of less than half a cent (at Paris). In a ||boyhood, the splendid phenomena of the clouds, but blackening in a moment, rise common coffee biggin, the same quantity Boreal Aurora, in almost all the latitutudes and fall, whenever a ray or an interior arc of water may be boiled for about a cent.- under which it is usually seen, as far north begins to form, and it is remarkable, that [Jour. Connaiss. Us. et Prat.] as to have observed the sun at midnight, and this darkness usually accompanies the comApplication of Tannate of Gelatin to ta- particularly during a long sojourn in Shet-mencement of every change in the scene, king Casts from Medals, &c.-This sub land, where the people imagine, from its thereby increasing the majesty and beauty, stance is obtained by adding a decoction of extremely swift changes and inexpressible as well as the brilliancy of the spectacle. gall nuts, sumac, oak bark, or other sub- vividness, that they can actually hear its But it is impossible for any pen adequatestance containing tannin, to a solution of rushings, I have ever been anxious to ly to describe a phenomenon, which is conglue or isinglass, in water. It is fibrous seize all opportunities of endeavoring to tinually presented in these regions, and it and nearly insoluble. When exposed to catch its Protean forms, and to describe is with diffidence that I continue a task the air in thin layers, it hardens. When them, in hopes that by exciting attention to imposed on myself. It will, therefore, moist, it is elastic. facts concerning this wonder of northern be more satisfactory to detail the cirskies, science might be more attentive to cumstances attending a very recent repetiits appearances, and that at length it might tion of one of the most beautiful of those become a portion of the duty of meteorolo-which have been seen at Kingston this wingists to detail in their columns, all circum-ter, nearly the whole of which I saw, and stances concerning it, which they might ob- whatever escaped me was related by a serve. very accurate observer.

The substance which was found to give the best mixture for casts, was finely pulverized slate. Silica, emery, &c. give pastes which harden, and may be used for razor straps.

In making casts of the mixture of tannate of gelatin and pulverized slate, it must be left for a certain time in the mould, in order to preserve the impression. If, how-zling, and the quickness of its motions apever, it is allowed to remain there too long, proaches that of lightning. In other situit adheres strongly. The only difficulty in ations, it has also been observed to assume the application is to ascertain the precise irised colors. But although all these comtime required for due hardening. bined are eminently wonderful, and strike This substance may replace bronze in the spectator with profound admiration and ornaments, papier mache, card work, &c. awe, yet perhaps the regions of Upper -[Ibid.] Canada, bordering on Lake Ontario, exAnalysis of two varieties of Bronze-hibit, though not so splendid and varied a These specimens were analyzed by M. Ber- display of this mystery, yet one equally, or thier. The first was intended for the man perhaps more, interesting to the philosoufacture of cannon, but proved of bad qual-pher. I have now witnessed the Aurora at ity; its composition was ascertained to avoid the same proportions in other mix-Kingston for upwards of four years, and in a former volume of the Transactions, have tures. It consisted in 100 parts, of copper described a magnificent scene, which oc83.8, tin 15.7, lead 0.5.

The bronze used at Paris for the striking parts of clocks, was found to be composed in 100 parts, of 71 to 72 of copper, 26.56 to 27 of tin, 1.44 to 2 of iron.-[Ann. des Mines, vol. VII.]

Sheathing of Ships with Bronze.-The sheathing of this metal has been found by experiment, to lose but half the weight, in a given time, which copper would have lost. The composition used for making sheet bronze is 91 of copper and 9 of tin. -[Ibid.]

The Aurora in the high northern latitudes, when at its extreme, is almost daz-ber, 1835, the sky, after the sun had sunk, On the evening of the 11th of Decemwas dark and gloomy, and although there were but few clouds visible, and the stars ther was apparent. Snow had fallen, for were rapidly brightening, a change of weathe first time, on Wednesday, the 8th, after a short space of great cold, to the depth of about five inches, and the thermometer had sunk afterwards to 16°, at which it stood on Monday, the 13th. On Tuesday, it rose to 30°, and rain in abundance falling, removed the snow entirely. It was exactly midway between the extreme cold and the thaw, that the Aurora took place, the thermometer at the time standing at about 26°, and the wind, a gentle breeze from the north west. The barometer stood at 29.9,

*

Its first appearance, after darkness had completely set in, was by the luminous arch above mentioned assuming its wonted place. From this arch, in the north, arose almost incessant streamers of bright white light, which shot upwards to the zenith, and streaked the dark sky with their silvery

Once a mass of light suddenly opened in

curred there two years ago. During the winter months, on Lake On-at 9 P. M., at an elevation of forty feet tario, the Aurora may be said to be almost above the lake, which is two hundred constant companion of the dark and cheer- and nineteen feet above the level of the less nights, and it occasionally presents it- sea. self at all other times of the year, nor is it in winter a mere display of a glorious phenomenon, the utility of which has not yet been exemplified by science, for it sheds a continued and pleasing light, which resembles that of the crepuscular. The light does not, as in Europe, emanate from the Durability of Acacia Wood-It was vivid streamers which dance over the star-lines. found that in the mining galleries at Carry floor of the heavens, in ever charging maux, (France) the oak timber used to and inexplicable mazes, but proceeds from support the sides and top of the galleries, the northern horizon, over which a pale, lu- the zenith, and from it darted out innumerdecayed very rapidly, being effected by the minous, low, and depressed arch, embra-able pencils of bright rays, overspreading dry rot. A comparative experiment was cing an extent of from sixty to ninety de- the dark vault of heaven with their glories, made with acacia wood, from which it reThis arch is and seeming for a moment to illuminate the is commonly thrown. grees, sulted that the latter wood is much more generally luminous in its whole body, not sky with a star which its vast space was durable than the former, when exposed in on the rim or verge only, which fades away scarcely capable of containing. such situation. Oak timber decayed in into ethereal space, but from its superior Again, rods of white light would dart three months, while the acacia was unact-circumference to the chord formed by the forth from the northern horizon, and one ed upon, except at the sap-wood surface, horizon itself, and varies in its elevation, single one, in particular, spanned the whole from ten to fifteen and twenty degrees. arch of heaven, touching the southern horiWherever it embraces stars, these lumina-zon over the great lake. ries are either veiled or dimly seen, being strongly contrasted on a fine star light right, with their fellow orbs of the southern heavens, which appear to shine out with double brilliancy.

four years.

The lateral strength of this wood is about equal to that of Norway pine.-[Ann. des Mines, vol. VII.]

From the American Journal of Science and Arts. ACCOUNT OF AN AURORA BOREALIS, WITH

Within the space comprehended by this A NOTICE OF A SOLAR PHENOMENON; arch of light, continual changes are operata splendid BY CAPT. R. H. BONNYCASTLE, R. EN.,ing, if the Aurora assumes shape. Dark volumes of vapor, not like

TORONTO, UP. CANADA.

I. Aurora Borealis.

*Not having observed it elsewhere in Canada, Having witnessed from the days of my peak only of locality as a personal observer.

This play of the Aurora continued from seven till near nine, and was most brilliant and magnificent about nine, when it assumed another ard not less singular attitude, of which the following is a faint attempt to delineate.

*The barometrical observations were made at the Hospital on Point Henry, by a very accurate observer. On the 10th December, it indicated, at 9 A. M. 29 5, at 9 P. M. 297; on the 11th, at 9 A. M. 298, at I9 P. M. 29.9; on the 12th, at 9 A. M. 30.1, at 9 P. M. 30.1.

These arches are not so flat as they should be, but the space is insufficient to show them exactly. The lower one was usually the boundary of a very dark black, changing mass; between the lower arch and the second, the space was not so dark; and between the second and third, or upper arch, it was still lighter, excepting where the coruscations shot upwards out of the second arch, and there it was very dark. The second arch was incomplete. The ray shooting up on the right was

Stars were par-
brilliant in the extreme.
tially visible above the third arch, but the
bright ones in Ursa Major, on the left, had
lost all their splendor, and the constellation
The obscuration of
could just be traced.
the heavenly bodies reached almost to the
zenith, above the centre of the arch, and was
less over the extremetics.

The first appearance lasted long enough
for me to go into another part of the house
and make ahasty sketch; or my return to the
window, it was alt ring to the following form.

Both arcs or belts were now less distinct, the lower one almost obliterated, but still its place was well marked by the arch of vapor below, which was darker than ever. Three large spots of intense light now displayed themselves, one on the horizontal chord, and one an each side of the lower arch, whilst this lower zone shot out innumerable pencils and floods of light from its dark nucleus, the upper zone also darting forth long lines of brilliant rays; all these rays from both hands, moving in a very statelymarch or progression from east to west.

Towards the southern and western portions of the heavens, all was clear blueblack starlight, Orion being particularly brilliant; the north was as if overspread with a thin veil, through which the stars were barely visible.

I watched these alterations of the phenomenon until after ten; and the last I olserved presented this form; after which the arches became less distinct, and eventually, with the exception of the great arch, passed

away.

In this fourth change the Aurora, it will be observed, resumed its three arches, but they were no longer concentric, the third being broken on the right into a portion of a fourth. Between the second and third the darkness was the darkness of blackness, whilst the third arch was light itself; but the lower arches were not so bright, and the lower nucleus was only darkish, which was contrary to every state that it had presented, under any former observations for several years.

The lower arch had somewhat height-out of either of the changes of the Aurora, ened and become darker, with here and were so quick or so intensely vivid in their there spots of light in it, whilst from its action or light, as those seen in the more norcircumference shot out brilliant rays and thern regions, nor were they colored; but pencils of light. The second arch had al- they were always accompanied by the black together disappeared, but the upper one vapory shroud, which hid every thing else held its wonted place. It must be observed, from view, and added greatly to the lustre that the upper arch was always paler, and of their exodus from the horizon. Having made the foregoing sketch, I more indistinct in its outline than the others. Fairt stars now appeared through again returned to view the Aurora, which the darkish vapor, between the two bands had somewhat changed its appearance. or arches of light, and the lower band was band of bright light, cut off, both above and indistinct, excepting to the left of its cen- below, by very black vapory masses. tral space, where it was vividly depicted second appearance lasted, also, long enough and extremely well defined, by a sharp to enable me to make a hasty sketch None of the pencils or rays, which soth of it.

This

The constant arch of the Aurora of the Lakes has, I believe, never been noticed in any scientific publication, as is well worthy the attention of the learned. Whether it is created by a peculiar locality of the matter, of which the substance of the Aurora is composed, or whether the Aurora itself. as

although it is true there was a slight mist or almost complete circum-solar, rainbow fog. which appeared at Toronto, (U. C.) July, Since writing the above, I have seen an 1834, at 7 in the morning.

Applications of Chemistry to the Useful Arts, laboratories but on a larger scale. The being the substance of a Course of Lectures delivered in Columbia College, New-York, by James Renwick, Professor of Natura Experimental Philosophy and Chemistry.

entering beneath its lower surface. These || proceeds from its lower point, and is long|| long use, the charcoal will finally become pipes serve to convey the gas generated in enough to reach the car, is left open, in so charged with the offensive matter that cach barrel to a common reservoir, placed order that the gas in the balloon may be at it will cease to act. The filter must then in the centre of the circle around which liberty to escape as it tends to expand it- be opened and the charcoal replaced by they are arranged. This reservoir is of self, in consequence of its reaching regions another portion of the same substance, or the character of the chemical apparatus in the atmosphere less dense then those the old charcoal purified by heat. called a gasometer. It is formed of two nearer the surface of the earth. Although The same property of charcoal may be large tubs, one of which is inverted with- the escape of this gas renders the balloon applied to the purification and preservation in the other. The space between them, somewhat lighter, it must finally reach a of water in ships. For the first purpose it as well as the inner tub, is filled with water, position where its weight is exactly the is only necessary to mix thoroughly with the air being allowed to escape from the same as that of an equal bulk of the sur-the water in the casks a few ounces of latter by a tube adapted to its head and rounding air, and must cease to ascend. powdered charcoal; for the latter the casks furnished with a stop-cock. As soon as A farther height may be attained by throw-may be charred within. The purification this tab is filled with water the stop-cock is ing out ballast. This is done by opening of water from insoluble matter by filtering closed. the bags in which it is contained. is performed by nature on a large scale within the crust of the earth, and that which issues from springs, and is found in wells is usually purified; but it may thus receive soluble impurities, although there are unquestionably some cases where the natural filter has the property of decomposing and retaining the soluble matter. Thus, on islands which are mere sandbeaches, fresh water may often be found by digging, which can have no other source than the neighboring water of the ocean, but this natural process has not been imitated by

When it is wished to descend, the valve in the top of the balloon is opened until the collapse caused by the escape of the gas renders the balloon heavier than an equal bulk of the surrounding medium, and the force which causes the descent will be an

The tubes which convey the gas are passed over the edge of the outer tub or through its staves, and their open ends pass beneath the cavity of the inner tub. The gas therefore enters it, and rising to the surface of the water tends to buoy it up, which action is aided by a counterpoise un-increasing one, as the collapse is increased til the balloon is ready to receive it. by the increasing pressure of the denser Balloons are bags of a spherical or air. It may therefore be necessary to check sphersidal form, made of gores of silk, it by the discharge of ballast, and by doing coated with a varnish which renders it im- this in sufficient quantity, the balloon may perrious to air. The best for this purpose be rendered stationary or caused to ascend is made of caoutchouc. Each of the gores again. In the latter case it is no longer neis prolonged into a rectangular strip, and cessary to allow the gas to escape by the these, when sewed together, form a long tube beneath, which is therefore closed by cylindric tube. The air having been forced knotting it. from the balloon by compressing it, this A balloon has no other capacity of being tube is tied to that which is adapted to the directed except in ascent and descent. No inverted barrel, the counterpoise being power has yet been discovered, which can removed, and the pressure, if necessary, be called into action, of sufficient intensity aided by loading the gasometer with to propel a balloon through the air, and weights, the contained gas, with that which is subsequently generated in the barrels, is forced into the balloon until it is completely inflated.

make it move in a direction contrary to the
currents of wind, and which shall be pro-
duced by apparatus sufficiently light to be
carried up by a balloon.

USES AND PURIFICATION OF WATER.

art.

The mere separation of insoluble matter from water has sometimes been effected on a large scale by taking advantage of natural circumstances. Thus at Glasgow, instead of pumping water from the River Clyde, tunnels of brick laid in sand are sunk in the gravelly bank of the river; through this water filters, and is drawn from the tunnels by a steam engine. At Toulouse, the reservoir which supplies the city is a basin dug in a gravelly bank, and separated from the river by a narrow dyke, through which Hydrogen gas having not more than the water passes perfectly clear. This re7th of the density of atmospheric air, the Water as found in nature is never ab-servoir has another valuable quality which joint weight of a large balloon and the gas solutely pure. Even when it contains no we cannot avoid mentioning. The lower which it contains, is far less than an equal solid matter, either in solution or me- part of it is filled with large boulders, on bulk of atmospheric air, and it will not only chanically mixed, it is charged with gases. these smaller water worn stones are laid; rise itself but will carry with it a consider- The most important of these are carbonic these are succeeded in turn by gravel, and able additional weight. In order to attatch acid and oxygen. These however, so far the gravel by sand. The water which oca weight to it, a net work is formed of from being injurious, are absolutely neces-cupies the spaces between the stones is cords in such manner as to embrace the sary to render water palatable, and prothus maintained throughout the year at an upper half of the inflated balloon, and from bably increase its usefulness in the animal uniform temperature, and is neither affected its equator, straight cords proceed, to which economy. Water which falls in cities by the frost of winter, or the scorching heats a car is tied. The balloon must be of such where coal is used as a fuel, contains of summer. This temperature too, which size as not only to carry up the persons sulphurous acid gas in solution, which is that of native springs, is such as causes the who are to mount, with their necessary gives it a disagreeable taste. This water to retain the greatest quantity of the equipment, but also a considerable quantity may be readily separated by heating gases which render it palatable. of ballast. This is in the form of sand it to the boiling point; as,however,the othus Water which is conveyed great distances tied up in canvass bags. The object of gases will also be driven off, water ther in pipes, or is precipitated in falls, loses this combined with a valve in the top of the purified must be exposed to the air for some these gases and will not regain them until balloon, is to enable the aeronaut to ascend time, in order that it may again absorb exposed to the air. A remarkable instance or descend at pleasure as long as the ballast oxygen and carbonic acid. The water of of the last sort occurs at the Falls of and the gas in the balloon are not wholly rivers is often turbid, in consequence of Niagara, where the water above the fall is expended. their carrying with them earthy matter in a agreeable, and in the pool below as nauseous This valve is placed on the top of the state of minute division, it may also con- as that which has been boiled. The same balloon and is thus constructed: the gores, tain animal and vegetable matter, or even action has even been applied to procure air instead of meeting in a point, are united living animalculæ. Such organic matter separated from falling water, to be used upon a ring of whalebone, and thus leave renders it unwholsome. The earthy and in the manner of that forced from a bel a circular opening; to this a circular shut-heavier organic matter may be separated lows. ter of silk, spread upon a similar ring, is by placing the water in tanks and reservoirs Water which comes from springs in the adapted by a hinge; two cords proceed where it may remain at rest, and the clear vicinity of the sea or its arms is often imfrom this, over the net work, in opposite fluid may be drawn off, but in this way pregnated with marine salt. It is then directions to the car; by one of these the living animals and lighter substances will said to be brackish, and for this no remedy valve can be opened, and by the other, still remain. It is therefore better to purify has yet been propsed except the costly one closed. it by filtration. In order to deprive it of all of distellation. That from inland springs disagreeable taste or smell, a part of the often holds in solution carbonate of lime filter should be composed of charcoal. By by excess of acid, and sulphate of lime.

Then the balloon is released by cutting cords which held it down, the tube which

These give the water the character called |lution, when it boils add two ounces of soap butter or fat, and boiled in water, furnish hard, rendering it unfit for the solution of cut into small pieces, and stir the boiling a nourishing and palatable liquid, the soupė soap, for making vegetable extracts, and liquid until the whole of the soap is dissolved. for being used in the arts of bleaching and When this solution is added to the water to dyeing. It is also less wholesome as a be purified, the soap and sulphate of lime drink, and, except to persons whose taste mutually decompose each other, the insoluhas become vitiated, disagreeable. ble compound of the acids of the soap with the lime rises and coagulates at the surface, whence it may be skummed off.

Nature has provided a slow but sure remedy for this defect. On exposure to the air the excess of carbonic acid which holds the carbonate of lime in solution, is dissipated, and that earthy salt perciptate 1. If on the other hand sulphate of lime be contained in the water, the superior affinity of that earth for carbonic acid will cause it to attract that acid from the atmosphere, by which this insoluble carbonate will be formed. Thus the water of stagnant ponds, even in countries where calcareous matter abounds, may be well adapted to manufacturing purposes. unwholesome, as it undergoes decomposition from the presence of putrescent vegetable matter. But when large rivers flow for a great extent, with a regular and steady course, these chemical changes take place without the corresponding inconvenience arising, and in addition by an action not yet explained, all animal and vegetable matter is rendered insolubie. For this reason the waters of the Nile, the Ganges, and the Mississippi have a well founded reputation for their delicious taste. Even the water of rivers which receive every species of offensive animal and vegetable matter, is, when filtered, almost perfectly pure.

maigre of Catholic countries. The bones of animals contain large quantities of gelatine, but this is so intimately mixed with an insoluble substance (the phosphate of lime,) that it cannot be separated, except from the inere surface, by water at the ordinary temperature of boiling. Water, however, heated The sulphate of li.ne may be more slowly in close vessels to a higher temperature, decomposed, by adding a small quantity of acquires the power of separating gelatine carbonate of soda or potash. The acid of even from bones. For this purpose, an this will finally convert the lime into carbo- instrument was invented about 150 years nate, which will be precipitated when the since, by Papin, and called by him the diexcess of acid is expelled. The mode gester. It is a strong vessel of copper, to which immediately preceeds, is however, the mouth of which a circular lid is close more certain and rapid, and will fit the fitted by grinding. The vessel stands in water for every use in the arts. This is in an iron frame having four feet. To the the mode which was referred to in speaking top of these feet a cross of iron, which rests of the bleaching of wool as capable of su-upon the lid, is fastened by screws, and thus Such water is however perceding the cffensive matter which is now the lid is prevented from rising when the in use. first steam is generated within. To comWater is most extensively used in prep-plete the arrangement, a safety valve is aration of our food, and the proper applica- provided, by the weight of which the prestion of it to this purpose is by no means so sure of the steam within, and consequent simple as it might at first appear. The temperature of the water is regulated. fibrous flesh of animals is made up of two The arrangement for closing the lid of distinct substances, albumen and gelatine. Papin's Digester is too complicated for doThe former is insoluble in water, and coag-mestic use. In order to simplify this part, ulates at the temperature of boiling; the the digester has been modified into the Aulatter is slowly solable in cold, and more toclave. The mouth of this is of an oval rapidly in boiling water, by which it is previ- form; the shape of the lid is the same, but ously softened. Albumem exists nearly larger in each of its dimensions. In conpure in the white of an egg, gelatine when sequence of both having this figure, the lid separated from other matter becomes glue. may be passed into the vessel and turned When meat is to be cooked by boiling, around within it, until its longer axis is in if it be suddenly exposed to the boiling the same direction as that of the mouth. temperature, the albumen coagulates, and In this situation, the first steam that is genforming a hard coat, protects the gelatine erated presses the lid close against the vesfrom the action of the water, and although sel, and effectually closes the mouth. by long continued boiling the latter may be The presence of sulphate of lime rendissolved, the meat will remain in the form ders vegetable matter insoluble in water. of tough stringy fibres. But if it be slowly Hence green vegetables can only be well raised to the boiling heat, the albumen re-cooked, and appear of a good color, in soft tains its viscid liquid form until the gelatine water. The latter effect may, however, is softened and partially dissolved; part of be attained even with hard water, by adthe former also separates and rises to the ding a small quantity of pearlash to desurface of the fluid whence it may be compose the sulphate of lime. skimmed off.

We learn from this, tha in supplying cities with water, the true plan is to bring it so far as possible in channels formed like a canal in the natural earth. Channels of masonry are of all the most to be avoided, as the water cannot fail to be contaminated with calcareous matter which will render it unfit for use in any of the chemical arts. The antients did not feel this objection to the use of aqueducts of masonry, partly because they had not reached that advance in the chemical arts, which now makes their practice almost a necessary of life, but more particularly from the very superior quality of their masonry, which was so accurately jointed as hardly to admit the edge of a knife. This perfectiou is not beyond the reach of modern art, but would involve an expense which would not be

submitted to.

When water holds calcarous matter in solution, the lime combines with certain acids which exist in all soap, and form with that earth an insoluble compound, which is lighter than water and floats at its surface. The sulphate of lime, which is most frequent, may be decomposed by the saks of ammonia and hence the use of putrescent urine in the art of bleaching.

It is the solution of the gelatine in water, with a part of the liquid matter of the meat which forms the broth which is the basis of soup.

It will be easily seen from what has been stated, that sudden heat and rapid boiling will render the meat tough, or if continued until it be tender, stringy and tasteless. On the other hand, if gradually heated to the boiling temperature without being ever permitted to boil rapidly, the broth will be more readily charged with gelatine, the meat will be tender and full of its original juices.

MANUFACTURE OF CHARCOAL.

Rationale. When wood is burnt in the open air, under favourable circumstances, as a considerable part of it is either inflamable or volatile, it is dispersed in the process of combustion. The residue is earthy in appearance, and is known by the name of ashes. The quantity of ashes given by different woods, and by different parts of the same tree, vary very materially. Thus the wood of the linden yields eight times as much ashes as the wood of the pine, and bark from 15 to 30 times as much as the It is to the proper application of these prin- wood within. The linden seems to yield ciples that the great superiority of French the largest quantity of ashes, which is as over the English and American cookery is much as much as five per cent; oak yields As this sulphate has the property of com- mainly to be attributed, for the broth is not about 2 per cent; and pine eight tens th bining with vegetable matters and rendering only used by the French in the form of soup per cent. The character of these ashes them insoluble in water, water may be ren-but is the vehicle of all their sauces, and varies in different kinds of wood, but the subdered soft by boiling in it for a long time the meat whence the soup is prepared, in-stances which are almost always found, are some muculagincus vegetables. A more stead of being useless as with us, is the the cabonate of lime and magnesia; phos speedy method of rendering hard water most important of their dishes. phate of lime; chloride of potassium, and soft is as follows: The fat of animals is rendered soluble the sulphate and carbonate of potassa and in water by vegetable matters, and this fur-silicia, either pure or combined with potasnishes an important addition to the means sa and lime. of preparing food.

To purify 100 gallons of water; dissolve six pounds of pearlash, or subcarbonate of soda in a gallon of soft water, boil the so

Vegetables fried in By distillation and heat in close vessels,