nians understood it, and that Alexander himself addressed the army in Greek. It was, certainly, the language introduced by Ptolemy into Egypt; and exclusively spoken in the court of his successors. However, from a mixture of several barbarian nations, the Macedonian dialect was much debased; besides, as already noticed, some difference occurred in the languages spoken by the families descended from the different sons of Javan.

"The Thracians and Epirots, being still more exposed to the inroads of the neighbouring barbarians, many of whom settled among them, difficultly retained any traces of their original language, particularly the former. However, it was long retained in some parts of Thrace, as appears by the poems of Orpheus and Linus, composed in Greek. Pieria and Olympus were anciently parts of Thrace, though they were afterwards accounted to belong to Macedonia. From the prevailing mixture of barbarians, the Thracians were deemed to be also barbarians.

"That Epire was also inhabited by Greeks, though intermixed with many barbarian tribes, appears by Strabo, who tells us, the Molossi, an Epirotic tribe, were governed by kings of the race of Eacus; as was afterwards all Epire by Phyrrus. Besides, we find the Molossi sent a colony to lonia: now the Ionians would certainly not have received them, if they were not of Greek origin. It is true, they also received the Pelasgic Arcadians; for this reason only, that the Pelasgi were incorporated with the Arcadians, and could not be distinguished. See Herodot. Lib. I. cap. cxlvi. ; as they were also with the Athenians. Plin. Lib. IV. cap. i. reckons Macedonia, Epire, and Thrace, as part of

Greece; and so does Homer, ad II. v. 635.

"The descendants of Elisah, the eldest son of Javan, passed into Greece, properly so called, extending from Macedonia, on the north, to the southern extremity of Peloponnesus, and from the eastern to the western sea, and the adjacent islands. Thus, we see the terri tories of all the sons of Jon bordered on each other; and, I believe, it generally happened, that the progeny of each of the original pattiarchs, Japhet, Sem, and Cham, settled at a great distance from that of the other patriarchs; but the progeny of each of the sons of the same patriarch, for instance of Japhet, settled at a less consider able distance from each other; and the descendants of each of the grandsons, for instance the descendants from Javan, settled at a still less distance from each other.

"Elisah, in the Samaritan copy, is written Helas; and from him, after some ages, for reasons we shall presently mention, the Greeks were then called Hellenes. The Hellenes, then, not being permanently ex posed to barbarians, as the other descendants of Jon were, preserved the Greek language unmixed. Greece, before the arrival of the Hellenes, was inhabited by various barbarian tribes; as Strabo informs us from Hecateus; of whom the most powerful were the Pelasgi, who originally dwelled in the maritime parts, afterwards called Jonia, Hence, it is plain, by the testimony of a profane historian also, that the descendants of Jon passed into Greece, from the continent of Lesser Asia, after they had expelled the Pelasgi, who inhabited the coasts afterwards called Ionia. The Pelasgi, thus expelled from lonis, passed, probably, into the country afterwards

afterwards called Attica, as being nearest to them; but this being barren, they settled, in greater numbers, in Peloponnesus, and founded the kingdoms of Sicyon and Argos: the former, 2171 years before Christ, and the latter, 1779. Hence Ephorus, quoted by Strabo, says, Peloponnesus was anciently called Pelasgia; and Eschylus, in Sup

plices, 598, 600, (or rather 327 and 350, in my edition); and Pliny, Lib. IV.

"Thus have I proved, that the primeval language was introduced into Greece by the Ionians, who inhabited Attica; and shewn how, from them, it was extended to the different regions that composed it."

"I

"I. Introduction. N the Bakerian Lecture which I had the honour of presenting to the Royal Society last year, I described a number of decompositions and chemical changes produced in substances of known composition by electricity, and I ventured to conclude from the general principles on which the phenomena were capable of being explained, that the new methods of investigation promised to lead to a more intimate knowledge than had hitherto been obtained, concerning the true elements of bodies.

"This conjecture, then sanctioned only by strong analogies, I am now happy to be able to support by some conclusive facts. In the course of a laborious experimental application of the powers of electro-chemical analysis,te bodies which have appeared simple when examined by common chemical agents, or which at least have never been decomposed, it has been my good fortune to obtain new and singular results.

"Such of the series of experiments as are in a tolerably mature state, and capable of being arranged in a

connected order, I shall detail in the following sections, particularly those which demonstrate the decomposi tion and composition of the fixed alkalies, and the production of the new and extraordinary bodies which constitute their bases.

"In speaking of novel methods of investigation, I shall not fear to be minute. When the common means of chemical research have been employed, I shall mention only results. A historical detail of the progress of the investigation, of all the difficulties that occurred, and of the manner in which they were overcome, and of all the manipulations employed, would far exceed the limits assigned to this lecture. It is proper to state, however, that when general facts are mentioned, they are such only as have been deduced from processes carefully performed and often repeated.

the strength of the opposite electricities in the circuit, and to the conducting power and degree of concentration of the materials employed.

"In the first attempts that I made on the decomposition of the fixed alkalies, I acted upon aqueous solutions of potash and soda, saturated at common temperatures, by the highest electrical power I could command, and which was produced by combination of Voltaic batteries belonging to the Royal Institution, containing 24 plates of cop per and zine of 12 inches square, 100 plates of six inches, and 150 of 4 inches square, charged with solutions of alum and nitrous acid; but in these cases, though there was a high intensity of action, the water of the solutions alone was affected, and hydrogene and oxygene disengaged with the production of much heat and violent effervescence.

"The presence of water appearing thus to prevent any decomposition, I used potash in igneous fusion. By means of a stream of oxygene gas from a gasometer applied to the flame of a spirit lamp, which was thrown on a platina spoon containing potash, this alkali was kept for some minutes in a strong red heat, and in a state of perfect fluidity. The spoon was preserved in communication with the positive side of the battery of the power of 100 of 6 inches, highly charged; and the connection from the negative side was made by a platina wire.

"By this arrangement some brilliant phenomena were produced. The potash appeared a conductor in a high degree, and as long as the communication was preserved, a. most intense light was exhibited at the negative wire, and a column of flame, which seemed to be owing to the developement of combustible

matter, arose from the point of con

tact.

"When the order was changed, so that the platina spoon was made negative, a vivid and constant light appeared at the opposite point: there was no effect of inflammation round it; but aeriform globules, which inflamed in the atmosphere, rose through the potash.

"The platina, as might have been expected, was considerably acted upon; and in the cases when it had been negative in the highest degree.

“The alkali was apparently dry in this experiment; and it seemed probable that the inflammable matter arose from its decomposition. The residual potash was unaltered ; it contained indeed a number of dark grey metallic particles, but these proved to be derived from the platina.

"I tried several experiments on the electrization of potash rendered fluid by heat, with the hopes of being able to collect the combustible matter, but without success; and I only attained my object, by employing electricity as the common agent for fusion and decomposition.

Though potash, perfectly dried by ignition, is a non-conductor, yet it is rendered a conductor, by a very slight addition of moisture, which does not perceptibly destroy its aggregation; and in this state it rea-. dily fuses and decomposes by strong electrical powers.

"A small piece of pure potash, which had been exposed for a few seconds to the atmosphere, so as to give conducting power to the surface, was placed upon an insulateddisc of platina, connected with the negative side of the battery of the power, of 250 of 6 and 4, in a state of intense activity; and platina wire, communicating with the positive side,

P 2

was

was brought in contact with the upper surface of the alkali. The whole apparatus was in the open atmosphere.

"Under these circumstances a vivid action was soon observed to take place. The potash began to fuse at both its points of electrization. There was a violent effervescence at the upper surface; at the lower or negative surface, there was no liberation of elastic fluid; but small globules having a high metallic lustre, and being precisely similar in visible characters to quick silver, appeared, some of which burnt with explosion and bright flaine, as soon as they were formed, and others remained, and were merely tarnished, and finally covered by a white film which formed on their surfaces.

"These globules, numerous experiments soon shewed to be the substance I was in search of, and a peculiar inflammable principle the basis of potash. I found that the platina was in no way connected with the result, except as the medium for exhibiting the electrical powers of decomposition; and a substance of the same kind was produced when pieces of copper, silver, gold, plumbago, or even charcoal, were employed for completing the circuit.

"The phenomenon was independent of the presence of air; I found that it took place when the alkali was in the vacuum of an exhausted

receiver.

"The substance was likewise produced from potash fused by means of a lamp, in glass tubes confined by mercury, and furnished with hermetically inserted platina wires, by which the electrical action was transmitted. But this operation could not be carried on for any considerable time; the glass was

rapidly dissolved by the action of the alkali, and this substance soon penetrated through the body of the tube.

"Soda, when acted upon in the same manner as potash, exhibited an analogous result; but the decomposition demanded greater intensity of action in the batteries, or the alkali was required to be in much thinner and smaller pieces. With the battery of 100 of 6 inches in full activity, I obtained good results from pieces of potash weighing from 40 to 70 grains, and of a thickness which made the distance of the electrified metallic surfaces nearly a quarter of an inch; but with a similar power it was impossible to produce the effects of decomposition on pieces of soda of more than 15 or 20 grains in weight, and that only when the distance between the wires was about one-eighth or one-tenth of an inch.

"The substance produced from potash remained fluid at the temperature of the atmosphere at the time of its production; that from soda, which was fluid in the degree of heat of the alkali during its formation, became solid on cooling, and appeared having the lustre of silver.

"When the power of 250 was used, with a very high charge for the decomposition of soda, the globules often burnt at the moment of their formation, and sometimes violently exploded and separated into smaller globules, which flew with great velocity through the air in a state of vivid combustion, producing a beautiful effect of continued jets of fire.

"III. Theory of the Decomposition of the fixed Alkalies; their Composttion, and Production.

"As in all decompositions of compound