The works of the Honourable Robert Boyle, Esq., epitomiz'd by Richard Boulton ... ; illustrated with copper plates.

CHAP. XV. Additional Experiments about arresting and weighing of igneous Corpuscles.

EXPERIMENT I and II.

EIGHT ounces of Block-Tin being cut in pieces and put into a good round Vial, with a long neck, and being cautiously melted over Quick-Coals, the Glass being frequently shaken, to promote Calcination, near an hour, the neck of the Vial being most of the time preserved from the steams of the Coals with a cover of Paper; the Tin which was partly calcined, increased eighteen grains in weight. This being done we melted the remaining me∣tal into thin Plates, by which Operation, it lost three grains of the eighteen it had got; but being a second time exposed to Calcination in another Vial, it afforded a much greater Quantity of it than before, and increased in weight to eight ounces and twenty four grains. In which Tryals it is observable, that agitation much contributes to the Calcination of Metals.

EXPERIMENT III, IV, V.

Eight ounces of Tin being exposed to cal∣cine in a Bolt-head Hermetically sealed, the Glass flew in pieces, and a yellowish Liquor, which was of an odious taste and smell, was found in the neck. But the Experiment being a second time repeated, the Metal being suffe∣red to cool, before the Glass broke, the weight was twenty three grains more than before, tho' the whole Calx amounted to no more than four scruples and eight grains: The top of the Me∣tal was very asperous and of a dark colour, tho' the neighbouring Surface and some places near the dark colour'd Calx, which was between the bottom and lowest part of the lump, was of a Golden colour by candle-light. Two ounces of filings of Tin being exposed to Calcination two hours in a small Retort, at the first seve∣ral steams issued out at the small Apex of the Stem, but then the Apex being sealed up, a yellowish clammy substance thinly spread and which smelled like fetid Oyl of Tartar, was gathered in the neck; and the Glass being broke, the lump of Metal which was in some measure covered with a gray Calx, weigh∣ed twelve grains more than before.

EXPERIMENT VI and VII.

An ounce of filing of Zinke being kept in a Bolt-head four hours over live Coals; fumes copiously were emitted out of the unstoped A∣pex of the Stem; and the whole remaining

Zinke, and the flowers which had ascended be∣ing weighed, wanted five grains of an ounce. But four ounces of Lead being enclosed in a∣nother Retort, it was held over a fire two hours; and then the Apex which was small being sealed up, the Glass was exposed to the fire two hours longer; in which time the Sur∣face of the melted metal was dark and rugged, and Part of it was turned into a dark coloured Calx. The Lead being weighed had gained about thirteen grains in weight.

EXPERIMENT VIII and IX.

Pieces of red Coral being exposed to the fire, till of a dark colour, gained three grains and a half in weight. Fresh and strong Quick-lime being placed upon a Cupel two hours, and which before weighed two drams, encreased in weight twenty nine grains. From whence it appears, that tho' Lime hath been before ex∣posed to the fire, yet it is capable of having more igneous Corpuscles united with its substance; from whence we may infer, that tho' Lime-stone by calcination hath lost much of its weight, yet it may have recieved a consi∣derable addition from the fire, which may in Part make amends for those Corpuscles which have flown away; upon which account it may be uncertain in other Bodies, which we have made Tryals with, how much weight they have truly received from the fire, since it is uncer∣ain how much of their first weight might be lost in Exhalations.