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

Though fome of thefe Cuftom-house examinations are fingular enough; the Author himself accounts for what may appear extravagant in them. He allows, that formerly the Japanese were lefs exact in this vifitation; and exempted the chief of the factory and the captain of the veffel from it. This privilege they used in its utmost extent: each dreffed himself in a great coat, in which were two large pockets, or rather facks, for the reception of contraband goods; and they generally paffed backwards and forwards three times a day.'

Though the Author had the advantage of attending the Ambaffador of the Dutch Company, on his journey to Jeddo, the capital of this vaft empire, fituated at an immense distance from Nagafacci;' 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 abfence of 118 days. He faw temples, theatres, and many curious buildings;' but does not describe one of them; contenting himself with giving a short account of the drefs of the Japanese (the fashion of which, it feems, has remained unchanged from the highest antiquity), and of the general structure of their houses; adding a few obfervations relative to customs and manners, and precife dates of the times when the Ambaffador 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 Coaft of Coromandel: By Mr. Wil-
liam Roxburgh, Affiftant Surgeon to the Hofpital, &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 feries of obfervations made during the first fortnight in July, it appears that the variation of the needle was 22° 4; and that the mean of the observations on the dipping needle, made at the fame time, was 72° 21′.

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

ART.

ART. VI. PHILOSOPHICAL TRANSACTIONS of the Royal Society of London. Vol. LXX. For the Year 1780. Part II. Davis, &c. 1781.

MEDIC IN E.

Article 19. Account of an Offification of the Thoracic Duct: By Richard Browne Chefton, Surgeon to the Infirmary at Gloucefter, &c.

Article 33. Continuation of the Cafe of James Jones: By the fame. HESE two Articles contain an account of the fingular cafe

and in whose body, on diffection, were difcovered several remarkable appearances of offification; particularly in the thoracic duct, and the os innominatum. Thefe appearances are well represented in four plates.

CHEMISTRY.

Article 22. An Account of a new and cheap Method of preparing Pot-afh, with Obfervations: By Thomas Percival, M. D. F. R. and A. S. Member of the Royal Society of Phyficians at Paris, &c.

Though modern obfervations have fhewn that the vegetable fixed alcali is not, as had long and univerfally been supposed, a mere creature of the fire; but that it exifts ready formed in the fubftances from which it is procured by incineration: yet this is the first instance, we believe, of its having been detected in vegetable fubftances that have undergone the procefs of putrefaction. Nay M. Macquer, as the worthy and ingenious Author of this Paper obferves, has even afferted, that the very vegetables. which, in their natural ftate, furnish ashes replete with fixed alcali, fcarce exhibit an atom of that falt in their afhes, 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 difcovery to the ingenuity, and to the communicative spirit of Jofiah Birch, Efq; a gentleman who carries on an extensive manufac tory, and bleaches his own yarn. He evaporated a large quantity of dung-hill water, and burning the refiduum in an oven, the alcaline falt, thus procured, fo perfectly answered his expectations, that he has ever fince continued to prepare these ashes, and to employ them in the operations of bucking.

To give fome idea of the produce, and of the expence attending the process (which last however may be diminished), we fhall add, that from 24 wine pipes full of muck water he procured, by evaporation, in which no advantage was taken of the fun's heat, 9 C. 1 Q. 12 pounds of afhes; worth, at the prefent price of two guineas per C. 194. 13s. The expences of

the

the operation amounted to 47. 9 s.; and the clear profit conse quently to 15. 45.

Dr. Percival, from his chemical examination of these afhes, eftimates that they probably contain one third of their weight of pure alcali: whereas the white Mufcovy afhes are faid by Dr. Home to yield only one eighth part. This new pot-afh is of at greyish white appearance, and deliquefces a little in a moist air; though it acquires a powdery furface in a dry warm room. It 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-afh were neutralized by eleven drops of a weak fpirit of vitriol: twentyfour drops of the fame fpirit were found requifite to neutralize the like quantity of falt of tartar. Its tafte is acrid and fulphureous; and it exhibits marks of its containing much phlogiston. On folution in water, a purple coloured fediment fubfided, 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 obfervation a new and fingular effect produced by the electric fluid, in fhortening wires through which it paffes. From analogy it might rather have been expected, a priori, that a contrary effect would have been pro

duced.

A piece of hard-drawn iron wire, ten inches long, and onehundredth of an inch in diameter, was fo placed, in a flack ftate, as to tranfmit a charge from a battery containing 26 feet of coated furface. On the firft'difcharge, it was feen to fhorten, by becoming fenfibly tighter. Another wire from the fame piece having been measured, at two different intervals, after the fixth and ninth discharge, having been flackened before each difcharge, was found to have become fhorter 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 fame 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 10 inches to barely 8 inches 9-10ths. It had loft no weight, but feemed to be rather thicker. A fixteenth discharge melted it.

This experiment has been repeated, in the prefence of feveral gentlemen, with the fame precife event. Dr. Priestley, probably fufpecting that the effect might be produced by heat, heated a piece of wire, exactly fimilar, 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.

T

A fimi

A fimilar piece of copper wire was fhortened only 1-20th of an inch by a fimilar difcharge. A more fingular difference between the two wires was observed by the Author. The fame charge which caufed the iron wire to appear red hot, in a bright day, did not affect a fimilar piece of copper wire, fo 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 fuch effect was produced on the copper wire.

This feems to point out,' fays Mr. Nairne, that iron wire refifts the paffage of the electric fluid much more than copper; and alfo, that the culinary fire and electrical fire have different effects on iron and copper: for malleable iron, I am informed, is one of the moft 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 lefs charge of electric fire.'

MISCELLANEOUS ARTICLE S. Article 23. On the Degree of Salubrity of the common Air at Sea, compared with that of the Sea Shore, &c. By John Ingen Houfz, M. D. F. R. S. &c.

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

The Author's method of putting air to the teft 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 refidence, ten miles from London, while he was making the experiments here alluded to, the two measures above mentioned occupied between 103 and 109 divifions in the glass tube; inftead of 200, which would have been the space occupied by the mixture of a measure of nitrous air, and another of perfectly phlogifticated or noxious air.

The pureft fea 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 furprised to find the common air purer in general, in October, than he ufed to find it in the middle of fummer, in the country for one measure of common air, and one of nitrous

air, occupied only 100 divifions of the tube, or exactly one measure. But at the mouth of the Thames he found the fea air of a fuperior purity to any common air he had ever met with fince the month of June preceding, either in his country retirement, or in London. In fix different trials,' fays 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 fhort time at fea, 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 fomewhat worse, though ftill of a very good quality; the ufual measures occupying 100, or exactly one measure.

The worst air that the Author examined was, at the Hague, on December ift and 2d; where the air, on November 30, had been found to be at 104: but on December 1, the air undergoing a fudden and remarkable change, becoming warm, and the wind being foutherly and ftormy; the measures of the teft were 116, and 117. The father of the landlord of the house, labouring under a fevere afthma, accidentally attracting the Author's attention, on his vifiting him while he was employed in these experiments, told him, that he had paffed these two days very uncomfortably, finding the air fo uncommonly heavy, that he could fcarce 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 fea, and clofe to it, is in general purer and fitter for animal life than the air on the land; though it feems to be fubject to the fame inconftancy in its degree of purity with that of the land: fo that we may now with more confidence fend our patients, labouring under confumptive diforders, to the fea, or at least to places fituated close to the fea, which have no marfhes in their neighbourhood.'

Article 26. An Account of a most extraordinary Degree of Cold at Glasgow in January last; together with fome new Experiments and Obfervations on the comparative Temperature of HoarFroft and the Air near to it, &c. By Patrick Wilfon, M. A. &c.

The degrees of cold related in this Article, as well as fome circumftances obferved during the courfe of the obfervations, are very remarkable. On January 13, 1780, at one o'clock in the morning, the thermometer ftood at 6 degrees, and continued falling gradually; till at half an hour past five it had funk to o.