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ter is confined merely by the surrounding sheath. It can scarcely have escaped the notice of an observer, that when a new feather firft makes its appearance on the body of a bird, a tender filmy substance environs and defends it, during its infant Itate. But no sooner does the web increase to any strength, than the film gives way, and the feather continues to gro" to its perfect maturity.

* That this disease did not occasion the bird's death, I am certain; as it appeared healthy and well during the time it lived.'

Almost every article in this volume is illustrated with a plate, and sometimes with two or three, always very clearly and correctly engraved; in one or two instances beautifully and highly finished. On the whole, this first volume appears a very interesting and useful one. The great object of the Society to establish and correct the immense system of the Swedish naturalift, which, vast in its extent, and numerous in its subjects, cannot be accurately finished in every part, deserves our commendation. It is with pleasure we see that their attention is directed also to the natural history of this country. For each design, their knowledge, their abilities, and their opportunities, are well adapted. The botanical riches of this country, either in well-furnished conservatories, in vast collections of botanical authors, and particularly of Herbaria, unrivalled by any nation, perhaps by all the nations of Europe, may thus be drawn out for the public use, and contribute to extend the knowledge of nature in the most pleasing of her productions, In the other kingdoms, our opportunities are not defective; and we have every reason to believe, from this specimen, that the attention of the Society will be equally exerted.

The Tranfaétions of the Royal Irish Academy, MDCCLXXXIX.

410. 11. 55. Boards. Bonham, Dublin. 1790. TH

HIS volume is, like the former, divided into three parts;

comprehending articles which may be styled by the ge-neral term of scientific; those of polite literature, and of ante quities. We shall, as usual, follow them in their order.

Art. I. Experiments on the Alkaline Substances used in Bleaching, and on the Colouring Matter of Linen-Yarn. By Richard Kirwan, Esq. F. R. S. and M. R. I. A. It is to be regretted that chemistry, in this kingdom, has not been more carefully studied, or applied to the different arts. It is within our own memory that the mineral acids were first employed as fourings instead of milk, in its acetous state; and we only learnt the use of the oxygenated muriatic acid from our neighbours. The alkaline substances, which are more particularly the object of our present author, we are generally supplied with from

Ainerica

America or Spain. In the late war, our manufacturers were alarmed left these sources being stopped, bleaching, as well as the glass-houses and soap-furnaces, could be no longer supplied, except at a great and disproportioned expence. The decomposition of falt was then thought of; and application was made to parliament to take off the duties of that falt employed in the manufacture of mineral alkali. The peace quieted the fears of the manufacturers, and no farther attempt was made. We think, however, that it ought to be resunned, and we shall select our author's method.

. I have also contrived another process for decompofing common sale. The particulars of my experiment were as follows:

rift, I rendered the common salt pure by adding to its solarion a solution of mineral alkali until all the earthy matter was deposited.

• zdly, To a solution of three ounces of this purified salt in nine ounces of water, I gradually added a saturate solution of 4,75 ounces of sugar of lead, both hot, until the solution of lead fcarce excited any whiteness in that of the common sale. After one night's reft, part of the sugar of lead cryftallized in the bot. tom of the vessel, by which it is plain that too much of it had been used. These crydals weighed 240 grains; the fupernatent liquor I again evaporated to nearly two-thirds, and after two days obtained large pellicles of acetous foda, which I separated; they weighed 325 grains; to the refiduum, which still had a sweetilh 111e, I added a solution of mineral alkali, until no farther precipitation appeared; a very small quantity of the alkali was fuficient for this purpose. I then evaporated the remainder nearly to drynefs; and afterwards heated it in a crucible to redness: in this heat it in flamed, and when calcined nearly to whiteness, I took it out and dissolved it in twelve ounces of water, filtered it, and on adding a hot solution of allum, obtained a precipitate, which when dried, weighed 169 grains, and indicated the quantity of pure alkali to be 112 grains nearly. In this process nothing is Jott, for the lead may be either sevived or turned into a pigment:

Lastly, Glauber's sale may afford the mineral alkali, but most easily in the form of liver of sulphur: I endeavoured to decompose it by the above process, but the quantity of alkali obtained from a large quantity of it was very inconsiderable.'

We have reason to think that common falt, suffered to deliquesce on an iron plate in a damp cellar, will have the affinity of its ingredients at leaft weakened, if the acid does not entirely unite with the jron, and leave the alkali in the form of efflorela cence on the plate. Mr. Kirwan analyses the different afhes, &c. and finds the following results:

• Table 20 lbs.

1,666

Table of the quantity of mere alkali in one hundred avoirdupois

pounds of the following substances by the aluminous telt: • One hundred pounds,

Minerai alkali Crystallized foda Sweet barilha Mealy's Cunnamara kelp

3 437 Ditio defulphurated by fixed air

4,457 Strangford kelp

1,25 One hundred pounds,

Vegetable all oli. Dantzic pearl afh

63,33 lbs. Clarke's refined afh

26,875 Cashup

19 376 Common raw Trish weed ash Ditto fightly calcined

4,666 He next describes the method of preparing the ashes, and afterwards examines the nature of the colouring matter feparated from yarn. It seems to be an oily, or rather a resinous substance, though insoluble in effential oils. In his experiments on this subject, he found 4.2 grains of the saline substance of kelp performed as much as 75 of that of Dantzic; 38 of barilla; 15 of that of Calhup; 21 of that of Clarke; and 213 of foap. The following conclusions deserve transcribing :

• ist, Liver of fulphur is of all alkaline compounds the ftrongest solvent of the colouring matter; next to this the caustic vegeiable, and after this the caustic mineral alkali; the mild vegetable and the mild mineral alkali occupy the last place. Sulphur, it is faid, leaves a stain in linen; but if liver of sulphur be used in the beginning, that is to say, in bleaching the yarn, the fain will probably be removed by the purer alkalies afterwards used. Hence the solutions of kelp, calhup, and markoft are advantageously used in the first processes of bleaching, for which Dantzic and sweet barilha are less fit; but fix tun of kelp will be necessary to produce the same effect as one tun of calhup; yet as the former is manufactured at home it deserves the preference.

• zdly, As the alkali manufactured from inland weeds is more powerful than the mineral, Mr. Clarke's is more powerful, or may be rendered so, than any imported. It is already sufficiently caustic, and may be converted into liver of fulphur only by add. ing one-twentieth of its weight of sulphur to it when boiling, and thus it is fitted for the first processes of bleaching. In its primitive state it is fit for the second process, and by rendering it milder, which may be effe&ted by burning half a busel of charcoal in a pan in the same room in which its solution stands, it will be adapto ed to the laft processes, in which a less active alkali is required.

« 3dly, Clarke's falt converted into liver of sulphur is preferable to kelp, because this latter, by the present manner of manu. facturing it, holds charcoal in solution; this coaly matter it deposits on the yarn, and thus leaves a black tinge ; whereas Mr. Clarke's is free from this contamination, to say nothing of the far greater quantity of alkali it contains, insomuch that one tun of Clarke's is nearly equal to eight ton of kelp. Hence it clearly follows that the linen manufacture stands in 'no sort of need of foreign salts or ashes for the processes of bleaching.'

Art. II. Letter from Richard Kirwan, Esq. F. R. S. and M. R. I. A. to the Right Honourable the Earl of Charlemont, P. R. I. A.-Mr. Kirwan said that, in Englandi beds of coal less than two fect and a half in thickness, are judged not worth working. Mr. Mills assures him that thinner seams are worked in Cheshire, and particularly describes the strata at Blakelow, about a mile S. E. of Macclesfield.

Art. III. The Origin and Theory of the Gothic Arch. By the Rev. M. Young, D. D. F. T. C. D. and M. R. I. A. In this very able and ingenious essay, Dr. Young examines the different explanations given of the origin of the Gothic arch. Each seems to our author untenable, but he chiefly leans towards Mr. Barry's opinion, of which we many years fince spoke with respect. Ms. Barry supposed the pointed archy to have arisen from an accidental corruption of the rounded arch, in consequence of the variable changes which fancy or fashion craves, joined with the different views and inclinations of the conquerors of the western world: it certainly seems to have originated in Italy about the downfal of the Roman empire. Dr. Young appears to coincide with this idea, though he adds to it the superior advantages of the pointed arch. The comparison of the Gothic and Grecian arches is just and correct, but we think the view might be fimplified in this way. The resistance of the round arch certainly depends on the action of two circular arcs, each refting at one extremity on the pier, and at the other on the key-Itone, the resistance of either fupporting the other. In the comparison, therefore, the question returns to the comparative strength of a circular and au cliptical arc. If this view be pursued geometrically, it will lead to the fame conclusions in a shorter way than in Dr. Young's investigation, and include his last theorem of the fuperiority of eliptical arches. The difficulty of raising considera able weights on pointed arches will be equally apparent, as it acts to fo great a disadvantage if the arch is pointed very much, and so partially, unless the refillance at the sides is very great.

Art. IV. An Account of a Discafe which, until lately, proved fatal to a great number of Infants in the Lying-in Hospital of

Dublin, Dublin, with Obfervations on its Causes and Prevention. By Jofeph Clarke, M. D. Master of the Hospital above-mentioned, and M. R. I. A.-The disease which has been so fatal to child dren ; and in the Dublin hospital for many years carried off nearly 16 or 17 in 100, is convulsive. The nurses call it the nine-day fits, from the period of attack; and divide it into difs ferent species according to the appearance. This mortality was so surprising and considerable, that it induced our author to compare the circumstances in other hofpitals with those of Dublin: the facts we shall transcribe:

• That in an old hospital, which preceded the present, but inftia tuted by, and under the care of, the same gentleman, and in a less airy part of Dublin, of three thousand feven hundred and forty-fix children therein born, only two hundred and forty-one died within the first month, which are in the proportion of one to fifteen and a half, or from fix to seven in the hundred.

• That during a period of five or fix years in the British Lying in Hospital, London, of three thousand fix hundred and eleven therein born, only one hundred and forty-fix died within the first three weeks or month, which are as one to twenty five, or four ia the hundred.

• That in the London Lying-in Hospital I was positively assured the death of an infant was a rare occurrence.

It is there computed with some confidence (for I was told that no written account is kept) chat the number of till-born infants far exceed: the number of those dying after birth. The proportion of still-born we know to be about a twentieth part, or five in the hundred.

• That near forty years ago, when the diseases of children were less understood, and more especially the falutary practice of inocu. lation, Dr. Short compated, from some very extensive registers, that London lost thirty-nine per cent, under the age of two years Edinburgh and Northampton thirty-four or thirty-five-Sheffield twenty-eight-country places from twenty to twenty-eight; whereas in the Dublin hospital tbere was loft a number equal to half of that loft in many of these places, and nearly equal to the whole of that in some of them, in two weeks, or in about the fiftieth part of the same space of time. From which, and some other confiderations of less weight, I thought the uncommon mortality of children in the Dublin Lying-in Hospital satisfactorily proved."

The cause seemed to be too great closeness of the wards, which brought on a disease that has appeared in the different forms of a convulsive or a spasmodic disorder, affecting the jaw more partially, or the whole system more generally, in many parts of the world, and been described by various practitioners. The mortality of the women is not greater in the Dublin Hole CRT. Rev. N. AR. (IV.) Jan. 1792.

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