that Mr. Lee Pattinson, a practical chemist, and myself, have been endeavoring to ascertain whether we could invent some power to bring down the coal without an explosive mixture, such as gunpowder; and I am sorry to say that no very successful result has yet been arrived at; but up to the present time, I am afraid, notwithstanding gunpowder is a very old chemical invention, that very little progress has been made since it was first used, and that we are in ignorance of any substitute for it of equal power." He subsequently added that "if public attention were called to it, perhaps science might discover some substitute. And as this journal had previously solicited public notice to the subject, we again repeat that the researches of chemical and electrical discovery, which have in our times produced such marvellous results, could not be devoted to a nobler object of scientific ambition."

MEDICAL TREATMENT AFTER EXPLOSION.

The report of the South Shields committee, previously referred to, goes at considerable length into an explanation of the condition in which miners meet their death by explosions; the proportionate quantities of the gases, which create them, and the nature of the after-damp.

This after-damp is formed of

8 parts of nitrogen having a specific gravity of 0.9722.
2 parts of aqueous vapour.

1 part of carbonic acid gas, specific gravity, 1.5277.

The latter takes its place towards the bottom of the passages, and, probably, extends little more than six inches high. Hence it is inferred that when the men, after explosion, if not struck down at once by it, attempt to leave the mine through an atmosphere of afterdamp, they are at first rendered partially insensible by the nitrogen, which has been substituted for atmospheric air, and then, falling, they come in contact with a still more deleterious gas, a positive poison, [the carbonic acid gas], which having inhaled to a small extent, they pass rapidly into a state of asphyxia, owing to the state to which their systems have been previously reduced.

Two practical inferences are thus deduced

1. Where carbonic acid gas is abundant, the lights are instantaneously extinguished, and burn with a dull red flame as they approach it; on these indications the miner is warned to retire, as here flame is extinguished before life; but when there is a large admixture of nitrogen, the lamp continues to burn, as in sulphuretted hydrogen, even when the miner has been struck down-life in this case being extinguished before flame.

2d. That asphyxia, arising from nitrogen, and completed by carbonic acid gas, might probably indicate a different system of medical treatment from that hitherto pursued. The symptoms of asphyxia,always easy to be known, are the sudden cessation of respiration; of

the pulsation of the heart, and of the action of all sensitive functions; the countenance is swollen and marked with reddish spots; the eyes become protruded, the features discomposed, and the face often livid.

It is necessary to succour an asphyxed person with the utmost promptitude, and to continue the remedies with perseverance until it is certain that life is completely extinguished. The following general remedies should be adopted: immediate removal into fresh air; undress and dash the body with cold water; endeavour to make the patient swallow water slightly acidulated with vinegar; clysters of two-thirds water and one-third vinegar, to be followed by others of a strong solution of common salt, or of senna and epsom salts; introduce air into the lungs by blowing with a nozzle of a bellows, into one of the nostrils and compressing the other with the finger. Should these means not produce the desired effect, and the body still retain its natural warmth, recourse must be had to blood-letting, the necessity of which will be clearly indicated by the red face, swollen lips, and eyes protruding. If blood fails to flow from the jugular vein, an attempt should be made on the foot; the last effort which can be made is to make an opening in the trachea, and introduce air to the lungs by means of a small pipe and a pair of bellows. These various remedies should be applied with the greatest promptness. The absence of the beating of the pulse, and the want of respiration are not certain signs of death, nor should all be regarded as dead whose breath or pulmonary transpiration does not bedim the brightness of glass; nor those whose members appear stiff and insensible. giving these brief instructions, the committee hope that some of them may be judiciously practised, instead of the injurious plans sometimes adopted, until the arrival of a medical practitioner, who will thus find the patient prepared, uninjured for his professional skill, and his object facilitated, not obstructed, by the previous treatment he has received.

In

DRAINAGE OF COAL MINES.

In the mines which are situated in hilly or mountainous countries, it is generally easy to intersect the beds by galleries which commence at the lower part of some valleys; the galleries furnish a natural outlet for the waters of all the works which are above their level, and on this account are called in France galeries d'écoulement, or drainage galleries; in England, Wales and the United States, adits, or adit levels, and occasionally drifts and tunnels: but the word adit is the most distinctive of its object and uses.

The advantages of these adits are numerous, and have often decided the undertaking of long and expensive works.

In fact they are not only preferable to mechanical means of drainage, because when once made they require very little management or attention, but in giving issue to the upper waters, they also create a

moving power which can be employed in the service of extraction, or in the draining of the lower works; finally, they furnish the most economical means for the other services of the mine, such as the forced ventilation, or the extraction of the substances mined.

An adit level can often be so arranged as to serve, at the same time, the working of several veins. On account of all these united advantages, there has been undertaken in the district of Schemnitz, in Hungary, a gallery of 20,000 yards in length, or about 11 miles, designed for the use of the principal mines of the district, under the double service of draining the waters, of the carriage or gangway, and the creation of mechanical powers; it has been, besides, directed with a view to explore the ground for the discovery of new veins. At the Hartz, the great "galerie d'écoulement" of the mines of Clausthal, which is 13,000 yards in length, serves equally for a great number of mines, in different branches of the service. The use of these galleries is common in the countries where the mines are numerous and near together.

In relation to pumps, and the varieties of hydraulic machines employed in mines, for the purpose of drainage, we must refer to the various authorities who have written either in England or on the continent of Europe on this important subject, and which, moreover, would require the aid of numerous illustrations to render any description intelligible.

In the third volume of the Mining Review, p. 302, our readers will find a description of the pumps used in the deep mines of Cornwall, by Mr. John Taylor. The machinery brought to such perfection, and operating with so much economy and simplicity, is celebrated throughout the world. At the period of this communication, the steam engines of the district performed the work of 44,000 horses.

TRACING OF COAL BEDS IN THE ANTHRACITE DISTRICTS OF PENNSYL

VANIA.

In these basins, where the outcrops of the coal seams almost always present themselves at a very high angle, they are in general readily traced, by the subordinate depressions which may be observed ranging longitudinally along the sloping side of the mountain ridges; pursuing, of course, the direction or strike of the strata. These depressions are obviously formed by the removal of the decomposable and soft materials of the coal seams; that is to say, the shales, the under-clay, and the coal itself, and they are conspicuously in contrast with the rocky siliceous beds which flank them, and which being composed of less destructible materials, have longer resisted the atmospheric agencies. Thus, in numberless instances, these longitudinal grooves afford an unerring clue to the subjacent beds of anthracite. In the great bituminous coal region of the Alleghany mountains, where the strata closely approximate to a horizontal state, such guides as

those we have mentioned can, of course, have no existence, and we have there to seek for other phenomena which may indicate the presence of coal. Happily these are so abundant, that no coal region in the world, probably, presents more ready facilities for the ascertainment of what lies at so insignificant a depth beneath the surface.

To return to the more disturbed region which is occupied by anthracite in Pennsylvania. The disposition of the outcrops, to which we have alluded, materially influences the physical features of these coal districts, and modifies the contour of the surface by a numerous succession of terraces, steps, or benches, on the inner slopes of the mountains, facing the centres of the basins. Those who have ascended, from either side, the long parallel mountains which border the southern coal region of Schuylkill county, to the height of 1350 feet above the Susquehanna river, and more than 1650 feet above tide-water level, need not to be reminded of these characteristic details.

Between the external margins of the principal coal basins of Pennsylvania, subordinate axes of elevation are of frequent occurrence. Even the undulations of the surface between these limits are all attributable to these minor axes, and correspond, in great measure, with the local inclination of the upheaved stratification beneath. These undulations of groups of coal seams, so important to the proprietor, yet whose existence, until of late years, was scarcely suspected, are daily becoming more familiar to us, as the progress of development and practical investigation gradually advances.

The long narrow troughs, of which there are so many in central Pennsylvania, owe their contour to parallel synclinal axes, which present highly inclined or vertical coal beds; and occasionally even exhibit the strata of one of their sides tilted or leaning over so much that their inclination becomes almost parallel to, or conformable with, those of the opposite side of the basin.

In proportion as the anthracite basins become wider, their interior is the more disturbed or broken by undulations, consisting of one, two or three subordinate axes, each maintaining itself for a space as a parallel inferior ridge, and thus interrupting the general troughlike arrangement of the stratification. It is to be expected that the carboniferous beds in the vicinity of the centres of these synclinal axes are liable to be too much crushed to permit an advantageous working of their contents.

The southern anthracite region, in particular, furnishes numerous instances of the modified arrangement of which we speak, and we might introduce several illustrations from our own observation, which would exemplify the extent of the forces to which the anthracite country has been subjected, in the area between the Lehigh and the Susquehanna.

Beginning near the eastern extremity, at Nesquehoning, we see the ordinary basin-form arrangement modified by an upheaving or saddle in its centre, it being here scarcely one mile in width.

Next westward is a section in the meridian of the Mauch Chunk summit mines, where the basin, has now expanded to almost double the breadth that it occupied at Nesquehoning. The structure of the interior is now considerably complicated, and the enlarged breadth allows of a triplication at least of the coal series. So confused is its aspect at this point that we are by no means certain that our section embraces all the details.

Further westward we have the very interesting and magnificent transverse section formed by the stream of the Little Schuylkill, at Tamaqua, where the basin has again contracted to the simple synclinal axis, of scarcely one mile in breadth.

Our figure exhibits this section with the accuracy resulting from an original survey, and it is the more memorable from the presence of a particular seam in the Sharp Mountain, which is worked to the breadth or thickness of no less than seventy feet.

At Pottsville, the same region has widened to the extent of about five miles, affording, by the repetition of the coal beds, a vast industrial area; and at the head waters of the Swatara river there is now a breadth of no less than six miles. In the Pinegrove coal district we have at least three miles of breadth. Thus we perceive that in proportion to the space or breadth between the geological margins of the Schuylkill coal-field, so is the frequency of the undulations, the number of anticlinal elevations or axes, and the consequent repetitions of the same series of coal seams.

Westward of the Swatara or Pinegrove coal region, it bifurcates and stretches, with diminished breadth, for many miles towards the Susquehanna. The geological structure of these two forks is illustrated by the above diagram.