"So that in this experiment on the decomposition of ammonia, the weight of the gasses evolved is less by nearly than that of the ammo. nia employed; and this loss can only be ascribed to the existence of oxygene in the alkali; part of which probably combined with the platina wires employed for electrization, and part with hydrogene.

"After these ideas the oxygene in ammonia cannot well be estimated at less than 7 or 8 parts in the hundred; and it possibly exists in a Jarger proportion, as the gasses evolved may contain more water than the gas decomposed, which of course would increase their volume and their absolute weight.

"In supposing ammonia a triple compound of nitrogene, hydrogene, and oxygene, it is no less easy to give a rational account of the phenomena of its production and decomposition, than in adopting the generally received hypothesis of its composition.

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Oxygene, hydrogene, and nitrogene, are always present in cases

in which volatile alkali is formed; and it usually appears during the decomposition of bodies in which oxygene is loosely attached, as in that of the compounds of oxygene and nitrogene dissolved in water.

"At common temperatures, under favourable circumstances, the three elements may be conceived capable of combining and of remaining in union: but at the heat of ignition the affinity of hydrogene for oxygene prevails over the complex attraction, water is formed, and hydrogene and nitrogene are evolved; and according to these conclusions, ammonia will bear the same relations to the fixed alkalies, as the vegetable acids with compound bases do to the mineral ones with simple bases.

"Oxygene then may be consi dered as existing in, and as forming an element in all the true alkalies; and the principle of acidity of the French nomenclature, might now likewise be called the principle of alkalescence.

"From analogy alone it is reasonable to expect that the alkaline earths are compounds of a similar nature to the fixed alkalies, peculiar highly combustible metallic bases united to oxygene. I have tried some experiments upon barytes and strontites; and they go far towards proving that this must be the case. When barytes and strontites, moistened with water, were acted upor by the power of the battery of 250 of 4 and 6, there was a vivid action and a brilliant light at both points of communication, and an inflammation at the negative point. In these cases the water might possibly have interfered. Other experiments gave, however, more distinct results.

"Barytes and strontites, even when heated to intense whiteness, in the electrical circuit,b▾ a flame upported

supported by oxygene gas, are nonconductors; but by means of combination with a very small quantity of boracic acid, they become conductors; and in this case inflaminable matter, which burns with a deep red light in each instance, is produc ed from them at the negative surface. The high temperature has prevented the success of attempts to collect this substance; but there is much reason to believe that it is the basis of the alkaline earth employed.

"Barytes and strontites have the strongest relations to the fixed alkalies of any of the earthy bodies; but there is a chain of resemblances, through lime, magnesia, glucina, alumina, and silex. And by the agencies of batteries sufficiently strong, and by the application of proper circumstances, there is no small reason to hope, that even these refractory bodies will yield their elements to the methods of analysis by electrical attraction and repulsion.

"In the electrical circuit we have a regular series of powers, of decomposition, from intensity of action, so feeble as scarcely to destroy the weakest affinity existing between the parts of a saline neutral compound, to one sufficiently energetic to separate elements in the strongest degree of union, in bodies undecomposable under other circum

stances.

"When the powers are feeble, acids and alkalies, and acids and metallic oxides, merely separate from each other; when they are increased to a certain degree, the common metallic oxides and the compound acids are decomposed; and by means still more exalted, the alkalies yield their elements. And as far as our knowledge of the composition of bodies extends, all substances attracted by positive electricity, are oxy

gene, or such as contain oxygene in excess; and all that are attracted by negative electricity, are pure combustibles, or such as consist chiefly of combustible matter.

"The idea of muriatic acid, fluoric acid, and boracic acid containing oxygene, is highly strengthened by these facts. And the general principle confirms the conjecture just stated concerning the nature of the earths.

"In the electrization of boracic acid moistened with water, I find that a dark-coloured combustible matter is evolved at the negative surface; but the researches upon the alkalies have prevented me from pursuing this fact, which seems, however, to indicate a decomposi tion.

"Muriatic acid and fluoric acid in their gaseous states are non-conductors: and as there is every reason to believe that their bases have a stronger attraction for oxygene than water, there can be little hope of decomposing them in their aqueous solutions, even by the highest powers. In the electrization of some of their combinations there is, however, a probability of success.

"An immense variety of objects of research is presented in the powers and affinities of the new metals produced from the alkalies.

"In themselves they will undoubtedly prove powerful agents for analysis; and having an affinity for oxygene stronger than any other known substances, they may possibly supersede the application of electricity to some of the undecompounded bodies.

"The basis of potash I find oxidates in carbonic acid and decomposes it, and produces charcoal when heated in contact with carbonate of lime. It likewise oxidates' in muriatic acids; but I have had ́

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make idiocy so prevalent; and what were the most efficient modes of relief. The following results I beg leave to lay before the Royal Society.

"Cretinism is found not only in the valleys of the Alps, both on the French and Italian side of these mountains, but in the mountainous parts of Germany and Spain; aud it was observed in Chinese Tartary by Sir George Staunton, in a part of that country much resembling Switzerland and Savoy in its alpine appearance. The enlargement of the thyroid gland called goitre, is the most striking feature in the unsightly aspect of a cretin; but this is not a constant attendant. His head also is deformed, his stature diminutive, his complexion sickly, his countenance vacant and destitute of meaning, his lips and eye-lids coarse and prominent, his skin wrinkled and pendulous, his muscles loose and Habby. The qualities of his mind correspond to the deranged state of the body which it inhabits; and cretinism prevails in all the intermediate degrees, from excessive stupidity to complete fatuity.

"At a small village, not far dis tant from Martigny, I examined four cretins. One lad, twelve years old, could speak a few words; he was of a weak and feeble frame, silly, but had no goitre. Another boy, nine years old, was deaf and dumb, idiotic, with no goitre, the only child of his mother, who has a large goitre, which affects her respiration and her voice, though in other respects she is intelligent and weil formed, and the father enjoys good health; they are not natives of this place. I saw a family in which all the children were cretins; the eldest died a year ago, a miserable object; the second, a girl, twelve years old, is deaf and dumb and

cross-eyed, and has a monstrous goitre, with just intelligence enough to comprehend a few natural signs; the third, is a boy six years old, small and feeble, abdomen enlarged, no goitre, very feeble in mind and body, not entirely deficient in understanding; the mother had a moderate sized goitre, but was quite free from any mental affection; the father neither goitrous nor stupid, but of a delicate constitution.

"There is no necessary connexjon between goitre and cretinism, notwithstanding the assertions and ingenious reasoning adduced by Fodere. It is probable, the one has been assumed as the cause of the other, from the enlargement of the thyroid gland being a frequent occurrence in cretins; and as it forcibly strikes the observer from the deformity it occasions, this strong impression may have converted an accidental, though frequent occurrence, into a general and necessary cause. Cretinism is frequently observed without any affection of the thyroid gland, and that gland is often very much enlarged without any affection of the intellectual faculties. There seems to be some similarity between cre tinism and rickets, as they both take place in infancy, are both characterised by feebleness of body, and sooner or later by feebleness of mind, and they both affect males and females equally; but there is no sort of connexion between persons afflicted with bronchocele in England, ' and with rickets. For, although it might be granted, that there is some delicacy of frame in females about the period of pubescence, when bronchocele usually occurs, yet neither irregular formation of the bones, nor weakness of the intellectual powers, are common symptoms attending bronchocele in Britain.

To what peculiarities, then, in

the

the physical constitution of certain districts, are we to ascribe the production of this singular malady? Saussure's description of the Valais is exceedingly precise and accurate, and the causes which he has alleged appear sufficient to account for the phenomena. The valleys where cretinism is most frequent, are surrounded by very high mountains; they are sheltered from the currents of air, and exposed to the direct, and still more to the reflected rays of the sun. The effluvia from the marshes are very strong, and the atmosphere humid, close, and oppressive. All the cretins that I saw, were in adjoining houses, in the little village called La Batia, situated in a narrow corner of the valley, the houses being built up under ledges of the rocks, and all of them very filthy, very close, very hot, and miserable habitations. In villages situated higher up the mountains, no cretins are to be seen; and the mother of one of the children told me, of her own accord, without my asking the question, that her child was quite a different being when he was up the mountain, as she called it, for a few days.

"The production of cretinism, by the bad quality of the air and the food, the neglect of moral education, and other evils attendant upon poverty, is supported by facts so pointed, that the greater number of cases in mountainous districts where snow-water abounds, may safely be ascribed to these gencral causes. The notion of snow-water being the cause of goitre, and consequently of cretinism, seems to have been derived from Pliny (Lib. II. cap. 37,) and copied by almost every succeeding writer, because it coincided with their hypothesis of cold and crude matters, although directly contradicted by facts. In the first

place, persons born in places conti guous to the glaciers, who drink no other water than what flows from the melting of ice and snow, are not subject to this disorder; and, secondly, the disorder is observed in places where snow is unknown.

"The theory of water impreg nated with calcareous matter being the cause, is equally unfounded; because the common waters of Switzerland excel those of every other country in Europe for purity and flavour. There is not a village, nor a valley, but what is enlivened by limpid rivulets or streams gushing from the rocks. The water usually drank at La Batia and Martigny is from the river Dranse, which flows from the glacier of St. Bernard, and falls into the Rhone; it is remarkably free from earthy matter, and well tasted. At Martigny, there are two or three pumps, the water of which is pure and equally fit for culinary purposes, but said to be unwholesome, without any good reason. At Bern, the water is extremely pure, yet, as Haller remarks, swellings of the throat are not uncommon in both sexes, although cretinism is rare. With regard to the alleged causes of goitre, the general opinion of its being endemial in mountainous countries, is of no value, because the disease is rare in Scotland, and very common in the county of Norfolk.

"The causes of cretinism begin to operate upon the system svon after, perhaps even before birth; the want of energy in the parent is communicated to the offspring; the children become deformed and cachectic very early in life, the growth and developement of the body is impeded, the abdomen becomes enlarged, and the glands swelled in various degrees; and the powers of

the