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be passed without danger, and then pointing out these to the profession, to leave their body to prosecute and decide on the subject of discussion, —such seems to me the fittest mode of attempting to explore the medicinal resources which an untried Materia Medica may contain. It may be useful to add a formula for making the preparations which I have employed. The resinous extract is prepared by boiling the rich, adhesive tops of the dried Gunjah in spirit (Sp: gr. 835,) until all the resin is dissolved. The tincture thus obtained is evaporated to dryness in a vessel placed over a pot of boiling water. The extract softens at a gentle heat, and can be made into pills without any addition. The tincture is prepared by dissolving three grains of the extract in one drachm of proof spirit. Doses, &c.–In Tetanus a drachm of the tincture every half hour until the paroxysms cease, or catalepsy is induced. In Hydrophobia I would recommend the resin in soft pills, to the extent of ten to twenty grains, to be chewed by the patient, and repeated according to the effect. In Cholera ten drops of the tincture every half hour will be often found to check the vomiting and purging, and bring back warmth to the surface. My experience would lead me to prefer small doses of the remedy in order to excite rather than narcotise the patient.

Postscript.

While the proofs of this paper were under correction, Dr. Esdaile, of Hooghly, has communicated a case of traumatic tetanus, in which he has used the extract of Hemp and the patient recovered. The details will be subsequently published.

Mr. Sawers, the 1st Member of the Medical Board, has also favored me with the results of a very curious trial of the remedy on a pony which had been attacked by lockjaw as the sequel of forcible compression of the testes. I have the pleasure to insert an extract from Mr. Sawers' note.

“Having made no memorandum of the case of the pony, I am unable to give the particulars in detail. Before the Bhang was given the power of mastication had ceased for several days, and he had been supported by mixing suttoo (pounded pulse) and bran with his water; with this the powdered Bhang was mixed. When he had taken some doses the general rigidity of the muscles was in some degree removed, and he began to masticate hay and grass, and shortly was able to lie down and rise without assistance; but it was sometime ere he recovered the power of balancing the muscles so as to trot evenly.

“I direct the syce to give a little more of the Bhang than it was usual for a stout man to take for a dose, and it was given for eight or ten days, perhaps longer.

“The pony is now perfectly well. The disease was induced by compression of the spermatic chord, as a mode of castration. Tetanus is not so fatal in the horse as in man ; of the former I have known several instances of recovery, of the latter, in all my experience I have seen but one case which did not terminate fatally.

“After the battle of Laswarry several wounded Europeans and Sepoys were received into the Hospitals at Agra with Tetanus, but they all died. A Sepoy who had a large wound on the outside of his right thigh (which had been brushed by a cannon ball, removing the integuments,) was seized with lock-jaw a few days after his arrival. The only medicines he took were pills of opium and calomel, which he took in large quantity, with occasional aperients;—he recovered. The disease came on gradually, and for many days his jaws were so clenched that the small pills could only be administered by an opening between two of his teeth.

“I ought to have stated that the pony had enemata daily whilst taking the Bhang.

Signed, “J. SAWERS.”

ART. VII.—Memorandum of Experiments on the Explosion of Gunpowder under Water by the Galvanie Battery; with a notice of the successful destruction of the wreck of the “Equitable,” at Fultah Reach.—By W. B. O'Shaugh Nessy, M.D. Assistant Surgeon, &c. &c. Having recently undertaken a series of experiments on the application of the Galvanic Battery to the explosion of gunpowder under water, with reference to the destruction of the wreck of the barque “Equitable,” sunk in the channel of the Hooghly at Fultah Reach, I think it desirable to publish a succinct statement of the results to which these experiments have led. Description of the Galvanic Battery. The galvanic battery which I employed in my experiments is one of

my own construction, but on Daniell's constant principle. It consists of a series of rectangular copper cells, (water-tight) fifteen inches square, and the sides three-fourths of an inch apart. To one lip of the cell is soldered a small copper tube a (water-tight) in which a few drops of mercury are contained. One of these cells is shewn in the plate, fig. 1. Each copper-cell is provided with a sheet of zinc plate, fourteen and a half inches square, to which a thick copper wire, seven inches long, is firmly soldered. Each zinc plate is amalgamated with mercury, and enclosed in a pasteboard case, the construction of which deserves attention, as upon it depends much of the action of the battery. Two sheets of brown pasteboard are cut, of such dimensions that they will freely slide into the copper cells. The pasteboards are then placed over each other, and their edges fastened together at three sides by thin slips of teak, half an inch wide, bound together by a few copper screws. A case or bag of this kind when well made is water-tight at the joints, but allows slow filtration to take place through its sides. One of these cases is shewn at fig. 2. To arrange each cell the zinc sheet is introduced into the pasteboard case, and this into the copper cell. Twelve of these cells constitute what we may term one division. The cells must not touch, and are accordingly separated by slips of wood. The zinc sheet from cell No. 1 is connected by its wire with the copper cell No. 2, the zinc of 2 with the copper of 3, and so on, as shewn in fig. 4, in which twelve are placed in a box together. To excite the battery two different solutions are employed, one a solution of blue-stone (sulphate of copper, nila tutiya). This salt costs in the Calcutta bazars about twenty-two rupees per maund. The second solution is made of sulphate of soda, (Glauber salt, Kari nimuk), dissolved in warm water, and allowed to cool before use. Each copper cell is to be filled to two-thirds of its depth with the blue liquid. The pasteboard cases with their zinc sheets are to be steeped in the Glauber salt solution till thoroughly soaked, then slipped into the copper cells, and filled up with the same liquid. The battery is then ready for use.

Igniting effect produced on platinum or iron wire ; how influenced by distance and thickness of conductors, and length of platinum wire.

I abstain from all explanation as to the theory or mode of action of this battery, wishing to confine myself here to its effects in the ignition of metallic wires. To produce this effect, twist a copper bell-wire ten feet long to the wire of the last zinc plate, and connect a similar wire with the mercury tube of the first copper cell. If the free ends of these wires be joined by a fine platinum or iron wire, say two inches in length, the moment the junction is completed the platinum or iron becomes white hot, and if the battery be in full action, generally melts into numerous globules. The ready destructibility of iron by oxidation renders it inferior for the purpose now in view to platinum, which was accordingly used in all the subsequent experiments. But if the copper wires touch each other in any part between the battery and the platinum no heating is produced, because the electrical action does not extend beyond the first metallic junction. This most important fact is made use of in a self-acting apparatus which I employ for the explosion of mines at a certain fixed time after the experimentalist has retired to a safe distance. It also shews, that when we wish to produce ignition of platinum wire at a distance we must take some means for preventing the conductors from touching each other. But before describing how this may best be accomplished, it is necessary to examine the influence of two important circumstances over the ignition of the platinum wire, viz. the thickness of the conductors, and the distance of the platinum wire from the battery. A few experiments will render this quite intelligible. A constant battery of twelve cells was employed, and a platinum wire two inches long and 1-30th of an inch, in diameter. 1st Experiment—Using copper bell-wire 1-12th of an inch in diameter, this battery caused the platinum wire to become so hot as to kindle saltpetre match-paper at a distance of 130 feet. 2nd Experiment.—Each conductor was formed of two strands of bell-wire. The platinum was now heated to the same degree to exactly double the distance of the first experiment.

3rd Experiment.—Three strands of wire were now employed in each conductor, twisted into a cord. The igniting distance was rather more than trebled. My stock of wire was insufficient to carry this curious experiment further; but a trial with a weaker battery and shorter conductors as far as six strands in each, led to the inference, that the igniting distance increases in an arithmetical ratio with the mass of the conducting wire. A very extraordinary circumstance presented itself in these experiments, one which has been previously observed by Davy, but the great importance of which in the present inquiry demands a distinct description. If at the distance of 130 feet two inches of platinum wire become a bright red, we find that by shortening the wire to one inch the ignition is not increased, but diminishes remarkably. Shortened to half an inch the noire ceases to be even sensibly narm to the touch! This curious fact is one deserving all the ingenuity of the theorist to explain its nature, but my business now is with practical matters alone. It leads clearly to the employment of exploding wires of much greater length than we would employ were we ignorant of this very singular and apparently anomalous circumstance.

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Insulation of conductors not essential even in water.

The preceding observations refer to dry conductors. It is almost needless to say that dividing the wires in any part, and thus interrupting the circuit, at once causes the platinum to return to its natural degree of coldness.

It might be, and indeed generally is supposed, that were the conductors immersed in water, this fluid would carry off the electricity, and nullify all effect on the platinum. Thence it would be inferred that it would be necessary to insulate the wires, that is, to place them within a coating of some resinous, or other non-conducting substance, which would at the same time prove impervious to water and a barrier to the passage of the electric fluid.

Impressed with the idea that this insulation might be dispensed with, I instituted several experiments with the same battery and plati

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