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are not real oxalates, and he proposes to give to them, as well as to similar compounds that may be discovered, the name of carbonides. The oxalates which do not give water by drying, contain the oxalic acid entire; and as from its composition it will be named hereafter hydro-carbonic, the salts will take the name of hydro-carbonates.

M. Dulong is led by analogy to very general conclusions, by which he reduces under the same laws, not only the ordinary acids, but likewise the hydracids. But we shall give a more detailed account of his opinions, when he sends up the memoir in which he intends to consign them.

The chemical action of solar light on bodies is worthy of all the attention of philosophers, from its influence on most of the phenomena of living nature; yet it has hitherto been but little examined. M. Vogel has just added some experiments to those which we formerly possessed. Ammonia and phosphorus, which do not act on each other in the dark, when exposed to the solar light disengage phosphoretted hydrogen gas, and deposit a black powder composed of phosphorus and ammonia intimately united. Nearly the same thing takes place with phosphorus and potash. The action of the different rays are not always similar, the red rays produce no effect on the solution of corrosive sublimate in ether, while the blue and complete light produce a mutual decomposition. The metallic permuriates are brought in the same way to the state of protomuriates.

We have said a few words in our two last reports on the researches of M. Chevreul, assistant naturalist to the Museum of Natural History, concerning soap and saponification. This skilful experimenter has ascertained that the action of potash on tallow produces new modes of combination; from which result substances which did not exist before perfectly formed, and two of which, margarine and a species of fluid oil, acquire all the properties of acids. The author, pursuing his experiments, has ascertained that the same effects are produced by soda, the alkaline earths, and different metallic oxides, and that the resulting substances are in the same proportion, whatever agent we have employed. Magnesia and alumina, on the contrary, merely contract a certain union with tallow, without se

parating its elements into two distinct bodies. The quantity of alkali necessary to convert a given portion of tallow into soap is exactly that which saturates the margarine and oil which the tallow produces. Our laborious chemist has terminated his memoirs on this subject, by giving the capacity of saturation of margarine and fluid tallow, and by describing the properties of several new soapy combinations which he produced by double decompositions, by mixing a hot solution of soap, of fluid tallow, and potash, with different earthy and metallic salts. Thus he has rendered the soaps, the study of which has been hitherto neglected, almost as well known as the salts with which chemists have been the most occupied.

The late M. Fourcroy made known, under the name of adipocire, a substance separated by means of acids from the fatty matter into which animal bodies buried in the earth are converted. And he considered it as identical with the crystalline matter in human biliary calculi, and with the spermaceti found abundantly in certain cavities of the head of the Cachalot.

M. Chevreul, led by his experiments to examine these substances, has found that the crystalline matter of biliary calculi does not form soap, while spermaceti furnishes it as easily as tallow; but producing a somewhat different alteration in other proportions and with particular properties. The fatty matter of dead bodies is much more compound than Fourcroy had supposed, containing different fatty bodies combined with ammonia, potash, and lime. It is a fatty matter that has already experienced the action of alkalies.

Every person must have observed a resinous excretion of a yellowish-orange colour, which exudes from cracks in the bark of the beech faggots exposed to moisture. It has the shape of ribbons, twisted like vermicelli. M. Bidault de Villiers has made some chemical experiments on this matter. One portion of it dissolves in water, another in alcohol, and the residue possesses some of the properties of gluten. Nitric acid converts it into oxalic acid, into a yellowish bitter principle, which is very abundant, and into a fatty matter; but produces no saclactic acid. When heated it gives abundance of carbonate of ammonia, and a fetid oil; so that the commission

ers of the class were led to consider it as approaching very closely to an animal substance. It would be interesting to inquire into the cause of its production.

One of the periods in which chemistry has shown itself most brilliant and most useful, was certainly that in which France, separated for twenty years from countries whose productions had been considered for so long a period as real necessaries, was obliged to supply them by the products of its own soil. The known arts have been perfected and new ones created. We have seen in succession soda extracted from common salt; alum and copperas formed by uniting their ingredients; colours considered as fugitive rendered permanent; indigo from woad supplying that from the indigofera; madder supplying the place of cochineal; and sugar from beet employed as a substitute for that from the sugar cane.

This last article, the most important of all, is far from having lost its interest even at present. Many of the manufactories, indeed, have fallen; but those which were properly conducted still subsist and prosper; and according to M. le Comte Chaptal, their product will always be able to rival the sugar of the colonies. This skilful chemist gives an unanswerable proof of his assertion by continuing to manufacture with profit. It is true that in all the details of the culture, harvest, and preparation, and likewise in the employment of the different waste matters, he has applied all the lights of science and experience, so as never to throw away what can be of any service, and to apply to other uses what he is obliged to reject. He has described his processes in a manner sufficiently clear to be understood by all the manufacturers, and we have reason to hope that his work will assist in preserving to France a precious manufacture, which a thousand events may again render necessary to the country.

The third volume of the Elementary Chemistry of Thenard has been published. This skilful professor describes in it with great minuteness, and according to the most recent discoveries, for many of which the science is indebted to himself, the immediate principles of organized bodies, the different products of their decompositions, and their uses in the arts. The fourth, which is in the press, will terminate the work.

Professor LOEBEL's Observations upon the Benefit of Insolation in different Complaints, particularly in Cases of the Amau

rosis.

[From the London Medical and Physical Journal, for Feb. 1816.]

THE physicians of former times cured different complaints by exposing the suffering parts to the action of the sun-beams, and practised this method particularly in disorders of the lymphatic system, such as different kinds of dropsy, and the gout. Professor Loebel has proved, in a dissertation, that insolation is with injustice neglected at present. According to his opinion the effects of insolation upon the suffering organs are the following:

1. The warmth of the sun increases the activity of the lymphatic system, and of the vessels.

2. By the influx of light, the vital activity is roused and heightened both in the afflicted part and the whole body.

3. The development of oxygen, or vital air, caused by the action of the sun, also operates chemically upon the organization.

For these reasons, M. Loebel recommends insolation in the following cases :

1. In chronic anasarca, not founded upon any organic defect, where the extremities feel cold, and a general weakness and torpor appears in the lymphatic system, particularly in metastatic exanthema, after repelling the tinea capitis, the itch, or herpes, or after an ill-managed scarlatina.

2. In the chronic gout, particularly when all the organs are suffering by its long duration, when contractions, tumores ossium, and insupportable pains prevail, also where the gout leaves a partial palsy.

3. In all complaints attacking the tractus intestinorum, such as chronic spasms of the stomach, where weakness in the nervous system prevails, and in chronic diarrhea; as also in the fluxus cœliacus and hepaticus, in chronic catarrh and chronic erysipelas.

4. In different forms of venereal complaints, in particular during the use of mercurials, when it serves to heighten and increase the effect upon the lymphatic system and the skin.

5. In diseases of the bones, tumores ossium, and in general or partial caries.

6. In subjects weakened by immoderate venery.

7. In nervous apoplexy, and palsy of single parts.

8. In the nervous gout of the head.

9. Against aphony when the incapacity of speaking is transitory, and not occasioned by the destruction of the organs. 10. In the marasmus senilis.

11. In the palsy of the lower extremities; particularly where the nervi crurales have suffered, and a state of inactivity and want of irritability prevails in them.

12. In amaurosis, from idiopathic causes, and from weakness of the retina or ciliary nerves, or when a palsied state of the optic nerve produces this complaint, or when it arises from a metastasis of gouty, venereal, or itchy matter.

Contra indications of the method of cure are the following: a. In all diseases where an exalted irritability or plethora prevails, insolation must not be applied.

b. Neither in acute violent inflammations, general nor local; in affections of the lungs, which show a disposition to inflammations, spitting of blood, or congestion.

c. Apoplexy, the nature of which consists in a congestion. d. In hemorrhages both of the active and passive kind, insolation is improper.

e. Insolation must absolutely be refrained from where the patient shows an idiosyncrasy or apathy against this method of cure, or by persons whose nerves, when in health, were found too sensible of the action of light or sun-beams, and who felt head-ach or vertigo on the slightest action of sun-shine,

Manner of application.-1. This method of cure must not be applied in stormy or moist weather, or when east, west, and north winds prevail. Insolation requires calm days.

2. The patient during insolation must not sit or lie on the bare ground, but a leather skin must be placed under him, as was the custom of the Greek and Roman physicians.

3. Insolation must neither be applied on an empty stomach, nor directly after dinner; but, if the complaint requires the application during noon-tide, it is advisable to let the patient previously take a little food.

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