Faci. 
Tedine. 
‘rom spent soapers’ leys. 
18 
the furnace is found to be nearly full of melted matter, 
Tron rakes are then drawn rapidly backward and for- 
ward through the mass in the furnace, in order to com- 
pact it, or bring it into an equal state of fusion. It is 
then allowed to cool, when it is broken in .pieces, and 
carried into a store-house, to remain till shipped. 
The making of kelp from sea-weed was practised in 
France and England for more than half a century be- 
fore the manufacture was introduced into Scotland. 
Mr James Fea of Whitehall in Stronsay was the first 
person jin Orkney who (about 1722) exported a cargo 
of kelp; he sailed with it himself to Newcastle ; and 
his success in the enterprize soon aroused the attention 
of the Orcadians. At present, in coasting these islands, 
as well as the Hebrides, in the summer months, great 
volumes of smoke are every where to be seen rolling 
from the kelp furnaces, and the peculiar odour, pro- 
bably arising chiefly from muriatic acid gas, .is felt to 
a. considerable distance. From £40,000 to £50,000 
sterling, are thus yearly brought into the country ; but 
it must not be concealed, that in most of the islands 
agriculture has suffered, from the attention of the small 
tenants having been diverted from the land, and, by 
the influence of the landholders, turned almost exclu- 
sively to the manufacture of kelp. 
The fuci which are chiefly cut on our shores for this 
manufacture, are Fucus vesiculosus, nodosus, and serra- 
tus. In some places, F, loreus and filum are employed, 
but not to agreatextent. By means of aboat and long 
sharp hooks or bills, F. digitatus is cut in some places ; 
and this species, together with F. saccharinus, bulbosus, 
and esculentus, form much of the drift-ware employed 
in making of kelp. Some of these are no doubt richer in 
the alkaline salt than others ; but of all of them it may 
be said, that when dry and fit for burning, they are ca- 
pable of yielding about one-fitth of their weight in kelp. 
Besides the alkali, kelp affords, as already hinted, a 
peculiar simple or hitherto undecomposed substance 
named iodine. It was discovered in the year 1812, by 
a manufacturer of saltpetre at Paris named Courtois, 
and has since been examined by the most eminent 
French and English chemists. It is readily procured 
by pouring concentrated sulphuric acid on the mother 
water of kelp from which soda. has been extracted, or 
Heat is speedily produced, 
and the new substance appears as a_violet-coloured 
gas, perfectly homogeneous and transparent. This, on 
being collected in the usual mode, soon condenses, 
and assumes the appearance of plumbago. It forms 
acids with hydrogen, chlorine and tin, called the hy- 
drionic, chlorionic, and stannionic acids; and it com- 
bines readily with metals. The late Mr Tennant could 
detect no iodine in sea-water; sa that it appears to 
be entirely a product of marine plants. French kelp, 
it is remarked by Sir Humphry Davy, yields more 
iodine than British ; but for this, no reason: is assigned. 
Iodine has a peculiar odour, and. is decidedly poisonous, 
The name is derived from sans, violaceus, in allusion to 
the very striking circumstance of the substance yield- 
ing a violet coloured gas on being exposed to an increase 
of temperature. The following is the mode of procu- 
ring iedine recommended by Dr Wollaston: “ Dissolve 
the soluble part of kelp in water; concentrate ‘the 
liquid by evaporation, and separate all the crystals that 
can be obtained ; pour the remaining liquid into a clean 
vessel, and mix with it an excess of sulphuric acid ; boil 
this liquid for some time ; sulphur is precipitated, and 
muriatic acid driven off; decant off the clear liquid, 
® Thomson's Annals of Philosophy for April 1814. 
FUCL 
and strain -it h wool ; put it into a small flask, 
and mix it with as much black oxide of m ese as ~ 
you used before of sulphuric acid ; apply to the top of 
the flask a glass tube shut at one end ; then upon heat- 
ing the mixture in the flask, the iodine will sublime 
into the glass tube.” * | 
The species reckoned kelp fuci shall now be more Kelp fuct 
particularly described ; and as most of them, besides 
yielding kelp, serve other useful purposes, these shall 
at the same time be noticed. ' ff 
Fucus vesiculosus: “ The frond is coriaceous, flat, F. vesicu- 
mid-ribbed, linear, dichotomous, and quite entire ; the losus, 
vesicles are spherical, and innate in the membrane of 
the frond; the receptacles (containing tubercles and 
seeds) solitary, terminal, compressed, turgid, mostly el- 
liptical.”—In Scotland this is sometimes called Black 
tang ; sometimes Kelp ware ; and when the r cles 
are large and swollen, Strawberry-ware. The Norwe- 
ians call it Kue tang, because their cows feed on it, 
it is the Quereus marina or Sea oak of the older writers. 
F. inflatus. of Linteus and Lightfoot, and F. spiralis 
of English Botany, are to be considered as varieties onl 
of this species. The colour isa pale olivé green, which ~ 
becomes dull and almost black as the plant dries. It 
grows most plentifully on all our rocky shores, often 
not much below flood-mark. - It is readily distinguished 
from F. nodosus by the air-vesicles very generally oc- 
curring in parallel pairs, while in F. nodosus they are 
single ; and from F. serratus, by the edges of the frond 
being entire, or wanting the serratures which mark that 
species. It is generally from one to three feet long. 
It is the species most ia prized for the manufacture 
of kelp; being rich in alkaline salts. According to one 
account, 5 oz. of the ashes of the plant yielded about 24. 
oz. of alkali; and Dr Walker states that 1 lb. avoirdupois 
gavehim 3 oz. of kelp. In the north and west of Sc 
land many hundred tons of this species are for this pur- 
pose yearly cut from the rocks, with old reaping hooks. 
To the Scottish islanders it is likewise valuable in ano- 
ther way; it constitutes a your pcan of the winter 
food of their horses, cattle and sheep, which seem instinc« 
tively to migrate from the hills to the sea-shore at the 
ebbing of the tide. Lightfoot mentions that during severe 
snow-storms, stags have been known to descend from 
the Scottish mountains to the shores, and to feed chiefly 
on this species. Thesame author states, that in some 
of the islands, the inhabitants cover their cheeses with . 
its ashes, and thus supply the place of salt. Linnaus 
says, that the people in Gothland often boil the plant, 
and mixing it with some coarse flour, feed their pigs 
with it, and that it has hence received the name of 
Swine-tang. In the Channel islands it affords firing. . 
In Jersey, in particular, it is collected and dried in July, 
and then housed for winter fuel. It is there also em- 
ployed in smoke-drying pork, beef and fish. + 4 
F, ‘nodosus: “The frond is coriaceous, compress F, nodosis, 
ed, veinless, sub-dichotomous, branched in a pinnated 
manner ; the receptacles are distichous, pedunculated, 
roundish, mostly solitary.”—This is very common on 
the rocky shores of this country, growing about half 
way between flood-mark and the ebb; often on the 
intermediate space between F. vesiculosus and serratus, 
though it sometimes grows nearest to high-water mark, 
The fronds are from two to six feet in length, and at 
short distances swell into Jarge oblong vesicles or air- 
bladders ; by which, though not mentioned in the 
cific character, the plant is more familiarly distinguish- 
ed, and from which it has derived its title nodosus. Boys 
+ Communications to the Board of Agriculture, vol. 1. p.219. 
