pelatous inflammation of the latter, itching pain and exco. riation of the same, local inflammation of the skin, followed by exulceration, fungus, suppuration, and ichorous secretion, combined with wasting of the whole body, are described as the characteristic symptoms of scirrhus, or, which is the same with our author, of sarcocele. [In our next we shall give an account of Dr. Mansert's Treatise on Puncturing the Cornea.] Chemical Amusement, comprising a Series of curious and instructive Expe iments in Chemistry, which are easily performed, and unattended by danger. By FREDRICK ACCUM, Operative Chemist, &c. Crown 8vo. pp. 191; 1817. Callow. We know not a more useful companion, in the present state of pharmacy, than this little work. Most young men. have leisure in the morning, and in order to acquire a practical knowledge of chemistry, and a readiness at operating, they can no longer trust to preparations, which at present many of them receive from Apothecaries' Hall, or some chemist on whom they can depend. Thus, a youth, at the end of his apprenticeship, may have a theoretic knowledge of the principles of chemistry without the least facility at manipulation. These "Amusements," as they are very properly called, will furnish a rational mode of passing part of the morning, and produce a readiness at every experiment, which will be found necessary on many trying and unlooked-for occasions. The operator will require scarcely any instrument which the shop does not furnish, excepting the blow-pipe, which we have recommended on many occasions. We would advise him, for common occasions, to cultivate the habit of using the common blow-pipe with the mouth; but, for artificial gases, nothing can exceed the modern invention. We shall transcribe only a few experiments, to shew the plan of the whole. "Phosphoric Fire Bottle.-Take a common brimstone match, introduce its point into a bottle containing oxide of phosphorus, so as to cause a minute quantity of it to adhere to it: if the match be then rubbed on a common bottle cork, it instantly takes fire. Care should be taken not to use the same match a second time immediately, or while still hot, as it would infallibly set fire to the oxide of phosphorus in the bottle. "Rationale The friction on the cork raises the temperature of the oxide of phosphorus, which then inflames and sets fire to the sulphur with which the match is tipped. "The "The phosphoric fire bottles may be prepared in the following manner: Take a small phial, of very thin glass, heat it gradually in a ladleful of sand, and introduce into it a few grains of phosphorus; let the phial be then left undisturbed for a few minutes; and proceed in this manner until the phial is full, Another method of preparing this phosphoric bottle, consists in heating two parts of phosphorus, and one of lime, placed in layers, in a loosely-stopped phial, for about half an hour. Another very simple method is the following: Put a little phosphorus into a small phial; heat the phial in a ladleful of sand; and, when the phosphorus is melted, turn it round, so that the phosphorus may adhere to the sides of the phial; and then cork the phial closely." The following is the elegant experiment of Count Rumford, from which so many economic improvements have resulted: "To render visible the opposite currents into which fluids are thrown, whilst they change their temperature.-Fill a common eight-ounce phial, or cylindrical glass jar, about two inches or more in diameter, and five or six inches long, with cold water, and diffuse through it a small portion of pulverized amber: let the phial of water be immersed into a tumbler, or larger vessel, containing hot water: this being done, two currents, going in different directions, will be observed in the inner vessel, the one ascending, and the other descending; that is to say, the minute particles of amber, which were diffused through the fluid, and were at rest before the heat was applied to the water in the inner vessel, will be seen in motion: those particles that are situated towards the sides of the glass, or which are nearest to the source of heat, will move upwards, whilst those that are in the centre move downwards; and thus two distinct currents are formed in opposite directions, the central one being directed downwards, and the exterior one upwards. These currents gradually diminish in velocity; and, when the water in the inner vessel has acquired the same temperature as that in the outer one, the particles of amber will again be brought to a state of rest. "If the position of the two vessels be reversed, namely, if the glass containing hot water be immersed into a vessel containing cold water, the motion of the currents will also be reversed: the particles next to the sides of the glass are thrown into currents directed downwards, whilst the particles in the centre form a current directed upwards. The equilibrium of these two currents will also be restored, when the equalization of temperature of the water within, and that without, has been effected. "Rationale. In the first instance, the caloric of the hot water in the outer vessel is transmitted, by the medium of the glass, to the particles of the water next to the glass in the inner vessel; these particles expand, and are rendered specifically lighter, ascend, and form the outer current. During this process, they gradually part with their caloric to the lateral particles; they become condensed, and and thus produce the central current. In reversing the experiment, when the hot phial is surrounded with cold water, the external par ticles, instead of being heated, lose caloric, or become cooled, and consequently diminished in bulk: their specific gravity is lessened, and therefore they descend; and the central particles, being warmer, and specifically lighter, becoming forced up, the currents are reversed. "To render the experiment more decisive, the lower part of the water may be coloured by tincture of cabbage, or red ink, leaving the upper part uncoloured. If heat be then applied to the bottom part of the glass, the coloured part of the water gradually ascends, and uniformly tinges the whole fluid. Now this certainly can only take place by the actual mechanical interchange of the particles of the water itself. The heat which is applied to the lower strata of the water, becomes specifically lighter than the other particles; it is, therefore, pressed upwards by the adjoining particles, and, being at liberty to move, it changes its place, and is urged up to the surface, viz. in consequence of the fluidity of the body, and the expansion of the separated particles. New particles approach the source of heat, combine with it in their turn, are again displaced, and thus the currents are produced. The rapidity of the motion of the currents (the cause of which is a change in the specific gravity of the fluid, produced by a change of temperature) is in proportion to the change of the specific gravity of the fluid, by any given temperature." Rotary Motion of Camphor upon Water.-Fill a saucer or broad bason with water, and let fall upon it camphor, reduced to the form of coarse sand. The floating particles will instantly begin to move and acquire a progressive rotary motion, which continues for some minutes, and then gradually subsides. If the water be touched by any substance which is in the slightest degree greasy, all the floating particles briskly dart back, and are, as if by a stroke of magic, instantly deprived of their motion and vivacity. Rationale. A variety of opinions have been formed concerning this phenomenon. Lichtenberg assigned it to the emanation of an etherial gas from the morsels of the camphor. There was, however, always a certain mysterious caprice in these motions, according to which they sometimes could not be produced; and on other occasions, the motions were instantly stopped when the water was touched with certain bodies, without its being easy to guess the reason. And all these circumstances tended to envelope the phenomenon with obscurity. Venturi was the first who explained the experiment. He was led to the explanation in the following manner: Pieces of camphor were cut into the form of small columns, one inch in length; a base of lead was fixed to each column; they were then placed upright in very clean saucers, and pure water poured in, to half the height of the column. Two or three hours afterwards, an horizontal notch was manifest in the column of camphor at the surface Surface of the water; and in the course of twenty-four hours, by the notch becoming gradually deeper, the column of camphor was cut in two at the middle. The two pieces of the column, nevertheless, that is to say the lower, which was immersed in the water, and the upper in the air, suffered scarcely any perceptible diminution. From this experiment, and others made with different pieces of camphor, kept separately in the air, in the water, and at the surface of the water, Venturi deduces, that the most active virtue for dissolving camphor, resides at that part where both the air and the water touch it at the same time. The camphor at the surface of the water, does nothing, therefore, but dissolve; and, when dissolved at the ordinary temperature of the atmosphere, it is not at first in the state of vapour, as has been thought; it is simply a liquid, which extends itself over the surface of the water; and by this means, coming into contact with a great surface of air, it is afterwards absorbed and evaporated. The rotary motion of the pieces at the surface of the water, is therefore supposed to be simply the mechanical effect of the re-action which the oily or camphoric liquor, extending itself upon the water, exercises against the camphor itself. If the retro-active centre of percussion of all the jets do not coincide with the centre of gravity, a combined motion of rotation and progression must follow. And, as the departure of the camphoric solution takes place only at the surface of the water, the rotation cannot be effected but round an axis perpendicular to the horizon; and since, in similar bodies of different magnitudes the algebraic ratio of the sides to the mass increases in the inverse duplicate ratio of the sides themselves, the small particles must have proportionally more jets, and must re volve more speedily than the larger. No better explanation has yet been given.' The experiments are 103 in number, at the end of which Mr. Accum has added "A descriptive Catalogue of his apparatus and instruments employed in experimental and operative chemistry, in analytical mineralogy, and in the pursuits of the recent discoveries of voltaic electricity." MEDICAL AND PHILOSOPHICAL INTELLIGENCE. T it is painful to interfere with a contemporary Journal, it appears HE receipt of the following has embarrassed us greatly. Whilst not less illiberal and even cruel to refuse a foreigner that privilege with which an Englishman is often indulged. We are besides under obligations to M. von Embden for many valuable communications, which more than entitle him to the space his defence will occupy. We think it right to remark, that we have not taken the liberty we often assume with communications from abroad in our own lanNO. 225. 3 I guage. guage. What follows is printed exactly as we received it. We shall conclude with a fervent wish, for our own sake and the benefit of the public, that these contests may realize the adage of Hesiod which immediately precedes M. Von Embden's quotation. Ζηλοι δε τε γειτονα γειτων Εις άφενον σπευδοντ'. Αγαθη δ' ερις ηδε βροτοισι. DR. VON EMBDEN in Reply to the Reviewer of the If ever the sentence "dat veniam corvis vexat censura columbas" was in its proper place, I think I may apply it to myself. Aware of the advantages to be derived from liberal criticism, I besought the critics to let me reap the fruits of it, thus enabling me to improve my work for the general benefit of the faculty. This application, however, having been taken up erroneously, I was doubly disappointed, for, instead of receiving the healing dew of the bee, I obtained the poisonous sting of the wasp-instead of meeting with instruction founded on the basis of science and liberality, as I had solicited and had a right to expect, I met with nought but abuses resulting from rancour and acrimony. If information is not the purpose of censorial remarks; if instruction is not to be gleaned from them; if, instead of shewing us where we have erred, and modestly directing us where we have failed, they only wish to gratify their spleen, and let us feel their sarcasm, then indeed it cannot be taken in good part, for then criticism misses its object, and becomes debased to cavilling, and, as the poet says, "Teach us to mourn our nature, not to mend Unless the words of Hesiod be true, negaμɛvs xsgaμes nories, I am at a loss to conceive what could prompt the reviewer to indite me of such grammatical ignorance as to be unable to write a single line of English, or to impute to me such errors as no candid reader would hesitate a moment to lay to the charge of the composer and reviser. I have long enough had the honour of conversing with the faculty of Great Britain to know how far I may confide in my capability of conveying my ideas to them in their own language; and too long have I been in the habit of holding in the highest veneration the acknowledged liberality of the English public towards foreigners, not to despise the effusions of the gall-dipped pen of an illiberal individual, effusions which none but the hapless reviewer could writé!-I lay no claim to any competency in the English language beyond perspicuity, and well am I aware that it is not in the power of every body, and, least of all, in that of myself, to deliver my thoughts with elegance and in a flourishing style, yet, as a judicious critic observes in one of our favourite journals, Perspicuity is all that is required for the communication of prac tical points." I am certain to have aimed at that qualification, and dare likewise flatter myself to have attained it in a sufficient degree to |