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we say, dilate on all these topics, per. By other coxperiments he but we prefer extracting from the confirmed the observations of Mr. Quarterly Journal the little infor- Six, that the temperature of short mation it contains, setting it, we grass is always higher than that of hope, a proper example of doing long grass. The state of the herbage what our feeble powers permit to has always a considerable influ. promote the interosts of science in ence on the quantity of dew depo. preference to wounding the feel- sited, and the greater the body it ings of its professors. . . . presents, the more abundant it is · Art. I. "On some phenomena likely will be the formation. It relating to the formation of dew on bas been stated by Dr. Wells, that metallic surfaces, by George Har- woól is one of the substances vey, M. G.8., &c. &e.," gives an which is most productive of cold, account of several experiments, and consequently when exposed to instituted to confirm some facts re- the action of the atmosphere, collative to dew, which had been ob lects dew more abundantly than served by Dr. Wells. Mr. Harvey any other substance, a fact which exposed square pieces of gilt paper, was also confirmed by the obserspread over two pieces of wood vations of Mr. Harvey. There is formed into a cross, to the action perhaps in this paper too much of of the atmosphere, and he found the dandyism of science, but it is that where the metallic paper co- on the whole very neatly written vered the wood no dew was formed, and does honour to Mr. Harvey. while the rest of the metallic sur In Art. II. Mr. Swainson gives a face was covered with dew. He minute description of 6 Two new found also, that a small piece of and remarkable fresh water shells, glass, when presented to a clear one of which is a gigantic shell, and tranquil sky, had its surface being 84 inches in length, and 52, as readily covered with moisture inches in breadth.” This descrip as a larger piece of glass; but in tion, occupying four pages and a case of metals, a large metallic half, is a proof of the respect the plate is sometimes more readily Quarterly Journal has for trifles of dewed than a small one; and some descriptions. sometimes a large plate will pre- Art. III. explains that one cause serve a whole night a bright and of indistinct vision in optical inunsullied surface, while a small struments, is the admission of false piece is wholly covered with dew. lights, which the author, Dr. Gor The first formation of the dew, it ring, suggests a means of remedywas remarked, took place at the ing. We again meet with Mr. corners of the portions of the me- Swainson in Art. IV., who takes up tallic paper not in contact with the no less than ten pages of the jourwood; and it was interesting to nal with another description of observe, during the progressive some other shells, conchology being deposition of the moisture, that the apparently at present the favorite particles were disposed in triangu- science of the Quarterly Journal, Iar forms, similar to the right an. Art. V.“ Account of the earth gled triangles into which the metal- quake in Chili in November 1822, lic paper was divided by its contact from observations made by several with the cross. The parts of the pa- Englishmen residing in that counper in contact with the cross had no try,” is a neat and correct descripdewy particles on them, their junc- tion, we are disposed to think, of tion with the wood appearing that nnfortunate occurrence. offectually to prevent the forma- !. Art. VI. «On Evaporation, by tion of moisture. Another remark J.F. Daniell, Esq., F.R.S., M.R.I.. of Mr. Harvey is, that silver me- &c." This gentleman is known to tallic paper permits dew to be de- pay great attention to meteorology, posited op it sooner, and in greater and has put forth some peculiar abundance, than gold metallic pa- theories, which he seems anxious

to support, and concludes his pa- boring having been made in order per by endeavouring to show that to gain a perfect opening into the the heat emitted by the condensa- bed of the spring, which flowed tion of atmospheric vapour'would when first tapped tess copiously be sufficient to account for those than after the final depth was reachexpansions of the aërial currents ed. The chalk from which the water to which he has, in his Essay on immediately comes is soft, but the the Constitution of the Atmosphere, bottom of the well is hard chalk. ascribed the fluctuations of the The water in all the neighbouring barometer. We should have thought wells appears to have been obthe tunnel under the Thames was tained from about the same depth, too hackneyed a' subject for this and the strata through which the scientific journal to discuss, but perforations were made, are nearly it does contain a paper on this similar to those met within the subject, which makes Art. VII. present instance. The tackle and We see nothing new in it, ex instruments were very simple :/ a cept a grave enumeration of the scaffold, twenty feet above the propolitical advantages of the tun- posed orifice of the well, on which nel ; among which are included a platform was fixed to support a a military pass and an under- windlass, by which the rods used water way to the Tower. ' It is iu boring were lowered into and also to facilitate communication raised from the well. These rods between this great point d'appui of were of tough iron, about an inch the national strength and the ports and a half square, and ten feet of Woolwich, Chatham, and Sheer- long, the ends of each screwing on ness,--tending, of course, to protect to, or unscrewing from the top of the country from invasion. This the next, as they are lowered into is an advantage of the tunnel under or raised from the hole. The inthe Thames nobody ever before struments fixed, as occasion rethought'of. We would recommend quired, to the lower extremity of the right worthy projector to pro- the series of rods, when in action, vide his tunnel with sluices, and were augers of various dimensions bait it for the French army, when for boring, steel chisels for punchour navy is extinct, with all the ing, and a hollow iron cylinder, treasure of London, and then he called a shell, fitted with a valve at may have the glory of catching a its lower end, for drawing up soft few thousand men in his man-trap; mud. The rods, when an auger and though not effectual to prevent was attached to them, were turned an invasion, it may extinguish the round by means of moveable arms invaders.

or dogs, which were made to lay • Art. VIII. “An account of the hold of the part of the uppermost overflowing well in the garden of rod at the top of the hole. The the Horticultural Society at Chis- auger being thus forced through wick.” As we know this mode of thê stratum of clay or sand, was procuring water is an object of drawn up as soon as its cavity was considerable interest to many peo- filled with the substance it had ple, we shall extract this descrip- loosened. The chisels were omtion. ? In September 1823, Mr. ployed for punching through stones Worsencroft began the operation or other hard substances. The of boring, and after boring five rods, when these were attached, weeks without material interrup- were moved by means of a powertion, tapped the spring on October ful beam, acting as a lever, 18th, and finally completed his task and worked by four men. The on the following day. The depth water is discharged at the surfrom which the water was brought face of the ground, at the rate was 317 feet, and the whole depth of six gallons a minute, ands is of the well, when completed, was capable of being carried twenty 329 feet; the additional 12 feet of feet above the ground-level, and

then supplies na copious stream ligence at the end of the Journal The well is clined for the first 186 are collected with discrimination, feet with cast iron pipes, having a and got up with considerable care thrcerinch bore; the succeeding 77 and taste. Sre , feet are lined with copper pipes, 25 cinches in the bore, soldered MANUFACTURE OF SHAinto a single length, and resting in color, GREEN. the chalk, through which the remainder of the hole is bored, and

"" (Concluded from p: 71.) in which no pipes are used. The in. For the black shagreen, they emwhole series of pipes were intro- ploy, nut-galls and vitriol, in the duced at once, the hole having following manner :--The skins, still been prepared for receiving thein moist with the brine, are thickly as soon as it was ascertained that strewed with finely pounded nutthe augers had reached thc chalk galls, folded together, and laid one stratum. The land-springs in the on another, for 24 hours. In the gravel, above the blue clay, were meantime a new ley of bitter earth kept out, in the first instance, by salts, or schora, is boiled and extra iron pipes. The spring which poured bot in little troughs or was found in the sand, below the trays. In this ley each skin is blue clay and above the chalk, rose wavod to and fro several times, is to within a few feet of the sqrface, again strewed with pulverized nutbut did not overflow. The whole galls, and again laid in heaps for of the water is, however, excluded some time, , that the virtue of the from this well by the pipes with galls may thoroughly penetrate the which it is lined. The cost of the skins, which are then suffered to well, including that of the pipes, dry, and are beat out to clear them boring, and all expenses, did not from the galls. When this is done, exceed 1301., and the manner in the skin is smeared on the shagreen which it was executed was in every side with mutton suet, and laid a respect satisfactory. The principal little in the sun, that it may absorb impurity discovered in the water, the fat. It is the custom, likewise, by the action of re-agents, is com with the shagreen makers, to rollup mon salt, of which it contains about each skin apart, and to squeeze and 45 grains in the pint. When eva- press it against some solid body, in porated to dryness, the residue order to promote the absorption of contains a sufficient quantity of the unctuous particles. The surs carbonate of soda to render it ma- plus is again scraped off with a nifestly alkaline ; and this is also blunt wooden scraper. This being the case with the water of other done, and the skin having laip a deep wells in and about London, little while, a sufficient quantity of The remainder of the Articles in iron vitriol is dissolved in water, the Quarterly Journal are “ Astro- with which the shagreen is rubbed nomical and Nautical Collections;" on both sides, whereby it soon acbeing tables, most of them equally quires a boautiful black colour; as well adapted for an Epheme-, and now the edges and other derides or Almanack as for a Jour- fective parts are dressed. nal. BTS

To obtain white shagreen, the Having at the commencement of skin must first be steeped in strong. our Analysis thought proper to alum water on the shagreened side. make a few observations on the Having imbibed this, the skin is spirit which appears to prevail in well rubbed on both sides with a the reviews at the end of this Jour- paste of wheaten flour, and left to nal, we cannot conclude without dry with it, and then all the paste saying, that though they are writ- is washed away with alum water, ten with asperity, and with evident and the skin set to dry completely. Hliberality, they cannot be denied in the sun. As soon as the skins the merit of vivacity and acute- are dry, they are gently smeared *Dess. The small articles of intel over with clean melted mutton fat

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leaving them in the sun to imbibe ing, and sell much dearer than the 1t, and are worked and pressed others.--Pallas Neue Nord, Beytr.i. with the hands, to promote this p. 325. effect. Afterwards, the skins are The Kalmucks tan their leather fastened one by one on the above- with the dregs of their kirmiss, or mentioned stretching-bench, warm with sour milk, smoke it a little, and water is poured over them, and the afterwards rub it with scraped superfluous fat scraped off with ob- chalk. But the most laborious and tuse wooden instruments, to get rid ingenious of their productions are of which the warm water just pour- their leather vessels, which they ed on has much assisted. By this make in the following manner :process the shagreen receives a The hides, as they come out of the fine white colour, and needs only water, are spread in the sun; then in conclusion to be dressed and rub- the women who are skilled in the bed. This whiteness is, however, business proceed to cut out pieces given to the shagreen not so much of the shapes necessary for the that it may continue in that state, vessel to be made, sewing them tobut in order to impart to it a beau- gether with the sinews of animals, tiful high red hue, as this end and then drying them well in the could not be obtained to this per- smoke of a fire. In this manner fection without that preparation. they prepare not only vessels with

But the shagreens intended to large mouths, to which they give be stained red must not be brought the form with their hands as the out of the natron bitter salt ley skin is drying, but also big bellied into the brine, but must be made leathern bottles, for holding the white in the manner above de- kirmiss, and saddle flasks with a scribed, and afterwards supplied narrow neck, which, for giving with the brine, in which they are them their shape, they keep incesleft to lie about twenty-four hours santly blowing up with great paor less, from the dye. The dye is tience, at first over the fire, and made with cochineal, or kirmiss, then filling them with sand or as the Tartars call it. About a ashes, and ornament them on the pound of the dried herb tschagan, outside with a variety of strokes which grows plentifully on the and lines. They have even the salt steppes about Astrachan, and art of making large leathern teais a sort of kali (salsola ericoides), pots, with a narrow spout, shaped is put into a kettle large enough to like those in common use with us, contain about four vedros of water, in a very ingenious manner. In whereby the water acquires a order to prevent the leather from greenish colour; the herb is then becoming flaccid, and likewise dirtaken out, and about half a pound ty, by the hot water, these pots are of grated cochineal put into the smoked more strongly and for a kettle, with which the above dc- longer time, an operation which coction must boil another full hour, lasts for several days, till at last diligently stirring it on the fire, they are as transparent as horn, that the kettle may not boil over. and almost incorruptible. There Lastly, to this are added 15 or 20 are of the foregoing leathern botgrains of the materials which the tles that hold five or six runlets.dyers called lutter, perhaps orpi- Ib. vol. jii, p. 541. ment; let the dye boil a little more,

23:30 Thái Hà and then take the fire from under the kettle. Then the skins taken

ROPE BRIDGES OF SOUTH out of the brine are laid separately

adT AMERICA. OZ ORE in trays, pouring the dye upon The bridge over the Maypo (a them four times, rubbing it in with river not far from Santiago, the the hands, that it may be equally capital of Chili) is curious from its spread and imbibed, pressing it simplicity, and from the close reout every time, which done, they semblance it bears to the chain are ready for drying and ornament- bridges recently introduced into England, to which in principle it is physical properties as that of the precisely similar. It consists of a cow, with the single difference, that narrow roadway of planks, laid it is a little viscid. It has the same crosswise, with their ends resting taste in its chemical properties; it on straight ropes, suspended by differs sensibly from animal milk. 5 means of shortlines to a set of thick- It mixes with water in all proer lines drawn across the stream portions, and when thus diluted it from bank to bank. These strong does not coagulate by ebullition. sustaining ropes are six in number, The acids do not convert it into three at each side of the bridge, clots, as happens to cow's milk. and bang in flat curves one above Ammonia, instead of causing a another; the short vertical cords precipitate, renders it more liquid. which support the roadway being This character indicates the abi. so disposed as to distribute the sence of caoutchouc. Alcohol oca? weight equally. The main or sus- casions a feeble coagulation, or pending ropes are firmly secured rather renders the juice more easy to the angles of the rock on one of filtration. The recent juice side, at the height of thirty feet slightly reddens litmus. Its boilfrom the stream ; but the opposite irg temperature is the same as that bank being low, the consequent in- of water. Exposed to heat, it exclination is in some measure cor- hibits at first the same phenomena rected, by carrying them over a high as cow's milk. A pellicle is formed wooden pier, and attaching them at its surface, which prevents the afterwards to trees, and to posts disengagement of aqueous vapours. driven into the bank. The clear On removing the successive pellispan, from the pier on one side to cles, and evaporating it at a gentle the face of the rock on the other, heat, an extract is obtained resemis one hundred and twenty-three bling frangipane. When the acfeet. The materials being very tion of heat is longer continued, elastic, the bridge waved up and oily drops are formed, which indown, and vibrated from side to crease according as the water iss side, in so alarming a manner, that carried off, and, finally, afford an. at the recommendation of the guide oily liquid, in which a fibrous we dismounted and drove our matter floats, which becomes dry horses, one by one, before us; nei- and horny as the temperature of ther man nor horse appearing, how- the oil is raised. Then is diffused ever, much at ease during the the finest characteristic odour of passage.- Extracts of a Journal, 8c. meat frying in grease. By the acby Capl. Basil Hall, R. N. sto

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tion of heat, therefore, the vegeta

- ble milk is separable into two COW-TREE MILK. 0984 parts, the one fusible, and of a fat AMONG the astonishing vegetable nature, the other fibrous and of an productions that are met with at animal nature. If the evaporation every step in the equinoctial re- of the vegetable milk is not carried gions, a tree is found which yields too far, and if the fusible matter is in abundance a milky fluid, com not raised to ebullition, it may be parable in its properties to the obtained without alteration. It milk of animals, and which is em- then possesses the following proployed for the same purposes, as perties : M. de Humbolt witnessed at the It is of a white slightly yellowish farm of Barbula, (Cordillere Lit- colour, translucid, solid, and reterale de Venezuela), where he sists the impression of the finger. drank some of the milky juice. The It begins to melt at 40° centigrade, tree grows in considerable num- and when the fusion is completed, bers on the mountains which com- the thermometer indicates 600 mand Periquito, situated to the Alcohol at 40° (sp. gr. 0.817) disnorth-west of Maracay, a village to solves it totally by ebullition, and the west of the Caraccas. The ve- it precipitates on cooling. It sagetable milk possesses the same ponifies with caustic potash, and

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