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them were broken, left they should conceal contraband goods within them.'.

Though some of these Custom-house examinations are fingular enough; the Author himself accounts for what may appear extravagant in them. He allows, that formerly the Japanese were less exact in this visitation; and exempted the chief of the factory and the captain of the vessel from it. This privilege they used in its utmost extent: each dressed himself in a great coat, in which were two large pockets, or rather sacks, for the reception of contraband goods ; and they generally passed back wards and forwards three times a day.'

Though the Author had the advantage of attending the Ambassador of the Dutch Company, on his journey to Jeddo, the capital of this vast empire, situated at an immense distance from Nagasacci ;' we learn little more than that he went, and that he returned : setting out on this expedition on the 4th of March 1776, and returning after an absence of 118 days. He'' saw temples, theatres, and many curious buildings ;' but does not describe one of them ; contenting bimfelf with giving a short account of the dress of the Japanese (the fashion of which, it seems, has remained unchanged from the highest antiquity), and of the general structure of their houses ; adding a few observations relative to customs and manners, and precise dates of the times when the Ambassador arrived at or left certain places, or had an audience of the Emperor, or his heir apparent. Article 10. Account of an extraordinary Appearance in a Mift:

By Mr. William Cockin, Article 14. A Continuation of a Meteorological Diary, kept at

Fort St. George, on the coast of Coromandel : By Mr, Wil

liam Roxburgh, Affiftant Surgeon to the Hospital, &c. Article 15. A Journal of the Weather at Montreal: By Mr.

Barr, &c. Article 16. Meteorological Journal kept at the House of the

Royal Society (for the Year 1779). From a series of observations made during the first sortnight in July, it appears that the variation of the needle was 22° 4'1; and that the mean of the observations on the dipping needle, made at the same time, was 72° 21'.

An Account of the Mathematical and Aironomical Ar. ticles, contained in this and the following Part of this volume, shall be given in a subsequent Number.

ART.

THA

ÅRT. VI. PHILOSOPHICAL TRANSACTIONS of the Royal Society of

London. Vol. LXX. For the Year 1780. Part II. Davis, &c. 1781.

M EDI.C IN E. Article 19. Account of an Olification of the Thoracic Duet : By

Richard Browne Cheston, Surgeon to the Infirmary at Glou

cester, &c. Article 33. Continuation of the Case of James Jones : By the same. "HESE two Articles contain an account of the fingular cafe

of a young man who died in the Gloucester Infirmary; and in whose body, on dissection, were discovered several remarkable appearances of oflification ; particularly in the thoracic duct, and the os innominatum. These appearances are well represented in four plates.

CHE MI S T R Y. Article 22. An Account of a new and cheap Method of preparing

Pot-ash, with Observations : By Thomas Percival, M. D. F. R. and A. S. Member of the Royal Society of Physicians at Paris, &c.

Though modern observations have shewn that the vegetable fixed alcali is not, as had long and universally been supposed, a mere creature of the fire ; but that it exists ready formed in the substances from which it is procured by incineration : yet this is the first instance, we believe, of its having been detected in ve. getable substances that have undergone the process of putrefaca tion. Nay M. Macquer, as the worthy and ingenious Author of this Paper observes, has even asserted, that the very vegetables which, in their natural state, furnish alhes replete with fixed alcali, scarce exhibit an atom of that falt in their ashes, if their acid has previously been altered by a complete putrefaction.

It appears, however, from this very curious Paper, that the water which drains from dunghills contains a very large quantity of genuine fixed alcaline falt. The Public owe this discovery to the ingenuity, and to the communicative spirit of Josiah Birch, Esq; a gentleman who carries on an extensive manufactory, and bleaches his own yarn. He evaporated a large quantity of dung-bill water, and burning the residuum in an oven, the alcaline salt, thus procured, so perfectly answered his expectations, that he has ever since continued to prepare these alhes, and to employ them in the operations of bucking.

To give some idea of the produce, and of the expence attending the process (which last however may be diminished), we shall add, that from 24 wine pipes full of muck water he procured, by evaporation, in which no advantage was taken of the sun's heat, 9 C. 1 Q. 12 pounds of alhes; worth, at the present price of two guineas per C. 191. 135. The expences of

the

It

the operation amounted to 4l. 95.; and the clear profit consequently to 151. 45

Dr. Percival, from his chemical examination of these ashes, estimates that they probably contain one third of their weight of pure alcali: whereas the white Muscovy ashes are said by Dr. Home to yield only one eighth part. This new pot-ash is of a greyish white appearance, and deliquefces a little in a moist air; though it acquires a powdery surface in a dry warm room. emits no smell of volatile alcali, even when added to lime water; the volatile alcali having probably been expelled by the fixed alcali, during the boiling. Ten grains of this pot-ath were neutralized by eleven drops of a weak spirit of vitriol : twentyfour drops of the same spirit were found requisite to neutralize the like quantity of salt of tartar. Its taste is acrid and sulphureous; and it exhibits marks of its containing much phlogiston. On folution in water, a purple coloured sediment sublided, which amounted to about two thirds of the weight of the ashes used.

ELECTRICITY. Article 20. An Account of the Effect of Electricity in fhortening

Wires: By Edward Nairne, F.R.S. This paper presents to our observation a new and singular effect produced by the electric fluid, in shortening wires through which it passes. From analogy it might rather have been expected, a priori, that a contrary effect would have been produced.

A piece of hard-drawn iron wire, ten inches long, and onehundredth of an inch in diameter, was so placed, in a ack state, as to transmit a charge from a battery containing 26 feet of coated surface. On the first discharge, it was seen to shorten, by becoming sensibly tighter. Another wire from the same piece having been measured, at two different intervals, after the fixth and ninth discharge, having been slackened before each discharge, was found to have become shorter in the proportion of 3 quarters of a tenth of an inch, each time. Six more difcharges having been fent through it, it was found to have continued contracting nearly in the same proportion ; and at the end of the fifteenth, was found to be shortened full one inch and one tenth; so as to be reduced from io inches to barely 8 inches 9-10ths. It had lost no weight, but seemed to be rather thicker. A fixteenth discharge melted it.

This experiment has been repeated, in the presence of several gentlemen, with the fame precise event. Dr. Priestley, probably suspecting that the effect might be produced by heat, heated a piece of wire, exactly similar, red hot in a common fire: but on measuring it when cool, it was found to retain its original length of ten inches. Rev. April 1781.

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A fimi

A similar piece of copper wire was shortened only 1-20th of an inch by a similar discharge. A more fingular difference between the two wires was observed by the Author. The fame charge which caused the iron wire to appear red hot, in a bright day, did not affect a similar piece of copper wire, so as to make it appear of a red heat, though the room was made dark. If the battery was but a little more charged, the iron wire would be melted; but no such effect was produced on the copper wire.

* This seems to point out,' says Mr. Nairne, that iron wire resists the passage of the electric fuid much more than copper ; and also, that the culinary fire and electrical fire have different effects on iron and copper: for malleable iron, I am informed, is one of the most difficult metals to melt by the culinary fire, and requires a much greater heat to melt than copper ; whereas, on the contrary, the iron is melted with a much less charge of electric fire.'

MISCELLANEOUS ARTICLES. Article 23. On the Degree of Salubrity of the common fir at Sea,

compared with that of the Sea Shore, &c. By John Ingen Housz, M. D. F. R.S. &c.

The Author of this Article, an account of whose curious experiments relative to the dephlogisticated air emitted by vegetables we not long ago communicated to the Public, here gives an account of some of the trials which he made on the air, in his paflage from hence to the continent, and elsewhere. The purification of phlogisticated air, by agitation in water, rendered it probable that the air at sea might be made purer, by its vicinity to a great body of water.

The Author's method of putting air to the test confifted in introducing into the inverted glass tube one measure of air, the space occupied by which was divided into 100 equal parts; and then adding to it an equal measure of nitrous air. At the Author's country residence, ten miles from London, while he was making the experiments here alluded to, the two measures above mentioned occupied between 103 and 109 divisions in the glass tube; instead of 200, which would have been the space occupied by the mixture of a measure of nitrous air, and another of perfectly phlogisticated or noxious air.

The purest sea air which the Author seems ever afterwards to have met with occurred in his very first trial, in the mouth of the Thames, between Sheerness and Margate, on the 3d of November.----Formerly, on his return to town, and to his former lodgings in Pall Mall Court, in the vicinity of trees, he had been surprised to find the common air purer in general, in October, than he used to find it in the middle of summer, in the country: for one measure of common air, and one of nitrous

air, occupied only 100 divisions of the tube, or exactly one measure. But at the mouth of the Thames he found the sea air of a superior purity to any common air he bad ever met with since the month of June preceding, either in his country retirement, or in London. In fix different trials,' says the Author, 'made one after another, I found that the two measures of air (one.of common and one of nitrous air) occupied from 0.91 to 0.94.' The Author was only a short time at sea, and had not an opportunity of examining the quality of three vials of air, filled at sea on November 4th, till he arrived at Oftend, the following day : but he found it of an inferior quality to the preceding; for one measure of it, with one of nitrous air, occupied, in three different trials, 0.97. The common air at Oftend that day was nearly as good; the measure of the test being 0.98 : though in the afternoon it became somewhat worse, though still of a very good quality; the usual measures occupying 100, or exactly one measure.

The worst air that the Author examined was, at the Hague, on December 1st and 2d; where the air, on November 30, had been found to be at 104: but on December 1, the air undergoing a sudden and remarkable change, becoming warm, and the wind being foutherly and stormy; the measures of the test were 116, and 117. The father of the landlord of the house, Jabouring under a severe afthma, accidentally attracting the Author's attention, on his visiting him while he was employed in these experiments, told him, that he had passed these two days very uncomfortably, finding the air so uncommonly heavy, that he could scarce draw his breath.'

For the Author's other trials, and his deductions from them, we must refer to the article itself; only adding his first observation that the air at sea, and close to it, is in general purer and fitter for animal life than the air on the land ; though it seems to be subject to the fame inconstancy in its degree of purity with that of the land : so that we may now with more confidence fend our patients, labouring under consumptive disorders, to the sea, or at least to places situated close to the fea, which have no marshes in their neighbourhood.' Article 26. An Account of a moft extraordinary Degree of Cold

at Glasgow in January last; together with some new Experi ments and Observations on the comparative Temperature of HoarFrost and the Air near to it, &c. By Patrick Wilson, M. A. &c.

The degrees of cold related in this Article, as well as some circumstances observed during the course of the observations, are very remarkable. On January 13, 1780, at one o'clock in the morning, the thermometer stood at 6 degrees, and continued falling gradually ; till at half an hour past five it had funk to o

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