Faraday to John Gage   11 February 1832

<q>Royal Institution | Feb. 11, 1832

Dear Sir

I am anxious whilst I have time,¹ to give you an account of the antique matters committed to my charge for chemical examination. I shall make my letter as brief as possible, fearing that you will still find it too long[.]

The large glass vase or bottle, being cylindrical in the body, about 10 inches in diameter, and 8 inches high, would contain nearly 2 1/2 gallons. It was about two fifths full of liquor and burnt bones; the latter being well covered with the fluid. Some pieces of the bones had drops of fused light coloured glass adhering to them. The bones were burnt so much as to be most of them white on the exterior; but some were still black and carbonaceous on the outside and many were so within[.]

The pieces of glass adhering & fused to the bones, were light coloured & nearly white externally. They were not the consequence of fusion of the bones with the ashes of the wood, but were like the material of the bottles, and have resulted from glass, which either in the form of vessels or other‑wise, has been added, or rather subjected to the fire.

With respect to the cupreous coin found in the vase upon the top of the bones and adhering to one of the pieces, and also in reply to your ques‑tion whether I think it has the appearance of having been heated, I must state, though with great deference, that I do not think it has. All the carbonate & oxide of copper which encrusts it, may have been easily formed by the joint action of time, water, and air; and if it had been subjected to the same heat as that which the bones accompanying it have borne, I think it would have been melted, or at least oxydized so violently, and suddenly upon the surface, as to have taken away from the distinctness of the impression, more than it seems to have lost. From its position also, it seemed to have been the last thing put into the bottle, and its adhesion to the bone was just that which the gradual formation of oxide would occasion.

The liquor in this vessel was of a clear pale brown colour. It was a very weak aqueous solution, containing a little carbonated soda and traces of sulphate and muriate of soda; it contained no earthy salts. One fluid ounce left 4.2 grains of a pale brownish substance, which when heated, blackened and yielded a little ammonia, but did not flame or burn visibly.

I cannot tell when the water which has formed this weak solution entered the open vase; whether it was put in at the time of the interment, or whether it has gradually entered either by dropping in; or by differences of temperature, causing a species of distillation into the vessel, after it was inclosed in the vault & surrounded with earth. I can easily conceive that any of these cases may have happened[.]

The deposit upon the side of the large vase and also of its neighbour, was a dry flea brown powder, containing a few white specks. It was combustible with a very feeble flame, burning like ill made tinder or charred matter. It left a little pale light ash, containing carbonated alkali, carbo‑nate of lime & a little insoluble earth. This substance gave no trace of ammonia by heat. It is probably the result left upon the decay of organic matter but of what nature or in what situation that may have been I cannot say[.]

The liquor from the smallest vase did not amount to more than one sixth of an ounce, & was very dirty, i.e. it contained black insoluble matter, which when separated by a filter, was partly combustible & partly earthy, but I could make nothing of it. The filtered liquor was aqueous, clear, almost colourless, not alkaline; it contained in solution, sulphate of lime & sulphate & muriate of a fixed alkali.

Let me now proceed to the square narrow mouthed bottle. It had evidently been blown in a mould. It might hold about 1 1/2 pints. Its mouth was so narrow as but just to admit the little finger; and yet it was three fourths filled with a solid substance, which, though generally moulded to the form of the bottle, was not compact, but lying loosely in portions with intervening spaces or clefts. Some parts were light in colour, others discoloured, & others black.

Being removed from the bottle it weighed about 5 1/2 ounces. When a compact piece which had lain uppermost was broken, it presented a sharp fracture, yellowish & semi transparent in the middle, whiter and more opaque nearer to the external part, and dark brown or black at the exterior. It was of a fatty nature & could be cut with the nail.

Other portions towards the bottom of the bottle were soft, pale, yellow, and discoloured by brown matter; these also were fatty.

The darkest portions were in comparatively small quantity, but they also were fatty to the touch.

When the pale substance was heated, it fuzed at temperature lower than 212° F. and on cooling solidified becoming at the same time imper‑fectly crystallized. When heated with water it melted and floated on the water, but did not dissolve in it. It dissolved instantly upon the addition of a little alkali, forming a soap. It dissolved also freely in hot alcohol, a bulky crystalline mass being produced as the solution cooled. It dissolved less freely in cold alcohol. It burnt with a bright white smoky flame like fat, and had indeed all the characters of saponified fat or the margaric or stearic acid.

The brown parts also burnt with bright flame like fat, leaving a very little ash. When digested in alcohol, that fluid dissolved out a very great proportion of a nearly colourless fatty matter, like that described above, & left a few dark brown flocculi heavier than water. These being col‑lected, burnt on platina foil somewhat in the manner of tinder & not with flame. On examining a portion by heat in a tube upon the supposition of its being the residue of aluminous or gelatinous matter, no trace ammonia could be obtained from it.

Hence, the whole of the contents of this bottle may be resolved into nearly colourless fatty matter ie margaric or stearic acid and black films or flocculi. The substance cannot be the residue left by the decomposition of any ordinary fluid, such as blood, or milk, &c. &c. but has probably when introduced been fat poured in in the melted state. It may have been converted into fatty acid by heat before its introduction; or time may have ef‑fected that change in it since. From the form of the portions & their state in the bottle I think it not improbable, that there may have been a little aqueous fluid such as milk, blood, or some other decomposible substance in the bottle, before the fat was introduced & which by its intervention has caused the separation into portions, & by its decay has left the black patches of matter; or else that some decomposible substance has been introduced with the fat. Is it at all likely that any of the viscera or other parts of the body, have been introduced & the fat poured in with it, or upon it? The decay of such parts would account for the cavernous form of the fat & the black carbonaceous matter.

You gave me a piece of glass which was peculiar from its not having the greenish colour of the larger vases (which resemble in that respect some of our crown glass) but being rather pale yellow; & also earthy & white on the outside. The glass handle which you shewed me as accompanying the present specimen was coloured blue, & judging from appearance only, I think with cobalt. The piece of glass which I took (pale yellow) I found not to differ essentially from that of the large vases except in original purity of material. It was much freer from iron but it contained only alkali lime silica &c. &c. & no lead. The outside has been much altered by air & probably water & hence its white & earthy appearance[.]

The fragments of metal which I took from the handle of the tub, from the dish, and the vase, were all of them bronze, i.e. a combination of copper with tin.

Nothing now remains for me to refer to but the fragments of a neatly platted basket, or other such article. On the interior part of this fragment is an incrustation, about 1/12 of an inch thick, loose & crumbling, generally brown on the exterior, but white within when broken up. This substance is an odoriferous gum-resin. When heated, it evolves a fine aro‑ma, somewhat resembling that of myrrh or frankincense; and at a higher temperature it burns with a white smoky flame. Boiled in alcohol part dis‑solves and the solution is precipitated by water; or boiled in water part dissolves & the solution is precipitated by alcohol.

The incrustation appears, upon close examination, as if it consisted of numerous small white masses separated from each other by brownish matter. It may have been applied to the interior of the basket in the state of a paste, but there is little to indicate what has really been the process[.] The vegetable platted fibres of the basket, when separated from this incrustation, yield no aroma by heat; they burn with a pale flame & have the marks of old vegetable matter of ordinary character which has been well preserved².

I³ am | My dear Sir | Very Truly Yours | M. Faraday

John Gage Esq | &c &c &c