tion of codein absorbs cyanogen with avidity and yields a new base dicyanocodein, C40H21N3O6 or 2C2N, C36 H21 NO6. Distilled with four or five times its weight of soda-lime or potash-lime, codein yields several organic bases among which Anderson succeeded in identifying methylamine and propylamin, C6 H, N.-Ann. der Chemie und Pharmacie, March, 1851, Ixxvii, 341.

8. Acetic Acid from Sea-weeds.-STENHOUSE has found acetic acid in considerable quantity among the products of the fermentation of various species of sea-weed. Fucus nodosus yielded 145 per cent., Fucus vesiculosus 1.15 per cent. of the weight of the moist plant.

W. G.

9. New Test for the Nitrites and Nitrates; by GEORGE C. SCHAEFFER, Prof. of Chem. and Nat. Phil., Centre Coll., Danville, Ky., (Proc. Amer. Assoc., 4th meeting at New Haven, 1851, p. 403.)—Chemistry has hitherto furnished no distinctive test for the nitrites, when present in small quantities. From the supposed unfrequent occurrence of these salts, the want of such a test has never been felt.

For several years I have been engaged in a research which has led me to believe that the nitrites are of far more frequent occurrence than is commonly supposed, and that they have been mistaken for nitrates, as the usual process, with pure sulphuric acid and protosulphate of iron, will give the same reaction with both classes of salts. In order to settle the question, it was necessary to find a distinctive test, which should avoid all risk of confusion. I first tried acetic acid, which, as is well known, does not act upon the nitrates, while it decomposes nitrites. By substituting this acid for the sulphuric in the usual process, I succeeded perfectly. The test seemed even more delicate than that for the nitrates, and was more elegant in its operation.

Still the following difficulties were to be encountered. The slightest quantity of peroxyd in the sulphate gave a color with acetic acid, and injured the delicacy of the test. Moreover, the nitrites are generally either destroyed or converted into nitrates, with such readiness, that it would be almost impossible to concentrate their solutions.

At last I was led to the following process, which leaves nothing to be desired. To the solution supposed to contain a nitrite, add one or two drops of solution of yellow prussiate of potash-there should not be enough to give a perceptible tinge to the liquid. A few drops of acetic acid are then to be added, and immediately, or in a few minutes, according to the quantity of nitrite present, the liquid assumes a rich yellow tint.

As the re-agents used give nearly the same color, spontaneously, after some time, even in pure water, it is better, when testing for minute quantities, to use two similar vessels, one containing pure water, and the other the liquid under examination, to both of which the re-agents are to be added in precisely equal quantities. The vessels should be equally exposed to the light, with a sheet of white paper behind them. With these precautions, I have found this test astonishingly delicate, in fact, ranking with those for iron, iodine, &c. Using fused nitre, I have detected the presence of one pt. in 617,000 pts. of water; a bystander wholly ignorant of the nature of the operation, pronouncing as to the color. Yet this salt contained about one-half its weight of undecomposed nitrate.

It should be remarked that the presence of a large quantity of nitre has no influence upon this test, as with pure water it gives no color. The same reaction answers also for the hyponitrates.

The next step is to convert this test into one for the nitrates. The decomposition of the nitrates of lead and mercury by boiling with excess of their respective metals, has long been known. The reaction of metals with the alkaline nitrates does not seem to have been studied. I find that nitrate of ammonia is readily decomposed in presence of metallic lead, and what seems surprising, nitrate of potash is also decomposed, though not so readily.

To test for the nitrates, we have only to agitate the slightly warmed liquid, for a few minutes, with shavings of lead, and proceed as before. By a longer digestion more of the salt would be converted into nitrite, and the color would be stronger. In estimating the delicacy of this process, I had used pure rain water, but before completing the experiments I was obliged to be absent for several days; on my return, I soon found that the water from the same cistern contained so much of nitrates and nitrites, that it could no longer be used. From the readi ness with which the decomposition was effected, I presume that nitrate of ammonia was present. The interval had been marked by the occur. rence of frequent and severe thunder showers.

By using distilled water, I have been able to detect the presence of one pint of nitre in about 60,000 of water, digesting with lead for only a short time. Mercury containing a minute quantity of lead, seems to answer better than lead, for a time, in the above process; but after long use it loses its effect. It will not answer to add to it any perceptible quantity of lead, as the liquid then becomes muddy on agitation.

Oxalic, tartaric, and dilute hydrochloric acids may be substituted for the acetic, except when they produce precipitates, which would destroy the clearness of the liquid.

The yellow color produced in this test is the result of a complex decomposition. Everitt's yellow salt, and red prussiate, seem to be formed, and in some cases also very minute quantities of Clayfair's nitroprussid.

II. GEOLOGY.

1. On the Parallelism of Mountain Chains in America; by Mr. DESOR, (Proc. Boston Soc. Nat. Hist., Dec., 1850, p. 380.)—It is gen erally admitted that the Appalachian or Alleghany chain was raised during the deposition of the coal formation. It is consequently referred by Mr. Beaumont to his system of the Balloons, the direction of which (E. 16° S.), when transferred to Washington, becomes E. 43° 18′ N, a direction which indeed answers pretty accurately to that of the main portion of the Alleghany chain. This is also, according to Dr. C. T. Jackson, the main direction of the hills of New Hampshire and Maine. But there is besides in the Alleghanies another direction more nearly par allel to the meridian, which Professor Rogers considers as a mere devia. tion from the main direction, whereas Mr. Beaumont refers it to a previous upheaval, together with those ranges of hills in Massachusetts which Prof. Hitchcock has designated as the "oldest meridional system,"

and whose direction is a few degrees east of north. According to Mr. Beaumont, this latter system would not only be older than the Alleghanies, but even older than the oldest Silurian strata of North America, since it is supposed to have originated previous to the Taconic system.

Now to this system is ascribed a most conspicuous part in the constitution of the soil, not only of New England but of the whole continent, so that if true it must be of paramount importance. From Massachusetts, Mr. Beaumont traces it in a south southwest direction to the mouth of the Connecticut, and in the opposite direction across New Hampshire and the White Mountains to the sources of the Connecticut, from whence it extends across Labrador to Cape Chisley; nor is it supposed to stop here, for Mr. Beaumont follows it even beyond Davis' Strait into Greenland. The range is said to be not less extensive in the southern direction. Representing it as a great circle, starting from Amherst College in a direction south 15°, he supposes it to run parallel to the general direction of the coast of the United States from the mouth of the Hudson to Cape Hatteras. From thence it is sup posed to cross the eastern portion of Cuba, the Isthmus of Panama, and then to touch Cape Guyaquil, passing a little outside of the Coast of Choco, in a direction parallel to the principal mountain chains of New Grenada.

This system, thus laid down, is considered by Mr. Beaumont as one of the most remarkable mineralogical and metalliferous zones of the globe, including all the localities whence are derived the remarkable minerals of Greenland and Labrador, the gold mines of Vermont,* Virginia, North and South Carolina, Georgia, the several gold mines of Cuba, the gold and platinum mines of Hayti, and the gold and platinum mines of Choco and the Eastern Cordilleras in New Grenada.

If we now ask for the reason why this immense belt should be so much older than any other mountain chain of this continent, we are referred to the single statement, that in New Hampshire and Vermont the primary rocks following this direction are overlaid unconformably by the strata of the Taconic system. And since the Taconic system is supposed by Mr. Beaumont to be older than the oldest Silurian, the inference on his part was but natural, that the ridges of New Hampshire, Vermont, and Massachusetts must indeed be very old. They were thus made the point of departure of this vast system, to which most of the above-mentioned localities were added merely on account of their direction or of the minerals which they contain.

Now that serious doubts are entertained as to the existence of a Taconic system in New England, especially since it has been proved by the investigations of the geologists of Canada that the slates of the Green Mountains, which were referred to the Taconic, belong in reality to the Silurian formation, the theory of Mr. Beaumont cannot longer be relied upon, being thus deprived of its principal basis. If it is once ad

*After the reading of Mr. Desor's paper, Mr. Alger observed, that the gold found in Vermont, which he supposed was the authority for M. De Beaumont's allusion to the gold mines of that state, had proved to be of artificial origin. It was gold which had been thrown into a stream forty or fifty years since by counterfeiters, who were suddenly disturbed in their counterfeiting operations.

mitted that the Green Mountains are not Taconic but Silurian rocks, there is no reason why we should not refer them simply to the age of the Alleghanies, the more so as we have direct evidence in the raised conglomerates of Massachusetts, that at least some of the ridges of New England are not of an earlier age than the coal formation.

How far this reasoning might apply to the many other regions connected by Mr. Beaumont with this supposed oldest Meridional system, Mr. Desor was unable to say, but observed, that with all due regard for the great abilities of his illustrious teacher, he thought there was no sufficient reason for upholding any longer this peculiar system, unless it be established on better proofs.

In removing thus this so-called oldest Meridional system from its prominent place, it is not a little interesting to notice that those ranges of hills and mountains which are actually known to have been raised previous to the deposition of the oldest fossiliferous rocks, such as the primitive mountain ranges on the north bank of the St. Lawrence, the granite ranges of Lake Superior, and the iron-bearing old slates of that country are all more or less parallel to the equator. It would seem as if in these early times, there had been a prevailing disposition on the part of the earth crust to wrinkle in that direction. (We take it for granted that these old hills are the result of a shrinkage in consequence of the cooling of the earth's surface rather than a positive upheaval.) It is only at a later period that we meet with wrinkles running in the opposite direction (north and south).

2. Lower Silurian Reptile in Canada, (From Lyell's Anniv. Ad. dress before the Geol. Soc. of London, Feb., 1851, p. 59.)-I have not alluded in this Address to the recent discovery of the track of a quadruped imprinted on a lower silurian sandstone in North America. We are indebted to Mr. Logan, now at the head of the Government Survey in Canada, for having carefully determined the position of the rock containing it. The locality is the village of Beauharnois, on the south side of the St. Lawrence, twenty miles above Montreal. The rock, a fine-grained whitish sandstone, quarried for building, belongs to the group called the Potsdam sandstone by the New York surveyors, and lies at the base of the whole fossiliferous series of North America. The markings were first pointed out to Mr. Logan by Mr. Abraham, editor of the Montreal Gazette, who appreciated their geological im portance. Assuming the Chelonian origin of these foot-prints, they constitute the earliest indication of reptile-life yet known, and are not only anterior to the most ancient memorials of fish hitherto detected, but agree in date with the first known signs of well-defined organic bodies, such as Lingulæ, met with in the same rock. Professor Owen, of the College of Surgeons, has examined a slab of the sandstone, on the upper surface of which the foot-prints are impressed, together with a plaster cast of the remainder of the continuous trail, in all 123 feet long, brought to London by Mr. Logan; and the Hunterian Professor has had the kindness to communicate to me the following description.*

"The impressions are more numerous in regular succession than any that have been previously discovered; so that the evidence of

R. Owen-Letter to Sir C. Lyell, March 18th, 1851.

their having been made by successive steps, afforded by this succession of corresponding prints at regular intervals, is the strongest we possess. They are in pairs, and the pairs extend in two parallel linear series with a groove midway between the two series. The outer impression of each pair is the largest, and it is a little behind the inner one. Both are short and broad, with feeble indications of divisions at their fore part. They succeed each other at intervals much shorter than that between the right and left pair.

"The median groove is well defined and slopes down more steeply at its sides than towards the bottom, at some parts of the track. I conclude from these characters that the animal which left the track was a quadruped, with the hind-feet larger and wider apart than the fore-feet; with both hind and fore-feet very short, or impeded by some other part of the animal's structure from making any but short steps; that the fore and hind limbs were near each other, but that the limbs of the right and those of the left side were wide apart: consequently, that the animal had a short but broad trunk, supported on limbs either short or capable only of short steps; and that its feet were rounded and stumpy, without long claws.

"As to the median impression, that may be due either to a thick heavy tail, or to the under surface of the trunk, dragged along the ground. The shape of the hody and the nature of the limbs, indicated by the above-described characters of the steps, accord best with those of the land or freshwater tortoises, and the median groove might have been scooped out by the hard surface of a prominent plastron.

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The disproportion in the size of the fore and hind-feet is such as we find in some existing Terrapenes, e. g., the Emys geographica.”

III. ZOOLOGY.

1. On the Classification of the Cancroidea; by JAMES D. DANA.The Cancroidea (or Crustacea Cyclometopa), like the Maioidea, are characterized by having, (1) the branchia 9 in number, 7 of which lie so as to form the exterior of the branchial pyramid; (2) the efferent passage from the branchial cavity passing over the lateral portions of the palate; (3) the male genital orifices situated in the base of the posterior legs and covered by the abdomen; (3) the male abdomen not narrower at base than the corresponding part of the sternum; (4) the buccal area subquadrate, and the 4th joint of the outer maxillipeds articulated with the 3d by its inner angle. The Telphusidæ have these characters, and may be considered true Cancroidea, though approximating to the Grapsoidea in the large vacant space in the branchial cavity, and having some peculiarities in the branchiæ fitting them for freshwater life. The Corystes group also partake of the Cancroid character; yet they diverge from it, in the large outer antennæ more or less hairy, and both in this respect and in form, they approach the Hippa group, and thus have a much lower position in the series than the Cancroidea. They have no true relation in the character of the buccal area and efferent canal to the Leucosia group.

The genera Acanthocyclus and Corystoides (of Lucas) have the gen ital orifices, sternum and abdomen, and outer maxillipeds of the Cancroidea and Corystoidea; but the branchise (in Acanthocyclus at least) SECOND SERIES, Vol. XII, No. 34.-July, 1881.

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