8. That both the muscular and nervous systems, though independent of the sensorial system, are so influenced by it, that they may even be destroyed through it.

9. That although in the less perfect animals we find the muscular life existing alone, and the muscular and nervous existing without the sensorial life; in the more perfect animals they are so connected, that none can exist long without the others.

10. That nutrition, circulation, and respiration, are the means by which they are so connected.

Experiments to ascertain the Influence of the Spinal Marrow on the Action of the Heart in Fishes. By Mr. William Clift.

In this communication, Mr. Clift has given a very minute detail of the phenomena which he observed in four experiments made upon the carp, a fish which appears to be more tenacious of life than most others. The object which he had principally in view was to determine the influence of the spinal marrow upon the muscular system. The results which he obtained we shall transcribe.

1. The muscles of the body of a carp, four hours after the brain and heart are removed, can be thrown into powerful

action.

2. The moment the spinal marrow is destroyed, these muscles lose all power of action.

3. When water is admitted into the pericardium, and the fish allowed to swim about, the action of the heart ceases sooner than when that organ is exposed to the air, and the fish kept quiet.

4. Whether the heart is exposed or not, its action continues long after the spinal marrow and brain are destroyed, and still longer when the brain is removed without injury to its substance.

5. The action of the heart is accelerated for a few beats, by exposure of that organ; by exposure of the brain; injury to the brain; destruction of the spinal marrow while connected with the brain; by the connexion between the brain and spinal marrow being cut off: while removing the whole brain produces no sensible effect upon the heart's action, and destroying the spinal marrow after it is separated from the brain, renders the action of the heart slower for a few beats.

Some Experiments and Observations on the Colours used in Painting, by the Ancients. By Sir Humphrey Davy, LL.D. F.R.S.

The different colours examined by this eminent chemist, have VOL. VI, N.S. 2 E

been found in making excavations in the Roman territory; or in the ruins of ancient magnificence with which it abounds. He obtained permission also to examine the colours of a celebrated antique painting, the Nozze Aldobrandine. Of three reds found in the baths of Titus, one, was minium or red oxide of lead, the other two ochres of different tints; another red found on the walls of the bath proved on examination to be vermilion. The reds of the Aldobrandine painting proved to be all ochres. The yellows, of which three different varieties were submitted to examination, were mixtures of yellow ochres with different proportions of chalk, and one was a mixture of yellow ochre with red oxide of lead. The yellows in the painting were all ochres. The blues were of different shades from the mixture of different proportions of chalk, but they all owed their colour to the same substance, a fine blue powder, similar to the best smalt or ultra-marine, rough to the touch, which did not lose its colour by being heated to redness, but was semifused and agglutinated at a white heat. On applying the usual means of analysis, it was found to be a blue frit containing soda, and coloured by oxide of copper. It appears, too, that they were acquainted with a species of indigo. Different antique specimens of fine transparent blue glass, Sir H. ascertained to be coloured with oxide of cobalt. Other specimens of pastes and glass were coloured by oxide of copper, but the colour of these had a tint of green, and their transparency was much less perfect. The different greens examined proved to be mixtures and combinations of oxide of copper. The green glasses of the ancients were found also to be coloured by the oxide of copper. The purple, was found to be a lake mixed with carbonate of lime; but whether of animal or vegetable origin it was found impossible to determine. The blacks had all the characters of pure carbonaceous matter; and of the browns, several proved to be ochres, and one contained oxide of manganese, as well as oxide of iron. The whites presented the characters of carbonate of lime, and fine aluminous clay. Sir H. endeavoured to ascertain by what means the colouring matter had been fixed on several pieces of stucco, and on the Aldobrandine painting; but he could not detect the presence of any wax varnish, or any animal or vegetable gluten. Of these different colours, the azure, the red and yellow ochres, and the blacks, have preserved their colours perfectly in the ancient fresco paintings, not having undergone the smallest apparent change, but the others have all suffered more or less.

Some further Observations on the Current that often prevails, to the Westward of the Scilly Islands. By James Rennell, Esq. F. R. S.

This, as might be expected from its author, is an able and sa

tisfactory paper, but the facts and reasonings do not admit of sufficient compression for the purpose of an abstract; nor would it be easily intelligible without the aid of the chart by which the communication is illustrated.

Some Experiments on a solid Compound of Iodine and Oxygene, and on its Chemical Agencies. By Sir Humphrey Davy, LL.D F.R.S.

After many unsuccessful efforts to produce a combination of iodine and oxygene, Sir H. at length succeeded by exposing iodine to the action of the compound gas, to which he has given the name euchlorine, and which is a compound of oxygene and chlorine. When this gas and iodine are placed within the sphere of each other's action, there is an immediate action, even at the ordinary temperature of the atmosphere. The colour of the gas is changed to a bright orange, and a liquid is formed. And it the euchlorine gas is in sufficient quantity, a solid white substance is also produced. By the application of a gentle heat the orange coloured gas, which is a combination of oxygene and chlorine, may be separated in the elastic form, and the compound of oxygene and iodine remains behind. When it is entirely freed from the gaseous compound, it is a white semi-transparent solid, having a strong astringent sour taste, but without odour. Its specific gravity is so considerable that it sinks rapidly in sulphuric acid. It is decomposed by a strong heat, undergoing fusion at the moment, and is entirely resolved into its constituent elements, leaving no residuum whatever. The heat required for its decomposition, is rather below the boiling temperature of olive oil. This compound is very soluble in water, and deliquesces in a moist atmosphere. Its solution first reddens and then destroys vegetable blues, and reduces other vegetable colours to a dull yellow. When the aqueous solution is heated, as the water is evaporated, it gradually assumes the consistence of a syrup, becomes pasty, and at length, if the heat is sufficiently intense, it yields the solid substance unaltered. The pasty substance Sir H considers as an hydrat, as it yields moisture during its decomposition. The aqueous solution rapidly corrodes all the metals which have been exposed to its action, and its action upon gold is much more intense than upon platinum. When mixed and heated with charcoal, sulphur, resin, sugar, or the combustible metals in a state of minute division, detonations are produced. If the solution of it is poured into solutions of the alcalies, or alcaline earths, or their carbonats, triple compounds of oxygene, iodine, and the metallic bases, are formed. With solutions of the soluble salts. of baryta and strontia, a copious precipitation of their respec

tive oxyiodes takes place. These combinations are slightly soluble in water. It forms combinations with all the metallic oxides with which its agency has been tried; and precipitates lead and mercury from their combinations with nitric acid. Its action upon the acids is remarkable, for it forms compounds with all the solid or fluid acids, which it does not decompose. When sulphuric acid is dropped into a concentrated solution of it in hot water, a solid substance is precipitated, which is a combination of the acid with the compound. This substance was fusible when heated, and on cooling, rhomboidal crystals of a pale yellow colour were formed, which were very fusible, but the substance was permanent at the temperature at which the combination of oxygene and iodine is decomposed. By a much stronger heat it is partially sublimed, and partially decomposed. The compounds which it formed with the other acids which it did not decompose, were very analogous to that with sulphuric acid. All of them have a very acid taste; they redden vegetable blues, and dissolve gold and platinum. With the alkalies or earths, or saline solutions which they are capable of decomposing, common neutral salts and oxyiodes are formed at the same time. It is evident from these facts that these compounds of the new substance with acids, are true chemical combinations, in which the proportions are definite, and from the results of some of the decompositions Sir H. thinks it nearly certain that they are hydrates, and that the common acids carry their definite proportion of water into the combination. Sir H. proposes that the new anhydrous compound itself shall be called oxyiodine, and its acid combination with water os yiodic acid.

On the action of Acids on the Salts usually called Hyperoxymuriates, and on the Gases produced from them." By Sir Humphrey Davy, LL. D. F.R.S.

It is well known that when sulphuric acid is poured upon the hyperoxymuriate of potash, that the mixture becomes of a deep orange colour, but the presence of heat or moisture is so liable to produce detonation, that considerable difficulty has occurred in examining the results. Sir H. Davy however found, that when the oxymuriate in powder was mixed with a small quantity of sulphuric acid, and triturated together with a spatula of platinum until they had incorporated, a solid mass of a bright orange colour was produced, without any detonation. This mass introduced into a small glass retort, and exposed to the heat of water gradually warmed, afforded an elastic fluid of a bright yellowish green colour, which was rapidly absorbed by water, to which it communicated the same colour, but had no

sensible action on mercury. To make the experiment with safety, not more than forty or fifty grains of the salt should be employed, and care should be taken to exclude all combustible matter, and to keep the temperature below 212°, which is easily done by mixing alcohol with the water. The gas produced by this means over mercury, when compared with that disengaged from the same salt by muriatic acid, has a more brilliant colour, is more rapidly absorbed by water, has a peculiar and more aromatic odour, unmingled with the odour of chlorine. It destroys moist vegetable blues without reddening them, and when heated to about 212°, it explodes with more violence than euchlorine, and greater expansion of volume, and with much light. After the explosion, the expansion of volume is in the proportion of from 2.7. to 2.9. to 2; of which two volumes are oxygene, and the remainder chlorine. As however a little chlorine is always absorbed by the mercury during the explosion, Sir H. concludes that the gas is a compound of two volumes of oxygene, and one of chlorine, condensed into the space of two volumes, and consists in weight of one proportion of chlorine 67, and four of oxygen 60. None of the combustible bodies which have been tried, decompose it at common temperatures, except phosphorus, which occasions an explosion and burns in it with great brilliancy. Its saturated solution in water is of a deep yellow colour, and of an extremely astringent corroding taste. The gas produced from the hyperoxymuriate by muriatic acid, acts much more slowly upon water, than that disengaged by sulphuric acid, but it finally communicates to it the same colour and other properties, but when a large proportion of the gas is exposed to a small quantity of water, there is always a residuum of chlorine, so that the gas must either be a simple mixture, or the new gas must be formed by the action of the water. The action of nitric acid on the hyperoxymuriate affords the same results as with sulphuric acid, except that as the salt must be acted upon in solution, the gas is mixed with about of oxygene, while the gas from the solid mixture of sulphuric acid, and the hyperoxymuriate contained only of oxygene. The saturated solution of this gas in water mixed with a solution of the fixed alkalies or ammonia, does not immediately lose its colour, nor neutralize the alkalies; but after some time the effect is produced, and hyperoxymuriates are formed. The solution soon loses its colour if exposed to air, or if suffered to remain in close vessels; which Sir H. thinks is to be attributed to the decomposition of water, since some of it rather increased the volume of a small quantity of air to which it was exposed. Sir H. defers giving any name to this new substance until it shall have been determined whether euchlorine