286 Experiments on fome peculiar Matters 
moft of which lies at the diftance of 3% miles from Cape 
Reikianés. Between thefe the water is deep; ‘hips which 
go to, or come from, the weft fide of Iceland, commonly 
pafs through them, when they firft get fight of the land 
and rocks. By the Danifh feamen they are called Fugle- 
Skisr, becaufe they are frequented by a great number of fea- 
fowl]; but by the inhabitants they are called Eld Eyarne, 
(fire iflands.) May not this afford reafon to conjeéture that 
in former times they had volcanic eruptions? and the vol- 
cano which appeared in the year 1783 may probably have 
exifted long before. 
2 ———— 
XIV. Experiments on some peculiar Matters drawn from 
Animal Subfiances treated with the Nitric Acid> By 
©, WELTER * 
Tue author having treated filk with the nitric acid, to 
obtain from it the oxalic acid, was furprifed to find that at 
the end of his procefs he obtained a filky-Jooking falt of a 
golden-yellow colour, and which, on the approach of a piece 
of red-hot coal, exhibited all the effects of gunpowder. . As 
he made the experiment only once, he thought it of import- 
ance to give a particular account of the procels, i in order that 
it might be repeated. 
On one part of filk he poured fix parts of nitric acid of the 
fhops, adding a little concentrated nitric acid. After it had 
refted two days, he diftilled this mixture. He then poured 
what had paffed into the receiver, on what remained in the 
retort, and filtered the whole. The oxalic acid cryftallifing 
on the filtre, he put the whole again into the retort; and 
added a pretty large quantity of water, which had ferved to, 
wath the filtre. He diftilled off a part of the water; but as 
the refiduum did not cryftallife, returned, by elevating the 
receiver, what had paffed over; and, after repeating this ope- 
ration feveral times, obtained for refiduum an acid liquor of 
the weight of the filk employed, and which contained fmal] 
granulated cryftals, 
This liquor fhewed no traces, of the oxalic acid. It'was 
yellowifh, aud communicated that colour ta:the fingers and 
* Bulletin des Sciences, Vol. II. No. x. 
tg 
