FLU 
seed, as in the class Dioecia. In this man- 
ner is to he understood the general princi- 
ple with which the sexual method sets out, 
that every vegetable is furnished with 
flower and fruit. The essence of the flower, 
therefore, consists in the anthers and stigma, 
which constitute a flower, whether the co- 
vers, that is, the calyx and petals, are pre- 
sent or not. 
Flower de luce. See Iris, 
Flower de lis, or Flower de luce, in 
heraldry, a bearing representing the lily, 
called the queen of flowers, and the true 
hieroglyphic of royal majesty ; but of late 
it' is become more common, being borne in 
some coats one, in others three, in others 
five, and in some senree, or spread all over 
the escutcheon in great numbers. 
Flowers, in chemistry, a term formerly 
applied to a variety of substances procured 
by sublimation, and were, in .the form of 
slightly cohering powder : hence, in all old 
books, we find mention made of the flow- 
ers of antimony, arsenic, zinc, and bismuth, 
which are the sublimed oxides of these me- 
tals, either pure, or combined with a small 
quantity of sulphur: we have also stiil in 
use, though not generally, the terms flowers 
of sulphur, benzoin, &c. 
FLUATES, in chemistry, salts of which 
the Fluoric acid (which see) is the chief 
ingredient. Fluor spar, denominated fluate 
of lime, which is found in great plenty in 
many countries, and is very abundant in 
Derbyshire, where it. obtains the name of 
Derbyshire spar, is the most important 
among the fluates. The chief properties of 
these salts are, 1. When sulphuric acid is 
poured upon them, they emit acrid va- 
pours of fluoric acid, which corrode glass. 
2. When heated, several of them phospho- 
resce. 3. They are not decomposed by 
heat, nor altered by combustibles. 4. They 
combine with silica by means of heat. 
FLUENT, in fluxions, the flowing quan- 
tity, or that Which is continually either in- 
creasing or decreasing, whether line, sur- 
face, solid, &c. See Fluxion. 
FLUID, in physiology, an appellation 
given to all bodies whose particles easily 
yield to the least partial pressure or force 
impressed. 
All fluids, except those in the form of air or 
gas, are incompressible in any considerable 
degree. The Academy del Cimento, from 
the following experiment, supposed water 
to be totally incompressible. A globe made 
of gold, which is less porous than any other 
metal, was completely filled with water 
FLU 
and then closed up ; it was afterwards 
placed under a great compressive force, 
which pressed the fluid through the pores of 
the metal, and formed a dew all over its 
surface, before any indent could be made in 
the vessel. Now, as the surface of a sphere 
will contain a greater quantity than the 
same surface under any other form what- 
ever, the academy supposed that the com- 
pressive power which was applied to the 
globe must either force the particles of the 
fluid into closer adhesion, or drive them 
through the sides of the vessel before any 
impression could be made on its surface; 
for although the latter effect took place it 
furnishes no proof of the incompressibility 
of water, as the Florentines had no method 
of determining that the alteration of figure 
in their globe of gold occasioned such a 
diminution of its internal capacity, as was 
exactly equal to the quantity of water for- 
ced into its pores; but this experiment 
serves to shew the great minuteness of the 
particles of a fluid in penetrating the pores 
of gold, which is the densest of all metals. 
Mr. Canton brought the question of incom- 
pressibility to a more decisive determina- 
tion. He procured a glass-tube, of about 
two feet long, with a ball at one end, of an 
inch and a quarter in diameter: having 
filled the ball and part-of the tube with 
mercury, and brought it to the heat of 50° 
of Farenheit’s thermometer, he marked the 
place where the memtry stood, and then 
raised the mercury by heat to the top of 
the tube, and there sealed the tube, her- 
lnelrically ; then upon reducing the mercury 
to the same degree of heat as before, it 
stood in the tube °f an inch higher than 
the mark. The same experiment was re- 
peated with water, exhausted of air, instead 
of mercury, and the water stood in the 
tube above the mark. Now, since the 
weight of the atmosphere on the outside of 
the ball, without any counterbalance from 
within, will c (Impress the ball, and equally 
raise both the mercury and water ; it ap- 
pears that the water expands ^ of an inch 
more than the mercury, by removing the 
weight of the atmosphere. From this, and 
other experiments, he infers, that water is 
not only compressible but elastic ; and that 
it is more capable of compressibility in 
winter than in summer. 
AH fluids gravitate, or weigh, in propor- 
tion to their quantity of matter, not only in 
the open air, or in vacuo, but in their own 
elements. Although this law seems so 1 con- 
sonant to reason, it has been supposed by 
