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to drink tar-water which prevented the eryfipelas. 6. I never knew any thing fo good for the ftomach as tar-water: it cures indigeftion and gives a good appetite. It is an excellent medicine in an afthma. It imparts a kindly warmth and quick circulation to the juices without heating, and is therefore useful, not only as a pectoral and balfamic, but also as a powerful and fafe deobftruent in cachectic and hyfteric cafes. As it is both healing and diuretic, it is very good for the gravel. I believe it to be of great ufe in a dropfy, having known it cure a very bad anafarca in a perfon whofe thirst, though very extraordinary, was in a fhort time removed by the drinking of tar-water.

7. The usefulness of this medicine in inflammatory cafes is evident, from what has been already obferved (a). And yet fome perhaps may suspect that, as the tar itfelf is fulphureous, tar-water must be of a hot and inflaming nature. But it is to be noted, that all balfams contain an acid spirit, which is in truth a volatile falt. Water is a menftruum that diffolves all forts of falts, and draws them from their fubjects. Tar, therefore, being a balfam, it's falutary acid is extracted by water, which yet is incapable of diffolving it's gross refinous parts, whofe proper menftruum is fpirit of wine. Therefore tar-water, not being impregnated with refin, may be fafely used in inflammatory cafes and in fact it hath been found an admirable febrifuge, at once the fafeft cooler and cordial.

tues.

8. The volatile falts feparated by infufion from tar, may be fuppofed to contain it's fpecific virMr. Boyle and other later chemists are agreed, that fixed falts are much the fame in all bodies. But it is well known that volatile falts do greatly differ, and the easier they are separated

(a) Sect. 5.

from

1

from the fubject, the more do they poffefs of it's fpecific qualities. Now the most easy feparation is by infufion of tar in cold water, which to smell and talt fhewing it felf well impregnated, may be prefumed to extract and retain the moft pure volatile and active particles of that vegetable balfam.

9. Tar was by the ancients esteemed good against poisons, ulcers, the bites of venomous creatures, alfo for pthifical, scrophulous, paralytic and asthmatic perfons. But the method of rendering it an inoffenfive medicine and agreeable to the ftomach, by extracting it's virtues in cold water, was unknown to them. The leaves and tender tops of pine and fir are in our times used for diet-drinks, and allowed to be antifcorbutic and diuretic. But the most elaborate juice, falt, and fpirit of thofe evergreens are to be found in tar; whofe virtues extend not to animals alone, but also to vegetables. Mr. Evelyn in his treatise on Forest trees observes with wonder, that ftems of trees, fmeared over with tar, are preferved thereby from being hurt by the invenomed teeth of goats and other injuries, while every other thing of an unEtuous nature is highly prejudicial to them.

10. It seems that tar and turpentine may be had more or lefs, from all forts of pines and firs whatfoever; and that the native fpirits and effential falts of thofe vegetables are the fame in turpentine and common tar. In effect this vulgar tar, which cheapness and plenty may have rendered contemptible, appears to be an excellent balfam, containing the virtues of moft other balfams, which it eafily imparts to water, and by that means readily and inoffenfively infinuates them into the habit of the body.

11. The refinous exfudations of pines and firs are an important branch of the materia medica,

and

and not only useful in the prefcriptions of phyficians, but have been alfo thought otherwife conducive to health. Pliny tells us, that wines in the time of the old Romans were medicated with pitch and refin; and Jonftonus in his Dendrographia obferves, that it is wholefome to walk in groves of pine trees, which impregnate the air with balfamic particles. That all turpentines and refins are good for the lungs, against gravel alfo and obftructions, is no fecret. And that the medicinal properties of thofe drugs are found in tar-water, without heating the blood, or difordering the ftomach, is confirmed by experience: and particularly that pthifical and afthmatic perfons receive speedy and great relief from the use of it.

12. Balfams, as all unctuous and oily medicines, create a nauseating in the ftomach. They cannot therefore be taken in fubftance, fo much or fo long, as to produce all those falutary effects, which, if thoroughly mixed with the blood and juices, they would be capable of producing. It muft therefore be a thing of great benefit, to be able to introduce any requifite quantity of their volatile parts into the finest ducts and capillaries, fo as not to offend the ftomach, but, on the contrary, to comfort and strengthen it in a great degree.

13. According to Pliny, liquid pitch (as he calls it) or tar was obtained by fetting fire to billets of old fat pines or firs. The first running was tar, the latter or thicker running was pitch. Theophraftus is more particular: he tells us the Macedonians made huge heaps of the cloven trunks of those trees, wherein the billets were placed erect befide each other. That fuch heaps or piles of wood were fometimes a hundred and eighty cubits round, and fixty or even a hundred high and that having covered them with fods of earth to

prevent

prevent the flame from burfting forth (in which cafe the tar was loft) they set on fire thofe huge heaps of pine or fir, letting the tar and pitch run out in a channel.

14. Pliny faith, it was cuftomary for the ancients, to hold fleeces of wool over the steam of boiling tar, and squeeze the moisture from them, which watery fubftance was called piffinum. Ray will have this to be the fame with the piffelæum of the ancients; but Hardouin in his notes on Pliny, thinks the piffelæum to have been produced from the cones of cedars. What use they made of these liquors anciently I know not but it may be prefumed they were used in medicine, though at prefent, for ought I can find, they are not ufed at all.

15. From the manner of procuring tar (a) it plainly appears to be a natural production, lodged in the veffels of the tree, whence it is only freed and let loofe (not made) by burning. If we may believe Pliny, the first running or tar was called cedrium, and was of fuch efficacy to preserve from putrefaction, that in Egypt they embalmed dead. bodies with it. And to this he afcribes their mummies continuing uncorrupted for fo many ages.

16. Some modern writers inform us that tar flows from the trunks of pines and firs, when they are very old, through incifions made in the bark near the root; that pitch is tar infpiffated; and both are the oyl of the tree grown thick and ripened with age and fun. The trees, like old men, being unable to perfpire, and their fecretory ducts obftructed, they are, as one may fay, choaked and ftuffed with their own juice.

17. The method ufed by our colonies in America, for making tar and pitch, is in effect the fame with that of the ancient Macedonians; as

(a) Sect. 13.

B

appears

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appears from the account given in the Philofophical Tranfactions. And the relation of Leo Africanus, who defcribes, as an eye witnefs, the making of tar on mount Atlas, agrees in fubftance, with the methods used by the Macedonians of old, and the people of New England at this day.

18. Jonstonus in his Dendrographia, is of opinion, that pitch was anciently made of cedar, as well as of the pine and fir grown old and oily. It fhould feem indeed that one and the fame word was used by the ancients in a large fenfe, fo as to comprehend the juices iffuing from all those trees. Tar and all forts of exfudations from evergreens are, in a general acceptation, included under the name refin. Hard coarse refin or dry pitch is made from tar, by letting it blaze till the moisture is fpent. Liquid refin is properly an oily vifcid juice oozing from the bark of evergreen trees, either fpontaneously or by incifion. It is thought to be the oil of the bark infpiffated by the fun. As it iffues from the tree it is liquid, but becomes dry and hard being condensed by the fun or by fire.

19. According to Theophraftus, refin was obtained by stripping off the bark from pines, and by incifions made in the filver fir and the pitch pine. The inhabitants of mount Ida, he tells us, ftripped the trunk of the pine on the funny fide two or three cubits from the ground. He obferves that a good pine might be made to yield refin every year; and indifferent every other year; and the weaker trees once in three years; and that three runnings were as much as a tree could bear. It is remarked by the fame author, that a pine doth not at once produce fruit and refin, but the former only in its youth, the latter in its old age.

20. Turpentine is a fine refin. Four kinds of this are in ufe. The turpentine of Chios or Cy

prus

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