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space of a quarter of an hour or 20 minutes. It is thus in some measure softened, tho' not difsolved; and acquires a kind of transparency towards the edges. He then rolls it up firmly upon a mould prepared for the purpose, so as to make the edges overlap each other a little, and covers the whole mould with an uniform unbroken coating, and immediately wraps it all over with a piece of ribbon or tape, so as to comprefs the whole very firmly. In this state he al lows it to remain till it be quite dry; and then, on taking off the bandage, he finds that the whole forms an uniform compact coating, which retains the shape of the mould after it is withdrawn, and has the same kind of flexibility with the caoutchouc in its natural state. When the mould is a smooth cylinder like a wire, which he employed, he found it could be withdrawn merely by dipping the whole for a few minutes in boiling water, and then pulling it out.

In this way he thinks catheters, &c. may be formed as good as those that have hitherto been made by a solution of caoutchouc in æther, and at a much smailer expence; and in the same way may be constructed tubes and cases of va ́rious forms, for many purposes in economy and arts, a few of which thall be here briefly specified.

Pumps for acids, and tubes of various sorts.

It has been long a desideratum among those who deal in acids, to find a pump that could be conveniently employed for taking them from one vetsel into another. Perhaps it may be pofsible to supply that want by the contrivance above specified. For this purpose let a cylinder of the size wanted be provided; cover it as far as the length of the tube required. To give the tube the firmness required in the bore of a pump, take a pipe of thin tin plate, formed cylindrically, but having several small slits along its surface the whole way, of the precise breadth wanted, without being cemented. Let it then be laid over the cylinder covered with the caoutchouc, and firmly bound round

it the whole way, by a small wire, passed spirally around it. Then cover this plate directly with another coating of the same caoutchouc, laid over it in the same manner as before, taking special care that the plate be somewhat shorter at both ends than the caoutchouc coating. When thorough. ly dry, let the mould be withdrawn, and you have the cylinder required, the metal being so entirely coated as to preserve it effectually from the acids.

You will easily perceive that the use of the small slits in the metal was to allow the two coatings of caoutchouc to touch each other in these places, so as to make the whole adhere firmly together, and keep the tube closely encased.

By making holes of a sufficient size in the plate, wherever you want to have an opening, you will be enabled there to pierce the caoutchouc without touching the metal, and thus to insert other tubes either formed in the same manner, or of glafs, where circumstances admit of it.

By the same mode, the stalk of a piston may be entirely coated; and valves of any kind formed with the utmost facility.

Where а tube is wanted still to retain its elasticity, without danger of collapsing, the metal case may be omitted, and a spiral wire of a size suited for the oc casion, substituted in its stead.

Where the tube is long so as that it might be dif ficult to withdraw it, if it be of a considerable size, a mould may be made of tallow, or wax, which can be dissolved by immersing the whole in hot water; by the same means may be formed irregular moulds which could not otherwise be withdrawn; or such moulds be made of clay, which can be softened by means of water, and washed out.


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Socks for the feet impenetrable hy moisture, boots, dc. In this way also might be formed socks, which if put above the stocking, would guard the feet more effectually from wet than even Mr Hand's leather itself. For this, by being only covered with a thin coating of it, will be soon worn off and be thus rendered unserviceable. These socks might, for such as chose it, be continued upwards upon the legs, by way of boots, so as to defend them also effectually from wet even when employed for wading in water up to the knees, or even in acids or other corrosive liquors. If these were brought up so as to go under the kneeband of the breeches; and if a slip of the same kind were made to go over the thighs above the breeches, a traveller on horseback would be effectually guarded from wet in all weathers. By the same contrivance the arms and fhoulders might be covered with a coat without a-seam, perfectly impenetrable by moisture. The head also might be defended by a hood of the same sort to go under the hat, with laps covering the neck and shoulders. In this manner might a man be covered all over as with a coat of mail, so as to be in no danger of receiving wet any situation.


In this way might also be made gloves for the hands, especially of that sort where the fingers are all received into one bag. These would not only be convenient for travelling during rainy weather, but also for covering the hands of such persons as are under the necessity of handling corrosive liquors:

It would be tiresome to follow out this idea at greater length. It is enough to have barely hinted at it, as any man by a little reflection can easily perceive in what way this discovery might be employed for effecting any purpose he may have in view at the time.

But though this substance may be thus converted to some very useful purposes, yet it is sufficiently obvious

that all these manufactures must be both more clumsy, and much more expensive, than it could be formed from the fluid juice itself as it comes from the tree; and as it now appears that the juice cannot be brought from South America without being decomposed, I cannot help once more recommending the culture of that tree nearer home to the attention of my contrymen. Were it introduced into our West India islands, the voyage from thence is so fhort that it might perhaps admit of being brought hither in a perfect state. But fhould that be still too far, it might be tried in the Azores or Canaries, or on the new settlements in Africa. I cannot conceive a fitter object for a high premium by the society of arts, than for the introduction of this tree into any British settlement. I mention British here, merely because it is not to be supposed the socfety would bestow a premium for introducing it into other European settlements. But it is perhaps of little importance to us where it fhall be cultivated, if it is so near as to admit of the juice being brought hither while still in a perfect state.

For an account of the tree which produces this valuable juice, see Bee vol. 2. p. 101, where its leaves, fruit and flowers are accurately delineated.


THE Editor begs leave respectfully to inform his readers, that he has not as yet been able to find any portrait of Dr Cullen that satisfies him but as an artist of very promising talents is now employed to make a bust of the Doctor to be put up in the college here, of which he has already made a model in clay that has every appearance of being a striking and a good resemblance, Dr Auderson has resolved to defer making his engraving till that shall be finished, when he hopes he will be enabled to give a more striking and characteristic portrait of that great man than he otherwise could have done.

* ** Acknowledgements to correspondents deferred for want of






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Translated from the Russian language.
Dr Brown
Continued from p. 273.

AND now that our incomparable mistress has exalted her paternal throne, typified in her birth, won by her heroism, established by victorious coronation, and ornamented by noble deeds; fhe is in justice the true heiress of all his actions and all his praises. If then we praise Peter, we praise Elizabeth.

The arts, long since, ought to have repr ented his fame in vivid colours; they have long wished ee


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