all these substances, except fire, ,(the nature of which is
* The remainder of the Lecture on Chemistry was taken from
the author's Dictionary of Chemistry, published by Messrs. Car-
will, of New York.
still doubtful,) are compound ; air is composed of two
gases, called oxygen arid nitrogen ; water, of oxygen and
hydrogen ; and earth of a variety of substances, which in
their turn may be decomposed.
JNature offers substances in four different states, solid,
liquid, gaseous, or aerilbrm, and imponderable, or such
agents as are not known to possess weight. All matter
is composed of molecules, particles, or atoms ; these are
subject to two opposing laws, the force of attraction,
which tends to keep the atoms in contact, and that of
caloric, or heat, which separates or repels them.
Simple substances are those whose atoms are homogen-
eous, or^of the same nature. Thus zinc is considered as
a simple substance, because it contains no other atoms
than those of zinc.
Compound substances are such as contain two or more
simple elements ; thus, brass is a compound body, which
on being decomposed is found to contain atoms of zinc
and copper. The particles which constitute a simple
body are called integrant molecules, and the force which
keeps them together is called cohesion. The particles
which form a compound substance, are called constituent
molecules and the force which unites them is termed
affinity. Thus, zinc is formed of integrant molecules
united by the force of cohesion, and brass is formed of
constituent molecules united by the force of affinity.
Affinity. Affinity is that kind of attraction which
unites the heterogeneous molecules, or atoms of compound
bodies. A knowledge of chemical affinity is very impor-
tant in investigating chemical changes; the first conse-
quence of this law is a change of state of the bodies;
thus the union of two gasses, oxygen and hydrogen,
produces water. A second and important consequence
is a change of the property of the new substance; thus
from the combination of an acid and an alkali possessing
opposite properties, results a salt resembling neither of
the original substances. It is at present believed by
most chemists, that chemical affinity depends essential-
ly upon the electrical state of the substances, that elec-
tricity is divided into two fluids : the onepositive, the other
negative, and that molecules of the same kind of electri-
city repel, while those of opposite electricities attract
Theory of Atoms. By atoms or particles are under-
stood parts incapable of division or diminution ; much pre-
cision is given to the science of chemistry by admitting that
bodies consist of atoms which unite in certain proportions ;
thus in water we suppose two atoms of hydrogen united
to one of oxygen ; or which is the same thing, two hun-
dred atoms of the former to one hundred of the latter.
The theory of the proportions between the elements of
bodies is not hypothetical, but in many cases has been
proved by experiment ; thus the following proportions
are universally observed.
200 atoms of hydrogen and 100 of oxygen=water.
300 " " 100 nitrogen=arnmoniacal gas.
ammonia 50 carbon=salt of ammonia,
nitrogen 50 oxygen=protoxide of nitrogen.
100 =deutoxide of "
150 =nitrou8 acid.
250 =nitric acid.
Simple Elements. The number of simple elements
admitted by chemists, varies with the progress of the
science ; such substances as no chemical force can de-
compose are called simple ; many vvhich are thus named,
will, no doubt, in process of time be decomposed, while
other elements, now unknown, will be brought to light,
and found to be important agents in chemical changes.
Instead of the four elements of the ancients, chemists
at present admit more than 50 elementary bodies, if we
include the imponderable agents, chlorine, and some
other analogous substances; and the newly discovered
bodies, bromine, pluranium and thorium.
These may be comprehended under two grand divi-
sions ; 1. Imponderable agents , or such as have no
known weight; as
II. Ponderable bodies, or such as have known weight ;
these may be divided into four classes. Class 1. Sup-
porters of Combustion; as oxygen, &>e. Class 2. Com-
bustibles not metallic ; as hydrogen, &c. Class 3.
loids ; as silicon the base of silex, calcium of lime, &c.
Class 4. Metals; as gold, silver, &c.
Language of Chemistry. Among the most important
chemical agents is oxygen, the discovery of which
wholly changed the aspect of the science and gave rise
to our present nomenclature, or names of substances.
The term combustible, considered as synonymous with
oxygenable, is applied to all simple substances which can
be made to unite with oxygen ; this union is accompa-
nied with a disengagement of caloric or heat (though in
some cases imperceptible,) and often of light; the sub-
stance which has thus united with oxygen is said to be
burnt, or oxygenated.
The compounds which result from the union of oxy-
gen with simple bodies have received the name of oxides
and acids. When oxygen unites with a body but in one
proportion, forming either an oxide or an acid, the sub-
stance with which it combines is termed its radical; as
in the oxide of zinc; here zinc is the radical or base of
the oxide. If the oxygen combines in two or three pro-
portions, the first oxide is called protoxide, the second
deutoxide, the third tritoxide. When a body is oxidized
in the highest degree, it is termed the peroxide ; for
example, the combinations of oxygen and manganese,
which present us with all these varieties of oxides.
A similar rule governs with respect to the names of
acids ; if the oxygen forms but one acid, to its radical
is added the termination ic, as boracic acid. But if oxygen
combines in several proportions, the lowest proportion is
expressed by ous, and the highest by ic as sulphurous and
sulphuric acids ; to these terminations, are also added
hyper, which signifies more, and hypo, less ; thus hypo-
sulphurous acids denotes a body possessing a less quan-
tity of oxygen than sulphurous acid, &c.
Oxygen is not the only agent which unites to com-
bustible bodies to produce acids; hydrogen, chlorine,
with some other substances, possess this property ; thus
we Lave hydrochloric and hydriodic acids, resulting
from the union of hydrogen with chlorine and iodine.
When too binary,* burnt substances combine, a new
* The term Unary is derived from lis, two ; a binary compound
compound results, which when the constituents are an
acid and a metallic oxide, is called a salt. The salts
are very numerous; they are named by varying the ter-
mination of their acid; when the acid terminates in ous
and ic, the salts end in ite and ate; thus by the term
sulphate of tin, we understand the combination of tin
with sulphuric acid ; sulphite of tin expresses the com-
bination of the metdl with sulphurous acid.
IMPONDERABLE AGENTS. 1. Caloric. It would not
be possible to explain the sensation of heat to one
who never experienced it, any more than we could by
words give to the blind an idea of colors, or to the deaf,
of sounds. - A person says, ' I am warm,' or extending
his hand to a fire, says ' thejire is hot ;' in the first case
he properly expresses the sensation of heat; in the
second, the cause of this sensation. The fire itself is not
suppossed to be hot, but only~to possess the property of
producing in the animal system, the sensation of heat.
The cause of heat is distinguished from heat by the term
2. Light, as is well known, proceeds from the sun and
the fixed stars, as direct sources ; from the moon and
other planets by reflection, and from various terrestrial
substances, while experiencing combustion from phos-
phorescent matter, &c. The nature of light and caloric
is at present unknown ; from the intimate connexion
between them, they have by some been considered only
as modifications of the same substance.
Among the most important properties of caloric are,
1, its tendency to an equlibriu-n ; 2, its power of dilating
bodies ; 3, its susceptibility of being reflected from one
body to another ; 4, its power of increasing chemical
3. Electricity. From whence arises the peculiar
sensation which is experienced when a piece of zinc
placed upon the tongue, is brought in contact with a
piece of copper placed under this organ? What power
was that which, under the eyes of Galvani, animated the
IB one in which but two elements are united ; a ternary compound
consists of three elements ; a quaternary, of four,
limbs of a dead frog, when two metals, placed at the
extremity of a naked nerve, were made to communicate
by means of a metallic wire? What dazzling biilliancy
flashes in the skies, or darts downward upon earth,
fraught with terror and destruction ? It is the electric
fluid. But what is the nature of this fluid which divides
the material world into two great masses, the positively
and negatively electrified? Is it simple or compound?
Why is its presence so uniformly accompanied with light
and heat ? Are light and caloric anything more than
modifications of this fluid, and is not electricity indeed
the union of these two substances? Electricity, what-
ever it may be in itself, exercises an important influence
in chemical changes. The instrument called the voltaic
pile, causes the decomposition of a compound body,
which is submitted to its action ; the elements possessing
the positive electricity, go to the negative pole* and
those which have the negative electricity go to the posi-
tive pole of the pile.
4. The magnetic fluid gives to a mineral called the
load-stone (deutoxide of iron) the property of directing
its two extremities, either to the north or south pole of
the earth ; of attracting by its northern extremity the
southern extremity of another magnet, while it repels its
northern extremity or pole. It has recently been dis-
covered that the magnetic needle changes its direction
under the influence of the voltaic pile ; that the con-
ducting wires communicate magnetic properties to steel
and iron wires. It has therefore been conjectured that
magnetic attraction is but another modification of elec-
tricity. If these suggestions are founded in truth, we
may perhaps regard all the imponderable agents as the
result of one grand agent
PONDERABLE SUBSTANCES. **
Class 1. Supporters of Combustion. All substances
upon the globe except those already described under the
* The two extremities of a voltaic battery are called poles ; this
instrument was first called the Galvanic battery, from Galvani ;
afterwards, on being modified by Volta, it received its present
head of imponderables, are known to possess weight ; the
specific gravity even of the lightest gases have been as-
certained. After the discovery of oxygen, this gas was
for some time considered as the only supporter of combus-
tion, or the only substance which, by uniting with others,
could produce the phenomena of combustion. At present
four other analogous substances are ranked with oxygen
viz. chlorine, iodine, fluorine, and bromine. When any
one of these substances, existing in a binary compound,
is submitted to the action of the voltaic pile, the support-
er of combustion goes to the positive, and the combusti-
ble to the negative pole.
1. Oxygen unites with almost all ^substances, forming
acid and oxide compounds ; its name is derived from the
Greek, and signifies to generate oxides; these and most
of the acids being under the influence of this agent. Its
properties are very numerous, since its combinations ex-
ist in most bodies in the three kingdoms of nature. It
has been observed by a celebrated chemist, that ' Oxygen
may be considered as the central point, around which
The phenomena of combustion bear an intimate rela-
tion to oxygen ; so that the slightest union of this gas
with another substance, although neither accompanied
with sensible heat or light, is considered as a low degree
of combustion. Stahl supposed that the fire exhibited in
combustion was occasioned by the loss of an imaginary
substance, which he termed phlogiston, or the principle
of heat. Lavoisier proved the materiality of ogygen, by
showing that it was absorbed by the burnt substance ;
but neither of them accounted for the heat produced at
the moment of combustion, nor for the luminous appear-
ance or flame which accompanied it.
By observing the usual circumstances of kindling a
fire, we perceive that the temperature of the combustible
body is first increased by a borrowed heat. Now it is
known that electricity is developed by an increase of
heat, and that a union of the two electric fluids causes
an elevation of temperature : thus, when the caloric is
first added, the two electricities are brought forth; the
negative from the oxygen, and the positive from the com-
foustible substance ; and the union of these two electri-
cities is supposed to produce the heat which attends
combustion. When we assist combustion by the action
of the bellows, we direct a current of air upon the com-
bustible substance ; the oxygen being impelled upon its
surface, the fire becomes more intense. By repeating
the action of the bellows, we successively elevate the
temperature, until the combination of the two electrici-
ties is sufficiently energetic to give rise to flame. The
importance of oxygen as a supporter of combustion, is
manifested by various experiments ; even metals inflame
and burn spontaneously in this gas.
2. Chlorine was formerly called oxymuriatic acid, from
its supposed constituents, oxygen and muriatic acid. It
is at present, by the French and most English chemists,
regarded as a simple substance ; and muriatic acid is
now called hydro-chloric acid, being, as it is supposed,
a combination of hydrogen and chlorine. Chlorine may
be obtained by heating the pulverized peroxide of man-
ganese with hydro-chloric acid ; the hydrogen of the lat-
ter uniting with the oxygen furnished by the manganese,
disengages its chlorine in the form of a yellowish green
gas. Chlorine forms with oxygen several acids, as chlo-
ric, oxygenated chloric, &c. Its union with metals pro-
duces chlorides ; these dissolved in water are hydro-chlo-
3. Iodine, at the common temperature, exists in a
solid form ; its color is a bluish gray ; by heat it be-
comes a violet colored gas; it forms with oxygen, iodic
acid, and with hydrogen, hydriodic acid; combined
with sulphur phosphorous, and with metals, it forms
iodides. Iodine is obtained from sea-weeds, mineral
waters, minerals and sponge.
4. Fluorine is considered as the base of fluoric acid,
but as its actual existence has not been proved, it must
be regarded in the light of an imaginary substance.
Whether fluorice acid consists of oxygen united to the
combustible base fluorine, or whether, as is supposed by
some, this base is united to hydrogen, (hence the term
hydro-fluorice, instead of fluorice acid,) seems not yet
determined. This acid united to lime, constitutes the
fiuate of lime, or the beautiful Derbyshire spar : with
other bases it forms various Jluates.
5. Bromine, which has been recently discovered and
added to the list of simple substances, is obtained from
sea-water and the ashes of the same marine plants that
furnish iodine; it is a dark red liquid, so volatile as at
the common temperature to throw off red vapours ; with
oxygen it forms bromtc acid, which, uniting with various
bases, forms bromates and bromides.
Combustible Substances. Combustible substances are
such as possess the property of uniting with oxygen and
other supporters of combustion to form oxides and acids;
they may be divided into the following classes :
COMBUSTIBLES NOT METALLIC.
Class 2. Combustibles not metallic.
1. Hydrogen is a term derived from the Greek, signifying
to produce water, because this liquid is formed by the com-
bination of hydrogen with oxygen : in the language of
chemistry, water is the protoxide of hydrogen (or hydrogen
with one proportion of oxygen ; ) when another proportion
of oxygen is aflded, it becomes a dentoxide of hydrogen,
or oxygenated water. Hydrogen combined with oxygen
and carbon exists in all vegetable matter ; by the addi-
tion of nitrogen we have the constituents of animal sub-
stances. Hydrogen forms acids known by the general
name of hydracids ; with chlorine it forms hydrochloric,
with iodine hydriodic acids, &c. with sulphur, carbon,
&c., it forms sulphuretted hydrogen or hydrosulphric
acid, carburetted hydrogen, &c. It is highly combusti-
ble, and burns with much flame, furnishing, by its union
with carbon, the gas used in cities for lighting streets,
shops, &/c. On account of its being specifically lighter
than atmospheric air, it is used for inflating balloons.
2. Boron, combined with oxygen constitutes the base
of boracic acid; it is by the decomposition of this acid
that boron is obtained, it being never found pure in
3. Carbon, when pure and crystallized, constitutes the
diamond : it exists in charcoal with hydrogen, salts, and
other products of combustion, and may be obtained from
this combustion. Many attempts have been made to
crystallize carbon, in order to obtain diamonds, but
hitherto none have been successful. With a certain
proportion of oxygen, carbon forms carbonic acid with a
less proportion of oxygen, the oxide of carbon, or carbon-
ic oxide gas.
Carbon forms, with hydrogen, carburetted hydrogen,
or gas light ; with the alkalies it forms carbonates, as
carbonate of lime, (marble,) carbonate of soda, &/c. A
peculiar property of carbon is that of absorbing putrid
miasmata, or gasses ; a knowledge of this fact has given
rise to some important applications to culinary opera-
tions, medicine, &/c.
4. Phosphorus has received its name from two Greek
words,* signifying to bring light, this substance being al-
ways luminous in the air. With oxygen in different pro-
portions it forms phosphoric acid, phosphorous acid, hy-
pophosphorous acid, and oxide of phosphorrus. With
hydrogen it forms phosphuretted hydrogen, which in-
flames spontaneously in the air, producing the chal-
atious, or ignes fatui, which appear about burying-pla-
ces and marshes. Bones and other animal-substances
when decomposing, disengage oxygen, phosphorus, and
hydrogen; these united form phosphuretted hydrogen,
which being specifically lighter than the atmosphere,
ascends, and by its spontaneous combustion produces
those luminous vapors, which the superstitious and igno-
rant have referred to supernatural causes.
5. Sulphur, united to oxygen, forms sulphuric and
sulphurous acids; these acids, united to bases, form
sulphates and sulphites. With hydrogen, sulphur forms
sulphuretted hydrogen, and with the metals, various
sulphurets, as sulphuret of lead, &,c.
6. Selenium is less known than any of the non-metal-
lic combustibles ; it forms with oxygen selenic and selen-
ious acids and the oxide of selenium. Selenious acid
* Phos t light, and phero, I carry.
forms, with bases, salts called selenites ; selenic acid ;
orms salts called scleniates.
7. Nitrogen* when first discovered was called azotic,
which signifies a depriver of life ; this term appearing
objectionable, as it is not a direct destroyer of life, that
of nitrogen has been given from the circumstance of its
being, an essential ingredient in nitric acid. Nitrogen
combines with oxygen in five different proportions, form-
Protoxide of Nitrogen,
Deutoxide of Nitrogen,
With hydrogen it forms ammonia ; with carbon, cyano-
gen ; with chlorine and iodine, a chloride and an iodide,
The compound substance cyanogen (signifying by its name
the generator of blue) is the base of prussic acid (hydro-
cyanic acid,) which, uniting to iron, forms the color
called prussian blue.
Class 3. The Metalloids, or Earthly and Alkaline
The termination oids is from the Greek, and signifies
like or similar ; thus the term metalloids denotes like
metals. The substances comprehended in this class are,
in the strictest sense, metals ; but they differ from other
metals in their string affinity for oxygen, which renders
it extremely difficult either to obtain or preserve them in
a state of purity. It is but recently that they have been
known to exist ; potash, soda, Hme, &,c., were considered
as pure alkalies, until Davy, by means of the voltaic pile,
decomposed potash, and obtained a metal and oxygen ;
the metal he called potassium * thus it was discovered
* In giving nitrogen a place among combustibles, it must be
understood that it is not combustible in the common acceptation-
of the term, as it does not lake fire upon being brought in con-
tact with a burning substance ; but it is combustible in the chemi-
cal sense of the term, since it unites with oxygen and other sup-
porters of combustion.
that potash is not an elementary substance but an oxide
of potassium. Reasoning from analogy, Davy and some
of the French chemists were led to believe that soda,
lime, and other alkaline substances, had metallic bases :
a series of brilliant and convincing experiments have
now established this fact. Metals of this class seem
naturally divided into two sections.
Section 1. Earthy metals, or metals which are the
bases of earths ; these are
Silicon, the metal of Silex,
Glue in um,
Section 2. Alkaline metals.
Calcium, the metal of Lime,
Strontium, " " " Strontiart,
Barium, " " " Barytes,
Sodium, the metal of Soda,
Potassium, " " " Potash,
Lithium, " " " Lithia.
Class 4. Metals.
This class contains substances which have in general
less affinity for oxygen than the metalloids ; many of
them, such as silver and gold, cannot be easily oxida-
ted ; iron unites much more readily with oxygen, as maj
easily be perceived by exposing any iron vessel to the
action of the atmosphere ; in a short time it will be found
rusted, according to the common term, but which chem-
ically is said to be oxidated, the metal having combined
with oxygen from the atmosphere. Any article of gold
or silver is not thus acted upon by the atmosphere, nor
even by water, which iron soon decomposes, by uniting
with its oxygen.
We find, then, in examining the classification of
elements or simple substances,
Imponderable bodies, 4
Supporters of Combustion, 5
Combustibles not metallic, 7
Metals including metalloids, about 40*
Binary compounds (from bis, two) are such as are
formed by the union , of two simple substances ; these
eompounds are of three kinds; 1st, those which are
neither oxides nor acids; 2d, oxides; and 3d, acids.
The binary compounds, which possess neither the
properties of acids or oxides, are to be found in the
union of the simple combustibles among their own class;
as, carburetted hydrogen, consisting of carbon and hydro-
gen ; cyanogen, of carbon and nitrogen ; Moro-carbon-
ous gas of chlorine and carbon. Sulphur with bases
forms binary compounds, called sulphurets. Steel is a
binary compound, formed of carbon and iron. Oxygen?
in one, two, three, and even four proportions, forms a
great variety of binary compounds ; as with sulphur it
forms in the highest proportion sulphuric acid, in a
lower proportion it forms sulphurous acid, &c. The
most important acids are mostly binary compounds.
With the metals, oxygen forms oxides, protoxides, &/C.
There are eight non-metallic oxides, viz.
The Protoxide of Hydrogen, or water,
Peroxide of Hydrogen,
Oxide of Phosphorus,
Oxide of Carbon,
Oxide of Chlorine, or Euchlorine,
Protoxide of Nitrogen, or Exhilarating Gas,
Deutoxide of Nitrogen,
Oxide of Selenium.
The metallic oxides are very numerous ; the peroxide
of manganese is of great importance in chemistry, it
being used for procuring chlorine oxygen, &/c. The
deutoxide of iron possesses magnetical attraction ; it is
called the load-stone or magnet. The deutoxide of