ADDLED EGGS. 
tribe of ferns, comprising two other genera ; and 
it occurs in moist meadows throughout England, 
and is popularly believed to possess several medi- 
cinal virtues. It is found in the months of April 
and May. Its stem rises four inches froni the 
ground, and its seed-spike four inches from the 
stem; but.the whole plant is usually so con- 
cealed among the grass as to escape the notice of 
a careless observer. Its seed-spike possesses some 
resemblance of form to the tongue of the adder ; 
and has procured for the plant its repulsive 
name. Its leaf is single, oblong, smooth, thick, 
unveined, and of a bright green colour. Its root 
is fibrous. A balsam or salve made out of a 
trituration of the leaves, has been used for heal- 
ing green wounds,—though a bit of wax-cloth is 
probably worth fifty cart-loads of such old-wifish 
preparations ; the expressed juice of the leaves, 
drank with horse-tail water, has been recom- 
mended for the cure of internal wounds,—though 
this too smacks of quackery ; an ointment made 
of the leaves with lard, is proclaimed of excel- 
lent virtue for ulcers, burns, hot tumours, and 
_ exterior inflammations,—though most of the vir- 
tue is probably in the lard ; an infusion of the 
leaves, or a decoction of the whole plant, is said 
to be a good drink in fevers, and a cooling and 
strengthening eye-water,—it may be so, but we 
| should not like to try; and a fine powder of the 
whole of the dried herb is recommended to be both 
taken inwardly and applied outwardly incases of 
| rupture,—nearly all twaddle and tom-foolery ! 
ADDLED EGGS. Eggs which are unhatchable, 
and which become rotten under the hen. The epi- 
thet addled or addle is used by farmers in some 
parts of England in the broad sense of unproduc- 
tive, and is applied toany barren or infertile object. 
ADDUCTION. The action by which parts are 
drawn towards the axis of the body. The mus- 
cles which execute this particular function are 
called adductors. 
ADEPS. Hog’s lard, as used in medical or 
veterinary practice. It is tasteless, inodorous, 
and free from every stimulating quality ; and, 
with great propriety, forms the basis of most of 
the ointments now in use. But often, when com- 
pound unguents are applied, mere lard would be 
preferable ; and very often, an oleraceous leaf, a 
piece of wax cloth, or any thing which would ex- 
clude dirt and air, would be best ofall. For re- 
marks on lard, in other than a medicinal point of 
view, see the article on Far. 
ADHESION IN PHYSICS. One of the forces 
of attraction, called also heterogeneous attraction, 
to distinguish it from homogeneous attraction 
or cohesion ; for the latter is exerted between 
similar, adhesion between dissimilar particles of 
matter. A piece of glass plunged into water and 
again drawn out retains a portion of water on its 
surface, is wetted by it, while glass or iron 
plunged into mercury do not exhibit a similar 
result ; the former shows that there is adhesion 
between the glass and water, but there is little 
ADHESION IN PHYSICS. 43 
or none between the two metals, or it is over- 
come by superior cohesion of iron for iron and 
mercury for mercury. 
Adhesion exerts considerable influence in 
chemical operations; thus solution, filtration, 
alloying, cementation, &c., are all, more or less, 
subject to its control. The union of two differ- 
ent bodies, by a cement, exhibits this force ; thus 
when two.pieces of wood are joined by correspond- 
ing surfaces by the intervention of soft glue, the 
latter hardens, and draws the surfaces together. 
In the same way porcelain is united by albumen 
and lime, bricks and stones by mortar, and the 
adhesion is often so great that the pieces united 
will suffer fracture in another direction than in 
the place of adhesion. Adhesion is often a trou- 
blesome interference in chemical operations. 
Many precipitates adhere so firmly to a glass 
vessel, that friction will scarcely remove them, it 
being often necessary to redissolve and reprecipi- 
tate them to obviate the difficulty. The adhe- 
sion of fatty bodies to almost every kind of sur- | 
face renders operations with them tedious and 
annoying. On the other hand, we may avail 
ourselves of this force in many cases; thus to 
prevent a liquid from running down the outside 
of a vessel while pouring, the lip may be greased, 
which, for want of adhesion between the fat and | 
the liquid, keeps the latter in one stream by its | 
cohesive force, and to insure this more certainly | 
in quantitative analysis, a glass rod or tube is | 
laid on the lip, which, by adhesive force between | 
it and the liquid, gives direction to the current. 
The attraction of moisture from the air by pow- 
ders and porous substances, has considerable | 
effect on their weight, and hence a powder should 
be finally weighed just as soon as cool, or cooled 
over sulphuric acid, &c. 
highest importance in organic analysis, where 
the content of hygrometric water may entirely 
change the formula of a substance, since it would 
give more water and consequently less carbon, &c. 
The operation of filtering is dependent on the | 
same force as exerted in capillary attraction, the | 
liquid passing through the pores of paper, &c., 
independently of pressure, and collecting on the | 
underside in drops, by cohesion. See Finrratton. 
Solution of solids in liquids exhibits this at- 
traction and its limits; thus, if a piece of loaf- 
sugar be immersed in water by one small point 
of contact, the water will rise into its pores with 
some rapidity, until the saccharine cement hold- 
ing the crystalline particles together is dissolved 
by the continued exertion of this action, when 
the mass crumbles and the liquid is saturated. 
In the solution of sugar, salt, &c., we may con- 
ceive the particles of the solid spreading out 
into spaces between the particles of the liquid, 
as high as adhesion, diminished by gravity, will 
allow, and thus a stratum of the solution will re- 
main on the bottom of the vessel, until, by me- 
chanical mixture, they are spread through the 
liquid, and retained there by adhesive force. 
It is a point of the | 
