reservoir of water, and the tar and some other ingredients are here deposited. It next passes through a reservoir of lime-water. This takes up the sulphurous acid gas which is apt in the first instance to be mixed with it. The gas after this immersion is sufficiently pure for use. A recent discovery has shown that a gas can be obtained from oil which is even more commodious than what is obtained from coal. The mode of obtaining it, as adopted by Messrs. Taylor, is as follows. Oil is suffered to fall in drops into a furnace wherein are fragments of brick and tile heated red hot. An iron pipe conveys away the gas from the furnace; in the furnace nearly pure carbon is deposited. The gas which is produced is very fine carburetted hydrogen. The great advantage of this latter plan arises from its economy.

The circumstance of these gases being used for lights pre-supposes that they are inflammable. On this account, in coal mines and other places where they are produced by nature, they are very dangerous, owing to their taking fire when the miner's candles are carried through it. It was, however, discovered that hydrogen could not pass in a state of flame through a very small pipe; on this principle, (which seems but imperfectly accounted for,*) Sir Humphrey Davy constructed his justly celebrated safety-lamp. In this a cylinder of wire gauze is fixed over the light, each separation in which answers to the orifice of a small tube, and thus no conflagration is caused, though the whole covering of wire frequently becomes red hot.

Here let us pause for a moment, and consider the wonderful benefits experienced by society at large from the discoveries of chemistry. We need not allude to the more obvious improvements in medicine, which have resulted from a more extensive knowledge of this branch of science. The astonishing power of steam might never have been applied to common

The explanation commonly offered is, that the wire when in such close contact with the gas, abstracts from it a sufficient portion of caloric to extinguish the flame,

*

mechanical purposes, had not the chemist in his experiments upon water discovered an easy and safe method of applying it. The discovery also of gas as a substitute for oil is one of which all equally partake. To enumerate, however, the individual instances of improvements, our limits render impossible, their ramifications are so widely extended. From the more potent drugs of the physician, to the lock of the sportsman, its influence is felt. The study of chemistry must then be considered as most valuable. When the alchemist, buried in his cell, sought in vain for the universal menstruum, or the elixir of life, the study was productive of but slight benefit to any; but now, when it extends its influence to every department of the arts, the prospect is far different. Nor should the study of this science be neglected from the supposition that it has reached its height; on the contrary, many are the phenomena unexplained, many the theories uninvestigated. But to return to our subject.

Carbon unites also with nitrogen, and forms a gas called cyanogen. It may be obtained from heating prussiate of mercury in a small glass tube, to a dull redness. It must be collected over mercury. It has a smell very much resembling bitter almonds. It burns with a beautiful blue flame. It unites in different proportions with water and alcohol. Cyanogen and chlorine combine and form an acid designated the chlorocyanic acid.

Cyanogen and hydrogen unite and form hydrocyanic or prussic acid. This also has a strong smell, much resembling that of bitter almonds. It is in a liquid form. It is highly poisonous. A single drop of this acid, when much concentrated, placed upon the tip of the tongue, produces instant death. If a quantity be rubbed upon the bare arm it is said to produce death. It volatizes so rapidly as to freeze itself. This acid is used in medicine. It was called prussic

* A new method of making the locks of guns has been adopted. By this the use of flint and steel has been dropped, and a fulminating powder has been nsed in its stead. This has many advantages: rain does not prevent its discharge, and it goes off much quicker than in the old method,

peace-offerings of the poor Indians, by whom the place was crowded, as mass was celebrating at the time. The fervent piety and decent behaviour of this little congregation would have formed a fine contrast with the gaily dressed bustling assemblages in some of the churches of France and Italy. Before the building were two noble cypress trees, of great size and antiquity: at the top of the steps of the entrance is a rich-sculptured cross, of stone, with the date 1666 inscribed on it, and near it a short hymn in Spanish, to the Virgin is engraved on

a tablet.

"We descended with reluctance the side of this pyramid, whose base is more extensive than that of the great pyramid of Egypt. It is covered with trees of great variety, some of which I had not seen before, but they had evidently been planted there. On our descent to the plains we visit ed two detached masses, constructed, like the great pyramid, of unburnt brick and clay. The one to the north-east had been cut or taken away; its sides were broken, and so perpendicular as to prevent access to its summit, on which a cross had been erected. The other was easy of ascent, and appears to me to have been a fortified place, with a ditch and a wall on the top, forming an enclosure resembling the figure oo, and about 100 feet in length: here I found among the loose earth many human bones; pieces of red earthenware; and fragments of obsidian-the knives, spears, and arrow-heads of the ancient Mexicans. An excavation of this pile would probably prove an object of high interest to the antiquary-I know of no engraving of it: the other detached piece has been engraved by Humboldt; whose figure of the great pyramid conveys no idea of its present state, nor is the church on its summit at all like the original."

The city of Mexico itself is not half so interesting as several of the other places visited by our author.

"The existing state of this city exhibits only a shadow of the grandeur it had once attained. The period of its greatest splendour, wealth and lux

ury, may be placed within one century from its conquest by Cortez. The present internal decorations but ill accord with the magnificent houses and palaces on which thousands have been lavished, and prove at once the poverty of the present Mexicans and the wealth of their ancestors. The massive silver tables, staircases and chandeliers, &c. &c. have all disappeared. The profusion of jewels and the extravagant equipages are no longer to be seen in the streets, and the ensemble even of people of the highest rank, of the present day, reminds us in nothing of the authenticated descriptions of the inhabitants of the same place by writers 200 years ago."

Taking a cursory view of the chief objects of curiosity still remaining in the city of Mexico, our author observes

"Of the myriads of pictures with which the churches, convents, cloisters, &c. &c. are crowded, I saw few worth the expense of removing. The churches and cathedrals may, amongst the great numbers with which they are encumbered, have some good, and I am inclined to think they have; but the quantity of light admitted into these superb temples is too little, even in the brightest day, to render it practicable to discover their merits: they are lost to the world in the sacred gloom that pervades the place. The public, too, are prevented from a near approach by clumsy railings; but, from what information I was enabled to obtain by peeping through, it appeared to me that some of the finest productions of the Italian and Spanish schools may be here buried in oblivion. I visited the homes of many of the nobility, but found little worthy of notice. The Count of Valenciana's drawing-room has a set of prints from Claude, which, with the exception of a few fine things in the palace of the Bishop of Puebla, are the only works. worth mentioning connected with the old masters, that came under my inspection.

"In the many rambles I made through the city, I often examined the brokers' and furniture shops; as, amongst the countless number of

"Of carvers in wood there are many, as every house has a statue of a saint or madonna painted and generally superbly dressed. The art of engraving on stone is unknown in Mexico; but the Indians greatly excel in the modelling and working in wax. The specimens of different tribes with their costumes, with the habiliments of the gentry of the country, which I have brought over, will amply testify their merits in this department. They also model fruit and vegetables in a beautiful manner. A lady at Puebla de los Angeles executes, in a singular style, from pieces of old linen cloth, groups of comic figures, some of which I have also brought to England. Such was her skill, that, from having only seen me for a short time, on my first passing through the city, I was surprised to find, on my return, that she had executed a portrait of me in this style, which was immediately recognized by my friends."

There is but one theatre.

"The house is lighted from above by sconces, each holding a number of glass lamps; and is more pleasing than might be expected. It is open every night, and twice on Sunday, on which day, and on holydays, the price is double; but this establishment paid so ill, at the time of our visit, that its final close was announced from the stage while we were present-so that the capital of New Spain is now with out any dramatic entertainment.

"With very few exceptions, all present, of either sex, pursued their favourite habit of smoking; the ladies, even in the boxes, with a fan in one hand and a cigar in the other, enveloped in a cloud of smoke that rendered it difficult to see from one side of the house to the other. - -

"In the fine evenings, during the dry seasons, the environs of the city present a scene of bustle, gaiety, and pleasure, scarcely to be paralleled; hundreds of canoes, of various sizes, mostly with awnings, crowded with native Indians, neatly dressed, and their heads crowned with the most gaudy flowers, are seen passing in every direction: each boat, with its musician seated on the stern, playing on the guitar, and some of the party singing or dancing, and often both united, presents such a picture of harmless mirth as I fear is rarely to be met with at the fairs and wakes of our country."

"Domestic water-fowl are almost unknown in this part of New Spain. I never saw a tame duck, and geese but twice, in the whole country. Turkeys, fowls, pigeons, hares, and rabbits, are in great plenty, and venison is occasionally met with at table. Fish is scarce and dear, the lakes producing but few species: the pesca blanca, or white fish, resembling in appearance and taste our smelts, is the best. Tortoises, frogs, and the axolate, a species of salamander, (an aquatic animal much resembling a water-newt or lizard,) are abundant in the market, and all good eating; the latter have been the subject of dispute among naturalists since the discovery of America, and we are still in obscurity with respect to their doubtful history. They were so plentiful in the time of Cortez that his army principally subsisted on them, and I have seen them by thousands in the markets of Tollucca; yet they have never been discovered in a young state, nor has any sexual difference yet been noticed. I brought several home in spirits, which are now under the inspection of Sir Eve rard Home, from whom the public may shortly expect much information respecting this obscure species.

"The Indians also bring to market a considerable quantity of a small delicate fish, not more than two or three inches long, which they take in nets in the canals and ditches near the lakes. They are enclosed in the leaves or capsules which surround the