bine with a substance, the name of the compound is made to terminate in ate; for instance, snlphuric acid with soda forms sulphate of soda. If an acid whose name terminates in ous combine with a substance, then the name of the resulting compound is made to terminate in ite; for example, sulphurow* acid with soda forms sulphite of soda. When a simple substai ce unites with oxygen, and does not form an acid, the compound is simply termed an oxide. In like manner the combination of iodine, chlorine, bromine, sulphur, and fluorine, with other simple substances, forms chlorides or chlorurets, iodides or iodurets, bromides or bromurets, sulphides or su'phurets, and fluorides or fiuorurets. But the advantages of the new system of nomenclature are best displayed by some other examples which I now mean to give you.

"The chemist, Glauber, discovered a salt, which was long known by no other appellation than Glauber') salt; but this name conveys very little useful information indeed;—merely giving us to understand that Glauber was, in some manner or another, connected with it; a matter of very slight importance. Now Glauber s alt being a compound of sulphuric acid with soda, the framers of the new nomenclature called it sulphate of soda, a term which immediately bespeaks its composition, and affords us a very useful piece of information. Again, there exists a substance commonly known by the name of sal-ammoniac; but what information does this convey p None at all t whereas the term hydrochlorate of ammonia, informs us that it is a compound of hydrochloric acid and ammonia."

ATMOSPHERIC GASES.

By experiments carefully conducted, it has been found, that the composition of the atmosphere is extremely uniform in all parts of the earth, and at all heights above its surface, and that it consists of

By measure. By weight.

Oxygen 21 23

Nitrogen 79 77

100 100

Though these are the essential constituents of atmospheric air, it contains other bodies which are regarded as adventitious, and the quantity of which generally varies; of these, carbonic acid and aqueous vapour are the most important; the quantity of the former may be considered as amounting to about .01 per cent., so that

upon the whole, the constituents of the atmosphere may be regarded as follow s :—

By measure. By weight

Nitrogen .... 77.5 77-55

Oxygen 21 21.32

Aqueous vapour 1.42 1.0S

Carbonic acid.. 0.08 0.10

100 100

Nitrogen is a colourless gas, with neither taste nor smell, having no action upon vegetable colours nor lime-water; neither is it absorbed by water, unless that fluid has been deprived of its ordinary portion of air by boiling, when it takes up about one-and-a-half per cent. It is, rather lighter than atmospheric air, compared with which, its specific gravity is 0.972. Its specific gravity, in reference to hydrogen, is as 14 to 1. All animal immersed in nitrogen is instantly suffocated, whence it was called by Lavoiser uxote (from a privative and {Wis, life); but if that term be taken in its strictest sense, all gaseous bodies (excepting atmospheric air), might be included under it, for even oxygen itself will not indefinitely support life. The term nitrogen merely implying that it is a component of nitric acid; it is explicit and unobjectionable, therefore it is adopted in preference to azote. Nitrogen is a non-supporter of combustion. I t may be obtained by mixing equal weights of sulphur and iron filings into a paste with water, and expose them to a confined portion of atmospheric air for forty-eight hours; the oxygen will be absorbed, and the nitrogen left nearly pure.

Oxygen may be obtained by mixing powdered oxide of manganese and sulphuric acid in such proportions, as to be about the consistence of cream. This mixture is to be put in a glass retort, and heated over an Argand lamp; the gas will pass over, and may be collected in the usual way with the pneumatic trough. It is insipid, colourless, and inodorous. Its specific gravity, compared with air, is as 1.111 to 1.000; compared with hydrogen, as 16 to 1. When powerfully compressed by the powerful depression of a piston in a glass tube, it becomes enormously luminous, a property which has not been observed in any gaseous body, except such as contain oxygen, and which property may be considered as one of its characteristics. It is absorbed in very small quantity only by lime-water. It does not alter the colour of litmus, nor does it render lime-water turbid. It is a powerful supporter of respiration. A small animal confined in oxygen, lives thrice as long as when con

fined in the same quantity of common air; it has, therefore, been called vital air; but, as I before stated, it will not sustain life for any long period. A lighted taper when introduced into this gas, is very rapidly consumed, with intense ignition and enlargement of the flame. Sulphur, which burns in the air with a small blue flame, soon has its flame enlarged when immersed in a jar of oxygen, and burns with a beautiful colour. When phosphorus is burnt in oxygen, the light is so intense, that the eye can scarcely bear its brilliancy. Oxygen is more abundantly diffused throughout nature than any of the other elementary bodies. An account of carbonic acid will appear in one of my next papers on adds.

J. Mitchell.

MISCELLANEA.

The Sting of Beer. —Although the poison which a bee emits, when it inserts its sting, is proved to be a highly concentrated acid, it does but follow that the application of all alkalies will neutralize the acid. Ammonia, for example, we have known in several instances, to produce distressing consequences—such as excessive local rnriammstioo, temporary erysipelas, and general distress to the constitution. The more gentle alkalies—chalk or the " blue bag," are much more likely to effect a cure, and cannot injure. The same person will be variously affected by the song of a bee; at one time scarcely any inconvenience will attend it; at another much swelling: again, but little enlargement, although great pain, Sec. The eye suffers considerably, though in general the uneasiness is local; but if the back of the ear be stung, there is frequently a general affection of the system, sickness, giddiness, numbness, nervous trembling, etc., which will sometimes continue for hours. A draught of camphor julep, and total repose, we have known to be beneficial in this latter case, and would earnestly recommend it to our readers, should they be placed in circumstances to require assistance.

Drawing an Inference*—The proprietor of an immense number of water-side carts in Liverpool, who has raised himself by industry to be a man of considerable property, being in close conversation with a gentleman about some private business, was asked by the gentleman if he could draw an inference. "Not I," said he, " but I bought a mare the other day, and I'll lay a fire. poond note that she draws it, if it does not weigh more than five tons."—Noble's Compen

Lock Leven.—The origin of the name Loch Leven is somewhat curious. 'It arises from the circumstance of the number eleven frequently occurring in matters connected with the lake. As already mentioned, it is eleven miles in circumference; the lands of eleven lai rds at one time embraced its waters; there are eleven rivers and i running into it; it contains eleven kinds

of fish; and in the adjoining plantations are eleven kinds of wood. The name was, therefore, originally, Loch E leven; but in the course of time the E was omitted as at present.—Walks and Wandering* in the World of Literature, by the Author of " The Great Metropolis."

INSTITUTIONS.

LECTURES DURING THE WEEK.

London Mechanic* Institution, 29, Southampton, Buildings, Chancery-lane. Wednesday, Oct.

23, Rev. R. Vaughan, D.D., on the History and Antiquities of Athens. Friday, Oct. 25, S. C. Horry, Esq,, Barrister, on Petit Juries, their Origin, Rights, Duties, and Influence. At half-past eight precisely.

Westminster Literary and Scientific Institution, fland7, Great Smith-street. Thursday, Oct.

24, John Frederick Goddard, Esq., Lecturer on Optics at the Royal Gallery of Practical Science, on the Oxyhydrogen Microscope, with illustrations. At half-past eight

QUERIES.

What will be the thickness of metal required for a concave copper ball, eight inches diameter without, so as to sink to its centre in common water? A. D. M.

How to procure India-rubber thread, such as is used for braces, lapped with cotton twist

A Constant Reader.

Blackburn.

How to make crumpets, muffins, gingerbread, bi&cuiis, and buns? A. A.

The preparation to be applied to the stucco wall before papering, and likewise the ingredients used in making paper-hangers paste?

A Subscriber. How is steel to be gilt in the cheapest way, as steel pens? What kind of varnish is used for Dutch metal on paper or on wood, for preventing tarnishing? Is it oil or spirits of wine?

A Constant Rkaoer. The power, weight, and dimensions of Hancock's steam gig or phston? J. Mitchell.

If J. Mitchell can inform me how to obtain it presulphate of iron, he will much oblige a

Juvenile Kntertainer.

ANSWERS TO QUERIES.

To make Green Fire.—Seventy-seven parts of nitrate of baryta, thirteen parts of flowers of sulphur, five of chlorate of potassium, and the small quantity of charcoal.

To make Carbonic Acid Gas.—" A Subscriber," will find the process described in one of my papers on tho acids in Nos. 1 & 2 of the fifth volume. J. Mitchell.

To make Frankfort Black..-." F. J. F." This is made by calcining vine branches and other refuse lees of the vinegar vats of Germany ; they must be previously washed.

Juvenile Entertainer.

Toprocure Hydrogen.—Pour diluted sulphuric acid, or" spirits of vitriol, as it is generally called, upon iron or zinc filings, or turning in a Florence flask, adapted with a good cork, and a piece of bent tubing. It can then be collected with the pneumatic trough. I have used a very good and cheap substitute for the pneumatic trough, which will perhaps be useful to some of your readers:— A, the flask, containing the diluted acid and filings; B, the bent tube; c, the shelf; D, the receiving vessel, and E, the basin, answering the purpose of a pneumatic trough.

J. MlTCHHLL.

Paper may be stained scarlet by sponging It over with a weak solution of nitro-muriate of tin, and then again with a strong infusion of cochineal (in the proportion of about a quarter of an ounce of the powdered cochineal to eight ounces of boiling water, letting it infuse for one hour, then strain it). The paper is then glazed, by submitting it to a powerful pressure.

To make Fluoric Acid*—" Jones." Fluoric acid is procured from a substance well known in mining districts called fluoi spar. It is fonnd chrystallized in cubes of various colours, green, yellow, and purple. If this mineral be reduced to powder, mixed with twice its weight of strong sulphuric acid (oil of vitriol), and subjected to distillation, a powerful and highly corrosive liquid may be obtained. For this purpose, a leaden or silver retort and receiver must be employed; and while a moderate heat is applied to the retort, the receiver must be kept cool by pounded ice or snow. The acid thus formed must be preserved in silver or leaden bottles, with stoppers of the same materials. It is extremely volatile, and not easily confined. It is necessary to use great caution when experimenting with this substance, as its vapours are highly irritating, and when applied to the skin, it disorganizes it so rapidly, as 11 occasion dangerous ulcers. It acts strongly on glass, and corrodes it deeply.

To make an Infusion of Gentian.—'* F. J. F." Take of gentian root bruised, two drachms; dried orange peel, two drachms; and fresh lemon peel, four drachms; pour upon these ingredients one pint of boiling water; let them infuse for one hour. The above is the same as ordered in the London Pharmacopoeia.

To make Red Fire.—" G. R. C." Forty parts of dry nitrate of stroutia, thirteen of powdered sulphur, live of chlorate of potassa, four of sulphuretof antimony, and a veiy small quantity of charcoal. The chlorate and sulphuret should bo separately powdered and mixed together on paper with the other ingredients. Platter Figures may be Varnished after being done over two or three times with size, so that they will bear washing

To Polish Shells.—This may be done cither byhand labour, or by being varnished; in both cases all the rough parts must be well rubbed down with emery and water. If they are to be polished by hand (which is the best and most lasting''way), after they have received two and three courses of emery of different degrees of fineness, they must be finished with buff leather dressed, with rotten-stone and oil.

TO CORRESPONDENTS.

Juvenile Entertainer.—His apparatus for r«. maining under water, a drawing and description of which we have received, wc consider as not only ingenious, hut likely to become of great utility,especially in the canes he mentions; if it Ite his intention to divulge his invention, we shall feel pleasure in recording it in the u Mechanic;" but some egressions in hi* letter have caused a doubt whether he intended it as a private communication, or for insertion—we await hi* answer.

A. B., the inventor of an apparatus for stopping homes, is requested to tend us his address, a gentleman having tcritten to us expressing a wish to see the invention.

S. Rowbotham, Worcester, will receive a communication per post.

Tyro Ghemicus will find a letter addressed to him at our office. Letters are also left for our correspondents—Electron, J. Mitchell, Alpha, and C. 11.

Numerous queries and other communications, for which we have not sufficient space this week, art nevertheless intended for insertion.

A SPLENDID RAILWAY MAP!

With the Mechanic And Chemist of October

2flth, will be presented (gratis) a

SPLENDID MAP OF ENGLAND AND WALES J showing, in addition to all the Principal Towns, the routes of the Railways through the various Comities; forming a hand* some Frontispiece to Vol. IV. To ensure early impressions, give immediate orders to your Book* sellers or Newsmen.

London: G. Berger, Ilolywell-street, Strand; and all Booksellers in Town and Country.

London: Printed af'TiiECiTf Pkesb," 1, Long Lane, Aldersgate, by D. A. Doudnet (to whom all communications for the Editor must be addressed,' postage paid); published every Saturday, by G. Merger, Holywell-street. Strand; and may be had of all Uooksellcrs and Newsmen in Town and Country.

HISTORY OF ARCHITECTURE.

NO. VIII. (Concluded from page 362 J (See engraving, front page.) We have now briefly glanced at the propress of architecture in England up to the time of Sir Christopher Wren, many of whose works are extant. As a finale, we will give an example of the architecture of the present day by living architects. The one selected for this purpose is the Oxford and Cambridge University Club House, for the elevation of which, and the following particulars, the writer is indebted to the "Civil Engineers' and Architects' Journal."

"The front extends 87 feet in width, its height being 57 feet from the ground line to the top. An entablature, marking the separation of the ground story from the principal floor, and projecting forward in the centre of the building over four Corinthian columns, divides the front, horizontally, into two equal parts. The centre space on the ground floor is occupied by the portico which projects to the front line of the area; the centre intercolumnation is wider than the rest, forming the entrance to the hall; the four columns stand upon pedestals four feet high, with mouldings and cornices. The upper part of the building is terminated with a delicate Corinthian entablature and balustrade, proportioned to the whole height, breaking forward with the centre of the building, which corresponds in width with the portico on the ground-floor; thus the front is divided vertically into three main compartments, the centre being less in width than the other two, which assume the appearance of wings; the effect of a centre, indicated by the projecting portico on the ground-floor being thus maintained throughout the whole height of the building.

"The angles of the centre division, on the principal story, are formed of rusticated pilasters; the principal window occupies the space between these pilasters, which having neither bases nor capitals, produce a uniformity in the lines round the windows, giving it the appearance of being contained in a frame. This window, designed with antes, in lieu of architecture, supporting an enriched entablature, is much wider than the rest, and standing clear of the pilasters, with its mouldings to profile, forms in itself a feature in the design. Rusticated pilasters, similar to those already described, divide each wing on the principal floor into three equal, recessed, oblong spaces, containing

the windows, similar in design to the one already described, except that the mouldings to the antce and entablature do not profile, but stop against the inner side of the pilasters. The ground story is rusticated, and the windows have semicircular heads, with radiating rustics, and impost mouldings. A balcony, projecting three feet, continues throughout the whole line of front, and breaks forward with the portico, the parapet being formed of pedestals, with intervening panels of richlydesigned foliage, cast in metal in high relief, and the landing supported by elaborately enriched consoles. The frieze of the entablature over the ground story, is filled with convex panels, enriched with laurel leaves, and over each column of the portico are shields bearing the arms of the Universities. The whole of the ornamen. tal detail throughout is designed to correspond in richness of effect with the Corinthian capitals of the columns, which have their central volutes entwined. Below the ground story there are two stories, a mezzanine and basement, which are screened by the area parapet.

"The bas-reliefs in the panels above the windows of the principal floor require particular notice; they are executed in Roman cement by Mr. W. G. Nicholl, from designs by R. Smirke, Esq., R. A., and illustrate those exalted labours of the mind which it is the peculiar province of the Universities to foster and promote. They recall to mind the sovereignty of Greece and Italy in the divine art of poetry, and the full measure of intellectuality vouchsafed to the inhabitants of this our portion of the globe. In the centre panel Minerva and Apollo 'preside on Mount Parnassus, a female figure personifying the river Helicon, forms part of the group, and pours from an urn the source sacred to the God of verse; the Muses surround them at the foot of the Mount. In one of the extreme panels, allusion is made to the popularity of the Iliad, in which Homer is represented singing to a warrior, a female, and a youth; in the other, Virgil is represented singing his Georgics to a group of peasants. The remaining four panels represent, first, Milton reciting his verses to his daughter, inspired by a superior agency seen hovering over him; Shakespeare attended by Tragedy and Comedy; Newton explaining his system; and Bacon recommending his philosophy to his auditors."

This building is situated on the south side of Pall-mall, near St. James's Palace, and Sir Robert Smirke, R. A., F. R. S., and Sydney Smirke, Esq, are the architects.