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

Though fome of thefe Cuftom-house examinations are finguJar 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 immenfe diftance from Nagafacci;' we learn little more than that he went, and that he returned fetting 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 defcribe one of them; contenting himfelf with giving a fhort account of the drefs of the Japanese (the fashion of which, it seems, has remained unchanged from the highest antiquity), and of the general structure of their houfes; adding a few oblervations 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. William 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 Houfe of the Royal Society (for the Year 1779).

From a series 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 obfervations on the dipping needle, made at the fame time, was 72° 21′.

An Account of the Mathematical and Airenomical Atticles, contained in this and the following Part of this volume, fhall be given in a subsequent Number,

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

MEDICINE.

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

TH

Article 33. Continuation of the Cafe of James Jones: By the fame. HESE two Articles contain an account of the fingular cafe of a young man who died in the Gloucefter Infirmary ; and in whose body, on diffection, were discovered several remarkable appearances of offification; particularly in the thoracic duct, and the os innominatum. These appearances are well reprefented 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 Physicians 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 inftance, we believe, of its having been detected in vegetable fubftances that have undergone the procefs of putrefac tion. Nay M. Macquer, as the worthy and ingenious Author of this Paper obferves, has even afferted, that the very vegetables which, in their natural state, furnish ashes replete with fixed alcali, fcarce 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 difcovery to the ingenuity, and to the communicative fpirit of Jofiah Birch, Efq; a gentleman who carries on an extenfive manufactory, 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 anfwered his expectations, that he has ever fince continued to prepare these afhes, and to employ them in the operations of bucking.

To give fome idea of the produce, and of the expence attending the process (which laft 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. 135. The expences of

the

the operation amounted to 4. 9 s.; and the clear profit confequently to 157. 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 ashes are faid 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 moift air; though it acquires a powdery furface in a dry warm room. emits no fmell 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 same spirit 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 phlogifton. On folution in water, a purple coloured fediment fubfided, which amounted to about two thirds of the weight of the afhes used. ELECTRICITY.

Article 20. An Account of the Effect of Electricity in shortening 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 produced.

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 first discharge, it was feen to shorten, 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 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 fame proportion; and at the end of the fifteenth, was found to be shortened full one inch and one tenth; fo as to be reduced from 10 inches to barely 8 inches 9-10ths. It had lost no weight, but feemed to be rather thicker. A fixteenth discharge melted it.

This experiment has been repeated, in the presence of several 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 discharge. A more fingular difference between the two wires was obferved 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 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.'

ARTICLES.

MISCELLANEOUS 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 dephlogisticated 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 elfewhere. The purification of phlogifticated 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 glafs tube one measure of air, the fpace 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; instead 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 feems 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 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 sea 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 meafures 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 fea 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 teft 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 test 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 sea, 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 Hoar Froft 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 paft five it had funk to o.