250 
N A I 
for these fish usually lying in great numbers 
near one another, the embryos of one are 
often affixed to the shell of another. The 
fringed edge of the mussel, which Lewen- 
hoeck calls the beard, has in every the mi- 
nutest part of it such variety of motions as 
is inconceivable ; for being composed of long- 
ish fibres, each fibre has on both sides a vast 
many moving particles. 
1 he mussel is infested by several enemies 
in its own element; according to Reaumur it 
is in particular the prey of a small shell-fish 
of the trochus kind. This animal attaches 
NAP 
itself to the shell of the mussel, pierces it with 
a round hole, and introduces a sort of tube, 
five or six lines long, which it turns in a spiral 
direction, and with which it sucks the sub- 
stance of the mussel. Mussels are also sub- 
ject to certain diseases, which have been sup- 
posed to be the cause of those bad effects 
which sometimes happen from the eating of 
them. 
MYXINE, the hag; a genus of insects 
belonging to the order of vermes intestini. 
It lias a slender body, carinated beneath ; 
N A R 
mouth at the extremity, cirrated; the two 
jaws pinnated ; an adipose or rayless fin 
round the tail and under the belly. The 
only remarkable species is the glutinosa, 
about eight inches long. It inhabits the 
ocean ; enters the mouths of fish when on the 
hooks of lines that remain a tide under water ; 
and totally devours the whole, except the 
skin and bones. The Scarborough fisher- 
men often take it in the robbed fish, on draw- 
ing up their lines. Linmeus attributes to it 
the property of turning water into gube^ 
N 
IM" or n, the thirteenth letter of our alpha- 
^ ^ 5 bet ; as a numeral stands for 900 ; 
and with a dash over it, thus N, for 900,000. 
N, or N°, stands for numero, i. e. in number ; 
and N. 13. for nota bene, note well, or observe 
well. Among the antient Romans, N. denotes 
Nepos, Nonnius, &c. N. C. Nero Cssar, 
or Nero Claudius ; N. L. Non liquet ; N. P. 
Notarius Publicus; and N13L. stands for no- 
bilis. 
NADIR, in astronomy, that point of the 
heavens which is diametrically oppose to 
the zenith, or point directly over our heads. 
NAIAS: a genus of the monandria order, 
in the dioecia class of plants ; and in the na- 
tural method ranking with those of which the 
order is doubtful. The male calyx is cylin 
drical and bifid; the corolla quadrifid ; there 
is no filament, nor is there any female calyx 
or corolla; there, is one pistil, and the cap- 
sule is ovate and unilocular. There is one 
species, an aquatic of the South of Europe. 
NAIL, unguis. See Anatomy, and 
Horn. 
NAILS, in building, &c. small spikes of 
iron, brass, See. which being driven into 
wood, serve to bind several pieces together, 
or to fasten something upon them. The se- 
veral sorts of nails are very numerous: as, 1 . 
back and bottom nails, which are made with 
flat .shanks to hold fast, and not open the 
wood. 2. Clamp-nails, for fastening the 
dampy in. buildings, &c. 3. Clasp-nails, 
whose heads clasping and sticking into the 
wood, render the work smooth, so as to ad- 
3nit a plane over it. 4. Clench-nails, used 
by boat- and barge-builders, and proper for 
any boarded buildings that are to be taken 
down ; because they will drive without split- 
ting the wood, and draw without breaking ; 
of this there are many sorts. 5. Clout-nails, 
used for nailing on clouts to axle-trees. 6. 
Deck-nails, for fastening of decks in ships, 
doubling of shipping, and floors laid with 
planks. 7. Dog-nails, for fastening hinges 
on doors, Se c. 8. Flat-points, much used 
in shipping, and proper where there is occa- 
sion to draw and hold fast, and no conveni- 
ency of clenching. 9. Jobent-nails t for nail- 
ing thin plates of iron to wood, as small 
hinges on cupboard-doors, Sec. 10. Lead- 
nails, for nailing lead, leather, and canvas, to. 
hard wood. 11, Port-nails, for nailing liin- 
ges to the ports of ships. 12. Pound-nails, 
which are four square, and are much used in 
Essex, Norfolk, and Suffolk, and scarcely 
any where else, except for bailing. 13. Rib- 
bing-nails, principally used in ship-building, 
for fastening the ribs of ships in their places. 
1 4. Rose-nails, which are drawn four-square 
in the shank, and commonly in a round tool, 
as all common twopenny nails are ; in some 
countries all the larger sort of nails are made 
of this shape. 15. Rother-nails, which have 
a full head, and are chiefly used in fastening 
rother-irons to ships. I6i Round-head nails, 
tor fastening on hinges, or for any other use 
where a neat head is required; these are of 
several sorts. 17. Scupper-nails, which have 
a broad head, and are used for fastening lea- 
ther and canvas to wood. 18. Sharp nails ; 
these have sharp points and flat shanks, and 
are much used, especially in the West In- 
dies, for nailing soft wood. 19. Sheathing- 
nails,^ for fastening sheathing-boards to ships. 
20. Square nails, which are used for hard 
wood, aud nailing up wall-fruit. 21. Tacks, 
the smallest of which serve to fasten paper to 
wood, the middling for wool-cards, &c. and 
the larger for upholsterers and pumps. 
Nails are said to be toughened when too 
brittle, by heating them in a fire-shovel, and 
putting some tallow or grease among them. 
Nail, is also a measure of length, contain- 
ing the sixteenth part of a yard. 
NAIS, a genus of the vermes mollusca ; 
the generic character is, body creeping, long, 
linear, pellucid, depressed; peduncles or feet 
with small bristles on each side. There are 
ten species : the digitata is found with single 
lateral bristles, tail laciniate, in stagnant 
waters, or the sandy sediment of rivers, with 
its head attached to the stalk of aquatic 
plants ; it is about 4 lines long. 
NAMA, a genus of the digynia order, in 
the pentandria class of plants : and, in the 
natural method, ranking under the 13th 
order, succulentae. The calyx is pentaphyl- 
lous, the corolla quinquepartite, the capsule 
unilocular and bivalved. There is one spe- 
cies, an annual of Jamaica. 
NANDINA, a genus of the class and or- 
der liexandria monogynia. The calyx is 
many-leaved, imbricate "; corolla si^-petalled. 
There is oue species, a herb of Japan. 
X APiEA, a genus of the poTyandria order, 
m the poly adelphia class of plants ; and in the 
natural method ranking under the 37th order, 
columniferax The calyx is single and cy- 
liudric ; the ariili coalited and monospermous. 
There are two species ; both of them with 
perennial roots. Both of them are natives of 
Virginia and other parts of North America; 
from the bark of some of the Indian kinds a 
sort of fine hemp might be procured, capable 
being woven into very strong cloth. They 
are easily propagated by seed, which will 
thrive in any situation. 
NAPTHA a name given to the most 
liquid bitumen; it is light, transparent, and 
very inflammable. There are several varie- 
ties, found chiefly in Italy, and particularly 
near Modena. Kempfer, however, says, that 
great quantities are collected in several parts 
of Persia; naturalists attribute the formation 
of the liquid bitumens to the decomposition 
of those that are solid, by, the action of the 
subterraneous fires. Naptha is said to be 
the lightest, which the fire first disengages t 
naptha is very volatile, and so combustible, 
that it catches fire, if any thing burning be 
brought near it. In Persia, this and the 
other bitumens are employed for the purpose 
of giving light in lamps by means of wicks ; 
they may be used also to give heat ; for this 
purpose some naptha is poured on a few 
handfuls of earth, and kindled with paper, 
when it burns briskly, but diffuses a thick 
smoke, which adheres to every thing, and 
leaves a disagreeable smell. In India, the 
flame produced by it is worshipped, and the 
heat it emits is used for dressing victuals; 
and in some cases it has been successfully em- 
ployed in paralytic diseases. See Bitumen. 
NARCISSUS, a genus of the monogynia 
order, in the liexandria class of plants ; “and 
in the natural method ranking under the 9th 
order, spathaceae. There are six petals; 
the nectarium is funnel-shaped and mono- 
phyllous; the stamina are within the nec- 
arium. There are 15 species ; the most 
remarkable are : 
1 . The bastard narcissus, or common yel- 
tlow English daffodil, grows wild in great 
plenty in many of our woods and coppices, 
and under hedges, in several parts of Eng- 
land. Its commonness renders it of but 
11 
