៩

teals seem to be endowed with that admirable faculty of admitting such particles of pure chyle as they happen to be in contact with, and of accommodating their diameters to them, at the same time that by their natural irritability, and power of constriction, they obstinately exclude such as are astringent; which, were they to enter the lacteals, would either produce dangerous obstructions in these vessels, or if they got into the blood, would occasion polypous concretions in the larger vessels, or coagulations incapable of being transmitted through the minute vessels of the lungs; the effects of which would be either sudden death, or at least inflammations and suppurations from obstructions in the pulmonary vessels; inconveniences which nature, by precluding astringents from entering the lacteals, has carefully and wisely avoided.

Salt of steel, taken internally, must retain its astringency until it be precipitated which can scarcely ever fail to happen in the great guts, from the putrid fæces they contain, which are always observed to be tinged of a black colour from the metallic basis of the salt, part of which, as it has little or no astringency, may doubtless enter the blood, as Signor Menghini observed of the crocus, which is the same substance; and we know, from the experiments of Lister and Musgrave, that particles, much grosser than those of the white chyle, provided they be not astringent, or very acrid, are conveyed by the lacteals. But the metallic basis being separated from its acid, and thus reduced to a mere calx or earth, can scarcely be supposed to have any medicinal quality whatever, or at least to have any share in the virtues justly attributed to salt of steel.

As this salt is not only astringent, and consequently a strengthener, but at the same time acts with a gentle stimulus, all its virtues (which are known to be very great in diseases, where the fluids are either viscid, cold, and phlegmatic, or dissolved and watery, from a laxity of the solids) may be accounted for from its immediate effects on the stomach and primæ viæ, and on the system of the solids in general by consent; which it would be needless to illustrate by similar examples, because well known to every one the least versed in medical studies. Dr. W., from the obvious qualities of this medicine, and from what had been observed above, deduces the following corollaries: 1. That salt of steel has no deobstruent or aperient virtue by any immediate action that it can possibly have on the blood, or other animal fluids, as some have imagined; but that on the contrary it owes this quality to its not entering the blood, which it would other wise coagulate, and to its action on the solids alone. 2. That in diseases proceeding from a laxity of the solids, great care ought to be taken to restore and invigorate the primæ viæ; since a medicine (and this we may presume not the only one) whose immediate action is confined to those parts, is yet found by experience to produce so salutary effects in such diseases. 3. That as this salt does not enter the blood, and consequently cannot be in danger of too much

stimulating or constricting the vessels, on which it only acts by consent, it may, in small doses, be successfully used in many cases, where it has been imagined to be hurtful, particularly in consumptions of the lungs, so frequent and fatal in this island; which are commonly attended with too great a laxity of the prima viæ, and of the solids in general, though they seem more immediately to proceed from a laxity and weakness of the pulmonary vessels; in which circumstances it must be of the utmost consequence to restore the tone of those principal organs of chylification, the primæ viæ; as good chyle not only corrects the acrimony of the blood, which in the advanced stages of consumptions so much prevails, but likewise saves a great deal of labour, which the lungs (already too much oppressed) must otherwise undergo from a crude and ill-concocted chyle. Agreeably to this we find, in the Essays Physical and Literary of Edinburgh, two wellvouched histories of patients far gone in consumptions, with the usual symptoms of pain in the breast, cough, gross spitting of fetid matter, difficulty of breathing, hectic fits, and morning sweats, perfectly cured in a few weeks, by the use of the Hartfell-spa near Moffat; which, contrary to what is observed in most natural chalybeate waters, contains a fixed vitriol of iron.

LXXX. On the Antiquity of Glass in Windows. By the Rev. John Nixon, M.A., F. R. S. p. 601.

Mr. N. having formerly laid before the R.S. a few observations on some of the curiosities found at Herculaneum, among other articles he just mentioned a piece of a plate of white glass; and now he inquires into the uses to which such plates might be applied in the early age, to which this fragment undoubtedly belongs.

And first it is obvious to imagine that such plates might serve for specula, or looking-glasses. And indeed that specula were anciently made, not only of metals, and some stones, as the phengites, &c. but also of glass, may, he thinks, be collected from Pliny, who having mentioned the city of Sidon as formerly famous for glass-houses, adds immediately afterwards, siquidem etiam specula excogitaverat. But then it is to be observed, that before the application of quicksilver in the constructing of these glasses (which Mr. N. thinks is of no great antiquity), the reflection of images by such specula must have been effected by their being besmeared behind, or tinged through with some dark colour, especially black, which would obstruct the refraction of the rays of light. On these hypotheses (supposing the tincture to be given after fusion) the lamina before us may be allowed to be capable of answering the purpose here assigned.

It may further be suggested, that plates of this kind might be intended to be wrought into lenses, or convex glasses, either for burning or magnifying objects placed in their focus. But this designation cannot be supported by proper vouchers from antiquity. On the contrary, we are informed that the ancients

used either specula of inetal, or balls of glass for the former of these purposes; as it is well known, that glass was not applied to the latter in optical uses till the beginning of the 13th century. However, we may with greater probability propose another use for which the ancients might employ such plates of glass, as are now under consideration, viz. the adorning the walls of their apartments by way of wainscot. This he takes to be the meaning of the vitrea cameræ mentioned by Pliny, who intimates, that this fashion took its rise from glass being used by. M. Scaurus for embellishing the scene of that magnificent theatre, which he erected for exhibiting shows to the Roman people in his ædileship. And we may collect from the same author (what is further confirmed by his contemporary Seneca), that this kind of ornament had been admitted, in his name, into chambers in houses, baths, &c. Whether the plates used for this purpose were stained with various colours (as mentioned above), or had tints of divers kinds ap plied to the back part of them, he pretends not to determine: but in either way they would have a very agreeable effect.

The last destination, which the obvious congruity of the thing itself, countenanced by the practice of many ages past, as well as of the present time, would induce one to ascribe to such plates of glass, is that of windows for houses, baths, porticos, &c. But he was sensible that whoever should be hardy enough to advance such an hypothesis, would be censured as an innovator, in opposing the general opinion of the connoisseurs in antiquity. These gentlemen are al, most unanimous in asserting, that whenever we meet with mention made of specularia in ancient writers (especially those of, or near to, the age to which we must refer this fragment), we are to understand by that term nothing but fences made of laminæ, either of a certain stone called from its transparent quality, lapis specularis, brought first from Hispania Citerior, and afterwards found in Cyprus, Cappadocia, Sicily, and Africa; or of another stone of the same nature, viz. the phengites. These, though expressly distinguished from each other by Pliny, are yet reckoned by some moderns as one and the same thing; and thought to have been nothing but a kind of white transparent talc, of which according to Mons. Valois, there is found a great quantity in Moscovy at this day. Now that this lapis specularis, or phengites, was really used for windows by the ancient Romans in their houses, &c. cannot be denied: since, according to the opinion of the learned in antiquity, this usage is mentioned by Seneca, among other improvements in luxury introduced in his time. But whether it was so used exclusive of other materials (particularly glass), may he thinks admit a doubt. Salmasius is of opinion that nothing can be determined on this point from the word specular itself, which seems to be a generical term, equally applicable to windows of all kinds, whether consisting of the lapis specularis, or any other transparent substance. And as (according to this learned writer) there

is nothing in the term specular itself which hinders it from being extended to windows made of other materials besides those above mentioned; so others imagine, that there are some intimations in ancient authors which require that it should actually be so extended. Thus Mr. Castells, the ingenious illustrator of the villas of the ancients, thinks that if this had not been the case, Palladius would not have given directions to his husbandman to make specularia in the olcarium, or store-room, where the olives were preserved. For it appears, says this author, from Pliny's describing a temple built of the lapis specularis, or phengites, as the greatest rarity in his time, and the mention Plutarch makes of a room in Domitian's palace lined with it, that it was not common enough for husbandmen to purchase;' viz. in such quantities as were required for the purposes mentioned above.

Mr. N. does not pretend to decide on the weight of this argument of Mr. Castells; but only observes, that if any one should be induced by it to think, that the use of glass for windows may be of much greater antiquity than is commonly allowed, or even as old as the fragment which occasions these remarks, he may find other probable reasons to corroborate his opinion. As, first, that there seems to have been a natural and obvious transition from the practice of using glass plates for the ornamenting the walls of apartments to that of introducing light into those apartments, as we find the lapis specularis was in fact employed at the same time for both those purposes; and consequently it seems reasonable to suppose, that the latter of these applications could not be long in point of time after the former. But it appears from the authorities produced above, that the former of these usages did actually subsist in the age of Pliny; and therefore before the destruction of Herculaneum, where he lost his life. Whence we may draw no improbable conclusion, that the latter destination of plates of glass, viz.. for window-fences, did likewise precede the same event.

Mr. N. adds further, that this presumptive argument in favour of the antiquity of windows made of plates of glass, receives an additional force from the close relation which must be allowed to subsist between them, and those composed of the lapis specularis. The former must be considered as an improvement on the other, as they answered all the purposes of convenience, and at the same time were more beautiful; and being the manufacture of Italy, might probably be purchased at a less expence. On all which accounts it seems reasonable to conclude, that one of these inventions would naturally be introductory to the other: and consequently, that as window-lights of the lapis specularis began to be used within the memory of Seneca, who died under Nero, about Anno Christi 68, the original of those of glass may have fair pretensions to a place within the period assigned in the foregoing paragraph, viz. some years before the destruction of Herculaneum, in whose ruins the plate before us was buried.

Mr. N. concludes, that all the evidence here produced to prove the usage of glass windows to have been coeval with the fragment he is now considering, is the conjectural kind only: for he had not been able to trace it up by any positive. authority higher than about 200 years short of the epocha last mentioned, viz. to the latter end of the 3d century, when it is expressly mentioned by Lactantius in these words:-Manifestius est, mentem esse, quæ per oculos ea, quæ sunt opposita, transpiciat, quasi per fenestras lucente vitro aut speculari lapide obductas. De Opificio Dei, cap. 5.

LXXXI. Of an Extraordinary Case of the Ffficacy of the Bark in the Delirium of a Fever. By Nicholas Munckley, M. D., F. R. S. p. 609.

In this paper it is related that a patient who had been for several days ill of a fever (partaking of the nature of an irregular intermittent), and who from the reduced frequency of pulse and other circumstances appeared to be much better, was seized with a delirium, in which it was difficult for the attendants to keep him in bed. He laughed, played antic tricks, and used gestures the most opposite to his common demeanour when well; a state of mind having more the appearance of mania than of the delirium of a fever. Dr. M. prescribed the bark, which put a stop to the delirium, and effected a cure.

LXXXII. Of an Earthquake felt at Lingfield in Surrey, and Edenbridge in Kent, Jan. 24, 1758. By James Burrow, Esq. R. S. V.P. * p. 614.

This slight, and rather partial shock, happened between 1 and 2 o'clock in the morning of the day mentioned. It was felt in the parishes of Worthe, and East-Grinsted in Sussex; Lingfield in Surrey; and Edenbridge in Kent; and other adjacent places; which alarmed several of the inhabitants very much; but no damage ensued. The beds and windows, &c. were sensibly shaken, and at last it went off with a noise like a small gust of wind.

LXXXIII. On the Case of the first Joint of the Thumb torn off, with the Flexor Tendon in its whole Extent torn out. By Robert Home, Surgeon at Kingston on Hull. p. 617.

Jan. 2d, 1758, Win. Taylor, 17 years of age, an apprentice to a white-smith. * Sir James Burrow, an eminent lawyer, and master of the Crown-office, died in 1782, at a very advanced age, apparently upwards of 80. In 1773 acting as president of the R. S. till the time of the anniversary eiection that year, and the Society addressing the king at that time, he received the honour of knighthood on the occasion. Sir James published 4 vols. of Reports; and one of Deci. sions in the Courts of King's Bench. He wrote also an Essay on Punctuation, and some Anecdotes of Oliver Cromwell and family.

+ Mr. Home, in the prefatory observations to this communication states, that Marchetis has a case of the same kind, and that there are several others collected together by Mons. Morand in. the 2d vol. of the Memoirs of the Royal Academy of Surgery at Paris.