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The crimson coloured combination with mercury, united in the same manner to potash without decomposition; the addition of sulphuric acid to the combination, separated the compound of the substance with mercury, and sulphat of potash was formed.

The new substance combines with phosphorus with great rapidity at the temperature of the atmosphere, producing heat without light. A strongly acid gas arises from the mixture, the quantity of which is increased by the application of heat. When the new substance is in excess, a red coloured compound is formed, which is easily fusible and volatile, but when the phosphorus is in excess, the product is more fixed. The gaseous acid which it forms by combination with phosphorus, produces dense white fumes by combining with the aqueous vapour of the atmosphere; its odour resembles that of the solid compound of chlorine and phosphorus, which is very analogous to that of muriatic acid. It is rapidly absorbed by water. With ammonia it forms a dense white salt, from which sulphuric acid separates the peculiar substance, and the odour of hydrogen is at the same time perceptible. When mercury is heated in this acid gas, the same compound is formed as when that metal is combined directly with the new substance, and hydrogen equal in volume to half that of the gas is disengaged. It affords similar results with potassium ; that metal is converted into the same compound as is produced by the direct combination of potassium with the new body, and a gas having the properties of hydrogen, is disengaged, equal to half the volume of the acid gas.

Of the two compounds which this substance forms with phosphorus, that which is volatile and easily fusible, readily dissolves in water when assisted by heat, and affords a strong acid, wbich, when evaporated, leaves hydrophosphorous acid ; but, if neutralized by potash and acted upon by sulphuric acid, affords the peculiar substance. The other combination, which is with difficulty fusible, is acted upon by a small quantity of water, and heated in a glass tube, a spontaneously inflammable gas is disengaged, and a white sublimate is formed, which becomes hot when it is brought into contact with cold water, and affords a considerable quantity of hydrophosphoric gas. The solution of this crystalline substance in water, neutralized by potash, and decomposed by sulphuric acid, yields the peculiar body; but if the solution is heated strongly before it is neutralized, hydrophosphoric acid alone remains, which, when heated, gives off hydrophosphoric gas, and is converted into phosphoric acid. As this acid is formed by the combination of the peculiar substance with hydrogen, the existence of hydrogen in the phosphorus, or of hydrogen or water in the

substance itself, must be inferred. This inference is rendered more probable by the fact, that when the substance is previously distilled through quick lime, so as to separate all its moisture, the gas is produced in very small quantity, but is greatly increased when the substance is moistened. Sir H. therefore thinks the production is principally occasioned by the aqueous moisture which adheres to it, though the small proportion of hydrogen contained in the phosphorus, may influence the result in some degree. The gas which is obtained by the distillation of the fusible eompound with water in small quantity, is similar to that obtained during the formation of the compound while it is heated ; and when absorbed by water, they both afford, when acted upon by nitrate of silver, the product already noticed as being formed by the action of the substance itself in solution, upon that salt.

Sir H. attempted to form a direct combination of the substance with hydrogen, by heating it to redness in a glass tube filled with that gas. When the gas was moist, or any aqueous vapour was present, a strong acid liquid, of a deep yellow colour, was formed; but when care was taken to exclude the presence of moisture, there was an expansion of volume, and when the tube was broken, the gas which was set at liberty, precipitated the nitrate of silver in the same manner as that produced during the union of the substance with phosphorus. The acid thus produced by the union of this substance with hydrogen, has a very strong affinity for water; and a large quantity of the gas is absorbed by a very small quantity of water. It is evaporated with the water by heat; and in its liquid state it dissolves the substance rapidly, and becomes of a tawny colour.

The French chemists Desormes and Clement; had announced the ready solubility of this new body in solution of potash ; and Sir H., by carefully investigating the changes which accompany this combination, discovered the singular and curious fact, that by this combination a class of substances, analogous to the hyperoxymuriates, are formed. When the solution is evaporated and the product heated to redness, a substance precisely similar to the compound of the new body with potassium, is produced; but this combination can only take place by displacing the oxygen of the potash, and Sir H. found that the oxygen remained in a state of triple combination with the potassium and the new body. If the substance is dissolved to saturation in a moderately strong solution of potash, a considerable quantity of crystals fall down, and by evaporating the remaining solution, an additional quantity is obtained. The spontaneously formed crystals, are but little soluble in water, have a taste similar to that of the hyperoxy

muriates of potash ; they scintillate when thrown upon burning coals, and deflagrate with charcoal. When fused, they afford abundance of oxygen gas, and the compound of potassium and the new body, remains. After the mother liquor has ceased to yield crystals, if it is evaporated to dryness, it affords a large quantity of the compound of the substance with potassium; so that by dissolving the substance in solution of potash, the two new products are formed. When the substance in vapour is passed over dry red hot potash formed immediately from potassium, the oxygen of the potash is expelled, and the substance combines with potassium ; so that the triple combination of this compound with oxygen, does not exist at a red heat. It presents the same phænomena with solutions of soda and baryta. It is obvious, therefore, that the earlier discovery of this singular substance, would have led to the discovery of the fixed alcalies being oxidized metals, without the agency of Galvanic electricity. While it expels oxygen from some of its combinations, it is again displaced by chlorine from its combination with metals. Thus, when the compound of the substance with potassium is heated in chlorine gas, potassane is formed, and the violet coloured gas is separated, which soon combining with chlorine gas, forms the acid compound already noticed; but as the chlorine diminishes towards the end of the process, the violet gas again appears. It presents similar phenomena in its compounds with silver, mercury, and lead, heated in contact with chlorine.

The phenomena which its compounds present when acted upon by acids, are such as might be anticipated froin its analogy with chlorine. Concentrated sulphuric acid poured upon the combination with potassium, occasions the disengagement of some of the new body; but part of it enters into combination with hydrogen and water, and evaporates; and when condensed, appears of a deep orange colour, from holding some of the substance in solution. Part of it seems to be retained by the sulphuric acid; for it continues to be red after being strongly heated, and some sulphurous acid gas is disengaged. When sulphuric acid is poured on the triple saline compound of the new body, potassium, and oxygen, there is a slight effervescence, and the new matter reappears : part of the oxygen enters into combination with the potassium, and forms potash; the remaining portion is expelled, and occasions the effervescence.

Similar phenomeną are presented with nitric acid. When the triple compound is acted upon by muriatic acid, there is no (fervescence, but a substance which appears to be a compound of chlorine and the new substance, is formed, and potassane is pæcipitated. When the binary compound is exposed to the acion of the same acid, there is a complete solution with partial decomposition; and by applying heat, the excess of muriatic acid is driven off, and the acid resulting from the combination of the new substance with hydrogen, remains in the solution. When mixtures of the two salts are employed, the new body itself appears. When the new body is exposed to the action of liquid ammonia, a black powder is formed, and the liquid, when evaporated, yields à saline substance, having the properties of that produced by the combination of ammonia with the acid formed by the new body and hydrogen. This renders it probable that part of the ammonia is decomposed ; and when the experiment was made in a pneumatic apparatus, no azote was disengaged. The black powder is therefore most probably a compound of the new substance with azote. The highly detonating property of this powder was announced by Desormes and Clement, and Sir H. found on detonating it in a partially exhausted glass tube, that the results were the peculiar substance, and a non-inflammable gas, which does not support flame; and these seem to be the only products except moisture is present. From experiments made to determine the weight of its atom, Sir H. estimates it at about 160, a number higher than that of the simple inflammable bodies, and even greater than most of the metals.

This new body is not decomposed when Voltaic sparks are taken from ignited points of charcoal in its vapour. There is at first a production of white fumes; but these soon cease, and when the tube is cooled, the substance does not appear to have undergone any change.

There is strong reason to conclude from these facts, that it is a new simple body, which, though in its lustre and spe.. cific gravity, and the weight of its atom, it has a resemblance to the metals, yet in all its chemical properties appears to belong to the same class with oxygen and chlorine. It is a non-conductor of electricity; and like these bodies possesses the negative electrical energy in relation to metals, inflammable and alcaline substances, but the positive energy in relation to chlorine. This corresponds with their attractive energy, for chlorine expels it from all its combinations with which the experiment has been made. It possesses a stronger attraction for most of the metals than oxygen; but oxygen expels it from its combination with sulphur and phosphorus, The little production of heat and light when it entens inte combination, is probably connected with the great weight of its ultimate atoms, and its solid form. Its powers of saturation appear to be greater than those of oxygen, and less than that of chlorine. It agrees with chlorine and fluorine in forming an

acid when combined with hydrogen; and with oxygen in forming an acid with chlorine.

The French Chemists have proposed to name this new substance ione, from the violet colour of its gas. Our countryman apprehending that this would lead to some confusion, as we have already the words Ionic and Ionian, applied to very different objects, proposed to call it iodine. He almost destroys the force of his own objection, however, when he admits that the acid formed by its combination with hydrogen, may be with great propriety named hydroionic acid, and with chlorine, chlorionic, and with tin stannionic. Its combinations with the metals Sir H. proposes should be called iodes, prefixing the Greek numerals to indicate different proportions. This seems unobjectionable; but we forbear to enter into the consideration of the other suggestions of Sir H. on the subject of nomenclature, as their adoption appears to us likely to lead to an almost inextricable degree of confusion, and to be very far remote from the simplicity which ought to pervade all systematic noinencla. ture. Nor can we see any satisfactory reason, if it is to retain the name of iodine, that its acids should not be hydroiodic, chloroiodic, &c. At least this would be consistent ; nor does it appear that they are liable to objection on any ground whatever. Art. VII. Sermons designed chiefly for the Use of Villages and Families.

By Thornhill Kidd. In 2 vols (Second Edition of Vol.I.improved.)

Svo. pp. 710. Price 16s. Black, 1815. W E are very glad that the encouragement given to the former

V edition of Mr. Kidd's first volume, has induced him to reprint it with a second volume, equally adapted to the purpose for which the work is peculiarly designed. In our review of the first volume, (Oct. 1814,) we ventured to characterize it as con: taining some of the best sermons for the purpose of village and family reading, that we had seen. There is a genuine simplicity of manner pervading them, never degenerating into quaintness, which we are disposed to“ value the more, from the extreme rareness of the quality. Simplicity of style is, however, rather to be felt by the reader, in the strong impression it is adapted to produce, than to be at once perceived on a cursory inspection of the work; and on this account, what we deem the peculiar merit of Mr. Kidd's discourses in a literary respect, may not be so obvious, as their interesting variety of subject, their practical tendency, and their affectionate tone. We are nevertheless persuaded that the style Mr. Kidd has adopted, will be found the best calculated to exhibit in their most striking aspect, the obvious and acknowledged truths of which practical Christianity consists. It is impossible for a preacher, whose object is to adapt his style to the humblest level of intelligence, to

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