they will combine with elements for which, usually, they display no affinity. Thus nitrogen, as it exists in the atmosphere, shows no affinity either for carbon or hydrogen, yet when nascent, forms with hydrogen, ammonia, with carbon, cyanogen. On this account I have concurred in opinion with Berzelius, that the phenomena ascribed to ozone may be caused by oxygen in a peculiar state.

It is requisite to mention, that among the tests of the presence of ozonized air, the mixture of starch paste with a solution of iodid of

potassium is the most delicate. This is dependent upon an inexplica ble but well known property of starch to be rendered blue by a very minute portion of free iodine. A very small addition of chlorine, by seizing an equivalent portion of potassium, liberates enough iodine to produce blueness in mixture; and, in like manner, a very small pro. portion of ozonized air, whatever may be its source, renders starch blue by a like procedure.

In like manner, by exposure to ozonified air, strips of paper, drenched with a tincture of gum guaiacum, are rendered blue, as these changes would have resulted from the presence of chlorine, and as neither that nor any other of the known halogen bodies could be present, the agen cy of some undetected body of that class was reasonably to be inferred. Having given this preliminary brief sketch of the state of our knowl edge respecting ozone, it is time to proceed to explain its connection with the contrivance of the apparatus before us.

It had occurred to me that the smell and corruscations arising from the attrition of siliceous stones, briskly rubbed against each other, might be due to some cause, analogous, if not identical, with that to which the phenomena of ozone are indebted for their existence.

Nothing could be more unaccountable than this odor. That it cannot be due to any organic matter entering into the composition of the quartz must be evident; in the first place, because the smell is produced by the purest and most transparent specimens of rock crystal in the regular form, and in the second place, because ignition to bright redness does not destroy nor even diminish the property.

One thousand grains of cellular horn stone, or French burr, on igni. tion as above stated, lost five grains-that is to say, one-half per cent. of its weight, without, however, losing the property of producing light

and smell.

It occurred to me that it might help to remove the mystery, were an apparatus constructed by which the attrition of siliceous masses might be made more efficaciously than could be effected by an operator un aided by mechanism. Having suggested this idea to my friend, Prof. Henry, he said that I might have such an apparatus constructed at the expense of the Smithsonian Institution. The apparatus, which is before the meeting, was made accordingly.

Two pigmy mill-stones, each seven inches in diameter, made of cel lular horn stone, known vulgarly as French burr, and resembling those used in grist mills, were procured and supported as in the usual way, one above the other; excepting that the upper one hangs by means of a bolt upon a spiral spring of brass wire, sustained by a cross of iron, resting upon screw nuts, upheld by four iron rods, each inserted at its lower end in a circular plate of cast iron, so as to be equidistant from each other. The surface of the iron plate is turned true, so as to enable it to serve as an air-pump plate. It rests upon four columns, which elevate it from a base board sufficiently to admit of a pulley band and wheel to work in a parallel plane below that in which the plate is situ ated. There is also room for a lever, from which a stirrup hangs as a support for the spindle of the pulley, on the apex of which plane ex tended upwards through a perforation in the axis of the plate, the lower mill-stone rests. This spindle passes through a stuffing box, so as

to be air-tight; the stirrup allowing it to retain its perpendicularity, not'withstanding the curvilinear movement of the lever when employed to raise or lower the stone.

The nuts upon which the cross supporting the upper stone has been mentioned as resting, are so used as to render the lower surface of the stone horizontal, while, as it hangs upon a bolt which occupies the axis of the spiral spring, the pressure on the lower stone, when brought into contact with it, may be made as gentle as necessary. The lower stone being balanced on the point of the spindle, is made to turn with it by means of a pin proceeding from its lower surface and another proceeding from the spindle, which operates as a carrier in a lathe.

In order to put the apparatus in operation, the lower stone is made to revolve by means of the pulley, band, and wheel; while, by means of the lever, the stone is so raised as to produce sufficient contact with that suspended above it. Under these circumstances, scintillation and the odor which is the object of inquiry resulted. In no way, however, could I produce the chemical effects of ozone upon iodized starch or guaiacum. On directing a jet of hydrogen between the stones, it took fire forthwith; but I could not, by means of an electrometer, detect any electricity. When the upper stone was removed, and a piece of an old file of a large size made to scrape over the surface of the lower stone, a conducting connexion between the file and an electrometer was productive of no electrical indication.

The plate being ground to fit a large receiver, the stones were in successive experiments made to revolve in vacuo, in hydrogen, and in a vacuity previously replete with this gas, without any diminution of the luminous phenomena. These, it seems from the inflammation of the jet of hydrogen, constitute a simple case of ignition. During the collision of flint with steel, a portion of the metal being struck off, takes fire, and thus is enabled to convey ignition to tinder or punk. The incapacity of two pieces of quartz to produce fire in like manner, arises from the incombustibility of the particles struck off from them, which consequently cool before they meet any mass with which they are not in contact at the moment when the ignition supervenes.

As the burr stones are opaque, the light is much less advantageously seen when they are both employed, than when the upper one is replaced by a comparatively small mass of transparent quartz. The concentration of the frictional force, and the transparency of the mass under which the ignition is effected, makes the corruscations very brilliant in a room otherwise darkened.

So great is the resistance of the surfaces of the stones when brought into revolutionary collision, that the maximum effect which they are capable of producing, would require more force than can be communicated by the human power, through a single hand actuating the stones by means of a wheel, pulley, and band.

Of course cog wheels might be resorted to, and the power of steam or that of Professor Page's electro-magnetic machine, employed to ob tain a greater effect. I have lately been informed, that in English potteries where flint is employed as an ingredient in the ware manufactured, the grinding of this material is productive of an intolerable fœtidity. In an atmosphere thus imbued with fœtidity, chemical effects ought to SECOND SERIES, Vol. XII, No. 36.—Nov., 1851.

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be observable if there be any connexion between the source of this fætidity and that produced by ozonizing agents.

It is long since it occurred to me, that as the phenomena of light, under all the various hues which it is capable of producing, are ascribed to the undulatory affections of an ether pervading the universe; so the still greater variety of odors which influence our olfactory nerves, may be due to vibratory agitation of the same medium.

Consistently it may be conceived that the odor produced during ozonification, during the attrition of quartz, is due to an odoriferous etherial agitation.

II. BOTANY AND ZOOLOGY.

1. Note on the Vegetation of the Coal Period; by Mr. J. E, TESCHE MACHER, (communicated for this Journal.)-In 1843 my attention was first attracted to the remains of vegetables in the anthracite coal from Pennsylvania; by the year 1846 my collection of specimens was very numerous, and in 1847 I exhibited a small portion of them before the American Society for the Advancement of Science, at their annual meeting in Boston.

In 1846, the Natural Hist. Soc. of Haarlem, in Holland, adjudged a prize to Dr. H. R. Geppert, professor in the University of Breslau, for a most elaborate and well written dissertation in reply to the prize ques tion proposed by them,

Whether the beds of coal were composed of plants which grew on the spots where these coal beds now exist, or whether the vegetation grew in other places, and was floated or brought there by other means."

This dissertation, with between 30 and 40 plates, was published at Haarlem in 1848, and has been recently added to the library of the Nat. Hist. Soc. of Boston, from the funds left by James Lloyd which were in the possession of the Republican Institution, and were gener. ously devoted by the members, to the diffusion of science, by the presentation thereof to the Nat. Hist. Soc. for the purchase of the most recent sterling works in its several departments.

From this masterly dissertation it appears that Dr. Gæppert, for the purpose of elucidating this subject, had been pursuing the same course with the coal from various beds in Germany, as I had with those of Pennsylvania. And although the main question has received the same solution from both, namely, that the plants grew where the beds of coal now exist, and were solidified amongst other conditions under that of absolute rest, yet upon some minor points we differ, and I believe that the extent of the beds from which my specimens have been taken, has afforded much more varied appearances than have as yet met his eye. I should not attempt by any discussion at present to alter the views of Dr. Gæppert, unless I could exhibit to him my specimens, for many of my impressions were at first nearly the same as those he has expressed; and it was only by the reiterated and close examinations of fresh speci mens that I was led step by step to change my opinions. In fact, with out the inspection of regular series of specimens, presenting various details, it is impossible to arrive at satisfactory conclusions on many points of this occult subject, and it has several times occurred that a

single specimen has thrown unexpected light, not obtained by the inspection of fifty others of nearly the same appearance.

As it is, the questions in doubt are much more numerous than those which appear settled. One of the characters which seems to have escaped him is that of the fissures chiefly traversing well defined vegetable surfaces (epidermis). These are from line to inch in depth, describe various curves, or right lines, sometimes parallel lines, and forms of all kinds, they are sometimes filled with siliceous matter and sometimes with a charcoaly mass evidently of different structure to all around. Neither does he seem aware of the numerous fossil remains of fungi in the coal, some of these much resembling those which now exist in the siliceous epidermis of the bamboo and the rattan.

I also differ from him in what he considers the annual rings of Araucaria, although my first impressions were similar to his.

My specimens of Sigillaria, Lepidodendra, and Sagenaria are numerous, and there are various appearances, resembling the internal struc ture of some of these gigantic vegetables, which if they can be recog nized as such would cause considerable astonishment. The appearances which Dr. Goppert has at present probably no idea of, are many and very interesting, but without well and carefully drawn figures, descriptions of them, would be useless. In stating that I differ from so experienced a naturalist on this subject as the learned professor of Breslau, it is far from my intention to impute to him even erroneous views— yet it is only from difference of opinion that truth comes to light, and this is my only desire.

When this subject shall have been taken up and studied by scientific men whose minds are well prepared and who are possessed of sufficient leisure, I am sure that extremely interesting facts and consequences will be developed by their observations.

Boston, Sept. 13th, 1851.

2. Conspectus Crustaceorum, &c.; Crustacea of the Exploring Expedition; by JAMES D. DANA.-CRUSTACEA GRAPSOIDEA, (Proc. Nat. Sci., Philad., 1851, p. 247.)-This paper includes descriptions of the following new species :*

Eucrate crassimanus; Macrophthalmus pacificus; Gelasimus nitidus; Helocius inornatus; Pseudograpsus oregonensis, P. nudus: Grapsus planifrons, G. longitarsis, G. crinipes; Goniograpsus simplex, G. innotatus: Planes cyaneus; Hemigrapsus crassimanus, H. affinis; Cyrtograpsus angulatus; Sesarma obtusifrons, S. obesum; Sarmatium crassum; Cyclograpsus cinereus, C. granulatus; Chasmagnathus subquadratus, C. granulatus, C. lævis; Helice crassa; Acanthopus abbreviatus; Plagusia speciosa, P. glabra; Cardisoma obesum, C. hirtipes; Pinnothera faba; Fabia subquadrata; Halicarcinus pubescens; Hymenicus varius, H. Novi-Zealandiæ, H. pubescens.

2. Mastodon in Northern Illinois; by Prof. S. P. LATHROP.-A large tooth of a mastodon in a fine state of preservation has recently been found in the Kishwaukee river, in New Mifford Co., Illinois. It was drawn up by a seine, from near the mouth of the river.

*For the genera see this volume, page 283.