(bought at an apothecary's of the town) was placed in a small Hefhan crucible, brought by Mr. Ruffell, on a flux compofed of borax (also brought by him) a small piece of charcoal taken out of å feuttle (fortuitoudy) by Mr. D. Grofe, and examined by the rest of the company; and a fmall piece of nitre, alfo taken out without felection, by the Rev. Mr. Anderfon, from a quantity in common ufe, in the laboratory: these being pounded together in a mortar, which all the company had previously infpected, were pressed down into the crucible with a fmall peftle: on this flux the mercury was poured by Mr Anderson, and upon it half a grain, carefully weighed out by Mr. Ruffell, of a certain powder of a deep red colour, furnifhed by Dr. P. was put on it by Mr. Anderson. and food. The bulk of its fore-part is almost double that of the hind part; the back of its neck raifed high, and its legs fhort and thick. It lives in bare fields, where the lands are fallow, but not very hard; and, from its antipathy to damp and fade, chooses for its refidence the rifing part of the ground facing the east. Its dwelling is about four inches deep, and half an inch wide; at the bottom, it is curved, and there the infect fits in wet weather, and cuts its way out, if water gains upon it. It weaves a net at the mouth of the hole. Thefe fpiders do not live quite a year. In July they fhed their fkin, and proceed to propagation, which, from a mutual distrust, as they frequently devour one another, is a work undertaken with great circumfpection. They lay about feven hundred and thirty eggs, which are hatched in the The crucible was then placed in fpring; but the parent does not a fire of a moderate red heat, by live to fee her progeny, having Dr. P. who from his greater faci expired early in the winter. The lity in managing the fire from Ichneumon fly is their most formi- long habit, was thought most dable enemy. eligible to conduct the experiment. He repeatedly called the attention of the company to ob ferve the ftages of the procefs, and to remark in every part of it that any voluntary deception on his part was impoffible. An Account of fome Experiments on Experiment I. HAL ALF an ounce of mercury, In about a quarter of an hour from the projection of the powder the fire, he obferved to the com and the placing of the crucible in pany, who on infpection found his obfervation true, that the mer cury, though in a red hot crucible, thewed no figns of evaporation, or even of boiling: the fire was then gradually raifed, with attention on the part of the company, and repeated calls for that attention from Dr. P. that no un due due addition might be made to the matter in the crucible; in a strong glowing red, or rather whitered, a fmall dip was taken on the point of a clean iron rod, and when cold, the fcoria fo taken being knocked off, were fhewn to the company, and found replete with fmall globules of a whitifh coloured metal, which Dr. P. ob ferved to them could not be mercury, as being evidently fixed in that strong heat, but, as he reprefented to them, might be an inter. mediate fubftance between mercury and a more perfect metal. A fmall quantity of borax (brought by Mr. R.) was then injected by him, and the fire railed, but with the fame precautions on the part of Dr. P. to fubject every thing to the minute infpection of the perions prefent; and after continuing the crucibles in a ftrong red-white heat for about a quarter of an hour, it was carefully taken out, and gradually cooled, On breaking it, a globule of yellow metal was found at bottom, and in the fcoriæ fmaller ones, which, collected and placed in an accurate balance by Mr. Ruffel, were found to weigh fully ten grains. This metal was in the prefence of the above-mentioned gentlemen fealed up in a phial, impreffed with the feal of Mr. Anderfon, to be fubmitted to future examination, though every one prefent was perfuaded that the metal was gold. The feal being broke the next morning, in the prefence of the former company, and of Captain Auften, and the metal hydroftatically examined, the weight of the larger globule (the others being too minute for this mode of examination) was found to be in air 9 grains and a quarter, and ia diftilled water of temp. Fahren. 50 plus, it loft fomething more than (but not quite an half) of a grain: the difference was not appreciable, as no imaller weight than the eighth of a grain was at hand, but was judged by all the company to be nearly internediate; i. e. feven-tenths: - at half a grain the fp. gr. would be rather more than 18::; if only were loft in water, the fp. gr. would exceed 24: 1; the intermediate would be 21 and 1-7th nearly; but as the lofs feemed rather more than the intermediate, though apparently and decidedly lets than half a grain, the fpecific gravity must have been nearly as 20:1: and in this estimate all prefent acquiefced. After this hydroflatical examination, the globule was flattened by percuflion into a thin plate and examined by Mr. Ruf fell, in the manner of artifts for commercial purpofes. On finihing his fcrutiny, he declared it to be as good gold as the grain gold of the rafiners, and that he would readily purchafe fuch gold as that which he had just examined at the highest price demanded for the pure ft gold. The plate being then divided, one half was before the company fealed up by Mr. A. to be fubmitted to a trial of its purity, which Dr. P. propofed, requefting his friend Dr. Higgins, of Greek-ftreet, to make; the remainder being put into aq. regia of nit. acid and tal. ammon, atforded a folution fufficiently rich, before the company feparated, to yield with fol. of tin. a richly coloured crimfor precipitate. Capt. Capt. G. was accidentally abfent when the precipitate was made, but faw it next day. In about four hours the portion of metal employed was completely difiolved; and the next morning, before Capt. and Mr. D. Grote, and Mr. Ruffell (Mr. A. being prevented from coming) the folution being divided into three portions, the following experiments were made *. To the first portion, diluted with water, was added a quantity of cauftic vol. alk. and the precipitate, which was copious, being duly feparated and dried, about a grain of it, placed on a tin plate, was heated and found to explode fmartly. This experiment was repeated three times. To the fecond portion, diluted, was added a portion of fol. of tin, in aq. reg. A beautiful crimsoncoloured precipitate was immediately formed in confiderable quantity; which, when dried, was mixed with a fufible frit, compofed of flint-powder, and the Auxes proper for the ruby glass of cffus, in the proportion of 5 grains of the precipitate to 2 oz. of the frit, and in a vitrifying heat afforded in about three hours a tranfparent glafs, which, by heating again, affumed an elegant crimion colour; and the remain. der which continued in the fire alfo acquired a bright red colour. The third portion being mixed with vitriolic ether, imparted to it the yellow colour given to this fluid by folutions of gold and the ether being evaporated in a fhallow vefiel, a thin purplish pellicle adhered to the fide, fpotted in feveral places with yellow. Dr. Higgins foon after receiv ing the piece of metal, favoured the author with an antwer; in which he notified that the packet came to him under the proper feal: That he was well fatisfied of the purity of the gold he received; and that he confidered the author's experiments as exclufively fufficient to have afcertained the nature and purity of the metal. Experiment II. Made at Dr. Price's, May 8th, 1782, before Sir Philip Clarke, Dr. Spence, the Rev. Mr. Anderfon, Capt. Grofe, Mr. Ruffell, and Mr. D. Grofe. HALF an ounce of mercury, procured from one Mr Cunningham, an apothecary of the town, was placed on a flux compofed of an ounce of powdered charcoal, two drachms of horax, and one fcruple of nitre; and on it when a little warmed projected one grain of a white powder, furnished by Dr. Price. After the crucible had acquired a red heat, the company all faw the mercury lying quiet at the bot The fmall plate falling by accident on a globule of mercury on the table, readily amalgamated with it. This is mentioned in confequence of an obferv arion in the Critical Review. The Smiris Iifpanica is not in the least employed in the preparation injected on the mercy j The proce's is more analogous to tha of Dr. Brandt, referred to by the ingenious reviewer of this article, nj his very candid and fatisfactory critique. tom tom, without boiling or fmoking in the leaft, and it continued in this tranquil ftate after it had gained a full red heat. It was continued in a fire gradually aug mented to a white heat, near three quarters of an hour, a smaller crucible previously inspected, being inverted on it, to prevent coals from falling in: and the crucible being then withdrawn and cooled, many globules of white metal were found diffufed through the whole mafs of fcorie: of thefe globules were collected to the weight of ten grains, before the company feparated, and configned to the care of Mr. Ruffell, who took them away with him. Part of the remaining globules being afterwards collected, by pounding the crucible and washing over the powder, the whole when melted together amounted to thirteen grains. Dr. Price remarked on this procefs, that having taken too great a quantity of charcoal, the globules were thereby difperfed over the whole mafs, and the powder having been fprinkled against the fides of the crucible, had not produced its greatest effect: and that fome of the mercury which had efcaped its action must have been volatilized by the heat; and this on infpection of the covering crucible was found to be true. The experiment was therefore the next morning repeated in prefence of Mr. Anderfon, Capt. and EnSign Grofs, and Mr. Ruffell, Experiment III. The remaing half ounce of mercury was employed; the charcoal and borax both taken without felection from large quantities in the laboratory, were powdered by Mr Grofe, and the mercury plac ed in the crucible as in the former experiment. Barely half a grain of the white powder, weighed out by Mr Ruffell, was projected on the mercury, which by fone accidental delay had begun to boil in the crucible; but on the application of the powder the ebullition ceafed, although the crucible and contained mercury were fubjected to a much greater heat; and it continued without boiling, even when of a red heat. The crucible was gradually heated to a white heat; and when cooled and broke, there was found in the bottom a well collected bead of fine white metal, weighing four grains. Experiment IV. On the fame day, and the fame perfons being prefent as at the preceding experiment, the fol lowing was made on filver : Mr. Ruffel! weighed out fixty grains (one drachm) of grain-filver, which he had purchased of Meirs Floyer and Co. refiners in Love-lone, Wood-ftreet, Cheapfide: this quantity was placed in a fmall crucible on fonie of the flux made as above, before the company; and on the filver, when in fufion, was projected a bare half grain of the red powder, ufed in Experiment I. The crucible was then replaced in the fire, and continued there for about a quarter of an hour; a piece of borax taken at a venture out of a jar containing a large quantity, was thrown on the metal by Mr. Grofe. Dr. Price foon after, from the appearance of the fux, imagining the the crucible to be cracked (by the cold and moisture of the borax) took it out of the fire, and finding that what he fulpected had happened, did not replace it; when cool it was broke, and the button of metal was found in the bottom, which, when weighed, appeared not to have loft any of its original weight, fo that fortunately only the flux had tranfuded. Experiment V. That no doubt might arife from the failure of the crucible in the laft experiment, a fimilar one was made in the prefence of the fame perfons, with the addition of J. D. Garthwaite, of, Efq. who was alfo prefent at the latter part of Experiment IV. Thirty grains of the above-mentioned grain-filver was by Mr. Ruffell weighed out, and put into a finall Heian crucible on a flux of charcoal and borax made before the company, with the fame precautions as in Experiment 1. On the filver when fufed, was projected by Mr Anderfon a bare half grain of the red powder, and about five minutes after, fome glafs of borax (to avoid the moifture contained in crude borax) was thrown in by one of the company. The crucible after being kept in a red white heat for about fifteen minutes, was taken out, and when cold broke: at the bottom of the fcoriæ or rather flux, which in this experiment was neatly fufed, lay the button of metal; which was found nearly, if not exactly, of its original weight. It was then tried by Mr. Ruffell, in the artifts manner; as was alfo the piece of metal obtained in Experiment IV. He found both of them to contain gold; the lat ter in larger quantity, as might be expected, from the relative pro portion of the powder and filver in the two experiments. Dr. Price alfo examined the metal on the touchstone (basaltes) and with nitrous acid; when all the company faw the mark of gold remaining, while a mark made by a piece of the very parcel of grain-filver from which the por tion used in these experiments had been taken, and placed by the fide of the mark from the enriched filver, totally vanifhed on wetting it with the aqua-fortis. The mark from the enriched filver remained (of a yellow colour) after repeated affufions of weak and ftrong aqua-fortis; fo that the company were entirely convinced that gold was now contained in the futed filver. The chemical reader will probably anticipate the author's obfervation; that of the known metallic fubftances of a gold colour, fulphurated tin could not, without decompofition, have fuftained the heat employed in these experiments; and that copper, or regulus of Nickel, would have been diffolved by the nitrous acid, equally with the filver. The remark is indeed scarce neceffary; for had it been poffible to have fecretly introduced into the crucible any of thefe metals (and none of the company would for a moment tolerate the idea of fuch an attempt having been made) the identity of weight obferved was fufficient to prove that nothing but the crimfon powder had been added. After the pieces of metal had been thus feparately examined, they |