FOR 
FOR 
tlie title or form of the done or gift is stated 
in the writ ; there are three sorts, in the 
descender, remainder, and revertor. But 
these writs are now seldom brought, except 
in some special cases, where it cannot be 
avoided ; the trial of titles by ejectment is 
now the usual method, and is done with 
much less trouble and expense. 
FORMIC acid. It has long been known 
that ants contain a strong acid, which they 
occasionally emit ; and which may be ob- 
tained from the ants either by simple distil- 
lation or by infusion of them in boiling wa- 
ter and subsequent distillation of as much of 
the water as can be brought over without 
burning the residue. After this it may be 
purified by repeated rectifications, or by 
boiling to separate the impurities ; or after 
rectification it may be concentrated by 
frost. 
This has now lost its rank as a separate 
acid, and it has been shewn by Fourcroy 
and Vauquelin to be a compound of the 
malic and acetic. 
We have been informed that it has been 
employed among quacks as a wonderful 
remedy for the tooth-ach, by applying it to 
the tooth with the points of the fore-finger 
and thumb. 
FORMICA, in natural history, the ant 
or emmet, a genus of insects of the order 
Hymenoptera. Feelers four, unequal, with 
cylindrical articulations, placed at the tip 
of the lip, which is cylindrical and nearly 
membranaceous ; antennae filiform ; a small 
erect scale between the thorax and abdo- 
men ; females and neuters armed with a 
concealed sting ; males and females with 
wings, but to neuters there are no wings. 
This is a gregarious and very industrious fa- 
mily, consisting, as the generic character 
shews, of males, females, and neutrals. The 
last are well-known insects, who construct 
the nests or ant-hills, who labour with unre- 
mitting assiduity for the support of them- 
selves and the males and females, and who 
guard with such ferocity the larvae, or what 
are usually denominated ant’s eggs. They 
wander about all day in search of food or 
materials for the nest, and assist each other 
in bringing home what is too heavy or large 
for such as have attempted it. They bring 
out of their nest, to expose to the warmth 
of the sun, the newly hatched larvae, and 
feed them till they are able to provide for 
themselves. In the evening they consume 
together whatever has been collected during 
the day, and do not, as is commonly sup- 
posed, lay up any store for the winter* 
They are very covetous of aphides, (sec 
Aphis) and are themselves eagerly sought 
after by the formica-leo, and various birds. 
Ants feed on animal and vegetable sub- 
stances, devouring the smaller kind of in- 
sects, caterpillars, See. as well as fruits of dif- 
ferent kinds* The largest of the European 
ants is the F. herculanea, or great wood- 
ant, of a chesnut colour, which is found in 
dry woods of fir, where it inhabits a large 
nest or hillock, composed of dry vegetable 
fragments, chiefly of fir-leaves : the nest is 
internally distributed into several paths or 
tubes, converged towards a central part, 
and opening externally ; in the centre reside 
the larvae, which are nursed by neutral 
ants. When full grown, they envelope 
themselves in oval white silken cases, in 
which they undergo their change into the 
chrysalis state, and at length emerge in 
their complete form. 
F. nigra is the common black ant, well 
known in our gardens and fields. The great 
desire that ants have for animal food has 
been made use of by anatomists, who, when 
they wish to obtain the skeleton of an ani- 
mal too small or delicate to admit of being 
prepared in the usual way, dispose the ani- 
mals in a proper position in a small box, 
with perforations in the lid, and deposit it in 
a large ant-hill, in consequence of which, 
after a certain time, the whole of the softer 
parts are eaten away by these insects, and 
the skeleton remains in its proper position. 
F. rufa contains an acid which has under- 
gone a chemical analysis. See. See Formic 
acid. 
FORMULA, or Formulary, a rule or 
model, or certain terms prescribed or de- 
creed by authority, for the form and man- 
ner of an act, instrument, proceeding, or 
the like. 
Formula, in church history and theology, 
signifies a profession of faith. 
Formula, in medicine, imports the con- 
stitution of medicines, either simple or com- 
pound, both with respect to their prescrip- 
tion and consistence. 
Formula, a theorem or general rule or 
expression for resolving certain particular 
s d 
cases of some problem, &c. So - is a 
A A 
general formula for the greater of two quan- 
tities whose sum is s and difference d ; 
and ~ - 
d 
is the formula, or general value 
for the less quantity. Again dx — x- is 
the formula or general value of the ordinate 
