P H O 
P H O 
elates in the interior part of the country, find 
large quantities of them are exported to 
France and Italy. The crop is gathered to- 
wards the end of November. When the 
bundles are taken from the tree, they are 
hung up in some very dry place where they 
may be sheltered and secure from insects. 
Even the stones, though very hard, are 
not thrown away. They give them to their 
camels and sheep as food, after they have 
bruised them or laid them to soften in water. 
The date, as well as other trees which are 
cultivated, exhibits great variety in its fruit, 
with respect to shape, size, quality, and even 
colour. There are reckoned to be at least 
20 different varieties. Dates are very liable 
to be pierced by worms, and they soon cor- 
rupt in moist or rainy weather. 
From what has been said, it may easily be 
perceived that there is, perhaps, no tree 
whatever used for so many and so valuable 
purposes as the date-tree. 
PliORMIUM, flax-plant, a genus of the 
class and order hexandria monogynia. There 
is no calyx ; the corolla is six-petalled, three 
inner larger; capsule oblong, three-sided; 
seeds oblong, compressed. Of this plant 
there is one species : the leaves resemble 
those of Hags; the dowers are in one variety 
vellow, and in the other a deep red. Of the 
leaves of these plants, with very little prepa- 
ration, the New Zealanders make all their 
common apparel, and also their strings, lines, 
and cordage, for every purpose; which are 
so much stronger than any thing we can make 
with hemp, that they will not bear a compa- 
rison. From the same plant, by another 
preparation, they draw long slender dbres, 
which shine like silk, and are as white as 
snow. Of these, which are very strong, they 
make their finest cloths; and of the leaves, 
without any other preparation than splitting 
them into proper breadths, and tying the 
strips together, they make their fishing-nets, 
some of which are of an enormous size. The 
seeds of this valuable plant have been brought 
over into England ; but upon trial appeared 
to have lost their vegetating power. 
PHOSPHATS, salts formed by the phos- 
phoric acid, with the alkalies, earths, and me- 
tallic oxides. They may be distinguished 
by the following properties : (1 .) When heat- 
ed with combustibles, they are not decom- 
posed, nor is phosphorus obtained. (2.) Be- 
fore the blowpipe they are converted into a 
globule of glass, which in some cases is trans- 
parent, in others opaque. (3.) Soluble ill 
nitric acid without effervescence, and preci- 
pitated from that solution by lime-water. 
(4.) Decomposed, at least partially, by sul- 
phuric acid; and their acid, which is separat- 
ed, when mixed with charcoal and heated to 
redness, yields phosphorus. (5.) After being 
strongly heated, they often phosphoresce. 
The phosphats readily combine with an 
excess of acid, and form superphosphats. 
The phosphats at present known amount to 
12; two of which are triple salts. Some of 
tiiese salts occur in different states, constitut- 
ing varieties. 
Phospliat of barytes. It may be prepared 
either by saturating phosphoric acid with 
barytes or carbouat of of barytes, or by mix- 
ing together an alkaline phospliat and nitrat or 
muriat of barytes. In either case the phos- 
phat of barytes precipitates immediately in 
the form of a white powder. 
PHO 
This salt is tasteless, incrystallizable by art, 
insoluble in water, and not altered by expo- 
sure to the air. Its specific gravity is' 1. 2867. 
When strongly heated, it melts into a grey- 
coloured enamel. The proportion of its com- 
ponent parts is unknown. 
i his salt lias not been applied to any use. 
When phosphoric acid is dropt into a solu- 
tion of barytes-water, a precipitate ot phos- 
phat of barytes immediately falls. But this 
precipitate is redissolved by adding an excess 
of acid. Hence it follows, that this salt is 
capable of combining with an additional dose 
ot acid, and forming a superphosphat of 
barytes. 
Phosphat of sir o ntian. Like the former, it 
may be formed by dissolving carbouat of 
strontian in phosphoric acid, or by mixing to- 
gether nitrat of strontian and phosphat of 
soda. A white precipitate immediately falls, 
which is the phosphat of strontian. 
I his alt is tasteless, insoluble in water, and 
not alterable by exposure to the air. It is 
soluble in an excess of phosphoric acid ; a 
property which distinguishes it from phos- 
phat ot barytes. Before the blowpipe it fuses 
into a white enamel, and at the same time 
emits a phosphoric light It is completely 
decomposed by sulphuric acid, but by no 
other. According to Vauquelin, it is com- 
posed of 41.24 acid 
58.76 strontian. 
100.00 
Phosphat of lime. Of this salt there are 
two varieties, the first neutral, the other a 
supersalt. 
1. Phosphat of lime. As this salt consti- 
tutes the basis of bones, it is not necessary 
to prepare it artificially. It may be obtained 
in a state of purity by the following pro- 
cess: Calcine the bones to whiteness, reduce 
them to powder, and wash them repeatedly 
with water, to separate several soluble salts 
which are present. Dissolve the whole in 
muriatic acid, and precipitate by means of 
ammonia. The precipitate, when well wash- 
ed and dried, is pure phosphat of lime. 
Phosphat of lime, thus prepared, is always 
in the state of a white powder ; but it is found 
native in regular crystals. In that state it is 
known by the name of apatite. The primi- 
tive form of its crystals is, according toPIauy, 
the regular six-sided prism; and the primitive 
form ot its integrant particles is a three-sided 
prism, whose bases are equilateral triangles: 
but it very often assumes other forms. It is 
destitute of taste, insoluble in water, and not 
liable to be altered by exposure to the air. 
It may be exposed to a strong heat without 
undergoingany change; butin a very violent 
heat it becomes soft, and is converted into a 
white semitransparent enamel, or rather 
porcelain. According to the experiments 
of Saussure, a heat ot 378° Wedgewood is 
necessary to produce this effect. 
Sulphuric, nitric, muriatic, fluoric, and 
several vegetable acids, are capable of de- 
composing phosphat of lime; but the de- 
composition is only partial. Fourcroy and 
Vauquelin have ascertained, that these acids 
are only capable of abstracting 0.40 parts of 
the lime, while the remainder continues com- 
bined with the phosphoric acid, constituting 
a superphosphat of lime. Hence the reason 
that phosphoric acid is capable also of de- 
lD 
413 
composing partially the combinations of these* 
acids with lime; it abstracts as much of the 
lime as is sufficient to convert it into super- 
phosphat. Phosphat of lime, according to 
1'ourcroy and Vauquelin, is composed ot 
4l acid 
59 lime 
160 . 
2. Superphosphat of lime. It is this sail' 
which always remains in the aqueous solution': 
when calcined bones are decomposed by 
means of sulphuric acid ; and it may be form- 
ed artificially by dissolving phosphat of lime 
in phosphoric acid, till the acid refuses to 
take up any more, and afterwards evaporat- 
ing the solution till the salt crystallizes, its 
crystals are usually thin brilliant plates, re- 
sembling mother-of-pearl, which easily ad- 
here together, and acquire a kind of gluey, 
consistency. Its taste is strongly acid. Water 
dissolves it, and in a greater proportion when 
boiling-hot than when cold Hence a satu- 
rated solution of it in boiling water crystal- 
lizes on cooling. It attracts a little moisture 
when exposed to the air. When heated, it 
readily undergoes the watery fusion, then- 
swells up and dries. In a high temperature 
it melts into a semitransparent glass, which is 
tasteless and insoluble, and is not altered by- 
exposure to the air. When this salt is heated 
to redness along with charcoal, its excess of 
acid is ^composed, and converted into phos- 
phorus, and phosphat of lime remains behind. 
It is from this salt that phosphorus is usually 
obtained; but the process of Fourcroy, 
which consists in decomposing 'the super- 
phosphat of lime by means of acetat of lead, 
and afterwards decomposing the phosphat of 
lead by means of charcoal, must yield a 
much greater proportion of phosphorus. 
No acid hitherto tried is capable of decom- 
posing this salt, except the oxalic, which abs- 
tracts its base completely, and precipitates 
with it in the form ofoxalat of lime; but it is 
decomposed and reduced to the state of phos- 
phat of lime by all the alkaline and earthy 
bases. It is composed, according to the ana- 
lysis of Fourcroy and Vauquelin, of 
5.4 acid . 
46 lime 
100 . 
Phosphat of potass. Of this salt there arc 
two varieties: the first, which contains an 
excess of acid, and is in reality a superphos- 
phat, has been long known, and appears to 
have been first mentioned by Lavoisier in 
1774; but it is to Vauquelin that we are in- 
debted for an examination of its properties. 
The second, which is a neutral salt, was 
lately discovered by Darracq. It had been 
formed indeed previously by Guyton Mor- 
veau and Desormes; but these gentlemen 
had mistaken it for phosphat of lime. 
1. Superphosphat of potass is prepared by 
dropping carbouat of potass into phosphoric 
acid till all effervescence ceases, and then 
evaporating, to the proper consistency. It 
does not crystallize. When evaporated suffi- 
ciently, it assumes the form ot a jelly ; and if 
the evaporation is carried farther, it becomes 
dry altogether. Its specific gravity, when 
dry, is 2.85. It is exceedingly soluble in 
water, and when dry readily attracts moisture 
