7.-On Caproic Acid. By M. A. WURTZ.

M. Wurtz has made the very interesting observation, that the caproic acid obtained by Frankland and Kolbe by the action of potash upon cyanide of amyle, exerts a right-handed rotatory power, while it is probable that the same acid, obtained from cocoa-nut oil, has not any such power. Annal. de Chim. et de Phys., t. li. (November, 1851), p. 358.

8.-Researches on the Phosphorus Bases. By A. W. HOFMANN and A. CAHOURS.

About ten years ago M. Paul Thenard pointed out, in a note on the action of chloride of methyl upon phosphide of calcium, the existence of a series of bodies, which may be viewed as phosphoretted hydrogens, whose hydrogen has been replaced by an equivalent quantity of methyl. The discovery of methylamine, ethylamine, and the other compound ammonias, having given a new and peculiar interest to the subject, the authors took up the unfinished labour of M. Thenard, with a view of completing it, by a careful study of the bodies which he discovered, and by an extension of their number.

Instead of following the method of preparation proposed by M. Thenard, they found that they could procure such compounds more readily by the action of terchloride of phosphorus on zinc-methyl, zinc-ethyl, etc. The bases Me,P and EP, which the authors propose to call respectively, trimethylphosphine and triethylphosphine, remain united with chloride of zinc, and may be liberated by a simple dilution with an alkali. They are obtained in this way as volatile oils of a peculiar and strongly marked odour, and possessing distinct basic properties.

The following is a list of the compounds which they have studied, and the details respecting the preparation, properties, and analyses of which, form the subject of a lengthened memoir presented to the Royal Society :

The compounds named in the preceding table exhibit an almost perfect parallelism with the corresponding terms of the analogous nitrogen, arsenic, and antimony series; we have similar formulæ, similar modes of combination, similar decompositions. This analogy is particularly manifest in the compounds belonging to the ammonium-type. In these remarkable bodies, nitrogen, phosphorus, arsenic, and antimony, appear to play absolutely the same part. The oxides of these compound metals exhibit almost perfect identity of properties, to such a degree, that a mere study of their reactions would never indicate the presence of elements so dissimilar as nitrogen, phosphorus, arsenic, and antimony; while their alkaline power is so great that they might be confounded with potash and soda. The derivatives of nitrogen are only distinguished from the corresponding members of the phosphorus, arsenic, and antimony series, by the behaviour of the hydrated oxides under the influence of heat.

The compounds formed on the ammonia-type exhibit, on the other hand, a gradual increase in intensity of the electro-positive character, as we proceed from the nitrogen to the antimony series. Thus, trimethylamine and triethylamine are not capable of uniting with oxygen, chlorine, bromine, and iodine; while the corresponding members of the phosphorus, arsenic, and antimony series possess this power in a high degree.

Triethylamine unites with the acids producing compounds of the ammonium-type, and containing

E,N, HCI

EN, HSO
EN, HNO

Chemists have not yet succeeded in preparing the corresponding compounds in the arsenic and antimony series. Triethylarsine and triethylstibine only combine directly with oxygen, chlorine, sulphur, etc., producing saline bodies, which have the composition respectively of

The two classes are, however, represented in the phosphorus series. Triethylphosphine not only forms compounds analogous to the salts of

triethylamine, but also the terms corresponding to the binoxides of triethylarsine and triethylstibine. Thus :

Corresponding

to salts of Triethylamine to binoxides of Triethylarsine, etc.

E.P, HCI

EP, HSO
EP, HNO

E,PO
EPCI

E3PS2

The phosphorus compounds accordingly hold a position intermediate between the nitrogen compounds, on the one hand, and the arsenic and antimony series on the other; but exbibiting a tendency rather towards the latter than towards the former. Considering the close analogies which phosphorus and arsenic present in other directions, this tendency cannot surprise us. Besides the circumstance that the acids of phosphorus and arsenic are polybasic (the acids of antimony have not been yet sufficiently investigated), while those of nitrogen are monobasic, the remarkable connection which subsists between the combining numbers of phosphorus, arsenic, and antimony, may be mentioned. If we compare those numbers we will find that the difference between the equivalents of phosphorus and arsenic is virtually the same as that between those of arsenic and antimony :—

whilst the equivalent of nitrogen stands altogether apart from the rest." The same relative position of the elements nitrogen, phosphorus, arsenic, and antimony, may also be traced in their hydrides, H,N, HP, H,As, HSb. Ammonia is a powerful alkali; phosphoretted hydrogen unites only with hydrobromic and hydriodic acids, whilst in arsenietted and antimonietted hydrogen the power of combining with acids has altogether disappeared. In these hydrogen compounds the gradation of pro

The authors do not appear to have noticed the very singular circumstance that the sum of the equivalents of nitrogen, phosphorus, and arsenic, is equal to the equivalent of antimony :

The equivalent of nitrogen cannot, therefore, be said to stand apart. Indeed the difference (44 to 45) between the equivalents of phosphorus and arsenic on the one hand, and between arsenic and antimony on the other, noticed by the authors, is nearly equal in the former case, and exactly equal in the latter, to the sum of the equivalents of nitrogen and phosphorus. We may also point out another curious relation between the equivalents of those bodies, which is this: If we add the equivalents of phosphorus and antimony, the sum will be 151; if this be divided by 2, the product will be 75.5, or virtually the equivalent of arsenic.-W. K. S.

perties is, indeed, even more marked than in their trimethylated and triethylated derivatives. On comparing the terminal points of the series, ammonia and antimonietted hydrogen, we cannot fail to be struck by the dissimilarity of properties, which at the first glance appears to limit the analogy of the two compounds to a mere parallelism of composition.

In the methylated and ethylated derivatives of these compounds, the intensity of the chemical tendencies in general is so much raised, that the gradation is no longer perceptible to the same extent.-Proceedings of the Royal Society, vol. viii., No. 27.

MINERALOGY AND GEOLOGY.

9.-Researches on the hygroscopic properties of the minerals of the family of the zeolites. By M. DAMOUR.

The author, who has already on various occasions pointed out the property which certain minerals possess of losing and again readily taking up the water which enters into their composition, when they are suc cessively submitted to the action of a perfectly dry atmosphere and of a more or less moist one, has made some interesting experiments, with a view of determining within what limits this property is possessed by the zeolites. The following is a summary of his results: 1. the zeolites, with a single exception (analcime), possess the property of losing considerable quantities, and sometimes the whole, of their water of combination, either when placed in a perfectly dry atmosphere, or when exposed to temperatures comprised between +40° C. and incipient redness; 2. zeolites which have been subjected to partial deshydratation, can recombine with the whole of the water which they have lost, by simple exposure to the air; 3. the temperature at which the water is disengaged, without altering the power of the mineral to take it up again, varies with the species of mineral; 4. the facility with which the deshydratation is effected, is usually in direct ratio to the number of equivalents of water contained in the mineral.

These results appear to the author to confirm the opinion that the zeolites, although usually found in crevices, cavities, or veins of certain rocks considered to be of volcanic origin, have been formed by aqueous dissolution, and not, like lavas, by igneous fusion. The author proposes to examine whether the deshydratation of minerals takes place in constant proportions, and corresponding to determinate temperatures.— Comptes rendus, t. xliv., No. 19, p. 975.

10.-On the Gases evolved by the volcanic vents of Southern Italy. By MM. CHARLES SAINTE-CLAIRE DEVILLE and FELIX LEBLANC.

Any one acquainted with volcanic regions can easily imagine the difficulties which beset the experimenter in collecting the gaseous emanations which issue from vents. The high temperature of the localities where these vents occur, the suffocating odour of the gases evolved, the disposition of the ground, which renders their collection not only difficult, but often dangerous, and, lastly, the atmospheric conditions under which the greater part of the volcanic orifices are placed, are all so many obstacles to be overcome. The authors, by means of very ingenious apparatus, specially invented for the purpose, succeeded however in overcoming every difficulty; and accordingly, M. C. Deville visited, between the end of May and the commencement of August, 1856, the principal centres of emanations of Vesuvius, the Phlegræan Fields, Etna, Sicily, aud the Æolian or Lipari Islands, and collected the gases. These he examined on the spot by means of a small portable laboratory; but, in addition, sixty-six tubes, first exhausted of air, were filled at these various localities, and sealed up by the blowpipe, and brought safely to Paris, where they were examined by the authors conjointly. The apparatus employed in the analysis was that of M. Doyère: the results were also controlled by comparative experiments made by the eudiometer of M. Regnault.

The chief results obtained by the authors may be summarized as follows:

1. Atmospheric air plays a considerable part in the majority of volcanic emanations, sometimes even preponderating; but this air is almost always impoverished in oxygen, to an extent which, in some of the experiments, reached more than 3 per cent. So that the cone of Vesuvius,

for example, may be compared to a kind of downflow chimney, in which certain gases are burned, owing to the high interior temperature, and at the expense of the oxygen of the air which flows in.

2. The higher crater of Vesuvius disengages carbonic acid; but this disengagement takes place through orifices quite distinct from those which evolve hydrochloric and sulphurous acids, and which play a totally different part in the distribution of volcanic forces. This circumstance establishes an analogy hitherto unobserved between certain of the higher fumoroles of Vesuvius, and the emanations of carbonic acid from the volcanoes of New Granada, long since noticed by M. Boussingault.

3. The nature of the gaseous elements escaping by the same orifice is subject to incessant variations. At the grand solfatara of Puzzuoli, the gas, which is expelled at the same time with the vapours of water under strong pressure and a considerable noise, and which deposits chloride of ammonium and sulphide of arsenic, was collected at two different epochs-the 10th of June and 30th of July, 1856, two specimens being collected on each occasion. The following table contains the results of the analyses of these specimens: