PHARMACY. 
sdlution, placed upon some cold body, shews 
a disposition to crystallize, or at furthest 
only until the first appearance of a pellicle. 
Ihe solution is then covered up, and set 
aside to cool, and the more slowly it cools 
the more regular are the crystals. The 
mother -water, or solution which remains 
after the crystals are formed, may be re- 
peatedly treated in the same way as long as 
it is capable of furnishine; any more salt. 
When very large and beautiful crystals 
are wanted, they may be obtained by lay- 
ing w’ell-fonned crystals in a saturated so- 
lution of the same salt, and turning them 
every day. In this way their size may be 
considerably increased, though not without 
limitation, for after a certain time they 
grow smaller instead of larger. 
Crystallization is employed to obtain 
crystallizable substances in a state of purity j 
or to separate them from each other, by 
taking advantage of their different solubility 
at different temperatures. 
General Analysis resulting from the Applica- 
tion of chemical Powers. 
The simple elementary substances into 
which bodies are capable of being reduced 
submitted to chemical action, are light, ca- 
loric, electricity, galvanism, magnetism, 
oxygen, hydrogen, nitrogen, carbon, sul- 
phur, soda, potash, phosphorus, metals, and 
earths. Of these the first five have no appre- 
ciable gravity, which is evinced by all the 
rest. Of the latter, again, some are com- 
bustible, others incombustible ; some oxy- 
genizable, others destitute of all affinity for 
oxygen. But to enter minutely into these 
subjects would be to carry us beyond the 
limits of this article, and to infringe upon those 
that belong to chemistry as a general sci- 
ence, and to which, as also to the several ar- 
ticles above enumerated in the alphabetical 
order, we refer the reader for further infor- 
mation. So little progress, however, have 
we hitherto made in the general science of 
chemistry, that perhaps we are even now 
committing a double error in offering the 
above as a table of simple elementaiy sub- 
stances. It is possible that not one of these 
substances is, strictly speaking, a simple 
element, or, in other words, totally un- 
compounded of rudiments that are more 
simple. We may also be in an error in con- 
ceiving every one of them to be a distinct 
substance from every other : we have many 
reasons, for example, for supposing that 
galvanism and electricity are the very same 
substance, only in different states of modi- 
fication ; and some philosophers have ven- 
tured to suspect that magnetism, or the 
magnetic power, is, in like manner, in unity 
with both. Neither soda nor potash, again, 
are scarcely any longer to be regarded as 
simple substances ; we have many valuable 
experiments of Mr. Davy before us, by 
which they appear to have been completely 
decomposed ; and there can be little doubt 
of the full confirmation of these experi- 
ments by subsequent trials of other che- 
mists. And in this case it is possible that 
metallic substances will have to be as com- 
pletely struck out of the list of simple ele- 
ments as potash or soda. There are also 
several of the acids which are still admitted 
into the same catalogue ; but whose preten- 
sions are every day becoming still more 
doubtful, and of which, on this very ac- 
count, we have taken no notice, though we 
shall have occasion to advert to them, and 
especially the muriatic acid, as we proceed. 
See Light, Caloric, Electricity, &c, 
PART II. 
PHARMACEUTICAL PREPARATIONS, 
The classes into which these are divided 
have a considerable difference, as well in 
number as in arrangement, in our different 
collegiate Pharmacopoeias. That of the 
London College in present use is become 
perfectly obsolete, both in order and no- 
menclature. To the nomenclature of the 
Edinburgh we have little to object, but can- 
not altogether approve of its order. Why 
the Sulphurea should lead the way, and be 
so far separated from the Metallica, with 
which they are so intimately connected by 
nature, we know not. We have reason to 
believe, that the forthcoming Pharmacopoeia 
of the London College, will, in this, as well 
as m several other respects, evince a more 
systematic attention. In the mean time 
while we give the general heads of both’ 
we shall take the liberty of arrangmg them 
in the following manner ; 
1. Acida, acids. 
2. Alkalina, alkalines. 
3. Terrea, earths, 
4. Sulphurea, sulphureous preparations, 
5. Metallica, metalline preparations. 
6. Olea fixata, fixed oils. 
7. Aquae distillatae, distilled waters. 
8. Olea volatilia, volatile oils. 
9. Spiritus distillati, distilled spirits, 
10. Decocta, decoctions. 
11. Infusa, infusions. 
12. Syriipi, syrups. 
