fore, increafing the general perfpiration by the falutary friction of a flannel waistcoat, change of fituation, and more especially long journies on horfeback, conducted as much as poffible through a thin, fharp, dry air, will feldom fail of removing the complaint.

But on the contrary, if the cough, fhould, at the fame time that it is petulant and fatiguing to the breaft, continue dry, huiky, and without expectoration; provided there is reafon to hope that no tubercles are forming, or yet actually formed, there is not perhaps a more efficacious remedy for it than half a drachm of gum ammoniacum, with eighteen or twenty drops of laudanum made into pills, and taken at bed time, and occafionally repeated. This excellent remedy Sir John Pringle did me the honour to communicate to me, and I have accordingly found it, in a great many inftances, amazingly fuccefsful, and generally very expeditiously fo, for it feldom fails to produce an expectoration, and to abate the diftreffing fatigue of the cough. In thofe circumftances I have likewife found the common remedy of 3fs. or 3. of half. fulph. anifat. taken twice a day, in a little powdered fugar, or any other vehicle, a very efficacious one. I have alfo, many times, known a falutary revulfion made from the lungs by the fimple application of a large plaifter, about five or fix inches diameter, of pix Burgund. between the fhoulders; for the perfpirable matter, which is locked up under it, becomes fo fharp and acrid, that in a few days it feldom fails to produce a very confiderable itching, fome little tendency to inflammation, and very frequent

ly, a great number of boils. This application fhould be continued (the plaifter being occafionally changed) for three weeks, or a month, or longer, if the complaint is not fo foon removed.

Antidotes against the poisonous Effets of Arfenic, Corrofive Sublimate, Verdigrife, and Lead. Tran flated from the French of P. M. Touffant Navier, Physician to the King of France.

OR perfons who have been

poifoned with arfenic, M. Navier recommends large quantities of milk, as that liquid diffolves the arfenic as easily and as effectually as water, and at the same time softens the vifcera that have been irritated by its corrofive influence. He affirms that the arfenic, far from curdling the milk, actually prevents its coagulation: and be prohibits the ufe of oil, because it is incapable of diffolving the arfenic. Af ter the milk, the patient is to take a drachm of the liver of fulphur of Mars, in a pint of warm water; but, if this cannot be readily procured, he may take a dixivium gently alkaline, or soap-water, and thereupon a folution of iron in vinegar or any other acid; or even a portion of ink, if nothing else is at hand. The cure is finished by the ufe of milk and warm fulphureous waters, which experience has shewn to be very powerful in removing the numbnefs, convulfions, and pa ralytic complaints, which are the conftant effects of poifon.

The remedies adapted to corrofive fublimate are the fame with thofe employed againft arfenic, that is to fay, the different preparations

of

of liver of fulphur, which decompounds or refolves the mercurial falt, and forms, by the addition of the alkali to the acid, a neutral falt no wife cauftic: efpecially if the remedy be applied quickly. Acids, even of the moft gentle kind, are fatal in the prefent cafe, as they evidently increafe, inftead of dimi nifhing, the poifonous acrimony: thus even lemonade, and theriaca, or treacle, are pernicious, and contribute to the painful and certain death of the patient.

What this learned and humane' Phyfician fays of the effects of ver. digrife deferves a particular degree of attention, as we are daily

expofed to them from the ufe of copper utenfils in cookery: on this fubject his cautions and admonitions might appear exaggerated, had not the most eminent chymists and phyficians of the prefent age given us repeated warnings of the like nature. But, where this poifon is known to have been recently fwallowed, he prefcribes, firft, emetics, and afterwards cold water gently alkalifed, which must be drank plentifully.

Though lead is not to be confi. dered as a corrofive poifon, its pernicious effects will be corrected by the remedies already mentioned; which will render thofe violent and dangerous purgatives ufually adminittered againft lead unneceffary: but patients of this clafs may drink largely of acidulated liquors; the liver of fulphur afterwards makes the principal part of the cure, which will be compleated by gentle

purges.

The falutary properties of liver of fulphur, particularly of the liver of fulphur of Mars, an antidote against thefe deftructive fubitances, is a most valuable difcovery; and

one of the happieft applications of chemistry to medical purposes, that the prefent age has produced.

In our VIth Vol. page 121, and

VIIth Vol. page 143, we have inferted three Papers on the Method of making Nitre: this has occafioned our being favoured with a fbort Account of the Procefs ufed for that purpose at Paris, as collected on the Spot (in the year 1771) at the defire of an eminent Phyfician, fince dead, by Dr. Thomas Houlton, of Liverpool.

A Paris, there is a company Aof perfons employed in mak

ing falt-petre, in number about twenty. They were incorperated fo long ago as the reign of Charles IX. and have feveral ftatutes for their regulation. Any of them can, when a houfe is taken down, place a man in it, and, during three days, he has a right to take, gratis, fuch part of the old plafter as he fhall chufe, or think worth the pains of lixiviating.

The quantity made annually, is from 6 to 700,000 lb. They are obliged to deliver it in, rough, to the Royal Arfenal, where they receive for it 7 fous (about 3 d.) per lb. It is there purified, undergoing three lixiviations, and is then fold at 10, 15, and 18 fous per lb.

Monf. Bouret, from whom this information was received, makes every year from 35 to 36,000 lb. He employs therein fix men, night and day, two rooms, twenty large cafks, and three horfes. The cafks are filled half with old plafter, which is changed every time of pouring on water, and the lower half with wood afhes, which are K 2

changed

changed but once in five lixivia. tions. The water poured on, foaks through both the plafter and afhes, and is five times paffed through fresh plafter. It is then boiled down in a copper pan, fo fet, that the flame paffes quite round its fides. The fires are of wood, which is very dear, and forms a confiderable article of expence. The lixivium, when properly evaporated, is fet to cryflallize, and the cryftals to drain. The fcum taken off in the boiling, is thrown upon the plafter collected, which the longer it lies in heaps (wetted from time to time) the ftronger it becomes; as alfo the more putrid matters are thrown on it. The plafter ufed in the buildings at Paris, is made of that gypfeous earth, called plafter of Paris,

and found in the neighbourhood of that city. No lime is mixed with it in general, but, where there is lime mixed, it is remarke ed that the nitie made from thence is not fo good, nor in fo great quantity. They know when the old plafter is worth being collect. ed and employed, by the faltifh tate of it. The nalliness of the French houfes, even in fome parts of the great ones; the durability of their buildings, the nature of their plafter, and the regulations of their police, give that nation an advantage over us in making ni tre, which it will be well if the ingenuity and fcience of thofe who attempt it among us, may fuffice to counterbalance. It is made alfo in other great towns in France,

der; and let fome oil of vitriol be at hand. The veffel B, together with C (fig 1.) must be taken off from A, and put on the wooden ftand F (fig. 2.) Let the veffel B be filled with fpring, or any other drinking water, or even with dif. tilled water; and let it be joined again with the upper veffel C.

Let fome water be poured on the lower veffel A, fo as to cover the rifing part of its bottom: but if this appears too vague a direction, pour in fourteen or fixteen measures of water, with the glafsp (fig. 5.) then fill the fame phialp with oil of vitriol, and pour it into the fame veffel A, along with the water.

It will be, however, much eafier to have made beforehand the mixture of oil of vitriol and water, in the above proportion. In this cafe it will not be liable to fuch bad confequences, as fometimes happen with ftrong oil of vitriol, which, if fpilt, burns and deftroys almoft every thing it meets with. But when weakened by the mixture of about fourteen or fixteen times as much water, as its own bulk (or twenty times its bulk, if the oil of vitriol is well concentrated) hardly will it then be able to do any mifchief, no more than the juice of lemons, or any other fuch acid, as vinegar, &c It is true that its bulk becomes greatly increafed but its carriage will be

:

fafer, and its value very confiderably cheaper to the purchafer.

After the acid is poured into the vefel A, let the glafs funnel ? (fig. 4.) be put into the fame veffel and filling the trough R (fig. 6.) with the pounded chalk or marble, let it be thrown into it. Take off the funnel q, which is ufed only to prevent the chalk from touching the infide of the mouth of this veffel; fince otherwife it will stick fo ftrongly to the neck of the veffel B, as not to allow the taking it off again without breaking. Then immediately place the two veffels B and C, as they are, over the mouth of the veffel A; and all the fixed air which is difengaged from the chalk or marble, by the force of the di luted acid, will pass up, through the valve V, into the veffel B. When this fixed air comes to the top of the veffel B, it will diflodge from thence as much water as its bulk: and this water, fo diflodged, will go up, by the crooked tube 2, 1, into the vessel C.

Care must be taken not to fhake the veffel A, when the powdered chalk is poured in; for otherwife a great and fudden effervefcerce will enfue, which will, perhaps, expel part of the contents. fuch a cafe, it will be neceffary to open the ftopple m, in order to give vent to the effervefcence for a moment; otherwife the veffel A

In

may,