If in the ureic residue of oxaluric acid we substitute hydrogen for hydroxyl, we get the formula for allanturic (lantanuric) acid, C,H,N,O,,

and the mode in which this acid is produced from allantoine by assimilation of water and separation of urea becomes evident if we give to allantoine, CH.NO,, the following formula (2), viewing it as a di-ureide derivative of oxalic acid, with which it appears in fact to be closely connected, producing oxalates by heating with alkaline solutions, by fermentation with yeast, &c. By reference to the formula proposed further on for uric acid it will appear how this latter yields allantoine on boiling an aqueous solution with lead dioxide, the middle carbon atom of the mesoxalic acid residue being removed as carbon dioxide, and hydroxyl and hydrogen respectively taken up from a molecule of water by the two ureic residues, which at the same time assume a different mode of attachment to the oxalic acid nucleus; the further action of an excess of lead dioxide decomposing the allantoine itself, with formation of urea and lead oxalate. The formula of Gibbs for allantoine (as for hydantoine and glycolurile) would lead us to expect an acid character, whereas such compounds as are formed by this body with metals and metallic oxides manifestly are of the same order as those produced with similar substances by urea itself. In the other di-ureide, viz: mycomelic acid, C.HẠN,O,,

4

Mycomelic acid (monobasic).

H

Z::::

N H-N-H

we have an example of what I agree with Professor Gibbs in assuming as very probable, namely, the similarity of function

of nitrogen with two free bonds to the outside oxygen in oxatyl,* so that I represent one of the two such oxygen atoms in oxalic acid as replaced by a urea residue connecting itself by its amidic extremity, the hydrogen of the corresponding hydroxyl of the acid retaining its basic character; while the second residue of urea, attached by the opposite end of its chain of atoms, replaces hydroxyl instead of oxygen, and thus changes a di-basic into a mono-basic acid. Here we have an instance of what seems to me the error arising in many of the older formulas from considering merely the number of atoms, with their additions or subtractions, without noticing the character of the compounds in question as an indication of molecular structure. Odlingt says of mycomelic acid that it bears "exactly the same relation to oxalic acid that uric has to mesoxalic acid." So it does, in so far as the summation of the atoms present is concerned, but the two last named acids are both di-basic, while oxalic and mycomelic acids are di-basic and mono-basic respectively. It will be seen presently that the formulæ I propose account fully for this, the two urea residues in uric acid being similarly connected with the residue of the original acid, while in mycomelic acid they are connected by what I have called the amidic and imidic ends respectively.

4

Passing to the 3-carbon acids, from malonic acid, C,H,O,, No. 1, may be derived barbituric acid, C,H,N,O,, No. 2.

4 4 2

1. Malonic acid (dibasic). 2. Barbituric acid (dibasic).

Gibbs' formula (in which there is a trifling misprint) would imply a mono-basic acid.

Naquet speaks of "l'hydantoine, qui représente de l'acide allanturique moins un atome d'oxygène, et qui est, par conséquent, à l'acide allanturique ce que l'acide barbiturique est à l'acide dialurique." But of these two pairs of substances,

As in the polymerides of true cyanic acid. Prof. Gibbs proposes to call (CNOH)" cyanyl, as analogous to (COOH)', oxatyl.

Lectures on Animal Chemistry, London, 1866, p. 132.
Principes de Chimie (1875), ii, 578.

hydantoine is neutral, and allanturic acid a mono-basic acid, while barbituric and dialuric acids are di-basic and mono-basic respectively. The formulæ proposed in this paper furnish an explanation of the difference.

Any formula I have seen for bromo-barbituric acid, C,H, BrN,O,, would lead one to expect for it exactly the same degree of basicity as that of barbituric acid. But the following (No. 1) with the urea residue oppositely attached) will show how the former acid is mono-basic, while the latter is di-basic.

2 2

A further replacement of hydrogen by bromine gives us what has been called di-bromo-barbituric acid, C1H2Br2N ̧ O ̧, a body which is, however, really devoid of acid character, not forming salts. With the formula now proposed (No. 2, above), this non-acid character becomes intelligible, and the name brom-alloxan, originally employed by Baeyer, becomes fully justified on comparison with alloxan as represented further on. The conversion of this body into dialuric acid by the action of hydro-sulphuric acid in the presence of water is explained by the formula for dialuric acid given further on.

3

3 2 2

On pushing the action of bromine still further, brom-alloxan is converted, with separation of carbon dioxide, into tri-bromacetyl-urea, C,H,Br,N,O, (from the 2-carbon acid residue), the formula of which (No. 3, above) is very simply derived from No. 2, and brings us back to that of acetyl-urea as already given.

From mesoxalic acid, C,H,O, (No. 1), we get the acid monureide dialuric acid, C,H,N,O. (No. 2),

4

4 2 4

1. Mesoxalic acid (di-basic). 2. Dialuric acid (mono-basic).

in which the ureic hydroxyl is replaced by hydrogen. The production of this acid by hydrogenation of alloxan will be seen presently to be readily intelligible.

And from dialuric acid is derived the amide, uramile (dialuramide), C,H,N ̧0, (No. 1).

1. Uramile (neutral).

H-N-H

3

3

For the production of this body from alloxantine by the action of ammonium chloride, with separation of alloxan and hydrochloric acid, see the formula given beyond for alloxantine.

2 2

The formula of alloxan, C,H,N,O,, also a mon-ureide, becomes as represented in No. 2, while alloxanic acid, C,H,N,O,, formed by attachment of the urea residue by its opposite extremity, and with assumption of a molecule of water, may be viewed as in No. 3 above. Claus and Emde* have noticed the difference of character between the last two substances, and suggested in explanation the following formula:

one of the few instances in which I find an attempt made to carry out the idea urged in this paper. Gibbs's formulæ would imply that both substances were acid, and of the same degree of basicity. The parallelism between alloxan and paraban is seen to be brought out by the mode of representation now suggested, and an explanation is afforded of the fact that whereas, as Naquett says (looking only at the number of atoms concerned), alloxanic acid bears the same relation to alloxan that oxaluric acid does to paraban, the former acid is di-basic and the latter mono-basic only.

*Ber. d. deutsch. chem. Gesellsch., vii, 226. + Principes de Chimie (1875), ii, 578. (To be continued.)

ART. XXIV.-On Flint-implements from the Stratified Drift of the vicinity of Richmond, Virginia; by CHARLES M. WALLACE.

THE James River, upon the left bank of which Richmond is situated, approaches the city from the southwest-running in the Mannikin country over fields of bituminous coals, and pouring its waters in headlong rapids over a broad belt of granite, through which it has cut a channel sixty feet or more deep. Huge bowlders, some of them weighing many tons, crowd the drift-beds near the falls, and strew the surface of the uplands below them. Many of those which were in the way of the early settlers have been broken up and removed, but others that remain, sufficiently indicate the course and level of the Drift. In some instances that I have noted, the marks of ancient pot-holes are legibly impressed upon them, proving unmistakably the fact of their descent from the rapids above.

The trend of the prehistoric river is distinctly traced on its south side by the great upper terrace, which probably formed one of its borders before the bed-rock on the Richmond side had been scooped out. As far as I have explored this even and lofty plane-say twenty miles up the basin -it appears to be capped on its inner slope with gravel of the same general character as that which has been excavated at corresponding levels on the opposite shore. A succession of parallel slopes of limited extent show how the current has been diverted from a straight-forward course, and how, upon approaching the tide-water, it has slid away to the north side, forming a wide horseshoe of several miles in extent.

The shelving of the left bank with its relief of hills is quite in contrast with the picturesque island-terraces upon which the neighboring city of Manchester is built. Main street in Richmond runs through the center of the drift-field which abuts upon the steep sides of the city hills, and converges to a point before being swept by the freshets of Gillies Creek and James River. It is on the exposed flank of this field that I have found some of the best specimens of drift-flints in my collection.

My first discoveries were made a little more than a year ago in the elevated beds of the Appomattox, below its falls, and in the brick-earths that uniformly overlie the drifts of this valley.

One of the implements I extracted from a deep bed of brickclay on the left bank of James River, which has been recently cut away for an avenue to the Free Bridge; it was firmly imbedded in the stiff clay--on its flat side-about seven or eight feet below the surface of the terrace, which at this point attains an elevation of forty or more feet above the rapids. It is of