MINES.

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'hey also allow gas to escape to the discharge plug, to the imminent risk of occasioningI 1 r e with ignorant or careless servants; and finally, they have the complex dial-plate'"dexes, so liable to misapprehension.

4. The meter of Mr. Edge. This instrument is quite exempt from all the abovehefucts, and is equally delicate and just in its indications, being mounted with a leverv alve of great mobility, and a new index which any one who knows numbers can not[discount. I have subjected this meter to every kind of test and find that it can notbe made to give false indications, either by awkwardness or intention. Its inventor is'herefore \yell entitled to the warm patronage both of the public and all gas companies"’ho love their dealing.

MILK has been adulterated with a solution of potato starch, from which it derives" creamy consistence. This fraud may be detected by pouring a few drops of iodine'"ater into it, which immediately causes it to assume a blue or purple tint. Emulsionsweet almonds, with which the milk at Paris has been adulterated, may be readilybctected by the taste.

MINES. The miner, in sinking into the earth, soon opens up numerous springs, whose"aters, percolating into the excavations which he digs, constitutes one of the greatest°hstacles that nature opposes to his toils. When his workings are above the level ofs 0ote valley and at no great distance, it is possible to get rid of the waters by leading thema mng a trench or a gallery of efflux. This forms always the surest means of drainage;? a d notwithstanding the great outlay which it involves, it is often the most economical,the great advantages accruing from these galleries, lead to their being always estab-J s hed, and without risk, in mines which promise a long continuance. There ■are manyjMleries several leagues in length ; and sometimes they are so contrived as to discharge' e Waters of several mines, as may be seen in the environs of Freyberg. Merely suchj* slope should be given them as is barely sufficient to make the water run, at the ut-01 °st from _l_ to so as to drain the mine at the lowest possible level.

..Whenever the workings are driven below the natural means of drainage, or below"e level of the plain, recourse must be had to mechanical aids. In the first place, theIhantity of percolating water is diminished as much as possible by planking, walling,jb calking up with the greatest possible care those pits and excavations which traversejbe water levels ; and the lower workings are so arranged that all the waters may unitebto wells placed at the bottom of the shafts, or inclined galleries ; whence they may beSniped up to the day, or to the level of the gallery of efflux. In most mines, simple""king pumps are employed, because they are less subject to give way, and more easyj repair; and as many of these are placed over each other, as the shaft is ten yardse "P, beldw the point where the waters have a natural run.

. fhese draining machines are set in motion by that mechanical power which happensp “e the least costly in the place where they are established. In almost the whole of"gland, and over most of the coal-mines of France and Silesia, the work is done by^Cam-engines ; in the principal metallic mines of France , and in almost the whole of/'"■'many and Hungary , by hydraulic machines; and in other places, by machines[boved by horses, oxen, or even by men. If .it be requisite to lift the waters merely tobe level of a g a n er y 0 f efflux, advantage may be derived from the waters of the upper™ r ts of the mine, or even from waters turned in from the surface, in establishing in the. *ne of the gallery-level, water-pressure machines, or overshot water-wheels, for pump-Up the lower water. This method is employed with success in several mines of^""gary, Bohemia, Germany, Derbyshire, Cornwall, in those of Poullaouen in Brittany ,t .It has been remarked, however, that the copious springs are found rather towarde surface of the soil than in the greatest depths.

TRANSPORT OF ORES TO THE SURFACE.

So'^ le ore being extracted from its bed, and having undergone, when requisite, a firstty"bng, it becomes necessary to bring it to the day, an operation performed in differentr_.y? according to circumstances and localities, but too often according to a blindj-’bne. There are mines at the present day, where the interior transport of ores isis°n the backs of men; a practice the most disadvantageous possible, but which)i ^"dually wearing out. The carriage along galleries is usually effected by means ofr "les, barrows, or, still better, by little wagons. These consist of frames resting onWheels ; two larger, which are placed a little behind the centre of gravity, and twol e "ber, placed before it. When this carriage is at rest, it bears on its four wheels, andbon bbrward. But when the miner, in pushing it before him, rests on its posterior""r, he makes it horizontal; in which case ft rolls only upon the two larger wheels.o f l ® s > the friction due to four wheels is avoided, and the roller or driver bears no partH 0 ‘" e burden, as he would do with ordinary' wheelbarrows. To ease the draught stillre > two parallel rails of wood or iron are laid along the floor of the gallery, to which