the movement of which solution is rendered visible by the particle, of clay which it holds in suspension. Though there be no longer then the jet of bubbles of hydrogen gas, the fragment of alloy does not discontinue to be agitated by an effect of recoil or reaction; it is not then the effluvium of this hydrogen gas which is the cause of this effect of recoil, as is supposed admitted by Serullas; this gas like water obeys an electric repulsion, and it is this repulsion which is the sole cause of the effect of recoil. Serullas has here taken the effect for the cause.

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23. I make here an important remark to be taken into consideration. Upon the contact of camphor or of oily bodies with water, electric attraction is the primordial effect, repulsion is the secondary effect whilst this is the inverse of what takes place on the contact of the alloy of potassium and antimony with water. Thus, a piece of camphor being placed under the microscope, at the brink of a small sheet of water on a plate of glass, and holding particles of clay in suspension, we see at the moment, that the water charged with argillous particles is precipitated, by the effect of attraction, towards the middle of the piece of camphor, and then divided into two currents, the one turning to the right and the other towards the left, which receive the repulsive action and retreat, by each accomplishing a revolution, in order to return and join themselves in the unique and medium current due to attraction. Now a piece of the alloy of potassium with antimony being placed similarly in this experiment, the effect which takes place will be inverse. We see, at the moment of contact, the water, or rather the alkaline solution, charged with argillous particles and mixed with bubbles of hydrogen, shoot forward from the middle of the piece of alloy by the effect of repulsion, and become divided afterwards into two currents, the one right and the other left, which then obeying the attraction, return towards the piece of alloy by thus accomplishing a revolution, in order to unite itself anew to the unique and medium current due to the repulsive action. Thus on the contact with water of combustible, oily or resinous bodies, susceptible of uniting themselves with this liquid, we observe an afflux, by the attraction of the water as the primordial phenomenon; the subsequent repulsion of this liquid is the secondary phenomenon. On the contact of water and potassium, which is a combustible body of another kind, it is the repulsion of the water which is the primordial phenomenon, its subsequent attraction is the secondary phenomenon. Now it is not the potassium which becomes dissolved in water, it is the potash which forms by the combination of the oxygen of the water with the potassium. Thus it is to the solution of potash that we must attribute the electrical phenomena which manifest themselves in the contact of the alloy of potassium and antimony with water. We have already seen (11) that these electrical phenomena manifest themselves in the same way, but in a less apparent manner, on the immediate solution of a caustic alkali in water. The spontaneous movements which are manifested in a manner more or less apparent,

by all other bodies soluble in water, when they are kept artificially floating at the surface of this liquid, prove that they equally develope under these circumstances, an electricity which is the cause of these spontaneous movements. I shall designate these electromotive phenomena due to the action of solution, by the name of diluo-electric phenomena. Now it results from some of the observations which have just been detailed, that two diluo-electric pheno mena, different up to a certain point, since they produce two rotations in inverse directions, are produced by the solution of combustible bodies in water, and by the solution in the same liquid of bodies that are non-combustible. We feel then the necessity of here distinguishing the two orders of diluo-electric phenomena. As I shall not have to employ myself in this memoir with the diluo-electric phenomena produced by the solution of non-combustible bodies in water, I need not impose upon them a particular name. It will be with the diluo-electric phenomena, produced by the penetrating or superficial solution of bodies combustible in water, that I shall occupy myself exclusively; and I shall designate them by the special name of camphoro-electric phenomena; and that because it was camphor which first presented these phenomena to observation, and it is camphor likewise, under this point of view, which is in some manner the type of all the bodies which are susceptible of presenting these same phenomena. I shall give also to all those combustible bodies, considered under the point of view of special electric phenomena which they are susceptible of producing, the general name of camphoroidal bodies.

24. I have previously observed (10) that one of the characteristics of the movement of camphoroïdal bodies on water, was the suddenness of the accidental and intermitting acceleration of this movement which present from time to time the appearance of lively jerks. In observing, by a microscope, the movement of the argillous particles in suspension in the water which was in contact with a piece of soap, I have seen at the moment of these sudden jerks, that the argillous particles, and consequently the water which held them in suspension, suddenly underwent an impetuous repulsion. We cannot then doubt that these sudden jerks proceeded from a sudden discharge of electricity in the proper manner to produce the repulsion of the water, from whence it follows that the piece of soap was suddenly moved in an opposite direction by the effect of recoil.

25. It is not only at the surface of the water that these camphoroïdal bodies can move; they have even been observed to move, under certain circumstances, in the middle of the water. Thus the alcohol, which is imbibed by pieces of cork, gives a very active movement to those pieces placed on the surface of the water; now when this same liquid is imbibed by small fragments of organic matters whose specific gravity causes them to penetrate into the interior of the water, it then gives a very vigorous movement of progression to these small fragments, and the movement takes place, as ordinarily, by sudden jerks. We must remark, that this electricity which has

birth from the contact and of the reciprocal solution of alcohol and of water, does not manifest itself as a moving cause except in the alcohol, and not at all in the water. Thus the small pieces of organic substances soaked in water do not move at all spontaneously when they are put into alcohol.

26. The diluo-electric phenomena, of which the camphoro-electrics form a division, seem to hold the middle between the phenomena of static electricity and those of dynamic electricity. They belong to this latter by their origin, which is taken from a chemical reaction; they present like the former, successive attractions and repulsions to the bodies which surround the electrised body, which is not produced by dynamic electricity. Does the electricity form in any manner a part? I abstain from giving any opinion in this respect. Taken altogether, the numerous experiments go to show that this electricity possesses special properties, and properties which appear strangers to static electricity as well as to dynamic electricity. These properties are in relation, first, with the nature of the material of the vase which contains the liquid on which the camphor moves, or more generally, the camphoroidal body, and with certain physical states in which the vessel may be found; secondly, with the chemical nature of the aqueous liquids on which the camphoroidal bodies are susceptible of motion, and with certain physical states of these same liquids. It was very necessary that I should run in its entire extent the vast field of research which embraces the novel order of facts which I have made known: but I have only, in this respect, merely opened the way. Camphor especially, and almost exclusively, served me in my experiments; I have only made a very small number with soap, which is a camphoroidal body. The aqueous liquids of which I have made use have been pure water, different alkaline, acid, or saline, solutions. Glass vessels are those of which I have especially made use; I made a great number of experiments, however, in which I employed metallic vessels, vessels of baked earth, of wood either in its natural state or varnished, of wax, &c. I submitted successively these different experiments, the principal results of which I have deposed in a pacquet under a sealed envelope, which the Academy accepted at its session of the 1st November last.

On the Perchlorate of the Oxide of Ethule, or Perchloric Ether.By CLARK HARE and MARTIN H. BOYE.*

THE energetic properties of perchloric acid, and its stability, compared with the other compounds of chlorine with oxygen, led us to the belief that this acid might be combined with the substance which performs the part of a base in that class of organic salts which are generally designated by the name of ethers, and for which Berzelius, in consequence of his theoretical views, has adopted the name of oxide of ethule. For this purpose a concentrated solution of per

• Read before the American Philosophical Society, Dec. 4, 1840.

chlorate and sulphovinate of barytes, in equivalent proportions, was subjected to distillation. The sulphovinate of barytes may be considered as a double sulphate of barytes and the oxide of ethule; and we anticipated that when heat was applied a double decomposition would take place between the latter and the perchlorate of barytes. So long as the salts remained in solution, no reaction occurred, but as soon as they became solid, in consequence of the distillation of the water, a reciprocal decomposition ensued, and a sweet etherial liquid distilled into the receiver. This liquid is the per

chlorate of ethule.

As this substance is extremely explosive, it is necessary, in order to prepare it with safety, to operate on small quantities. We have employed from seventy to ninety grains of crystallised sulphovinate of barytes, with an equivalent proportion of perchlorate of barytes;* but we would recommend, especially on the first performance of the experiment, the employment of considerably smaller quantities. The salts should be intimately mixed in a mortar, and placed in a small retort attached to a refrigerator containing ice, and a receiver similarly cooled. The retort is to be heated in an oil bath, in which a thermometer is suspended, so as to indicate the temperature. A wooden screen, furnished with openings covered with thick plate glass, at such intervals as to afford a full view of the different parts of the apparatus, should be erected in front of it, and strings passed around the screen and attached to a bar traversing on a pivot, and supporting an argand spirit lamp, by which heat is communicated to the oil bath, so as to enable the flame of the lamp to be removed from or applied to the apparatus, according to the indications of the thermometer, without exposing the person of the operator. After the heat has reached 212° F., below which the salts employed do not react on each other, it should be raised very gradually, and the distillation finished below 340° F. Under these circumstances but little danger is to be apprehended from the retort, but the ether in the receiver must be treated with the greatest caution, since it has exploded in our hands in attempting to remove it with a pipette from the stratum of water which covers it. This water, therefore should be removed by the cautious use of strips of blotting paper, moistened at the end, and introduced into the tube employed as a receiver.

To avoid the danger attendant on the management of the ether in its pure state, it may be received in strong alcohol, since it is not explosive when dissolved in alcohol. If the experiment be performed with seventy grains of sulphate of barytes, from one to two

The amount of barytes in the perchlorate should be ascertained by an experiment, as it retains water with great tenacity. It may be worth while to mention, that the perchlorate of potassa cannot be substituted for the perchlorate of barytes, since the sulphovinate is decomposed without acting on it. We were equally unsuccessful in an attempt to procure the ether by the distillation of perchlorate of barytes and concentrated sulphovinic acid.

drachms of absolute alcohol will be found sufficient for this purpose. By the addition of an equal volume of water the ether may subsequently be separated from this solution in small quantities, for the purpose of examination. But in this case, a loss of ether is sustained by the decomposing influence of the water employed.

The perchlorate of ethule obtained in this way is a transparent, colourless, liquid, possessing a peculiar, though agreeable smell, and a very sweet taste, which on subsiding leaves a biting impression on the tongue, resembling that of the oil of cinnamon. It is heavier than water through which it rapidly sinks. It explodes by ignition, friction, or percussion, and sometimes without any assignable cause. Its explosive properties may be shown, with but little danger, by pouring a small portion of the alcoholic solution into a porcelain capsule, and adding an equal volume of water. The ether will collect in a drop at the bottom, and may be subsequently separated by pouring off the greater part of the water, and throwing the rest on a moistened filtre, supported by a wire. After the water has drained off, the drop of ether remaining at the bottom of the filtre may be exploded, either by approaching it to an ignited body, or by the blow of a hammer. We are induced to believe that in explosive violence it is not surpassed by any substance known in chemistry. By the explosion of the smallest drop an open porcelain plate will be broken into fragments, and by that of a larger quantity be reduced to powder. In consequence of the force with which it projects the minute fragments of any containing vessel in which it explodes, it is necessary that the operator should wear gloves, and a close mask, furnished with thick glass plates at the apertures for the eyes, and perform his manipulations with the intervention of a moveable wooden screen. **

In common with other ethers, the perchlorate of ethule is insoluble in water, but soluble in alcohol; and its solution in the latter, when sufficiently dilute, burns entirely away without explosion. It may be kept for a length of time unchanged, even when in contact with water; but the addition of this fluid, when employed to precipitate it from its alcoholic solution, causes it to be partially decomposed. Potassa, dissolved in alcohol, and added to the alcoholic solution, produces immediately an abundant precipitate of the perchlorate of that base, and when added in sufficient quantity, decomposes the ether entirely. It would appear, therefore, impracticable, to form either perchlorovinates or perchlorovinic acid.

We have subjected the perchlorate of ethule to the heat of boiling water without explosion or ebullition.

It may be observed that this is the first ether formed by the combination of an inorganic acid containing more than three atoms of

• Having suffered severely on several occasions from the unexpected explosion of this substance, we would earnestly recommend the operator not to neglect the precautions mentioned above.